Professor of Psychiatry and Behavioral Sciences (Major Laboratories and Clinical and Translational Neurosciences Incubator)


  • VTA dopaminergic neurons regulate ethologically relevant sleep-wake behaviors. Nature neuroscience Eban-Rothschild, A., Rothschild, G., Giardino, W. J., Jones, J. R., de Lecea, L. 2016; 19 (10): 1356-1366


    Dopaminergic ventral tegmental area (VTA) neurons are critically involved in a variety of behaviors that rely on heightened arousal, but whether they directly and causally control the generation and maintenance of wakefulness is unknown. We recorded calcium activity using fiber photometry in freely behaving mice and found arousal-state-dependent alterations in VTA dopaminergic neurons. We used chemogenetic and optogenetic manipulations together with polysomnographic recordings to demonstrate that VTA dopaminergic neurons are necessary for arousal and that their inhibition suppresses wakefulness, even in the face of ethologically relevant salient stimuli. Nevertheless, before inducing sleep, inhibition of VTA dopaminergic neurons promoted goal-directed and sleep-related nesting behavior. Optogenetic stimulation, in contrast, initiated and maintained wakefulness and suppressed sleep and sleep-related nesting behavior. We further found that different projections of VTA dopaminergic neurons differentially modulate arousal. Collectively, our findings uncover a fundamental role for VTA dopaminergic circuitry in the maintenance of the awake state and ethologically relevant sleep-related behaviors.

    View details for DOI 10.1038/nn.4377

    View details for PubMedID 27595385

  • Sleep disruption impairs haematopoietic stem cell transplantation in mice NATURE COMMUNICATIONS Rolls, A., Pang, W. W., Ibarra, I., Colas, D., Bonnavion, P., Korin, B., Heller, H. C., Weissman, I. L., de Lecea, L. 2015; 6


    Many of the factors affecting the success of haematopoietic cell transplantation are still unknown. Here we show in mice that donor sleep deprivation reduces the ability of its haematopoietic stem cells (HSCs) to engraft and reconstitute the blood and bone marrow of an irradiated recipient by more than 50%. We demonstrate that sleep deprivation downregulates the expression of microRNA (miR)-19b, a negative regulator of the suppressor of cytokine signalling (SOCS) genes, which inhibit HSC migration and homing. Accordingly, HSCs from sleep-deprived mice have higher levels of SOCS genes expression, lower migration capacity in vitro and reduced homing to the bone marrow in vivo. Recovery of sleep after sleep deprivation restored the reconstitution potential of the HSCs. Taken together, this study provides insights into cellular and molecular mechanisms underlying the effects of sleep deprivation on HSCs, emphasizing the potentially critical role of donor sleep in the success of bone marrow transplantation.

    View details for DOI 10.1038/ncomms9516

    View details for Web of Science ID 000364930800001

    View details for PubMedID 26465715

    View details for PubMedCentralID PMC4621781

  • Antagonistic interplay between hypocretin and leptin in the lateral hypothalamus regulates stress responses NATURE COMMUNICATIONS Bonnavion, P., Jackson, A. C., Carter, M. E., de Lecea, L. 2015; 6


    The hypothalamic-pituitary-adrenal (HPA) axis functions to coordinate behavioural and physiological responses to stress in a manner that depends on the behavioural state of the organism. However, the mechanisms through which arousal and metabolic states influence the HPA axis are poorly understood. Here using optogenetic approaches in mice, we show that neurons that produce hypocretin (Hcrt)/orexin in the lateral hypothalamic area (LHA) regulate corticosterone release and a variety of behaviours and physiological hallmarks of the stress response. Interestingly, we found that Hcrt neuronal activity and Hcrt-mediated stress responses were inhibited by the satiety hormone leptin, which acts, in part, through a network of leptin-sensitive neurons in the LHA. These data demonstrate how peripheral metabolic signals interact with hypothalamic neurons to coordinate stress and arousal and suggest one mechanism through which hyperarousal or altered metabolic states may be linked with abnormal stress responses.

    View details for DOI 10.1038/ncomms7266

    View details for Web of Science ID 000350202800016

    View details for PubMedID 25695914

    View details for PubMedCentralID PMC4335349

  • Optogenetic disruption of sleep continuity impairs memory consolidation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Rolls, A., Colas, D., Adamantidis, A., Carter, M., Lanre-Amos, T., Heller, H. C., de Lecea, L. 2011; 108 (32): 13305-13310


    Memory consolidation has been proposed as a function of sleep. However, sleep is a complex phenomenon characterized by several features including duration, intensity, and continuity. Sleep continuity is disrupted in different neurological and psychiatric conditions, many of which are accompanied by memory deficits. This finding has raised the question of whether the continuity of sleep is important for memory consolidation. However, current techniques used in sleep research cannot manipulate a single sleep feature while maintaining the others constant. Here, we introduce the use of optogenetics to investigate the role of sleep continuity in memory consolidation. We optogenetically targeted hypocretin/orexin neurons, which play a key role in arousal processes. We used optogenetics to activate these neurons at different intervals in behaving mice and were able to fragment sleep without affecting its overall amount or intensity. Fragmenting sleep after the learning phase of the novel object recognition (NOR) task significantly decreased the performance of mice on the subsequent day, but memory was unaffected if the average duration of sleep episodes was maintained at 62-73% of normal. These findings demonstrate the use of optogenetic activation of arousal-related nuclei as a way to systematically manipulate a specific feature of sleep. We conclude that regardless of the total amount of sleep or sleep intensity, a minimal unit of uninterrupted sleep is crucial for memory consolidation.

    View details for DOI 10.1073/pnas.1015633108

    View details for Web of Science ID 000293691400068

    View details for PubMedID 21788501

    View details for PubMedCentralID PMC3156195

  • Tuning arousal with optogenetic modulation of locus coeruleus neurons NATURE NEUROSCIENCE Carter, M. E., Yizhar, O., Chikahisa, S., Nguyen, H., Adamantidis, A., Nishino, S., Deisseroth, K., de Lecea, L. 2010; 13 (12): 1526-U117


    Neural activity in the noradrenergic locus coeruleus correlates with periods of wakefulness and arousal. However, it is unclear whether tonic or phasic activity in these neurons is necessary or sufficient to induce transitions between behavioral states and to promote long-term arousal. Using optogenetic tools in mice, we found that there is a frequency-dependent, causal relationship among locus coeruleus firing, cortical activity, sleep-to-wake transitions and general locomotor arousal. We also found that sustained, high-frequency stimulation of the locus coeruleus at frequencies of 5 Hz and above caused reversible behavioral arrests. These results suggest that the locus coeruleus is finely tuned to regulate organismal arousal and that bursts of noradrenergic overexcitation cause behavioral attacks that resemble those seen in people with neuropsychiatric disorders.

    View details for DOI 10.1038/nn.2682

    View details for Web of Science ID 000284525800018

    View details for PubMedID 21037585

    View details for PubMedCentralID PMC3174240

  • Phasic Firing in Dopaminergic Neurons Is Sufficient for Behavioral Conditioning SCIENCE Tsai, H., Zhang, F., Adamantidis, A., Stuber, G. D., Bonci, A., de Lecea, L., Deisseroth, K. 2009; 324 (5930): 1080-1084


    Natural rewards and drugs of abuse can alter dopamine signaling, and ventral tegmental area (VTA) dopaminergic neurons are known to fire action potentials tonically or phasically under different behavioral conditions. However, without technology to control specific neurons with appropriate temporal precision in freely behaving mammals, the causal role of these action potential patterns in driving behavioral changes has been unclear. We used optogenetic tools to selectively stimulate VTA dopaminergic neuron action potential firing in freely behaving mammals. We found that phasic activation of these neurons was sufficient to drive behavioral conditioning and elicited dopamine transients with magnitudes not achieved by longer, lower-frequency spiking. These results demonstrate that phasic dopaminergic activity is sufficient to mediate mammalian behavioral conditioning.

    View details for DOI 10.1126/science.1168878

    View details for Web of Science ID 000266246700044

    View details for PubMedID 19389999

  • Neural substrates of awakening probed with optogenetic control of hypocretin neurons NATURE Adamantidis, A. R., Zhang, F., Aravanis, A. M., Deisseroth, K., de Lecea, L. 2007; 450 (7168): 420-U9


    The neural underpinnings of sleep involve interactions between sleep-promoting areas such as the anterior hypothalamus, and arousal systems located in the posterior hypothalamus, the basal forebrain and the brainstem. Hypocretin (Hcrt, also known as orexin)-producing neurons in the lateral hypothalamus are important for arousal stability, and loss of Hcrt function has been linked to narcolepsy. However, it is unknown whether electrical activity arising from Hcrt neurons is sufficient to drive awakening from sleep states or is simply correlated with it. Here we directly probed the impact of Hcrt neuron activity on sleep state transitions with in vivo neural photostimulation, genetically targeting channelrhodopsin-2 to Hcrt cells and using an optical fibre to deliver light deep in the brain, directly into the lateral hypothalamus, of freely moving mice. We found that direct, selective, optogenetic photostimulation of Hcrt neurons increased the probability of transition to wakefulness from either slow wave sleep or rapid eye movement sleep. Notably, photostimulation using 5-30 Hz light pulse trains reduced latency to wakefulness, whereas 1 Hz trains did not. This study establishes a causal relationship between frequency-dependent activity of a genetically defined neural cell type and a specific mammalian behaviour central to clinical conditions and neurobehavioural physiology.

    View details for DOI 10.1038/nature06310

    View details for Web of Science ID 000250918600055

    View details for PubMedID 17943086

  • Hypocretin/Orexins and Hyperarousal de Lecea, L. SPRINGERNATURE. 2020: 31
  • Neural and Hormonal Control of Sexual Behavior. Endocrinology Jennings, K. J., de Lecea, L. 2020


    Gonadal hormones contribute to the sexual differentiation of brain and behavior throughout the lifespan, from initial neural patterning to 'activation' of adult circuits. Sexual behavior is an ideal system in which to investigate the mechanisms underlying hormonal activation of neural circuits. Sexual behavior is a hormonally regulated, innate social behavior found across species. Although both sexes seek out and engage in sexual behavior, the specific actions involved in mating are sexually dimorphic. Thus, the neural circuits mediating sexual motivation and behavior in males and females are overlapping yet distinct. Furthermore, sexual behavior is strongly dependent on circulating gonadal hormones in both sexes. There has been significant recent progress on elucidating how gonadal hormones modulate physiological properties within sexual behavior circuits with consequences for behavior. Therefore, in this mini-review we review the neural circuits of male and female sexual motivation and behavior from initial sensory detection of pheromones to the extended amygdala and on to medial hypothalamic nuclei and reward systems. We also discuss how gonadal hormones impact the physiology and functioning of each node within these circuits. By better understanding the myriad of ways in which gonadal hormones impact sexual behavior circuits, we can gain a richer and more complete appreciation for the neural substrates of complex behavior.

    View details for DOI 10.1210/endocr/bqaa150

    View details for PubMedID 32845294

  • Impaired hypocretin/orexin system alters responses to salient stimuli in obese male mice. The Journal of clinical investigation Tan, Y., Hang, F., Liu, Z., Stoiljkovic, M., Wu, M., Tu, Y., Han, W., Lee, A. M., Kelley, C., Hajos, M., Lu, L., de Lecea, L., de Araujo, I., Picciotto, M., Horvath, T. L., Gao, X. 2020


    The brain has evolved in an environment where food sources are scarce and foraging for food is one of the major challenges for survival of the individual and species. Basic and clinical studies show that obesity/overnutrition leads to overwhelming changes in the brain in animals and humans. However, the exact mechanisms underlying the consequences of excessive energy intake are not well understood. Neurons expressing the neuropeptide hypocretin/orexin (Hcrt) in the lateral/perifonical hypothalamus (LH) are critical for homeostatic regulation, reward seeking, stress response, and cognitive functions. In this study, we examined adaptations in Hcrt cells regulating behavioral responses to salient stimuli in diet-induced obese mice. Our results demonstrated changes in primary cilia, synaptic transmission and plasticity, cellular responses to neurotransmitters necessary for reward seeking and stress responses in Hcrt neurons from obese mice. Activities of neuronal networks in the LH and hippocampus were impaired as a result of decreased hypocretinergic function. The weakened Hcrt system decreased reward seeking while altering responses to acute stress (stress coping strategy), which were reversed by selectively activating Hcrt cells with chemogenetics. Taken together, our data suggest that a deficiency in the Hcrt signaling may be a common cause of behavioral changes (such as lowered arousal, weakened reward seek and altered stress response) in obese animals.

    View details for DOI 10.1172/JCI130889

    View details for PubMedID 32516139

  • Multisensory modulation of body ownership in mice. Neuroscience of consciousness Buckmaster, C. L., Rathmann-Bloch, J. E., de Lecea, L. n., Schatzberg, A. F., Lyons, D. M. 2020; 2020 (1): niz019


    Body ownership is a fundamental aspect of self-consciousness that reflects more than the presence of physical body parts. As demonstrated by the rubber hand illusion (RHI), human brains construct body ownership experiences using available multisensory information. Experimental conditions similar to those that induce the RHI in humans have been recently adapted to induce the rubber tail illusion (RTI) in mice. Here, we show that the RTI is enhanced in both sexes of mice by repetitive synchronous stroking comprised of correlated visual and tactile stimulation of real and rubber tails compared to visual-only mimicked stroking conducted without tactile stimulation. The RTI also appears to be enhanced in female but not male mice by slow compared to fast stroking that reflects an interoceptive manipulation associated with affective touch in humans. Sex differences in slow stroking effects are exploratory and require replication in mice. Sex differences have not been reported for the RHI in healthy humans, but women rate slow stroking as more affectively pleasant compared to the ratings of men. Results suggest that the RHI in humans resembles aspects of the RTI in mice. Studies of mice may therefore provide neurobiological insights on evolutionarily conserved mechanisms of bodily self-consciousness in humans.

    View details for DOI 10.1093/nc/niz019

    View details for PubMedID 31988796

    View details for PubMedCentralID PMC6977007

  • The hypocretin (orexin) system: from a neural circuitry perspective. Neuropharmacology Li, S. B., de Lecea, L. n. 2020; 167: 107993


    Hypocretin/orexin neurons are distributed restrictively in the hypothalamus, a brain region known to orchestrate diverse functions including sleep, reward processing, food intake, thermogenesis, and mood. Since the hypocretins/orexins were discovered more than two decades ago, extensive studies have accumulated concrete evidence showing the pivotal role of hypocretin/orexin in diverse neural modulation. New method of viral-mediated tracing system offers the possibility to map the monosynaptic inputs and detailed anatomical connectivity of Hcrt neurons. With the development of powerful research techniques including optogenetics, fiber-photometry, cell-type/pathway specific manipulation and neuronal activity monitoring, as well as single-cell RNA sequencing, the details of how hypocretinergic system execute functional modulation of various behaviors are coming to light. In this review, we focus on the function of neural pathways from hypocretin neurons to target brain regions. Anatomical and functional inputs to hypocretin neurons are also discussed. We further briefly summarize the development of pharmaceutical compounds targeting hypocretin signaling. This article is part of the special issue on Neuropeptides.

    View details for DOI 10.1016/j.neuropharm.2020.107993

    View details for PubMedID 32135427

  • Neurobiological and Hormonal Mechanisms Regulating Women's Sleep. Frontiers in neuroscience Dorsey, A., de Lecea, L., Jennings, K. J. 2020; 14: 625397


    Sleep is crucial for optimal well-being, and sex differences in sleep quality have significant implications for women's health. We review the current literature on sex differences in sleep, such as differences in objective and subjective sleep measures and their relationship with aging. We then discuss the convincing evidence for the role of ovarian hormones in regulating female sleep, and survey how these hormones act on a multitude of brain regions and neurochemicals to impact sleep. Lastly, we identify several important areas in need of future research to narrow the knowledge gap and improve the health of women and other understudied populations.

    View details for DOI 10.3389/fnins.2020.625397

    View details for PubMedID 33519372

  • Hypothalamic circuitry underlying stress-induced insomnia and peripheral immunosuppression Science Advances Li, S. B., Borniger, J. C., Yamaguchi, H., Hédou, J., Gaudilliere, B., de Lecea, L. 2020; 6 (37)

    View details for DOI 10.1126/sciadv.abc2590

  • Sleep and neuropsychiatric illness NEUROPSYCHOPHARMACOLOGY Winkelman, J. W., de Lecea, L. 2020; 45 (1): 1–2

    View details for DOI 10.1038/s41386-019-0514-5

    View details for Web of Science ID 000499141800001

    View details for PubMedID 31486776

    View details for PubMedCentralID PMC6879507

  • Brain Circuit of Claustrophobia-like Behavior in Mice Identified by Upstream Tracing of Sighing. Cell reports Li, P. n., Li, S. B., Wang, X. n., Phillips, C. D., Schwarz, L. A., Luo, L. n., de Lecea, L. n., Krasnow, M. A. 2020; 31 (11): 107779


    Emotions are distinct patterns of behavioral and physiological responses triggered by stimuli that induce different brain states. Elucidating the circuits is difficult because of challenges in interrogating emotional brain states and their complex outputs. Here, we leverage the recent discovery in mice of a neural circuit for sighing, a simple, quantifiable output of various emotions. We show that mouse confinement triggers sighing, and this "claustrophobic" sighing, but not accompanying tachypnea, requires the same medullary neuromedin B (Nmb)-expressing neurons as physiological sighing. Retrograde tracing from the Nmb neurons identified 12 forebrain centers providing presynaptic input, including hypocretin (Hcrt)-expressing lateral hypothalamic neurons. Confinement activates Hcrt neurons, and optogenetic activation induces sighing and tachypnea whereas pharmacologic inhibition suppresses both responses. The effect on sighing is mediated by HCRT directly on Nmbneurons. We propose that this HCRT-NMB neuropeptide relay circuit mediates claustrophobic sighing and that activated Hcrt neurons are a claustrophobia brain state that directly controls claustrophobic outputs.

    View details for DOI 10.1016/j.celrep.2020.107779

    View details for PubMedID 32553161

  • Arousal-state dependent alterations in VTA-GABAergic neuronal activity. eNeuro Eban-Rothschild, A. n., Borniger, J. C., Rothschild, G. n., Giardino, W. J., Morrow, J. G., de Lecea, L. n. 2020


    Decades of research have implicated the ventral tegmental area (VTA) in motivation, learning and reward processing. We and others recently demonstrated that it also serves as an important node in sleep/wake regulation. Specifically, VTA-dopaminergic neuron activation is sufficient to drive wakefulness and necessary for the maintenance of wakefulness. However, the role of VTA-GABAergic neurons in arousal regulation is not fully understood. It is still unclear whether VTA-GABAergic neurons predictably alter their activity across arousal states, what is the nature of interactions between VTA-GABAergic activity and cortical oscillations, and how activity in VTA-GABAergic neurons relates to VTA-dopaminergic neurons in the context of sleep/wake regulation. To address these, we simultaneously recorded population activity from VTA-subpopulations and EEG/EMG signals during spontaneous sleep/wake states and in the presence of salient stimuli in freely-behaving mice. We found that VTA-GABAergic neurons exhibit robust arousal-state-dependent alterations in population activity, with high activity and transients during wakefulness and REM sleep. During wakefulness, population activity of VTA-GABAergic neurons, but not VTA-dopaminergic neurons, was positively correlated with EEG gamma power and negatively correlated with theta power. During NREM sleep, population activity in both VTA-GABAergic and VTA-dopaminergic neurons negatively correlated with delta, theta, and sigma power bands. Salient stimuli, with both positive and negative valence, activated VTA-GABAergic neurons. Together, our data indicate that VTA-GABAergic neurons, like their dopaminergic counterparts, drastically alter their activity across sleep-wake states. Changes in their activity predicts cortical oscillatory patterns reflected in the EEG, which are distinct from EEG spectra associated with dopaminergic neural activity.Statement of Significance Little is known about how ventral tegmental area (VTA) neural ensembles couple arousal to motivated behaviors. Using cell-type specific genetic tools, we investigated the population activity of GABAergic and dopaminergic neurons within the VTA across sleep/wake states and in the presence of salient stimuli. We demonstrate that coordinated neural activity within VTA-GABAergic neurons peaks during wakefulness and REM sleep. Furthermore, neuronal activity in VTA-GABAergic neurons is correlated with high frequency, low amplitude cortical oscillations during waking, but negatively correlated with high amplitude slower frequency oscillations during NREM sleep. Our results demonstrate that VTA-GABAergic neuronal activity is tightly linked to cortical arousal and highlight this population as a potential important node in sleep/wake regulation.

    View details for DOI 10.1523/ENEURO.0356-19.2020

    View details for PubMedID 32054621

  • Editorial: Hypocretins/Orexins. Frontiers in endocrinology Lopez, M., de Lecea, L., Dieguez, C. 2020; 11: 357

    View details for DOI 10.3389/fendo.2020.00357

    View details for PubMedID 32582031

  • CRISPR/Cas9 Editing of Neuropeptide Receptor Signaling Reveals an Extended Amygdala Circuit Mechanism Modulating Alcohol Drinking, Anxiety, and Avoidance Giardino, W., Yamaguchi, H., de Lecea, L. NATURE PUBLISHING GROUP. 2019: 505
  • Construction of Viral Vectors for Cell Type-specific CRISPR Gene Editing in the Adult Mouse Brain BIO-PROTOCOL Yamaguchi, H., de Lecea, L. 2019; 9 (16)
  • In vivo cell type-specific CRISPR gene editing for sleep research JOURNAL OF NEUROSCIENCE METHODS Yamaguchi, H., de Lecea, L. 2019; 316: 99–102
  • Hypocretin and the Regulation of Sleep-Wake Transitions HANDBOOK OF SLEEP RESEARCH, VOL 30 Nevarez, N., de Lecea, L., Dringenberg, H. C. 2019; 30: 89–99
  • In vivo cell type-specific CRISPR gene editing for sleep research. Journal of neuroscience methods Yamaguchi, H., de Lecea, L. 2018


    Sleep is an innate behavior conserved in all animals and, in vertebrates, is regulated by neuronal circuits in the brain. The conventional techniques of forward and reverse genetics have enabled researchers to investigate the molecular mechanisms that regulate sleep and arousal. However, functional interrogation of genes in specific cell subtypes in the brain remains a challenge. Here, we review the background of newly developed gene-editing technologies using engineered CRISPR/Cas9 system and describe the application to interrogate gene functions within genetically-defined brain cell populations in sleep research.

    View details for PubMedID 30439390

  • Parallel circuits from the bed nuclei of stria terminalis to the lateral hypothalamus drive opposing emotional states. Nature neuroscience Giardino, W. J., Eban-Rothschild, A., Christoffel, D. J., Li, S., Malenka, R. C., de Lecea, L. 2018


    Lateral hypothalamus (LH) neurons containing the neuropeptide hypocretin (HCRT; orexin) modulate affective components of arousal, but their relevant synaptic inputs remain poorly defined. Here we identified inputs onto LH neurons that originate from neuronal populations in the bed nuclei of stria terminalis (BNST; a heterogeneous region of extended amygdala). We characterized two non-overlapping LH-projecting GABAergic BNST subpopulations that express distinct neuropeptides (corticotropin-releasing factor, CRF, and cholecystokinin, CCK). To functionally interrogate BNSTLH circuitry, we used tools for monitoring and manipulating neural activity with cell-type-specific resolution in freely behaving mice. We found that Crf-BNST and Cck-BNST neurons respectively provide abundant and sparse inputs onto Hcrt-LH neurons, display discrete physiological responses to salient stimuli, drive opposite emotionally valenced behaviors, and receive different proportions of inputs from upstream networks. Together, our data provide an advanced model for how parallel BNSTLH pathways promote divergent emotional states via connectivity patterns of genetically defined, circuit-specific neuronal subpopulations.

    View details for PubMedID 30038273

  • Hypocretin as a Hub for Arousal and Motivation FRONTIERS IN NEUROLOGY Tyree, S. M., Bomiger, J. C., de Lecea, L. 2018; 9: 413


    The lateral hypothalamus is comprised of a heterogeneous mix of neurons that serve to integrate and regulate sleep, feeding, stress, energy balance, reward, and motivated behavior. Within these populations, the hypocretin/orexin neurons are among the most well studied. Here, we provide an overview on how these neurons act as a central hub integrating sensory and physiological information to tune arousal and motivated behavior accordingly. We give special attention to their role in sleep-wake states and conditions of hyper-arousal, as is the case with stress-induced anxiety. We further discuss their roles in feeding, drug-seeking, and sexual behavior, which are all dependent on the motivational state of the animal. We further emphasize the application of powerful techniques, such as optogenetics, chemogenetics, and fiber photometry, to delineate the role these neurons play in lateral hypothalamic functions.

    View details for PubMedID 29928253

  • Hypocretin/orexin deficiency decreases cocaine abuse liability NEUROPHARMACOLOGY Steiner, N., Rossetti, C., Sakurai, T., Yanagisawa, M., de Lecea, L., Magistretti, P. J., Halfon, O., Boutrel, B. 2018; 133: 395–403


    Compelling evidence indicates that hypocretin/orexin signaling regulates arousal, stress and reward-seeking behaviors. However, most studies on drug reward-related processes have so far described the effects of pharmacological blockers disrupting hypocretin/orexin transmission. We report here an extensive study on cocaine-related behaviors in hypocretin/orexin-deficient mice (KO) and their heterozygous (HET) and wildtype (WT) littermates. We evaluated behavioral sensitization following repeated administrations and preference for an environment repeatedly paired with cocaine injections (15 mg/kg). Mice were also trained to self-administer cocaine (0.5-1.5 mg/kg/infusion). Our observations show that whereas all mice exhibited quite similar responses to acute administration of cocaine, only Hcrt KO mice exhibited reduced cocaine-seeking behaviors following a period of abstinence or extinction, and reduced cocaine incubation craving. Further, if the present findings confirm that Hcrt deficient mice may display a hypoactive phenotype, possibly linked to a reduced alertness concomitant to a decreased exploration of their environment, hypocretin/orexin defiency did not cause any attentional deficit. We thus report that innate disruption of hypocretin/orexin signaling moderately alters cocaine reward but significantly reduces long-term affective dependence that may explain the lack of relapse for cocaine seeking seen in Hcrt KO mice. Overall, with blunted cocaine intake at the highest concentration and reduced responsiveness to cocaine cues after prolonged abstinence, our findings suggest that hypocretin deficient mice may display signs of resilience to cocaine addiction.

    View details for PubMedID 29454841

  • Neuronal Mechanisms for Sleep/Wake Regulation and Modulatory Drive NEUROPSYCHOPHARMACOLOGY Eban-Rothschild, A., Appelbaum, L., de Lecea, L. 2018; 43 (5): 937–52


    Humans have been fascinated by sleep for millennia. After almost a century of scientific interrogation, significant progress has been made in understanding the neuronal regulation and functions of sleep. The application of new methods in neuroscience that enable the analysis of genetically defined neuronal circuits with unprecedented specificity and precision has been paramount in this endeavor. In this review, we first discuss electrophysiological and behavioral features of sleep/wake states and the principal neuronal populations involved in their regulation. Next, we describe the main modulatory drives of sleep and wakefulness, including homeostatic, circadian, and motivational processes. Finally, we describe a revised integrative model for sleep/wake regulation.

    View details for PubMedID 29206811

    View details for PubMedCentralID PMC5854814

  • Optical Probing of Orexin/Hypocretin Receptor Antagonists. Sleep Li, S. B., Nevárez, N. n., Giardino, W. J., de Lecea, L. n. 2018


    The present study investigated the function of Hypocretin (Hcrt or Orexin/OX) receptor antagonists in sleep modulation and memory function with optical methods in transgenic mice.We used Hcrt-IRES-Cre knock-in mice and AAV vectors expressing channelrhodopsin-2 (ChR2) to render Hcrt neurons sensitive to blue light stimulation. We optogenetically stimulated Hcrt neurons and measured latencies to wakefulness in the presence or absence of OX1/2R antagonists and Zolpidem. We also examined endogenous Hcrt neuronal activity with fiber photometry. Changes in memory after optogenetic sleep disruption were evaluated by the novel object recognition test (NOR) and compared for groups treated with vehicle, OX1/2R antagonists, or Zolpidem. We also analyzed EEG power spectra of wakefulness, rapid eye movement (REM) sleep, and non-REM (NREM) sleep following the injections of vehicle, OX1/2R antagonists, and Zolpidem in young adult mice.Acute optogenetic stimulation of Hcrt neurons at different frequencies resulted in wakefulness. Treatment with dual OX1/2R antagonists (DORAs) DORA12 and MK6096, as well as selective OX2R antagonist MK1064 and Zolpidem, but not selective OX1R antagonist 1SORA1, significantly reduced the bout length of optogenetic stimulation-evoked wakefulness episode. Fiber photometry recordings of GCaMP6f signals showed that Hcrt neurons are active during wakefulness, even in the presence of OXR antagonists. Treatment with dual OX1/2R antagonists improved memory function despite optogenetic sleep fragmentation caused impaired memory function in a NOR test.Our results show DORAs and selective OX2R antagonists stabilize sleep and improve sleep-dependent cognitive processes even when challenged by optogenetic stimulation mimicking highly arousing stimuli.

    View details for PubMedID 30060151

  • Optical Probing of Orexin/Hypocretin Receptor Antagonists Sleep Li, S., Nevárez, N., Giardino, W. J., de Lecea, L. 2018

    View details for DOI 10.1093/sleep/zsy141

  • In vivo cell type-specific CRISPR knockdown of dopamine beta hydroxylase reduces locus coeruleus evoked wakefulness. Nature communications Yamaguchi, H. n., Hopf, F. W., Li, S. B., de Lecea, L. n. 2018; 9 (1): 5211


    Locus coeruleus (LC) neurons in the brainstem have long been associated with attention and arousal. Optogenetic stimulation of LC-NE neurons induces immediate sleep-to-wake transitions. However, LC neurons also secrete other neurotransmitters in addition to NE. To interrogate the role of NE derived from the LC in regulating wakefulness, we applied in vivo cell type-specific CRISPR/Cas9 technology to disrupt the dopamine beta hydroxylase (dbh) gene selectively in adult LC-NE neurons. Unilateral dbh gene disruption abolished immediate arousal following optogenetic stimulation of LC. Bilateral LC-specific dbh disruption significantly reduced NE concentration in LC projection areas and reduced wake length even in the presence of salient stimuli. These results suggest that NE may be crucial for the awakening effect of LC stimulation and serve as proof-of-principle that CRISPR gene editing in adult neurons can be used to interrogate gene function within genetically-defined neuronal circuitry associated with complex behaviors.

    View details for PubMedID 30523254

  • In vivo cell type-specific CRISPR knockdown of dopamine beta hydroxylase reduces locus coeruleus evoked wakefulness Nature Communications Yamaguchi, H., Hopf, F., Li, S., de Lecea, L. 2018; 9
  • Recent advances in understanding the roles of hypocretin/orexin in arousal, affect, and motivation. F1000Research Nevarez, N., de Lecea, L. 2018; 7


    The hypocretins (Hcrts) are two alternatively spliced neuropeptides (Hcrt1/Ox-A and Hcrt2/Ox-B) that are synthesized exclusively in the hypothalamus. Data collected in the 20 years since their discovery have supported the view that the Hcrts play a broad role in the control of arousal with a particularly important role in the maintenance of wakefulness and sleep-to-wake transitions. While this latter point has received an overwhelming amount of research attention, a growing literature has begun to broaden our understanding of the many diverse roles that the Hcrts play in physiology and behavior. Here, we review recent advances in the neurobiology of Hcrt in three sections. We begin by surveying findings on Hcrt function within normal sleep/wake states as well as situations of aberrant sleep (that is, narcolepsy). In the second section, we discuss research establishing a role for Hcrt in mood and affect (that is, anxiety, stress, and motivation). Finally, in the third section, we briefly discuss future directions for the field and place an emphasis on analytical modeling of Hcrt neural activity. We hope that the data discussed here provide a broad overview of recent progress in the field and make clear the diversity of roles played by these neuromodulators.

    View details for PubMedID 30254737

  • Hypothalamic Tuberomammillary Nucleus Neurons: Electrophysiological Diversity and Essential Role in Arousal Stability JOURNAL OF NEUROSCIENCE Fujita, A., Bonnavion, P., Wilson, M. H., Mickelsen, L. E., Bloit, J., de Lecea, L., Jackson, A. C. 2017; 37 (39): 9574–92


    Histaminergic (HA) neurons, found in the posterior hypothalamic tuberomammillary nucleus (TMN), extend fibers throughout the brain and exert modulatory influence over numerous physiological systems. Multiple lines of evidence suggest that the activity of HA neurons is important in the regulation of vigilance despite the lack of direct, causal evidence demonstrating its requirement for the maintenance of arousal during wakefulness. Given the strong correlation between HA neuron excitability and behavioral arousal, we investigated both the electrophysiological diversity of HA neurons in brain slices and the effect of their acute silencing in vivo in male mice. For this purpose, we first validated a transgenic mouse line expressing cre recombinase in histidine decarboxylase-expressing neurons (Hdc-Cre) followed by a systematic census of the membrane properties of both HA and non-HA neurons in the ventral TMN (TMNv) region. Through unsupervised hierarchical cluster analysis, we found electrophysiological diversity both between TMNv HA and non-HA neurons, and among HA neurons. To directly determine the impact of acute cessation of HA neuron activity on sleep-wake states in awake and behaving mice, we examined the effects of optogenetic silencing of TMNv HA neurons in vivo We found that acute silencing of HA neurons during wakefulness promotes slow-wave sleep, but not rapid eye movement sleep, during a period of low sleep pressure. Together, these data suggest that the tonic firing of HA neurons is necessary for the maintenance of wakefulness, and their silencing not only impairs arousal but is sufficient to rapidly and selectively induce slow-wave sleep.SIGNIFICANCE STATEMENT The function of monoaminergic systems and circuits that regulate sleep and wakefulness is often disrupted as part of the pathophysiology of many neuropsychiatric disorders. One such circuit is the posterior hypothalamic histamine (HA) system, implicated in supporting wakefulness and higher brain function, but has been difficult to selectively manipulate owing to cellular heterogeneity in this region. Here we use a transgenic mouse to interrogate both the characteristic firing properties of HA neurons and their specific role in maintaining wakefulness. Our results demonstrate that the acute, cell type-specific silencing of HA neurons during wakefulness is sufficient to not only impair arousal but to rapidly and selectively induce slow-wave sleep. This work furthers our understanding of HA-mediated mechanisms that regulate behavioral arousal.

    View details for PubMedID 28874450

  • To sleep or not to sleep: neuronal and ecological insights. Current opinion in neurobiology Eban-Rothschild, A., Giardino, W. J., de Lecea, L. 2017; 44: 132-138


    Daily, animals need to decide when to stop engaging in cognitive processes and behavioral responses to the environment, and go to sleep. The main processes regulating the daily organization of sleep and wakefulness are circadian rhythms and homeostatic sleep pressure. In addition, motivational processes such as food seeking and predator evasion can modulate sleep/wake behaviors. Here, we discuss the principal processes regulating the propensity to stay awake or go to sleep-focusing on neuronal and behavioral aspects. We first introduce the neuronal populations involved in sleep/wake regulation. Next, we describe the circadian and homeostatic drives for sleep. Then, we highlight studies demonstrating various effects of motivational processes on sleep/wake behaviors, and discuss possible neuronal mechanisms underlying their control.

    View details for DOI 10.1016/j.conb.2017.04.010

    View details for PubMedID 28500869

  • Neuronal substrates for initiation, maintenance, and structural organization of sleep/wake states. F1000Research Eban-Rothschild, A., de Lecea, L. 2017; 6: 212-?


    Animals continuously alternate between sleep and wake states throughout their life. The daily organization of sleep and wakefulness is orchestrated by circadian, homeostatic, and motivational processes. Over the last decades, much progress has been made toward determining the neuronal populations involved in sleep/wake regulation. Here, we will discuss how the application of advanced in vivo tools for cell type-specific manipulations now permits the functional interrogation of different features of sleep/wake state regulation: initiation, maintenance, and structural organization. We will specifically focus on recent studies examining the roles of wake-promoting neuronal populations.

    View details for DOI 10.12688/f1000research.9677.1

    View details for PubMedID 28357049

  • Rat intersubjective decisions are encoded by frequency-specific oscillatory contexts. Brain and behavior Schaich Borg, J. n., Srivastava, S. n., Lin, L. n., Heffner, J. n., Dunson, D. n., Dzirasa, K. n., de Lecea, L. n. 2017; 7 (6): e00710


    It is unknown how the brain coordinates decisions to withstand personal costs in order to prevent other individuals' distress. Here we test whether local field potential (LFP) oscillations between brain regions create "neural contexts" that select specific brain functions and encode the outcomes of these types of intersubjective decisions.Rats participated in an "Intersubjective Avoidance Test" (IAT) that tested rats' willingness to enter an innately aversive chamber to prevent another rat from getting shocked. c-Fos immunoreactivity was used to screen for brain regions involved in IAT performance. Multi-site local field potential (LFP) recordings were collected simultaneously and bilaterally from five brain regions implicated in the c-Fos studies while rats made decisions in the IAT. Local field potential recordings were analyzed using an elastic net penalized regression framework.Rats voluntarily entered an innately aversive chamber to prevent another rat from getting shocked, and c-Fos immunoreactivity in brain regions known to be involved in human empathy-including the anterior cingulate, insula, orbital frontal cortex, and amygdala-correlated with the magnitude of "intersubjective avoidance" each rat displayed. Local field potential recordings revealed that optimal accounts of rats' performance in the task require specific frequencies of LFP oscillations between brain regions in addition to specific frequencies of LFP oscillations within brain regions. Alpha and low gamma coherence between spatially distributed brain regions predicts more intersubjective avoidance, while theta and high gamma coherence between a separate subset of brain regions predicts less intersubjective avoidance. Phase relationship analyses indicated that choice-relevant coherence in the alpha range reflects information passed from the amygdala to cortical structures, while coherence in the theta range reflects information passed in the reverse direction.These results indicate that the frequency-specific "neural context" surrounding brain regions involved in social cognition encodes outcomes of decisions that affect others, above and beyond signals from any set of brain regions in isolation.

    View details for PubMedID 28638715

    View details for PubMedCentralID PMC5474713

  • Optogenetic Investigation of Arousal Circuits. International journal of molecular sciences Tyree, S. M., de Lecea, L. n. 2017; 18 (8)


    Modulation between sleep and wake states is controlled by a number of heterogeneous neuron populations. Due to the topological proximity and genetic co-localization of the neurons underlying sleep-wake state modulation optogenetic methods offer a significant improvement in the ability to benefit from both the precision of genetic targeting and millisecond temporal control. Beginning with an overview of the neuron populations mediating arousal, this review outlines the progress that has been made in the investigation of arousal circuits since the incorporation of optogenetic techniques and the first in vivo application of optogenetic stimulation in hypocretin neurons in the lateral hypothalamus. This overview is followed by a discussion of the future progress that can be made by incorporating more recent technological developments into the research of neural circuits.

    View details for PubMedID 28809797

  • Hypocretins and Arousal. Current topics in behavioral neurosciences Li, S., Giardino, W. J., de Lecea, L. 2016


    How the brain controls vigilance state transitions remains to be fully understood. The discovery of hypocretins, also known as orexins, and their link to narcolepsy has undoubtedly allowed us to advance our knowledge on key mechanisms controlling the boundaries and transitions between sleep and wakefulness. Lack of function of hypocretin neurons (a relatively simple and non-redundant neuronal system) results in inappropriate control of sleep states without affecting the total amount of sleep or homeostatic mechanisms. Anatomical and functional evidence shows that the hypothalamic neurons that produce hypocretins/orexins project widely throughout the entire brain and interact with major neuromodulator systems in order to regulate physiological processes underlying wakefulness, attention, and emotions. Here, we review the role of hypocretins/orexins in arousal state transitions, and discuss possible mechanisms by which such a relatively small population of neurons controls fundamental brain state dynamics.

    View details for DOI 10.1007/7854_2016_58

    View details for PubMedID 28012091

  • Obesity- and gender-dependent role of endogenous somatostatin and cortistatin in the regulation of endocrine and metabolic homeostasis in mice SCIENTIFIC REPORTS Luque, R. M., Cordoba-Chacon, J., Pozo-Salas, A. I., Porteiro, B., de Lecea, L., Nogueiras, R., Gahete, M. D., Castano, J. P. 2016; 6


    Somatostatin (SST) and cortistatin (CORT) regulate numerous endocrine secretions and their absence [knockout (KO)-models] causes important endocrine-metabolic alterations, including pituitary dysregulations. We have demonstrated that the metabolic phenotype of single or combined SST/CORT KO-models is not drastically altered under normal conditions. However, the biological actions of SST/CORT are conditioned by the metabolic-status (e.g. obesity). Therefore, we used male/female SST- and CORT-KO mice fed low-fat (LF) or high-fat (HF) diet to explore the interplay between SST/CORT and obesity in the control of relevant pituitary-axes and whole-body metabolism. Our results showed that the SST/CORT role in the control of GH/prolactin secretions is maintained under LF- and HF-diet conditions as SST-KOs presented higher GH/prolactin-levels, while CORT-KOs displayed higher GH- and lower prolactin-levels than controls under both diets. Moreover, the impact of lack of SST/CORT on the metabolic-function was gender- and diet-dependent. Particularly, SST-KOs were more sensitive to HF-diet, exhibiting altered growth and body-composition (fat/lean percentage) and impaired glucose/insulin-metabolism, especially in males. Conversely, only males CORT-KO under LF-diet conditions exhibited significant alterations, displaying higher glucose-levels and insulin-resistance. Altogether, these data demonstrate a tight interplay between SST/CORT-axis and the metabolic status in the control of endocrine/metabolic functions and unveil a clear dissociation of SST/CORT roles.

    View details for DOI 10.1038/srep37992

    View details for Web of Science ID 000389199600001

    View details for PubMedID 27901064

    View details for PubMedCentralID PMC5128804

  • Hubs and spokes of the lateral hypothalamus: cell types, circuits and behaviour JOURNAL OF PHYSIOLOGY-LONDON Bonnavion, P., Mickelsen, L. E., Fujita, A., de Lecea, L., Jackson, A. C. 2016; 594 (22): 6443-6462


    The hypothalamus is among the most phylogenetically conserved regions in the vertebrate brain, reflecting its critical role in maintaining physiological and behavioural homeostasis. By integrating signals arising from both the brain and periphery, it governs a litany of behaviourally important functions essential for survival. In particular, the lateral hypothalamic area (LHA) is central to the orchestration of sleep-wake states, feeding, energy balance and motivated behaviour. Underlying these diverse functions is a heterogeneous assembly of cell populations typically defined by neurochemical markers, such as the well-described neuropeptides hypocretin/orexin and melanin-concentrating hormone. However, anatomical and functional evidence suggests a rich diversity of other cell populations with complex neurochemical profiles that include neuropeptides, receptors and components of fast neurotransmission. Collectively, the LHA acts as a hub for the integration of diverse central and peripheral signals and, through complex local and long-range output circuits, coordinates adaptive behavioural responses to the environment. Despite tremendous progress in our understanding of the LHA, defining the identity of functionally discrete LHA cell types, and their roles in driving complex behaviour, remain significant challenges in the field. In this review, we discuss advances in our understanding of the neurochemical and cellular heterogeneity of LHA neurons and the recent application of powerful new techniques, such as opto- and chemogenetics, in defining the role of LHA circuits in feeding, reward, arousal and stress. From pioneering work to recent developments, we review how the interrogation of LHA cells and circuits is contributing to a mechanistic understanding of how the LHA coordinates complex behaviour.

    View details for DOI 10.1113/JP271946

    View details for Web of Science ID 000389029900003

    View details for PubMedID 27302606

    View details for PubMedCentralID PMC5108896

  • Fasting modulates GH/IGF-I axis and its regulatory systems in the mammary gland of female mice: Influence of endogenous cortistatin. Molecular and cellular endocrinology Villa-Osaba, A., Gahete, M. D., Cordoba-Chacon, J., de Lecea, L., Castaño, J. P., Luque, R. M. 2016; 434: 14-24


    Growth hormone (GH) and insulin-like growth factor-I (IGF-I) are essential factors in mammary-gland (MG) development and are altered during fasting. However, no studies have investigated the alterations in the expression of GH/IGF-I and its regulatory systems (somatostatin/cortistatin and ghrelin) in MG during fasting. Therefore, this study was aimed at characterizing the regulation of GH/IGF-I/somatostatin/cortistatin/ghrelin-systems expression in MG of fasted female-mice (compared to fed-controls) and the influence of endogenous-cortistatin (using cortistatin-knockouts). Fasting decreased IGF-I while increased IGF-I/Insulin-receptors expression in MGs. Fasting provoked an increase in GH expression that might be associated to enhanced ghrelin-variants/ghrelin-O-acyl-transferase enzyme expression, while an upregulation of somatostatin-receptors was observed. However, cortistatin-knockouts mice showed a decrease in GH and somatostatin receptor-subtypes expression. Altogether, we demonstrate that GH/IGF-I, somatostatin/cortistatin and ghrelin systems expression is altered in MG during fasting, suggesting a relevant role in coordinating its response to metabolic stress, wherein endogenous cortistatin might be essential for an appropriate response.

    View details for DOI 10.1016/j.mce.2016.06.014

    View details for PubMedID 27291340

  • In vivo assessment of behavioral recovery and circulatory exchange in the peritoneal parabiosis model SCIENTIFIC REPORTS Castellano, J. M., Palner, M., Li, S., Freeman, G. M., Andy Nguyen, A., Shen, B., Stan, T., Mosher, K. I., Chin, F. T., de Lecea, L., Luo, J., Wyss-Coray, T. 2016; 6


    The sharing of circulation between two animals using a surgical procedure known as parabiosis has created a wealth of information towards our understanding of physiology, most recently in the neuroscience arena. The systemic milieu is a complex reservoir of tissues, immune cells, and circulating molecules that is surprisingly not well understood in terms of its communication across organ systems. While the model has been used to probe complex physiological questions for many years, critical parameters of recovery and exchange kinetics remain incompletely characterized, limiting the ability to design experiments and interpret results for complex questions. Here we provide evidence that mice joined by parabiosis gradually recover much physiology relevant to the study of brain function. Specifically, we describe the timecourse for a variety of recovery parameters, including those for general health and metabolism, motor coordination, activity, and sleep behavior. Finally, we describe the kinetics of chimerism for several lymphocyte populations as well as the uptake of small molecules into the brains of mice following parabiosis. Our characterization provides an important resource to those attempting to understand the complex interplay between the immune system and the brain as well as other organ systems.

    View details for DOI 10.1038/srep29015

    View details for Web of Science ID 000378851500002

    View details for PubMedID 27364522

    View details for PubMedCentralID PMC4929497

  • Cortistatin Is a Key Factor Regulating the Sex-Dependent Response of the GH and Stress Axes to Fasting in Mice ENDOCRINOLOGY Cordoba-Chacon, J., Gahete, M. D., Pozo-Salas, A. I., de Lecea, L., Castano, J. P., Luque, R. M. 2016; 157 (7): 2810-2823


    Cortistatin (CORT) shares high structural and functional similarities with somatostatin (SST) but displays unique sex-dependent pituitary actions. Indeed, although female CORT-knockout (CORT-KO) mice exhibit enhanced GH expression/secretion, Proopiomelanocortin expression, and circulating ACTH/corticosterone/ghrelin levels, male CORT-KO mice only display increased plasma GH/corticosterone levels. Changes in peripheral ghrelin and SST (rather than hypothalamic levels) seem to regulate GH/ACTH axes in CORT-KOs under fed conditions. Because changes in GH/ACTH axes during fasting provide important adaptive mechanisms, we sought to determine whether CORT absence influences GH/ACTH axes during fasting. Accordingly, fed and fasted male/female CORT-KO were compared with littermate controls. Fasting increased circulating GH levels in male/female controls but not in CORT-KO, suggesting that CORT can be a relevant regulator of GH secretion during fasting. However, GH levels were already higher in CORT-KO than in controls in fed state, which might preclude a further elevation in GH levels. Interestingly, although fasting-induced pituitary GH expression was elevated in both male/female controls, GH expression only increased in fasted female CORT-KOs, likely owing to specific changes observed in key factors controlling somatotrope responsiveness (ie, circulating ghrelin and IGF-1, and pituitary GHRH and ghrelin receptor expression). Fasting increased corticosterone levels in control and, most prominently, in CORT-KO mice, which might be associated with a desensitization to SST signaling and to an augmentation in CRH and ghrelin-signaling regulating corticotrope function. Altogether, these results provide compelling evidence that CORT plays a key, sex-dependent role in the regulation of the GH/ACTH axes in response to fasting.

    View details for DOI 10.1210/en.2016-1195

    View details for Web of Science ID 000378877200022

    View details for PubMedID 27175972

  • Superficial Layer-Specific Histaminergic Modulation of Medial Entorhinal Cortex Required for Spatial Learning CEREBRAL CORTEX He, C., Luo, F., Chen, X., Chen, F., Li, C., Ren, S., Qiao, Q., Zhang, J., de Lecea, L., Gao, D., Hu, Z. 2016; 26 (4): 1590-1608


    The medial entorhinal cortex (MEC) plays a crucial role in spatial learning and memory. Whereas the MEC receives a dense histaminergic innervation from the tuberomamillary nucleus of the hypothalamus, the functions of histamine in this brain region remain unclear. Here, we show that histamine acts via H1Rs to directly depolarize the principal neurons in the superficial, but not deep, layers of the MEC when recording at somata. Moreover, histamine decreases the spontaneous GABA, but not glutamate, release onto principal neurons in the superficial layers by acting at presynaptic H3Rs without effect on synaptic release in the deep layers. Histamine-induced depolarization is mediated via inhibition of Kir channels and requires the activation of protein kinase C, whereas the inhibition of spontaneous GABA release by histamine depends on voltage-gated Ca(2+) channels and extracellular Ca(2+). Furthermore, microinjection of the H1R or H3R, but not H2R, antagonist respectively into the superficial, but not deep, layers of MEC impairs rat spatial learning as assessed by water maze tasks but does not affect the motor function and exploratory activity in an open field. Together, our study indicates that histamine plays an essential role in spatial learning by selectively regulating neuronal excitability and synaptic transmission in the superficial layers of the MEC.

    View details for DOI 10.1093/cercor/bhu322

    View details for Web of Science ID 000374246700021

    View details for PubMedID 25595181

  • Resting easy with a sleep regulator ELIFE Giardino, W. J., de Lecea, L. 2015; 4

    View details for DOI 10.7554/eLife.12093

    View details for Web of Science ID 000367511500001

    View details for PubMedID 26651823

    View details for PubMedCentralID PMC4744186

  • Not So Giants: Mice Lacking Both Somatostatin and Cortistatin Have High GH Levels but Show No Changes in Growth Rate or IGF-1 Levels ENDOCRINOLOGY Pedraza-Arevalo, S., Cordoba-Chacon, J., Pozo-Salas, A. I., Lopez, F. L., De Lecea, L., Gahete, M. D., Castano, J. P., Luque, R. M. 2015; 156 (6): 1958-1964
  • Obesity Alters Gene Expression for GH/IGF-I Axis in Mouse Mammary Fat Pads: Differential Role of Cortistatin and Somatostatin PLOS ONE Villa-Osaba, A., Gahete, M. D., Cordoba-Chacon, J., de Lecea, L., Pozo-Salas, A. I., Javier Delgado-Lista, F., Alvarez-Benito, M., Lopez-Miranda, J., Luque, R. M., Castano, J. P. 2015; 10 (3)


    Locally produced growth hormone (GH) and IGF-I are key factors in the regulation of mammary gland (MG) development and may be important in breast cancer development/progression. Somatostatin (SST) and cortistatin (CORT) regulate GH/IGF-I axis at various levels, but their role in regulating GH/IGF-I in MGs remains unknown. Since obesity alters the expression of these systems in different tissues and is associated to MG (patho) physiology, we sought to investigate the role of SST/CORT in regulating GH/IGF-I system in the MGs of lean and obese mice. Therefore, we analyzed GH/IGF-I as well as SST/CORT and ghrelin systems expression in the mammary fat pads (MFPs) of SST- or CORT-knockout (KO) mice and their respective littermate-controls fed a low-fat (LF) or a high-fat (HF) diet for 16wks. Our results demonstrate that the majority of the components of GH/IGF-I, SST/CORT and ghrelin systems are locally expressed in mouse MFP. Expression of elements of the GH/IGF-I axis was significantly increased in MFPs of HF-fed control mice while lack of endogenous SST partially suppressed, and lack of CORT completely blunted, the up-regulation observed in obese WT-controls. Since SST/CORT are known to exert an inhibitory role on the GH/IGFI axis, the increase in SST/CORT-receptor sst2 expression in MFPs of HF-fed CORT- and SST-KOs together with an elevation on circulating SST in CORT-KOs could explain the differences observed. These results offer new information on the factors (GH/IGF-I axis) involved in the endocrine/metabolic dysregulation of MFPs in obesity, and suggest that CORT is not a mere SST sibling in regulating MG physiology.

    View details for DOI 10.1371/journal.pone.0120955

    View details for Web of Science ID 000351880000116

    View details for PubMedID 25806796

    View details for PubMedCentralID PMC4373840

  • The Hypocretin/Orexin System: An Increasingly Important Role in Neuropsychiatry MEDICINAL RESEARCH REVIEWS Chen, Q., de Lecea, L., Hu, Z., Gao, D. 2015; 35 (1): 152-197


    Hypocretins, also named as orexins, are excitatory neuropeptides secreted by neurons specifically located in lateral hypothalamus and perifornical areas. Orexinergic fibers are extensively distributed in various brain regions and involved in a number of physiological functions, such as arousal, cognition, stress, appetite, and metabolism. Arousal is the most important function of orexin system as dysfunction of orexin signaling leads to narcolepsy. In addition to narcolepsy, orexin dysfunction is associated with serious neural disorders, including addiction, depression, and anxiety. However, some results linking orexin with these disorders are still contradictory, which may result from differences of detection methods or the precision of tools used in measurements; strategies targeted to orexin system (e.g., antagonists to orexin receptors, gene delivery, and cell transplantation) are promising new tools for treatment of neuropsychiatric disorders, though studies are still in a stage of preclinical or clinical research.

    View details for DOI 10.1002/med.21326

    View details for Web of Science ID 000346080200005

    View details for PubMedID 25044006

  • Optogenetic control of hypocretin (orexin) neurons and arousal circuits. Current topics in behavioral neurosciences de Lecea, L. n. 2015; 25: 367–78


    In 1998, our group discovered a cDNA that encoded the precursor of two putative neuropeptides that we called hypocretins for their hypothalamic expression and their similarity to the secretin family of neuropeptides. In the last 16 years, numerous studies have placed the hypocretin system as an integrator of homeostatic functions with a crucial, non-redundant function as arousal stabilizer. We recently applied optogenetic methods to interrogate the role of individual neuronal circuits in sleep-to-wake transitions. The neuronal connections between the hypocretin system and the locus coeruleus (LC) seem to be crucial in establishing the appropriate dynamic of spontaneous awakenings.

    View details for PubMedID 25502546

    View details for PubMedCentralID PMC5047484

  • Optogenetics in Freely Moving Mammals: Dopamine and Reward. Cold Spring Harbor protocols Zhang, F., Tsai, H., Airan, R. D., Stuber, G. D., Adamantidis, A. R., de Lecea, L., Bonci, A., Deisseroth, K. 2015; 2015 (8): pdb top086330-?


    Brain reward systems play a central role in the cognitive and hedonic behaviors of mammals. Multiple neuron types and brain regions are involved in reward processing, posing fascinating scientific questions, and major experimental challenges. Using diverse approaches including genetics, electrophysiology, imaging, and behavioral analysis, a large body of research has focused on both normal functioning of the reward circuitry and on its potential significance in neuropsychiatric diseases. In this introduction, we illustrate a real-world application of optogenetics to mammalian behavior and physiology, delineating procedures and technologies for optogenetic control of individual components of the reward circuitry. We describe the experimental setup and protocol for integrating optogenetic modulation of dopamine neurons with fast-scan cyclic voltammetry, conditioned place preference, and operant conditioning to assess the causal role of well-defined electrical and biochemical signals in reward-related behavior.

    View details for DOI 10.1101/pdb.top086330

    View details for PubMedID 26240415

  • A Framework for Quantitative Modeling of Neural Circuits Involved in Sleep-to-Wake Transition. Frontiers in neurology Sorooshyari, S., Huerta, R., de Lecea, L. 2015; 6: 32-?


    Identifying the neuronal circuits and dynamics of sleep-to-wake transition is essential to understanding brain regulation of behavioral states, including sleep-wake cycles, arousal, and hyperarousal. Recent work by different laboratories has used optogenetics to determine the role of individual neuromodulators in state transitions. The optogenetically driven data do not yet provide a multi-dimensional schematic of the mechanisms underlying changes in vigilance states. This work presents a modeling framework to interpret, assist, and drive research on the sleep-regulatory network. We identify feedback, redundancy, and gating hierarchy as three fundamental aspects of this model. The presented model is expected to expand as additional data on the contribution of each transmitter to a vigilance state becomes available. Incorporation of conductance-based models of neuronal ensembles into this model and existing models of cortical excitability will provide more comprehensive insight into sleep dynamics as well as sleep and arousal-related disorders.

    View details for DOI 10.3389/fneur.2015.00032

    View details for PubMedID 25767461

    View details for PubMedCentralID PMC4341569

  • Potential role of orexin and sleep modulation in the pathogenesis of Alzheimer's disease JOURNAL OF EXPERIMENTAL MEDICINE Roh, J. H., Jiang, H., Finn, M. B., Stewart, F. R., Mahan, T. E., Cirrito, J. R., Heda, A., Snider, B. J., Li, M., Yanagisawa, M., de Lecea, L., Holtzman, D. M. 2014; 211 (13): 2487-2496


    Age-related aggregation of amyloid-β (Aβ) is an upstream pathological event in Alzheimer's disease (AD) pathogenesis, and it disrupts the sleep-wake cycle. The amount of sleep declines with aging and to a greater extent in AD. Poor sleep quality and insufficient amounts of sleep have been noted in humans with preclinical evidence of AD. However, how the amount and quality of sleep affects Aβ aggregation is not yet well understood. Orexins (hypocretins) initiate and maintain wakefulness, and loss of orexin-producing neurons causes narcolepsy. We tried to determine whether orexin release or secondary changes in sleep via orexin modulation affect Aβ pathology. Amyloid precursor protein (APP)/Presenilin 1 (PS1) transgenic mice, in which the orexin gene is knocked out, showed a marked decrease in the amount of Aβ pathology in the brain with an increase in sleep time. Focal overexpression of orexin in the hippocampus in APP/PS1 mice did not alter the total amount of sleep/wakefulness and the amount of Aβ pathology. In contrast, sleep deprivation or increasing wakefulness by rescue of orexinergic neurons in APP/PS1 mice lacking orexin increased the amount of Aβ pathology in the brain. Collectively, modulation of orexin and its effects on sleep appear to modulate Aβ pathology in the brain.

    View details for DOI 10.1084/jem.20141788

    View details for Web of Science ID 000346366100001

    View details for PubMedID 25422493

    View details for PubMedCentralID PMC4267230

  • Hypocretin (orexin) neuromodulation of stress and reward pathways CURRENT OPINION IN NEUROBIOLOGY Giardino, W. J., de Lecea, L. 2014; 29: 103-108


    Hypocretin (also known as orexin) is a peptide neuromodulator that is expressed exclusively in the lateral hypothalamic area and plays a fundamental role in wakefulness and arousal. Chronic stress and compulsive drug-seeking are two examples of dysregulated states of hyperarousal that are influenced by hypocretin transmission throughout hypothalamic, extended amygdala, brainstem, and mesolimbic pathways. Here, we review current advances in the understanding of hypocretin's modulatory actions underlying conditions of negative and positive emotional valence, focusing particularly on mechanisms that facilitate adaptive (and maladaptive) responses to stressful or rewarding environmental stimuli. We conclude by discussing progress toward integrated theories for hypocretin modulation of divergent behavioral domains.

    View details for DOI 10.1016/j.conb.2014.07.006

    View details for Web of Science ID 000347128200015

    View details for PubMedID 25050887

    View details for PubMedCentralID PMC4267967

  • Basal Forebrain Cholinergic Modulation of Sleep Transitions SLEEP Irmak, S. O., de Lecea, L. 2014; 37 (12): 1941-U104


    The basal forebrain cholinergic system is involved in cognitive processes that require an attentive state, an increased level of arousal, and/ or cortical activation associated with low amplitude fast EEG activity. The activity of most neurons in the basal forebrain cholinergic space is tightly correlated with the cortical EEG and the activity state. While most cholinergic neurons fire maximally during waking and REM sleep, the activity of other types of basal forebrain neurons vastly differs across different arousal and sleep states. Numerous studies have suggested a role for the basal forebrain cholinergic neurons in eliciting cortical activation and arousal. However, the intricate local connectivity within the region requires the use of cell-specific manipulation methods to demonstrate such a causal relationship.Here we have combined optogenetics with surface EEG recordings in freely moving mice in order to investigate the effects of acute cholinergic activation on the dynamics of sleep-to-wake transitions. We recorded from naturally sleeping animals and analyzed transitions from NREM sleep to REM sleep and/ or wakefulness in response to photo-stimulation of cholinergic neurons in substantia innominata.Our results show that optogenetic activation of BF cholinergic neurons during NREM sleep is sufficient to elicit cortical activation and facilitate state transitions, particularly transitions to wakefulness and arousal, at a time scale similar to the activation induced by other subcortical systems. Our results provide in vivo cell-specific demonstration for the role of basal forebrain cholinergic system in induction of wakefulness and arousal.

    View details for DOI 10.5665/sleep.4246

    View details for Web of Science ID 000345827600011

    View details for PubMedID 25325504

  • Control of sleep-to-wake transitions via fast amino acid and slow neuropeptide transmission NEW JOURNAL OF PHYSICS Mosqueiro, T., de Lecea, L., Huerta, R. 2014; 16
  • Light and chemical control of neuronal circuits: possible applications in neurotherapy. Expert review of neurotherapeutics Whittle, A. J., Walsh, J., de Lecea, L. 2014; 14 (9): 1007-1017


    Millions of people worldwide suffer from diseases that result from a failure of central pathways to regulate behavioral and physiological processes. Advances in genetics and pharmacology have already allowed us to appreciate that rather than this dysregulation being systemic throughout the brain, it is usually rooted in specific subsets of dysfunctional cells within discrete neurological circuits. This article discusses the advent of opto- and chemogenetic tools and how they are providing the means to dissect these circuits with a degree of temporal and spatial sensitivity not previously possible. We also highlight the potential applications for treating disease and the key developments likely to have the greatest impact over the next 5 years.

    View details for DOI 10.1586/14737175.2014.948850

    View details for PubMedID 25115180

  • Hypocretin (orexin) regulation of sleep-to-wake transitions FRONTIERS IN PHARMACOLOGY de Lecea, L., Huerta, R. 2014; 5


    The hypocretin (Hcrt), also known as orexin, peptides are essential for arousal stability. Here we discuss background information about the interaction of Hcrt with other neuromodulators, including norepinephrine and acetylcholine probed with optogenetics. We conclude that Hcrt neurons integrate metabolic, circadian and limbic inputs and convey this information to a network of neuromodulators, each of which has a different role on the dynamic of sleep-to-wake transitions. This model may prove useful to predict the effects of orexin receptor antagonists in sleep disorders and other conditions.

    View details for DOI 10.3389/fphar.2014.00016

    View details for Web of Science ID 000347042700001

    View details for PubMedID 24575043

    View details for PubMedCentralID PMC3921570

  • Establishing a fiber-optic-based optical neural interface. Cold Spring Harbor protocols Adamantidis, A. R., Zhang, F., de Lecea, L., Deisseroth, K. 2014; 2014 (8): pdb prot083337-?


    Selective expression of opsins in genetically defined neurons makes it possible to control a subset of neurons without affecting nearby cells and processes in the intact brain, but light must still be delivered to the target brain structure. Light scattering limits the delivery of light from the surface of the brain. For this reason, we have developed a fiber-optic-based optical neural interface (ONI), which allows optical access to any brain structure in freely moving mammals. The ONI system is constructed by modifying the small animal cannula system from PlasticsOne. The system for bilateral stimulation consists of a bilateral cannula guide that has been stereotactically implanted over the target brain region, a screw cap for securing the optical fiber to the animal's head, a fiber guard modified from the internal cannula adapter, and a bare fiber whose length is customized based on the depth of the target region. For unilateral stimulation, a single-fiber system can be constructed using unilateral cannula parts from PlasticsOne. We describe here the preparation of the bilateral ONI system and its use in optical stimulation of the mouse or rat brain. Delivery of opsin-expressing virus and implantation of the ONI may be conducted in the same surgical session; alternatively, with a transgenic animal no opsin virus is delivered during the surgery. Similar procedures are useful for deep or superficial injections (even for neocortical targets, although in some cases surface light-emitting diodes or cortex-apposed fibers can be used for the most superficial cortical targets).

    View details for DOI 10.1101/pdb.prot083337

    View details for PubMedID 25086020

  • Control of sleep-to-wake transitions via fast aminoacid and slow neuropeptide transmission. New journal of physics Mosqueiro, T. n., de Lecea, L. n., Huerta, R. n. 2014; 16


    The Locus Coeruleus (LC) modulates cortical, subcortical, cerebellar, brainstem and spinal cord circuits and it expresses receptors for neuromodulators that operate in a time scale of several seconds. Evidences from anatomical, electrophysiological and optogenetic experiments have shown that LC neurons receive input from a group of neurons called Hypocretins (HCRTs) that release a neuropeptide called hypocretin. It is less known how these two groups of neurons can be coregulated using GABAergic neurons. Since the time scales of GABA A inhibition is several orders of magnitude faster than the hypocretin neuropeptide effect, we investigate the limits of circuit activity regulation using a realistic model of neurons. Our investigation shows that GABA A inhibition is insufficient to control the activity levels of the LCs. Despite slower forms of GABA A can in principle work, there is not much plausibility due to the low probability of the presence of slow GABA A and lack of robust stability at the maximum firing frequencies. The best possible control mechanism predicted by our modeling analysis is the presence of inhibitory neuropeptides that exert effects in a similar time scale as the hypocretin/orexin. Although the nature of these inhibitory neuropeptides has not been identified yet, it provides the most efficient mechanism in the modeling analysis. Finally, we present a reduced mean-field model that perfectly captures the dynamics and the phenomena generated by this circuit. This investigation shows that brain communication involving multiple time scales can be better controlled by employing orthogonal mechanisms of neural transmission to decrease interference between cognitive processes and hypothalamic functions.

    View details for PubMedID 25598695

    View details for PubMedCentralID PMC4292803

  • The hypocretins/orexins: integrators of multiple physiological functions BRITISH JOURNAL OF PHARMACOLOGY Li, J., Hu, Z., de Lecea, L. 2014; 171 (2): 332-350


    The hypocretins (Hcrts), also known as orexins, are two peptides derived from a single precursor produced in the posterior lateral hypothalamus. Over the past decade, the orexin system has been associated with numerous physiological functions, including sleep/arousal, energy homeostasis, endocrine, visceral functions and pathological states, such as narcolepsy and drug abuse. Here, we review the discovery of Hcrt/orexins and their receptors and propose a hypothesis as to how the orexin system orchestrates these multifaceted physiological functions.

    View details for DOI 10.1111/bph.12415

    View details for Web of Science ID 000328712000005

    View details for PubMedID 24102345

  • Optogenetics: opsins and optical interfaces in neuroscience. Cold Spring Harbor protocols Adamantidis, A. R., Zhang, F., de Lecea, L., Deisseroth, K. 2014; 2014 (8): pdb top083329-?


    Optogenetics is defined as the integration of optics and genetics to control well-defined events within specified cells of living tissue. In this introduction, we focus on the basic techniques necessary for employing microbial opsins as optogenetic tools in mammalian brains. We provide a guide for the fundamentals of optogenetic application-selecting an opsin, implementing expression of opsins based on the neuroscientific experimental requirements, and adapting the corresponding optical hardware for delivery of light into mammalian brains.

    View details for DOI 10.1101/pdb.top083329

    View details for PubMedID 25086025

  • Sleep to forget: interference of fear memories during sleep. Molecular psychiatry Rolls, A., Makam, M., Kroeger, D., Colas, D., De Lecea, L., Heller, H. C. 2013; 18 (11): 1166-1170


    Memories are consolidated and strengthened during sleep. Here we show that memories can also be weakened during sleep. We used a fear-conditioning paradigm in mice to condition footshock to an odor (conditioned stimulus (CS)). Twenty-four hours later, presentation of the CS odor during sleep resulted in an enhanced fear response when tested during subsequent wake. However, if the re-exposure of the CS odor during sleep was preceded by bilateral microinjections of a protein synthesis inhibitor into the basolateral amygdala, the subsequent fear response was attenuated. These findings demonstrate that specific fear memories can be selectively reactivated and either strengthened or attenuated during sleep, suggesting the potential for developing sleep therapies for emotional disorders.

    View details for DOI 10.1038/mp.2013.121

    View details for PubMedID 24081009

    View details for PubMedCentralID PMC5036945

  • Paradoxical Effect of Cortistatin Treatment and Its Deficiency on Experimental Autoimmune Encephalomyelitis JOURNAL OF IMMUNOLOGY Souza-Moreira, L., Morell, M., Delgado-Maroto, V., Pedreno, M., Martinez-Escudero, L., Caro, M., O'Valle, F., Luque, R., Gallo, M., de Lecea, L., Castano, J. P., Gonzalez-Rey, E. 2013; 191 (5): 2144-2154


    Cortistatin is a cyclic-neuropeptide produced by brain cortex and immune cells that shows potent anti-inflammatory activity. In this article, we investigated the effect of cortistatin in two models of experimental autoimmune encephalomyelitis (EAE) that mirror chronic and relapsing-remitting multiple sclerosis. A short-term systemic treatment with cortistatin reduced clinical severity and incidence of EAE, the appearance of inflammatory infiltrates in spinal cord, and the subsequent demyelination and axonal damage. This effect was associated with a reduction of the two deleterious components of the disease, namely, the autoimmune and inflammatory response. Cortistatin decreased the presence/activation of encephalitogenic Th1 and Th17 cells in periphery and nervous system, and downregulated various inflammatory mediators, whereas it increased the number of regulatory T cells with suppressive effects on the encephalitogenic response. Moreover, cortistatin regulated glial activity and favored an active program of neuroprotection/regeneration. We further used cortistatin-deficient mice to investigate the role of endogenous cortistatin in the control of immune responses. Surprisingly, cortistatin-deficient mice were partially resistant to EAE and other inflammatory disorders, despite showing competent inflammatory/autoreactive responses. This unexpected phenotype was associated with elevated circulating glucocorticoids and an anxiety-like behavior. Our findings provide a powerful rationale for the assessment of the efficacy of cortistatin as a novel multimodal therapeutic approach to treat multiple sclerosis and identify cortistatin as a key endogenous component of neuroimmune system.

    View details for DOI 10.4049/jimmunol.1300384

    View details for Web of Science ID 000323393300015

    View details for PubMedID 23918980

  • Optogenetics in psychiatric diseases. Current opinion in neurobiology Touriño, C., Eban-Rothschild, A., de Lecea, L. 2013; 23 (3): 430-435


    Optogenetic tools have revolutionized the field of neuroscience, and brought the study of neural circuits to a higher level. Optogenetics has significantly improved our understanding not only of the neuronal connections and function of the healthy brain, but also of the neuronal changes that lead to psychiatric disorders. In this review, we summarize recent optogenetic studies that explored different brain circuits involved in natural behaviors, such as sleep and arousal, reward, fear, and social and aggressive behavior. In addition, we describe how alterations in these circuits may lead to psychiatric disorders such as addiction, anxiety, depression, or schizophrenia.

    View details for DOI 10.1016/j.conb.2013.03.007

    View details for PubMedID 23642859

  • Cortistatin Inhibits Migration and Proliferation of Human Vascular Smooth Muscle Cells and Decreases Neointimal Formation on Carotid Artery Ligation CIRCULATION RESEARCH Duran-Prado, M., Morell, M., Delgado-Maroto, V., Castano, J. P., Aneiros-Fernandez, J., de Lecea, L., Culler, M. D., Hernandez-Cortes, P., O'Valle, F., Delgado, M. 2013; 112 (11): 1444-?


    Proliferation and migration of smooth muscle cells (SMCs) are key steps for the progression of atherosclerosis and restenosis. Cortistatin is a multifunctional neuropeptide belonging to the somatostatin family that exerts unique functions in the nervous and immune systems. Cortistatin is elevated in plasma of patients experiencing coronary heart disease and attenuates vascular calcification.To investigate the occurrence of vascular cortistatin and its effects on the proliferation and migration of SMCs in vitro and in vivo and to delimitate the receptors and signal transduction pathways governing its actions.SMCs from mouse carotid and human aortic arteries and from human atherosclerotic plaques highly expressed cortistatin. Cortistatin expression positively correlated with the progression of arterial intima hyperplasia. Cortistatin inhibited platelet-derived growth factor-stimulated proliferation of human aortic SMCs via binding to somatostatin receptors (sst2 and sst5) and ghrelin receptor, induction of cAMP and p38-mitogen-activated protein kinase, and inhibition of Akt activity. Moreover, cortistatin impaired lamellipodia formation and migration of human aortic SMCs toward platelet-derived growth factor by inhibiting, in a ghrelin-receptor-dependent manner, Rac1 activation and cytosolic calcium increases. These effects on SMC proliferation and migration correlated with an inhibitory action of cortistatin on the neointimal formation in 2 models of carotid arterial ligation. Endogenous cortistatin seems to play a critical role in regulating SMC function because cortistatin-deficient mice developed higher neointimal hyperplasic lesions than wild-type mice.Cortistatin emerges as a natural endogenous regulator of SMCs under pathological conditions and an attractive candidate for the pharmacological management of vascular diseases that course with neointimal lesion formation.

    View details for DOI 10.1161/CIRCRESAHA.112.300695

    View details for Web of Science ID 000319448900013

    View details for PubMedID 23595952

  • Functional wiring of hypocretin and LC-NE neurons: implications for arousal FRONTIERS IN BEHAVIORAL NEUROSCIENCE Carter, M. E., de Lecea, L., Adamantidis, A. 2013; 7


    To survive in a rapidly changing environment, animals must sense their external world and internal physiological state and properly regulate levels of arousal. Levels of arousal that are abnormally high may result in inefficient use of internal energy stores and unfocused attention to salient environmental stimuli. Alternatively, levels of arousal that are abnormally low may result in the inability to properly seek food, water, sexual partners, and other factors necessary for life. In the brain, neurons that express hypocretin neuropeptides may be uniquely posed to sense the external and internal state of the animal and tune arousal state according to behavioral needs. In recent years, we have applied temporally precise optogenetic techniques to study the role of these neurons and their downstream connections in regulating arousal. In particular, we have found that noradrenergic neurons in the brainstem locus coeruleus (LC) are particularly important for mediating the effects of hypocretin neurons on arousal. Here, we discuss our recent results and consider the implications of the anatomical connectivity of these neurons in regulating the arousal state of an organism across various states of sleep and wakefulness.

    View details for DOI 10.3389/fnbeh.2013.00043

    View details for Web of Science ID 000319055000001

    View details for PubMedID 23730276

    View details for PubMedCentralID PMC3657625

  • Hypothalamic Neurotensin Projections Promote Reward by Enhancing Glutamate Transmission in the VTA JOURNAL OF NEUROSCIENCE Kempadoo, K. A., Tourino, C., Cho, S. L., Magnani, F., Leinninger, G., Stuber, G. D., Zhang, F., Myers, M. G., Deisseroth, K., de Lecea, L., Bonci, A. 2013; 33 (18): 7618-?


    The lateral hypothalamus (LH) sends a dense glutamatergic and peptidergic projection to dopamine neurons in the ventral tegmental area (VTA), a cell group known to promote reinforcement and aspects of reward. The role of the LH to VTA projection in reward-seeking behavior can be informed by using optogenetic techniques to dissociate the actions of LH neurons from those of other descending forebrain inputs to the VTA. In the present study, we identify the effect of neurotensin (NT), one of the most abundant peptides in the LH to VTA projection, on excitatory synaptic transmission in the VTA and reward-seeking behavior. Mice displayed robust intracranial self-stimulation of LH to VTA fibers, an operant behavior mediated by NT 1 receptors (Nts1) and NMDA receptors. Whole-cell patch-clamp recordings of VTA dopamine neurons demonstrated that NT (10 nm) potentiated NMDA-mediated EPSCs via Nts1. Results suggest that NT release from the LH into the VTA activates Nts1, thereby potentiating NMDA-mediated EPSCs and promoting reward. The striking behavioral and electrophysiological effects of NT and glutamate highlight the LH to VTA pathway as an important component of reward.

    View details for DOI 10.1523/JNEUROSCI.2588-12.2013

    View details for Web of Science ID 000318420400002

    View details for PubMedID 23637156

  • Repeated in vivo exposure of cocaine induces long-lasting synaptic plasticity in hypocretin/orexin-producing neurons in the lateral hypothalamus in mice JOURNAL OF PHYSIOLOGY-LONDON Rao, Y., Mineur, Y. S., Gan, G., Wang, A. H., Liu, Z., Wu, X., Suyama, S., de Lecea, L., Horvath, T. L., Picciotto, M. R., Gao, X. 2013; 591 (7): 1951-1966


    Hypocretin (orexin), a neuropeptide synthesized exclusively in the perifornical/lateral hypothalamus, is critical for drug seeking and relapse, but it is not clear how the circuitry centred on hypocretin-producing neurons (hypocretin neurons) is modified by drugs of abuse and how changes in this circuit might alter behaviours related to drug addiction. In this study, we show that repeated, but not single, in vivo cocaine administration leads to a long-lasting, experience-dependent potentiation of glutamatergic synapses on hypocretin neurons in mice following a cocaine-conditioned place preference (CPP) protocol. The synaptic potentiation occurs postsynaptically and probably involves up-regulation of AMPA-type glutamate receptors on hypocretin neurons. Phosphorylation of cAMP response element-binding protein (CREB) is also significantly increased in hypocretin neurons in cocaine-treated animals, suggesting that CREB-mediated pathways may contribute to synaptic potentiation in these cells. Furthermore, the potentiation of synaptic efficacy in hypocretin neurons persists during cocaine withdrawal, but reverses to baseline levels after prolonged abstinence. Finally, the induction of long-term potentiation (LTP) triggered by a high-frequency stimulation is facilitated in hypocretin neurons in cocaine-treated mice, suggesting that long-lasting changes in synapses onto hypocretin neurons would probably be further potentiated by other stimuli (such as concurrent environmental cues) paired with the drug. In summary, we show here that hypocretin neurons undergo experience-dependent synaptic potentiation that is distinct from that reported in other reward systems, such as the ventral tegmental area, following exposure to cocaine. These findings support the idea that the hypocretin system is important for behavioural changes associated with cocaine administration in animals and humans.

    View details for DOI 10.1113/jphysiol.2012.246983

    View details for Web of Science ID 000316918300030

    View details for PubMedID 23318871

    View details for PubMedCentralID PMC3624862

  • Mechanism for Hypocretin-mediated sleep-to-wake transitions PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Carter, M. E., Brill, J., Bonnavion, P., Huguenard, J. R., Huerta, R., de Lecea, L. 2012; 109 (39): E2635-E2644


    Current models of sleep/wake regulation posit that Hypocretin (Hcrt)-expressing neurons in the lateral hypothalamus promote and stabilize wakefulness by projecting to subcortical arousal centers. However, the critical downstream effectors of Hcrt neurons are unknown. Here we use optogenetic, pharmacological, and computational tools to investigate the functional connectivity between Hcrt neurons and downstream noradrenergic neurons in the locus coeruleus (LC) during nonrapid eye movement (NREM) sleep. We found that photoinhibiting LC neurons during Hcrt stimulation blocked Hcrt-mediated sleep-to-wake transitions. In contrast, when LC neurons were optically stimulated to increase membrane excitability, concomitant photostimulation of Hcrt neurons significantly increased the probability of sleep-to-wake transitions compared with Hcrt stimulation alone. We also built a conductance-based computational model of Hcrt-LC circuitry that recapitulates our behavioral results using LC neurons as the main effectors of Hcrt signaling. These results establish the Hcrt-LC connection as a critical integrator-effector circuit that regulates NREM sleep/wake behavior during the inactive period. This coupling of distinct neuronal systems can be generalized to other hypothalamic integrator nuclei with downstream effector/output populations in the brain.

    View details for DOI 10.1073/pnas.1202526109

    View details for Web of Science ID 000309604500009

    View details for PubMedID 22955882

    View details for PubMedCentralID PMC3465396

  • Shining Light on Wakefulness and Arousal BIOLOGICAL PSYCHIATRY de Lecea, L., Carter, M. E., Adamantidis, A. 2012; 71 (12): 1046-1052


    Alterations in arousal states are associated with multiple neuropsychiatric disorders, including generalized anxiety disorders, addiction, schizophrenia, and depression. Therefore, elucidating the neurobiological mechanisms controlling the boundaries between arousal, hyperarousal, and hypoarousal is a crucial endeavor in biological psychiatry. Substantial research over several decades has identified distinct arousal-promoting neural populations in the brain; however, how these nuclei act individually and collectively to promote and maintain wakefulness and various arousal states is unknown. We have recently applied optogenetic technology to the repertoire of techniques used to study arousal. Here, we discuss the recent results of these experiments and propose future use of this approach as a way to understand the complex dynamics of neural circuits controlling arousal and arousal-related behaviors.

    View details for DOI 10.1016/j.biopsych.2012.01.032

    View details for Web of Science ID 000304471300005

    View details for PubMedID 22440618

  • Hypocretins and the neurobiology of sleep-wake mechanisms OREXIN/HYPOCRETIN SYSTEM de Lecea, L. 2012; 198: 15-24


    In 1998, our group discovered a cDNA that encoded the precursor of two putative neuropeptides that we called hypocretins for their hypothalamic expression and their similarity to the secretin family of neuropeptides. In the past 15 years, numerous studies have placed the hypocretin system as an integrator of homeostatic functions with a crucial, nonredundant function as an arousal stabilizer. Here, we discuss some of the data that have accumulated over the years on the integrating capacity of these hypothalamic neurons and their role on sleep-to-wake transitions.

    View details for DOI 10.1016/B978-0-444-59489-1.00003-3

    View details for Web of Science ID 000311106700004

    View details for PubMedID 22813967

  • Cortistatin Is Not a Somatostatin Analogue but Stimulates Prolactin Release and Inhibits GH and ACTH in a Gender-Dependent Fashion: Potential Role of Ghrelin ENDOCRINOLOGY Cordoba-Chacon, J., Gahete, M. D., Pozo-Salas, A. I., Martinez-Fuentes, A. J., de Lecea, L., Gracia-Navarro, F., Kineman, R. D., Castano, J. P., Luque, R. M. 2011; 152 (12): 4800-4812


    Cortistatin (CST) and somatostatin (SST) evolve from a common ancestral gene and share remarkable structural, pharmacological, and functional homologies. Although CST has been considered as a natural SST-analogue acting through their shared receptors (SST receptors 1-5), emerging evidence indicates that these peptides might in fact exert unique roles via selective receptors [e.g. CST, not SST, binds ghrelin receptor growth hormone secretagogue receptor type 1a (GHS-R1a)]. To determine whether the role of endogenous CST is different from SST, we characterized the endocrine-metabolic phenotype of male/female CST null mice (cort-/-) at hypothalamic-pituitary-systemic (pancreas-stomach-adrenal-liver) levels. Also, CST effects on hormone expression/secretion were evaluated in primary pituitary cell cultures from male/female mice and female primates (baboons). Specifically, CST exerted an unexpected stimulatory role on prolactin (PRL) secretion, because both male/female cort-/- mice had reduced PRL levels, and CST treatment (in vivo and in vitro) increased PRL secretion, which could be blocked by a GHS-R1a antagonist in vitro and likely relates to the decreased success of female cort-/- in first-litter pup care at weaning. In contrast, CST inhibited GH and adrenocorticotropin-hormone axes in a gender-dependent fashion. In addition, a rise in acylated ghrelin levels was observed in female cort-/- mice, which were associated with an increase in stomach ghrelin/ghrelin O-acyl transferase expression. Finally, CST deficit uncovered a gender-dependent role of this peptide in the regulation of glucose-insulin homeostasis, because male, but not female, cort-/- mice developed insulin resistance. The fact that these actions are not mimicked by SST and are strongly gender dependent offers new grounds to investigate the hitherto underestimated physiological relevance of CST in the regulation of physiological/metabolic processes.

    View details for DOI 10.1210/en.2011-1542

    View details for Web of Science ID 000297376500034

    View details for PubMedID 21971153

    View details for PubMedCentralID PMC3230064

  • Plasma levels of neuropeptides and metabolic hormones, and sleepiness in obstructive sleep apnea RESPIRATORY MEDICINE Sanchez-de-la-Torre, M., Barcelo, A., Pierola, J., Esquinas, C., de la Pena, M., Duran-Cantolla, J., Capote, F., Masa, J. F., Marin, J. M., Vila, M., Cao, G., Martinez, M., de Lecea, L., Gozal, D., Montserrat, J. M., Barbe, F. 2011; 105 (12): 1954-1960


    Obstructive sleep apnea (OSA) is related to obesity and metabolic disorders. The main clinical symptoms are excessive daytime sleepiness (EDS) and snoring. However, not all patients with OSA manifest EDS. Hypocretin-1, neuropeptide Y, leptin, ghrelin and adiponectin are implicated in both metabolic and sleep regulation, two conditions affected by OSA. We hypothesized that levels of these peptides may be related to EDS in OSA patients.We included 132 patients with EDS, as defined by an Epworth Sleepiness Scale (ESS) score ≥ 13 (mean ± SD, 15.7 ± 2.3) and 132 patients without EDS as defined by an ESS score ≤ 9 (6.5 ± 1.9). All patients had an apnea-hypopnea index (AHI) ≥ 20 h(-1). Both groups were matched for gender (males; 83.3% vs. 85.6%), age (50.15 ± 11.2 yrs vs. 50.7 ± 9.9 yrs), body mass index (BMI) (31.8 ± 5.6 kg m(-2) vs. 32.1 ± 4.8 kg m(-2)), and apnea-hypopnea index (AHI) (45.5 ± 19.1 h(-1) vs. 43 ± 19.2 h(-1)).OSA patients with EDS showed significantly higher plasma hypocretin-1 levels (p < 0.001) and lower plasma ghrelin levels (p < 0.001) than OSA patients without EDS. There were no statistically significant differences in neuropeptide Y (p = 0.08), leptin (p = 0.07) and adiponectin (p = 0.72) between the two groups. In the multiple linear regression model ESS score was associated with plasma levels of hypocretin-1, ghrelin and total sleep time.Our study shows that EDS in patients with OSA is associated with increased circulating hypocretin-1 and decreased circulating ghrelin levels, two peptides involved in the regulation of body weight, energy balance, sympathetic tone and sleep-wake cycle. This relationship is independent of AHI and obesity (two key phenotypic features of OSA).

    View details for DOI 10.1016/j.rmed.2011.08.014

    View details for Web of Science ID 000297779900026

    View details for PubMedID 21889324

  • Activation of Central Orexin/Hypocretin Neurons by Dietary Amino Acids NEURON Karnani, M. M., Apergis-Schoute, J., Adamantidis, A., Jensen, L. T., de Lecea, L., Fugger, L., Burdakov, D. 2011; 72 (4): 616-629


    Hypothalamic orexin/hypocretin (orx/hcrt) neurons regulate energy balance, wakefulness, and reward; their loss produces narcolepsy and weight gain. Glucose can lower the activity of orx/hcrt cells, but whether other dietary macronutrients have similar effects is unclear. We show that orx/hcrt cells are stimulated by nutritionally relevant mixtures of amino acids (AAs), both in brain slice patch-clamp experiments, and in c-Fos expression assays following central or peripheral administration of AAs to mice in vivo. Physiological mixtures of AAs electrically excited orx/hcrt cells through a dual mechanism involving inhibition of K(ATP) channels and activation of system-A amino acid transporters. Nonessential AAs were more potent in activating orx/hcrt cells than essential AAs. Moreover, the presence of physiological concentrations of AAs suppressed the glucose responses of orx/hcrt cells. These results suggest a new mechanism of hypothalamic integration of macronutrient signals and imply that orx/hcrt cells sense macronutrient balance, rather than net energy value, in extracellular fluid.

    View details for DOI 10.1016/j.neuron.2011.08.027

    View details for Web of Science ID 000297180100012

    View details for PubMedID 22099463

  • Neural Integration of Reward, Arousal, and Feeding: Recruitment of VTA, Lateral Hypothalamus, and Ventral Striatal Neurons IUBMB LIFE Gutierrez, R., Kay Lobo, M., Zhang, F., de Lecea, L. 2011; 63 (10): 824-830


    The ability to control neuronal activity using light pulses and optogenetic tools has revealed new properties of neural circuits and established causal relationships between activation of a single genetically defined population of neurons and complex behaviors. Here, we briefly review the causal effect of activity of six genetically defined neural circuits on behavior, including the dopaminergic neurons DA in the ventral tegmental area (VTA); the two main populations of medium-sized spiny neurons (D1- and D2-positive) in the striatum; the giant Cholinergic interneurons in the ventral striatum; and the hypocretin- and MCH- expressing neurons in the lateral hypothalamus. We argue that selective spatiotemporal recruitment and coordinated spiking activity among these cell type-specific neural circuits may underlie the neural integration of reward, learning, arousal and feeding.

    View details for DOI 10.1002/iub.539

    View details for Web of Science ID 000295375800010

  • Optogenetic Interrogation of Dopaminergic Modulation of the Multiple Phases of Reward-Seeking Behavior JOURNAL OF NEUROSCIENCE Adamantidis, A. R., Tsai, H., Boutrel, B., Zhang, F., Stuber, G. D., Budygin, E. A., Tourino, C., Bonci, A., Deisseroth, K., de Lecea, L. 2011; 31 (30): 10829-10835


    Phasic activation of dopaminergic neurons is associated with reward-predicting cues and supports learning during behavioral adaptation. While noncontingent activation of dopaminergic neurons in the ventral tegmental are (VTA) is sufficient for passive behavioral conditioning, it remains unknown whether the phasic dopaminergic signal is truly reinforcing. In this study, we first targeted the expression of channelrhodopsin-2 to dopaminergic neurons of the VTA and optimized optogenetically evoked dopamine transients. Second, we showed that phasic activation of dopaminergic neurons in freely moving mice causally enhances positive reinforcing actions in a food-seeking operant task. Interestingly, such effect was not found in the absence of food reward. We further found that phasic activation of dopaminergic neurons is sufficient to reactivate previously extinguished food-seeking behavior in the absence of external cues. This was also confirmed using a single-session reversal paradigm. Collectively, these data suggest that activation of dopaminergic neurons facilitates the development of positive reinforcement during reward-seeking and behavioral flexibility.

    View details for DOI 10.1523/JNEUROSCI.2246-11.2011

    View details for Web of Science ID 000293171900010

    View details for PubMedID 21795535

    View details for PubMedCentralID PMC3171183

  • Optogenetic investigation of neural circuits in vivo TRENDS IN MOLECULAR MEDICINE Carter, M. E., de Lecea, L. 2011; 17 (4): 197-206


    The recent development of light-activated optogenetic probes allows for the identification and manipulation of specific neural populations and their connections in awake animals with unprecedented spatial and temporal precision. This review describes the use of optogenetic tools to investigate neurons and neural circuits in vivo. We describe the current panel of optogenetic probes, methods of targeting these probes to specific cell types in the nervous system, and strategies of photostimulating cells in awake, behaving animals. Finally, we survey the application of optogenetic tools to studying functional neuroanatomy, behavior and the etiology and treatment of various neurological disorders.

    View details for DOI 10.1016/j.molmed.2010.12.005

    View details for Web of Science ID 000291135600005

    View details for PubMedID 21353638

    View details for PubMedCentralID PMC3148823

  • Neuropeptide S facilitates cue-induced relapse to cocaine seeking through activation of the hypothalamic hypocretin system PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Kallupi, M., Cannella, N., Economidou, D., Ubaldi, M., Ruggeri, B., Weiss, F., Massi, M., Marugan, J., Heilig, M., Bonnavion, P., de Lecea, L., Ciccocioppo, R. 2010; 107 (45): 19567-19572


    Drug addiction is a chronic relapsing disorder characterized by compulsive drug seeking and use. Environmental conditioning factors are among the major determinants of relapse in abstinent cocaine users. Here we describe a role of the neuropeptide S (NPS) system in regulating relapse. In rats with a history of cocaine self-administration, presentation of stimuli predictive of drug availability reinstates drug seeking, triggering relapse. Intracerebroventricular (ICV) injection of NPS increased conditioned reinstatement of cocaine seeking, whereas peripheral administration of the NPS receptor antagonist SHA 68 reduced it. Manipulation of the NPS receptor system did not modify cocaine self-administration. We also found that ICV NPS administration activates c-Fos expression in hypocretin-1/orexin-A (Hcrt-1/Ox-A) immunoreactive neurons in the lateral hypothalamus (LH) and in the perifornical area (PeF). Of note, intra-LH and intra-PeF administration of NPS increased conditioned reinstatement of cocaine responding, an effect that was selectively blocked with the Hcrt-1/Ox-A receptor selective antagonist SB334867. Finally, results showed that intra-LH injection of the NPS antagonist [D-Cys(tBu) (5)]NPS blocked cue-induced cocaine seeking, indicating a role for this system in the pathophysiology of drug relapse.

    View details for DOI 10.1073/pnas.1004100107

    View details for Web of Science ID 000283997800079

    View details for PubMedID 20974945

    View details for PubMedCentralID PMC2984152

  • Sleep and metabolism: Role of hypothalamic neuronal circuitry BEST PRACTICE & RESEARCH CLINICAL ENDOCRINOLOGY & METABOLISM Rolls, A., Borg, J. S., de Lecea, L. 2010; 24 (5): 817-828


    Sleep and metabolism are intertwined physiologically and behaviorally, but the neural systems underlying their coordination are still poorly understood. The hypothalamus is likely to play a major role in the regulation sleep, metabolism, and their interaction. And increasing evidence suggests that hypocretin cells in the lateral hypothalamus may provide particularly important contributions. Here we review: 1) direct interactions between biological arousal and metabolic systems in the hypothalamus, and 2) indirect interactions between these two systems mediated by stress or reward, emphasizing the role of hypocretins. An increased understanding of the mechanisms underlying these interactions may provide novel approaches for the treatment of patients with sleep disorders and obesity, as well as suggest new therapeutic strategies for symptoms of aging, stress, or addiction.

    View details for DOI 10.1016/j.beem.2010.08.002

    View details for Web of Science ID 000285813600011

    View details for PubMedID 21112028

  • Hypocretins in the Control of Sleep and Wakefulness CURRENT NEUROLOGY AND NEUROSCIENCE REPORTS Bonnavion, P., de Lecea, L. 2010; 10 (3): 174-179


    During the past 10 years since the discovery of hypocretins (Hcrt, also called orexins), the list of their physiologic implications has been growing, from their primary roles in the sleep-wake cycle and feeding to the control of the cardiovascular system, pain, locomotion, stress, and addiction as well as their involvement in psychiatric disorders such as panic, anxiety, and depression. This diverse set of functions is consistent with the localization of Hcrt neurons in the lateral hypothalamus, a major integrating center of sensory inputs and emotional processes, and their widespread excitatory projections throughout the brain. Newly developed optical tools allow us to manipulate the activity of genetically identified neurons with millisecond precision in vivo and to test specific hypotheses about the causal relationships between Hcrt cells and specific behaviors. Here, we review the basic roles of the Hcrt peptides and discuss how these new technologies increase our understanding of the underpinnings of alertness and arousal.

    View details for DOI 10.1007/s11910-010-0101-y

    View details for Web of Science ID 000278111700003

    View details for PubMedID 20425032

  • Reelin Regulates Postnatal Neurogenesis and Enhances Spine Hypertrophy and Long-Term Potentiation JOURNAL OF NEUROSCIENCE Pujadas, L., Gruart, A., Bosch, C., Delgado, L., Teixeira, C. M., Rossi, D., de Lecea, L., Martinez, A., Delgado-Garcia, J. M., Soriano, E. 2010; 30 (13): 4636-4649


    Reelin, an extracellular protein essential for neural migration and lamination, is also expressed in the adult brain. To unravel the function of this protein in the adult forebrain, we generated transgenic mice that overexpress Reelin under the control of the CaMKIIalpha promoter. Overexpression of Reelin increased adult neurogenesis and impaired the migration and positioning of adult-generated neurons. In the hippocampus, the overexpression of Reelin resulted in an increase in synaptic contacts and hypertrophy of dendritic spines. Induction of long-term potentiation (LTP) in alert-behaving mice showed that Reelin overexpression evokes a dramatic increase in LTP responses. Hippocampal field EPSP during a classical conditioning paradigm was also increased in these mice. Our results indicate that Reelin levels in the adult brain regulate neurogenesis and migration, as well as the structural and functional properties of synapses. These observations suggest that Reelin controls developmental processes that remain active in the adult brain.

    View details for DOI 10.1523/JNEUROSCI.5284-09.2010

    View details for Web of Science ID 000276178000014

    View details for PubMedID 20357114

  • A decade of hypocretins: past, present and future of the neurobiology of arousal ACTA PHYSIOLOGICA de Lecea, L. 2010; 198 (3): 203-208


    In 1998, two groups independently identified the hypocretins, also known as orexins, as two hypothalamic peptides derived from the same precursor expressed in a few thousand neurones restricted to the perifornical area. A decade later, an amazing set of discoveries has demonstrated a key role for this neurotransmitter system in arousal and beyond. Here I review some of the experiments that led to these discoveries and the implications in the neurobiology of the hypothalamus and our understanding of brain arousal.

    View details for DOI 10.1111/j.1748-1716.2009.02004.x

    View details for Web of Science ID 000274147900003

    View details for PubMedID 19473132

  • The role of hypocretin in driving arousal and goal-oriented behaviors BRAIN RESEARCH Boutrel, B., Cannella, N., de Lecea, L. 2010; 1314: 103-111


    The hypocretins (Hcrts), also called orexins, are two neuropeptides secreted by a few thousand neurons restricted to the lateral hypothalamus. The Hcrt peptides bind to two receptors located in nuclei associated with diverse cognitive and physiological functions. Experimental evidence has demonstrated that the physiological roles of hypocretins extend far beyond its initial role in food consumption and has emerged as a key system in the fields of sleep disorders and drug addiction. Here, we discuss recent evidence demonstrating a key role of hypocretin in the motivation for reward seeking in general, and drug taking in particular, and we delineate a physiological framework for this peptidergic system in orchestrating the appropriate levels of alertness required for the elaboration and the execution of goal-oriented behaviors. We propose a general role for hypocretins in mediating arousal, especially when an organism must respond to unexpected stressors and environmental challenges, which serve to shape survival behaviors. We also discuss the limit of the current experimental paradigms to address the question of how a system normally involved in the regulation of vigilance states and hyperarousal may promote a pathological state that elicits compulsive craving and relapse to drug seeking.

    View details for DOI 10.1016/j.brainres.2009.11.054

    View details for Web of Science ID 000275312400010

    View details for PubMedID 19948148

  • Hypocretins Regulate the Anxiogenic-Like Effects of Nicotine and Induce Reinstatement of Nicotine-Seeking Behavior JOURNAL OF NEUROSCIENCE Plaza-Zabala, A., Martin-Garcia, E., de Lecea, L., Maldonado, R., Berrendero, F. 2010; 30 (6): 2300-2310


    Emerging evidence suggests that the hypocretinergic system is involved in addictive behavior. In this study, we investigated the role of these hypothalamic neuropeptides in anxiety-like responses of nicotine and stress-induced reinstatement of nicotine-seeking behavior. Acute nicotine (0.8 mg/kg, s.c.) induced anxiogenic-like effects in the elevated plus-maze and activated the paraventricular nucleus of the hypothalamus (PVN) as revealed by c-Fos expression. Pretreatment with the hypocretin receptor 1 (Hcrtr-1) antagonist SB334867 or preprohypocretin gene deletion blocked both nicotine effects. In the PVN, SB334867 also prevented the activation of corticotrophin releasing factor (CRF) and arginine-vasopressin (AVP) neurons, which expressed Hcrtr-1. In addition, an increase of the percentage of c-Fos-positive hypocretin cells in the perifornical and dorsomedial hypothalamic (PFA/DMH) areas was found after nicotine (0.8 mg/kg, s.c.) administration. Intracerebroventricular infusion of hypocretin-1 (Hcrt-1) (0.75 nmol/1 mul) or footshock stress reinstated a previously extinguished nicotine-seeking behavior. The effects of Hcrt-1 were blocked by SB334867, but not by the CRF1 receptor antagonist antalarmin. Moreover, SB334867 did not block CRF-dependent footshock-induced reinstatement of nicotine-seeking while antalarmin was effective in preventing this nicotine motivational response. Therefore, the Hcrt system interacts with CRF and AVP neurons in the PVN and modulates the anxiogenic-like effects of nicotine whereas Hcrt and CRF play a different role in the reinstatement of nicotine-seeking. Indeed, Hcrt-1 reinstates nicotine-seeking through a mechanism independent of CRF activation whereas CRF mediates the reinstatement induced by stress.

    View details for DOI 10.1523/JNEUROSCI.5724-09.2010

    View details for Web of Science ID 000274398200030

    View details for PubMedID 20147556

    View details for PubMedCentralID PMC2829191

  • Optogenetic interrogation of neural circuits: technology for probing mammalian brain structures NATURE PROTOCOLS Zhang, F., Gradinaru, V., Adamantidis, A. R., Durand, R., Airan, R. D., de Lecea, L., Deisseroth, K. 2010; 5 (3): 439-456


    Elucidation of the neural substrates underlying complex animal behaviors depends on precise activity control tools, as well as compatible readout methods. Recent developments in optogenetics have addressed this need, opening up new possibilities for systems neuroscience. Interrogation of even deep neural circuits can be conducted by directly probing the necessity and sufficiency of defined circuit elements with millisecond-scale, cell type-specific optical perturbations, coupled with suitable readouts such as electrophysiology, optical circuit dynamics measures and freely moving behavior in mammals. Here we collect in detail our strategies for delivering microbial opsin genes to deep mammalian brain structures in vivo, along with protocols for integrating the resulting optical control with compatible readouts (electrophysiological, optical and behavioral). The procedures described here, from initial virus preparation to systems-level functional readout, can be completed within 4-5 weeks. Together, these methods may help in providing circuit-level insight into the dynamics underlying complex mammalian behaviors in health and disease.

    View details for DOI 10.1038/nprot.2009.226

    View details for Web of Science ID 000275234900006

    View details for PubMedID 20203662

  • Optogenetic deconstruction of sleep-wake circuitry in the brain. Frontiers in molecular neuroscience Adamantidis, A., Carter, M. C., de Lecea, L. 2010; 2: 31-?


    How does the brain regulate the sleep-wake cycle? What are the temporal codes of sleep and wake-promoting neural circuits? How do these circuits interact with each other across the light/dark cycle? Over the past few decades, many studies from a variety of disciplines have made substantial progress in answering these fundamental questions. For example, neurobiologists have identified multiple, redundant wake-promoting circuits in the brainstem, hypothalamus, and basal forebrain. Sleep-promoting circuits have been found in the preoptic area and hypothalamus. One of the greatest challenges in recent years has been to selectively record and manipulate these sleep-wake centers in vivo with high spatial and temporal resolution. Recent developments in microbial opsin-based neuromodulation tools, collectively referred to as "optogenetics," have provided a novel method to demonstrate causal links between neural activity and specific behaviors. Here, we propose to use optogenetics as a fundamental tool to probe the necessity, sufficiency, and connectivity of defined neural circuits in the regulation of sleep and wakefulness.

    View details for DOI 10.3389/neuro.02.031.2009

    View details for PubMedID 20126433

    View details for PubMedCentralID PMC2814554

  • A role for Melanin-Concentrating Hormone in learning and memory PEPTIDES Adamantidis, A., de Lecea, L. 2009; 30 (11): 2066-2070


    The neurobiological substrate of learning process and persistent memory storage involves multiple brain areas. The neocortex and hippocampal formation are known as processing and storage sites for explicit memory, whereas the striatum, amygdala, neocortex and cerebellum support implicit memory. Synaptic plasticity, long-term changes in synaptic transmission efficacy and transient recruitment of intracellular signaling pathways in these brain areas have been proposed as possible mechanisms underlying short- and long-term memory retention. In addition to the classical neurotransmitters (glutamate, GABA), experimental evidence supports a role for neuropeptides in modulating memory processes. This review focuses on the role of the Melanin-Concentrating Hormone (MCH) and receptors on memory formation in animal studies. Possible mechanisms may involve direct MCH modulation of neural circuit activity that support memory storage and cognitive functions, as well as indirect effect on arousal.

    View details for DOI 10.1016/j.peptides.2009.06.024

    View details for Web of Science ID 000271733100017

    View details for PubMedID 19576257

  • Sleep Homeostasis Modulates Hypocretin-Mediated Sleep-to-Wake Transitions JOURNAL OF NEUROSCIENCE Carter, M. E., Adamantidis, A., Ohtsu, H., Deisseroth, K., de Lecea, L. 2009; 29 (35): 10939-10949


    The hypocretins (Hcrts) (also called orexins) are two neuropeptides expressed in the lateral hypothalamus that play a crucial role in the stability of wakefulness. Previously, our laboratory demonstrated that in vivo photostimulation of Hcrt neurons genetically targeted with ChR2, a light-activated cation channel, was sufficient to increase the probability of an awakening event during both slow-wave sleep and rapid eye movement sleep. In the current study, we ask whether Hcrt-mediated sleep-to-wake transitions are affected by light/dark period and sleep pressure. We found that stimulation of Hcrt neurons increased the probability of an awakening event throughout the entire light/dark period but that this effect was diminished with sleep pressure induced by 2 or 4 h of sleep deprivation. Interestingly, photostimulation of Hcrt neurons was still sufficient to increase activity assessed by c-Fos expression in Hcrt neurons after sleep deprivation, although this stimulation did not cause an increase in transitions to wakefulness. In addition, we found that photostimulation of Hcrt neurons increases neural activity assessed by c-Fos expression in the downstream arousal-promoting locus ceruleus and tuberomammilary nucleus but not after 2 h of sleep deprivation. Finally, stimulation of Hcrt neurons was still sufficient to increase the probability of an awakening event in histidine decarboxylase-deficient knock-out animals. Collectively, these results suggest that the Hcrt system promotes wakefulness throughout the light/dark period by activating multiple downstream targets, which themselves are inhibited with increased sleep pressure.

    View details for DOI 10.1523/JNEUROSCI.1205-09.2009

    View details for Web of Science ID 000269518500018

    View details for PubMedID 19726652

  • The Hypocretins and their Role in Narcolepsy CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS Kroeger, D., de Lecea, L. 2009; 8 (4): 271-280


    A series of discoveries spanning the last decade have uncovered a new neurotransmitter - hypocretin - and its role in energy metabolism, arousal, and addiction. Also, notably, a lack of hypocretin function has been unequivocally associated with the sleep disorder narcolepsy. Here we review these findings and discuss how they will influence future treatments of narcolepsy and other arousal and hyperarousal disorders. We introduce the concept of the hypocretin peptides and receptors and discuss the neuroanatomy and neurophysiology of the hypocretin system. A gain of function through pharmacolological and optogenetic means is also addressed in the following text, as is the loss of function: specifically narcolepsy in dogs, mice and humans and the challenges currently faced in treatment.

    View details for Web of Science ID 000271343800006

    View details for PubMedID 19689309

  • Neuropeptide S Reinstates Cocaine-Seeking Behavior and Increases Locomotor Activity through Corticotropin-Releasing Factor Receptor 1 in Mice JOURNAL OF NEUROSCIENCE Paneda, C., Huitron-Resendiz, S., Frago, L. M., Chowen, J. A., Picetti, R., de Lecea, L., Roberts, A. J. 2009; 29 (13): 4155-4161


    Neuropeptide S (NPS) is a recently discovered neuropeptide that increases arousal and wakefulness while decreasing anxiety-like behavior. Here, we used a self-administration paradigm to demonstrate that intracerebroventricular infusion of NPS reinstates extinguished cocaine-seeking behavior in a dose-dependent manner in mice. The highest dose of NPS (0.45 nM) increased active lever pressing in the absence of cocaine to levels that were equivalent to those observed during self-administration. In addition, we examined the role of the corticotropin-releasing factor receptor 1 (CRF(1)) in this behavior as well as locomotor stimulation and anxiolysis. CRF(1) knock-out mice did not respond to either the locomotor stimulant or cocaine reinstatement effects of NPS, but still responded to its anxiolytic effect. The CRF(1) antagonist antalarmin also blocked the increase in active lever responding in the reinstatement model and the locomotor activating properties of NPS without affecting its anxiolytic actions. Our results suggest that NPS receptors may be an important target for drug abuse research and treatment and that CRF(1) mediates the cocaine-seeking and locomotor stimulant effects of NPS, but not its effects on anxiety-like behavior.

    View details for DOI 10.1523/JNEUROSCI.5256-08.2009

    View details for Web of Science ID 000264767500019

    View details for PubMedID 19339610

  • The brain hypocretins and their receptors: mediators of allostatic arousal CURRENT OPINION IN PHARMACOLOGY Carter, M. E., Borg, J. S., de Lecea, L. 2009; 9 (1): 39-45


    The hypocretins (abbreviated 'Hcrts' - also called 'orexins') are two neuropeptides secreted exclusively by a small population of neurons in the lateral hypothalamus. These peptides bind to two receptors located throughout the brain in nuclei associated with diverse cognitive and physiological functions. Initially, the brain Hcrt system was found to have a major role in the regulation of sleep/wake transitions. More recent studies indicate Hcrts may play a role in other physiological functions, including food intake, addiction, and stress. Taken together, these studies suggest a general role for Hcrts in mediating arousal, especially when an organism must respond to unexpected stressors and challenges in the environment.

    View details for DOI 10.1016/j.coph.2008.12.018

    View details for Web of Science ID 000263817700007

    View details for PubMedID 19185540

  • The hypocretins as sensors for metabolism and arousal JOURNAL OF PHYSIOLOGY-LONDON Adamantidis, A., de Lecea, L. 2009; 587 (1): 33-40


    Sleep disturbances are associated with hormonal imbalances and may result in metabolic disorders including obesity and diabetes. Therefore, circuits controlling both sleep and metabolism are likely to play a role in these physiopathological conditions. The hypocretin (Hcrt) system is a strong candidate for mediating both sleep and metabolic imbalances because Hcrt neurons are sensitive to metabolic hormones, including leptin and ghrelin, and modulate arousal and goal-orientated behaviours. This review discusses the role of Hcrt neurons as a sensors of energy balance and arousal and proposes new ways of probing local hypothalamic circuits regulating sleep and metabolism with unprecedented cellular specificity and temporal resolution.

    View details for DOI 10.1113/jphysiol.2008.164400

    View details for Web of Science ID 000262151800012

    View details for PubMedID 19047201

    View details for PubMedCentralID PMC2670020

  • Sleep and metabolism: shared circuits, new connections TRENDS IN ENDOCRINOLOGY AND METABOLISM Adamantidis, A., de Lecea, L. 2008; 19 (10): 362-370


    Association between sleep disturbances and hormonal imbalances can result in metabolic disorders, including obesity and diabetes. The hypothalamus is likely to play a part in these pathophysiological conditions because it contains sleep-wake circuits that are sensitive to metabolic hormones, including leptin and ghrelin. Thus, shared hypothalamic circuits such as the hypocretin and melanin-concentrating hormone systems are strong candidates for mediating both sleep and metabolic imbalances. This review reveals new roles for these systems as sensors and effectors of sleep and wakefulness, and discusses their plasticity in regulating sleep and energy balance. New optical tools that remotely control neuronal circuit activity provide an effective means to understand the cooperativity of shared circuits in regulating hypothalamic functions such as sleep and metabolism.

    View details for DOI 10.1016/j.tem.2008.08.007

    View details for Web of Science ID 000261477600003

    View details for PubMedID 18938086

  • Optogenetic probing of hypocretin neuronal network 19th Congress of the European-Sleep-Research-Society Adamantidis, A. R., Zhang, F., Aravanis, A., Deisseroth, K., De Lecea, L. WILEY-BLACKWELL. 2008: 88–88
  • Effect of cortistatin on tau phosphorylation at Ser262 site JOURNAL OF NEUROSCIENCE RESEARCH Rubio, A., Perez, M., de Lecea, L., Avila, J. 2008; 86 (11): 2462-2475


    The development of intraneuronal lesions as a result of the progressive deposition of hyperphosphorylated tau at specific brain regions (such as hippocampus and cortex) plays a key role in the pathological process of Alzheimer's disease. However, the mechanisms by which tau phosphorylation is regulated, mainly in the pathology found in the cortex, are still poorly understood. Here, we analyzed the effect of cortistatin, a cortical neuropeptide related to somatostatin, on tau phosphorylation at Ser262 in cultures of murine cortical neurons. Both somatostatin and cortistatin induce tau phosphorylation at Ser262, a site modified in Alzheimer's disease, although with different kinetics in cortex. The effect of cortistatin likely is mediated by heterodimeric receptors composed of somatostatin receptor subtypes 2 and 4 and also by protein kinase C signaling. Cortistatin-deficient mice show decreased tau phosphorylation at Ser262 in the cortex but not in other brain regions tested. Our results suggest an important role for cortistatin in the regulation of tau phosphorylation that may be associated with the pathophysiology of Alzheimer's disease in regions such as the cerebral cortex.

    View details for DOI 10.1002/jnr.21689

    View details for Web of Science ID 000258478100011

    View details for PubMedID 18438934

  • Somatostatin, cortistatin and their receptors in health and disease. Foreword. Molecular and cellular endocrinology Castaño, J. P., Ghigo, E., Kineman, R. D., de Lecea, L., Malagón, M. M., Vaudry, H. 2008; 286 (1-2): 1-2

    View details for DOI 10.1016/j.mce.2008.03.010

    View details for PubMedID 18456395

  • Cortistatin - Functions in the central nervous system MOLECULAR AND CELLULAR ENDOCRINOLOGY de Lecea, L. 2008; 286 (1-2): 88-95


    Cortistatin (CST) is a neuropeptide from the somatostatin (SRIF)/urotensin (UII) family named after its predominantly cortical expression and ability to depress cortical activity, which was discovered a decade ago. In vitro assays show CST is able to bind all five cloned somatostatin receptors and shares many pharmacological and functional properties with SRIF. However, distinct from SRIF, CST has been shown to induce slow-wave sleep, reduce locomotor activity, and activate cation selective currents not responsive to somatostatin. Different lines of evidence also indicate that CST, like SRIF, is involved in learning and memory processes. CST-14 may also function as an endogenous anti-convulsant. In addition to its role in cortical synchronization, CST-14 has emerged as an important mediator of immunity and inflammation. This review will cover some of the basic properties of CST in the brain, and will discuss new data on the role of CST in cortical activity.

    View details for DOI 10.1016/j.mce.2007.12.014

    View details for Web of Science ID 000257024900013

    View details for PubMedID 18374474

  • Neuropeptide interactions and REM sleep: A role for Urotensin II? 1st Meeting of the Japan Branch of the International-Neuropeptide-Society de Lecea, L., Bourgin, P. ELSEVIER SCIENCE INC. 2008: 845–51


    Urotensin II (UII) is a peptide with structural similarity to the somatostatin family with potent vasoconstrictor activity. UII receptor is expressed broadly in the periphery, and most notably in the heart and microvessels. In the brain, the UII receptor can be detected in the spinal cord and in cholinergic nuclei in the brainstem known to be involved in REM sleep regulation. Recent data suggest that, in addition to their vasoactive properties, UII receptor ligands may have excitatory activity on a selective group of neurons that modulate REM sleep. This review focuses on the implications of these findings for the neurobiology of REM sleep regulation and discusses the possible impact of UII and other neuropeptides on the balance of the alternation between sleep states.

    View details for DOI 10.1016/j.peptides.2008.02.009

    View details for Web of Science ID 000256007400025

    View details for PubMedID 18406008

  • Physiological arousal: a role for hypothalamic systems CELLULAR AND MOLECULAR LIFE SCIENCES Adamantidis, A., de Lecea, L. 2008; 65 (10): 1475-1488


    The lateral hypothalamus (LH) has long been known as a homeostasis center of the brain that modulates feeding behavior, arousal and reward. The hypocretins (Hcrts, also called orexins) and melanin-concentrating hormone (MCH) are neuropeptides produced in two intermingled populations of a few thousand neurons in the LH. The Hcrts have a prominent role in regulating the stability of arousal, since Hcrt system deficiency leads to narcolepsy. MCH is an important modulator of energy balance, as MCH system deficiency in mice leads to leanness and increased metabolism. Recently, MCH has been proposed to modulate rapid eye movement sleep in rodents. In this review, we propose a working model of the cross-talk between Hcrt and MCH circuits that may provide an arousal balance system to regulate complex goal-oriented behaviors.

    View details for DOI 10.1007/s00018-008-7521-8

    View details for Web of Science ID 000256252500003

    View details for PubMedID 18351292

  • Somatostatin receptor subtype 4 couples to the m-current to regulate seizures JOURNAL OF NEUROSCIENCE Qiu, C., Zeyda, T., Johnson, B., Hochgeschwender, U., de Lecea, L., Tallent, M. K. 2008; 28 (14): 3567-3576


    The K(+) M-current (I(M), Kv7) is an important regulator of cortical excitability, and mutations in these channels cause a seizure disorder in humans. The neuropeptide somatostatin (SST), which has antiepileptic properties, augments I(M) in hippocampal CA1 pyramidal neurons. We used SST receptor knock-out mice and subtype-selective ligands to investigate the receptor subtype that couples to I(M) and mediates the antiepileptic effects of SST. Using pentylenetetrazole as a chemoconvulsant, SST(2), SST(3), and SST(4) receptor knock-out mice all had shorter latencies to different seizure stages and increased seizure severity when compared with wild-type mice. However, the most robust differences were observed in the SST(4) knock-outs. When seizures were induced by systemic injection of kainate, only SST(4) knock-outs showed an increase in seizure sensitivity. We next examined the action of SST and subtype-selective SST agonists on electrophysiological parameters in hippocampal slices of wild-type and receptor knock-out mice. SST(2) and SST(4) appear to mediate the majority of SST inhibition of epileptiform activity in CA1. SST lacked presynaptic effects in mouse CA1, in contrast to our previous findings in rat. SST increased I(M) in CA1 pyramidal neurons of wild-type and SST(2) knock-out mice, but not SST(4) knock-out mice. Using M-channel blockers, we found that SST(4) coupling to M-channels is critical to its inhibition of epileptiform activity. This is the first demonstration of an endogenous enhancer of I(M) that is important in controlling seizure activity. SST(4) receptors could therefore be an important novel target for developing new antiepileptic and antiepileptogenic drugs.

    View details for DOI 10.1523/JNEUROSCI.4679-07.2008

    View details for Web of Science ID 000254623500006

    View details for PubMedID 18385315