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Bjorness TE, Greene RW. Orexin-mediated motivated arousal and reward seeking. Peptides 2024; 180:171280. [PMID: 39159833 DOI: 10.1016/j.peptides.2024.171280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2024] [Revised: 08/03/2024] [Accepted: 08/05/2024] [Indexed: 08/21/2024]
Abstract
The neuromodulator orexin has been identified as a key factor for motivated arousal including recent evidence that sleep deprivation-induced enhancement of reward behavior is modulated by orexin. While orexin is not necessary for either reward or arousal behavior, orexin neurons' broad projections, ability to sense the internal state of the animal, and high plasticity of signaling in response to natural rewards and drugs of abuse may underlie heightened drug seeking, particularly in a subset of highly motivated reward seekers. As such, orexin receptor antagonists have gained deserved attention for putative use in addiction treatments. Ongoing and future clinical trials are expected to identify individuals most likely to benefit from orexin receptor antagonist treatment to promote abstinence, such as those with concurrent sleep disorders or high craving, while attention to methodological considerations will aid interpretation of the numerous preclinical studies investigating disparate aspects of the role of orexin in reward and arousal.
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Affiliation(s)
- Theresa E Bjorness
- Research Service, VA North Texas Health Care System, Dallas, TX 75126, USA; Departments of Psychiatry University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
| | - Robert W Greene
- Departments of Psychiatry University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba 305-8577, Japan
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2
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Mohammadkhani A, Qiao M, Borgland SL. Distinct Neuromodulatory Effects of Endogenous Orexin and Dynorphin Corelease on Projection-Defined Ventral Tegmental Dopamine Neurons. J Neurosci 2024; 44:e0682242024. [PMID: 39187377 PMCID: PMC11426376 DOI: 10.1523/jneurosci.0682-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 08/11/2024] [Accepted: 08/16/2024] [Indexed: 08/28/2024] Open
Abstract
Dopamine (DA) neurons in the ventral tegmental area (VTA) respond to motivationally relevant cues, and circuit-specific signaling drives different aspects of motivated behavior. Orexin (ox; also known as hypocretin) and dynorphin (dyn) are coexpressed lateral hypothalamic (LH) neuropeptides that project to the VTA. These peptides have opposing effects on the firing activity of VTADA neurons via orexin 1 (Ox1R) or kappa opioid (KOR) receptors. Given that Ox1R activation increases VTADA firing, and KOR decreases firing, it is unclear how the coreleased peptides contribute to the net activity of DA neurons. We tested if optical stimulation of LHox/dyn neuromodulates VTADA neuronal activity via peptide release and if the effects of optically driven LHox/dyn release segregate based on VTADA projection targets including the basolateral amygdala (BLA) or the lateral or medial shell of the nucleus accumbens (lAcbSh, mAchSh). Using a combination of circuit tracing, optogenetics, and patch-clamp electrophysiology in male and female orexincre mice, we showed a diverse response of LHox/dyn optical stimulation on VTADA neuronal firing, which is not mediated by fast transmitter release and is blocked by antagonists to KOR and Ox1R signaling. Additionally, where optical stimulation of LHox/dyn inputs in the VTA inhibited firing of the majority of BLA-projecting VTADA neurons, optical stimulation of LHox/dyn inputs in the VTA bidirectionally affects firing of either lAcbSh- or mAchSh-projecting VTADA neurons. These findings indicate that LHox/dyn corelease may influence the output of the VTA by balancing ensembles of neurons within each population which contribute to different aspects of reward seeking.
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Affiliation(s)
- Aida Mohammadkhani
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Min Qiao
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Stephanie L Borgland
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, AB T2N 4N1, Canada
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Marinescu AM, Labouesse MA. The nucleus accumbens shell: a neural hub at the interface of homeostatic and hedonic feeding. Front Neurosci 2024; 18:1437210. [PMID: 39139500 PMCID: PMC11319282 DOI: 10.3389/fnins.2024.1437210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 07/16/2024] [Indexed: 08/15/2024] Open
Abstract
Feeding behavior is a complex physiological process regulated by the interplay between homeostatic and hedonic feeding circuits. Among the neural structures involved, the nucleus accumbens (NAc) has emerged as a pivotal region at the interface of these two circuits. The NAc comprises distinct subregions and in this review, we focus mainly on the NAc shell (NAcSh). Homeostatic feeding circuits, primarily found in the hypothalamus, ensure the organism's balance in energy and nutrient requirements. These circuits monitor peripheral signals, such as insulin, leptin, and ghrelin, and modulate satiety and hunger states. The NAcSh receives input from these homeostatic circuits, integrating information regarding the organism's metabolic needs. Conversely, so-called hedonic feeding circuits involve all other non-hunger and -satiety processes, i.e., the sensory information, associative learning, reward, motivation and pleasure associated with food consumption. The NAcSh is interconnected with hedonics-related structures like the ventral tegmental area and prefrontal cortex and plays a key role in encoding hedonic information related to palatable food seeking or consumption. In sum, the NAcSh acts as a crucial hub in feeding behavior, integrating signals from both homeostatic and hedonic circuits, to facilitate behavioral output via its downstream projections. Moreover, the NAcSh's involvement extends beyond simple integration, as it directly impacts actions related to food consumption. In this review, we first focus on delineating the inputs targeting the NAcSh; we then present NAcSh output projections to downstream structures. Finally we discuss how the NAcSh regulates feeding behavior and can be seen as a neural hub integrating homeostatic and hedonic feeding signals, via a functionally diverse set of projection neuron subpopulations.
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Affiliation(s)
- Alina-Măriuca Marinescu
- Brain, Wire and Behavior Group, Translational Nutritional Biology Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Marie A. Labouesse
- Brain, Wire and Behavior Group, Translational Nutritional Biology Laboratory, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich, ETH Zurich, Zurich, Switzerland
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4
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Stanyer EC, Hoffmann J, Holland PR. Orexins and primary headaches: an overview of the neurobiology and clinical impact. Expert Rev Neurother 2024; 24:487-496. [PMID: 38517280 PMCID: PMC11034548 DOI: 10.1080/14737175.2024.2328728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/19/2024] [Indexed: 03/23/2024]
Abstract
INTRODUCTION Primary headaches, including migraines and cluster headaches, are highly prevalent disorders that significantly impact quality of life. Several factors suggest a key role for the hypothalamus, including neuroimaging studies, attack periodicity, and the presence of altered homeostatic regulation. The orexins are two neuropeptides synthesized almost exclusively in the lateral hypothalamus with widespread projections across the central nervous system. They are involved in an array of functions including homeostatic regulation and nociception, suggesting a potential role in primary headaches. AREAS COVERED This review summarizes current knowledge of the neurobiology of orexins, their involvement in sleep-wake regulation, nociception, and functions relevant to the associated symptomology of headache disorders. Preclinical reports of the antinociceptive effects of orexin-A in preclinical models are discussed, as well as clinical evidence for the potential involvement of the orexinergic system in headache. EXPERT OPINION Several lines of evidence support the targeted modulation of orexinergic signaling in primary headaches. Critically, orexins A and B, acting differentially via the orexin 1 and 2 receptors, respectively, demonstrate differential effects on trigeminal pain processing, indicating why dual-receptor antagonists failed to show clinical efficacy. The authors propose that orexin 1 receptor agonists or positive allosteric modulators should be the focus of future research.
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Affiliation(s)
- Emily C. Stanyer
- Headache Group, Wolfson Sensory, Pain and Regeneration Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
- Sir Jules Thorne Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Jan Hoffmann
- Headache Group, Wolfson Sensory, Pain and Regeneration Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
| | - Philip R. Holland
- Headache Group, Wolfson Sensory, Pain and Regeneration Centre, Institute of Psychiatry, Psychology & Neuroscience, King’s College London, London, UK
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Li HT, Viskaitis P, Bracey E, Peleg-Raibstein D, Burdakov D. Transient targeting of hypothalamic orexin neurons alleviates seizures in a mouse model of epilepsy. Nat Commun 2024; 15:1249. [PMID: 38341419 PMCID: PMC10858876 DOI: 10.1038/s41467-024-45515-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 01/24/2024] [Indexed: 02/12/2024] Open
Abstract
Lateral hypothalamic (LH) hypocretin/orexin neurons (HONs) control brain-wide electrical excitation. Abnormally high excitation produces epileptic seizures, which affect millions of people and need better treatments. HON population activity spikes from minute to minute, but the role of this in seizures is unknown. Here, we describe correlative and causal links between HON activity spikes and seizures. Applying temporally-targeted HON recordings and optogenetic silencing to a male mouse model of acute epilepsy, we found that pre-seizure HON activity predicts and controls the electrophysiology and behavioral pathology of subsequent seizures. No such links were detected for HON activity during seizures. Having thus defined the time window where HONs influence seizures, we targeted it with LH deep brain stimulation (DBS), which inhibited HON population activity, and produced seizure protection. Collectively, these results uncover a feature of brain activity linked to seizures, and demonstrate a proof-of-concept treatment that controls this feature and alleviates epilepsy.
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Affiliation(s)
- Han-Tao Li
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology | ETH Zurich, 8603, Schwerzenbach, Switzerland
- Section of Epilepsy, Department of Neurology, Chang Gung Memorial Hospital at Linkou Medical Center and Chang Gung University College of Medicine, 333, Taoyuan, Taiwan
| | - Paulius Viskaitis
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology | ETH Zurich, 8603, Schwerzenbach, Switzerland
| | - Eva Bracey
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology | ETH Zurich, 8603, Schwerzenbach, Switzerland
| | - Daria Peleg-Raibstein
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology | ETH Zurich, 8603, Schwerzenbach, Switzerland
| | - Denis Burdakov
- Department of Health Sciences and Technology, Swiss Federal Institute of Technology | ETH Zurich, 8603, Schwerzenbach, Switzerland.
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Diepenbroek C, Rijnsburger M, van Irsen AAS, Eggels L, Kisner A, Foppen E, Unmehopa UA, Berland C, Dólleman S, Hardonk M, Cruciani-Guglielmacci C, Faust RP, Wenning R, Maya-Monteiro CM, Kalsbeek A, Aponte Y, Luquet S, Serlie MJM, la Fleur SE. Dopamine in the nucleus accumbens shell controls systemic glucose metabolism via the lateral hypothalamus and hepatic vagal innervation in rodents. Metabolism 2024; 150:155696. [PMID: 37804881 DOI: 10.1016/j.metabol.2023.155696] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/06/2023] [Accepted: 10/04/2023] [Indexed: 10/09/2023]
Abstract
BACKGROUND Growing evidence demonstrates the role of the striatal dopamine system in the regulation of glucose metabolism. Treatment with dopamine antagonists is associated with insulin resistance and hyperglycemia, while dopamine agonists are used in treatment of type 2 diabetes. The mechanism underlying striatal dopamine effects in glucose metabolism, however is not fully understood. Here, we provide mechanistic insights into the role of nucleus accumbens shell (sNAc) dopaminergic signaling in systemic glucose metabolism. METHODS Endogenous glucose production (EGP), blood glucose and mRNA expression in the lateral hypothalamic area (LHA) in male Wistar rats were measured following infusion of vanoxerine (VNX, dopamine reuptake inhibitor) in the sNAc. Thereafter, we analyzed projections from sNAc Drd1-expressing neurons to LHA using D1-Cre male Long-Evans rats, Cre-dependent viral tracers and fluorescence immunohistochemistry. Brain slice electrophysiology in adult mice was used to study spontaneous excitatory postsynaptic currents of sNAc Drd1-expressing neurons following VNX application. Finally, we assessed whether GABAergic LHA activity and hepatic vagal innervation were required for the effect of sNAc-VNX on glucose metabolism by combining infusion of sNAc-VNX with LHA-bicuculline, performing vagal recordings and combining infusion of sNAc-VNX with hepatic vagal denervation. RESULTS VNX infusion in the sNAc strongly decreased endogenous glucose production, prevented glucose increases over time, reduced Slc17A6 and Hcrt mRNA in LHA, and increased vagal activity. Furthermore, sNAc Drd1-expressing neurons increased spontaneous firing following VNX application, and viral tracing of sNAc Drd1-expressing neurons revealed direct projections to LHA with on average 67 % of orexin cells directly targeted by sNAc Drd1-expressing neurons. Importantly, the sNAc-VNX-induced effect on glucose metabolism was dependent on GABAergic signaling in the LHA and on intact hepatic vagal innervation. CONCLUSIONS We show that sNAc dopaminergic signaling modulates hepatic glucose metabolism through GABAergic inputs to glutamatergic LHA cells and hepatic vagal innervation. This demonstrates that striatal control of glucose metabolism involves a dopaminergic sNAc-LHA-liver axis and provides a potential explanation for the effects of dopamine agonists and antagonists on glucose metabolism.
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Affiliation(s)
- Charlene Diepenbroek
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Neuroscience, Cellular and Molecular Mechanisms, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Merel Rijnsburger
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Neuroscience, Cellular and Molecular Mechanisms, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Astrid A S van Irsen
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Neuroscience, Cellular and Molecular Mechanisms, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Leslie Eggels
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Alexandre Kisner
- National Institute on Drug Abuse, Intramural Research Program, Neuronal Circuits and Behavior Unit, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Ewout Foppen
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands
| | - Unga A Unmehopa
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | - Chloé Berland
- Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Sophie Dólleman
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | - Marene Hardonk
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | | | - Rudolf P Faust
- Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands; Department of Psychiatry, Amsterdam UMC, UvA, Amsterdam Neuroscience, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
| | - Rick Wenning
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands
| | - Clarissa M Maya-Monteiro
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Laboratory of Immunopharmacology, Oswaldo Cruz Institute (IOC), Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, Brazil
| | - Andries Kalsbeek
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Neuroscience, Cellular and Molecular Mechanisms, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology and Metabolism, Meibergdreef 9, Amsterdam, the Netherlands
| | - Yeka Aponte
- National Institute on Drug Abuse, Intramural Research Program, Neuronal Circuits and Behavior Unit, National Institutes of Health, Biomedical Research Center, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Serge Luquet
- Université Paris Cité, BFA, UMR 8251, CNRS, F-75013 Paris, France
| | - Mireille J M Serlie
- Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Amsterdam UMC, University of Amsterdam, Department of Endocrinology and Metabolism, Meibergdreef 9, Amsterdam, the Netherlands; Department of Endocrinology, Yale School of Medicine, New Haven, USA
| | - Susanne E la Fleur
- Amsterdam UMC, University of Amsterdam, Laboratory of Endocrinology, Department of Laboratory Medicine, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Neuroscience, Cellular and Molecular Mechanisms, Amsterdam, the Netherlands; Amsterdam Gastroenterology Endocrinology Metabolism, Endocrinology, Metabolism and Nutrition, Amsterdam, the Netherlands; Netherlands Institute for Neuroscience (NIN), an Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Meibergdreef 47, 1105 BA Amsterdam, the Netherlands.
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7
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Martianova E, Sadretdinova R, Pageau A, Pausic N, Gentiletti TD, Leblanc D, Rivera AM, Labonté B, Proulx CD. Hypothalamic neuronal outputs transmit sensorimotor signals at the onset of locomotor initiation. iScience 2023; 26:108328. [PMID: 38026162 PMCID: PMC10665817 DOI: 10.1016/j.isci.2023.108328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 09/27/2023] [Accepted: 10/20/2023] [Indexed: 12/01/2023] Open
Abstract
The lateral hypothalamus (LH) plays a critical role in sensory integration to organize behavior responses. However, how projection-defined LH neuronal outputs dynamically transmit sensorimotor signals to major downstream targets to organize behavior is unknown. Here, using multi-fiber photometry, we show that three major LH neuronal outputs projecting to the dorsal raphe nucleus (DRN), ventral tegmental area (VTA), and lateral habenula (LHb) exhibit significant coherent activity in mice engaging sensory-evoked or self-initiated motor responses. Increased activity at LH axon terminals precedes movement initiation during active coping responses and the activity of serotonin neurons and dopamine neurons. The optogenetic activation of LH axon terminals in either of the DRN, VTA, or LHb was sufficient to increase motor initiation but had different effects on passive avoidance and sucrose consumption. Our findings support the complementary role of three projection-defined LH neuronal outputs in the transmission of sensorimotor signals to major downstream regions at movement onset.
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Affiliation(s)
- Ekaterina Martianova
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Renata Sadretdinova
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Alicia Pageau
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Nikola Pausic
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Tommy Doucet Gentiletti
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Danahé Leblanc
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Arturo Marroquin Rivera
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Benoît Labonté
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
| | - Christophe D. Proulx
- CERVO Brain Research Center, Department of Psychiatry and Neurosciences, Université Laval, Québec, QC, Canada
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8
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Qi M, Fadool DA, Storace DA. An anatomically distinct subpopulation of orexin neurons project from the lateral hypothalamus to the olfactory bulb. J Comp Neurol 2023; 531:1510-1524. [PMID: 37434469 PMCID: PMC10758201 DOI: 10.1002/cne.25518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 05/15/2023] [Accepted: 05/19/2023] [Indexed: 07/13/2023]
Abstract
Olfactory cues play a key role in natural behaviors such as finding food, finding mates, and avoiding predators. In principle, the ability of the olfactory system to carry out these perceptual functions would be facilitated by signaling related to an organism's physiological state. One candidate pathway includes a direct projection from the hypothalamus to the main olfactory bulb, the first stage of olfactory sensory processing. The pathway from the hypothalamus to the main olfactory bulb is thought to include neurons that express the neuropeptide orexin, although the proportion that is orexinergic remains unknown. A current model proposes that the orexin population is heterogeneous, yet it remains unknown whether the proportion that innervates the main olfactory bulb reflects a distinct subpopulation of the orexin population. Herein, we carried out combined retrograde tract tracing with immunohistochemistry for orexin-A in the mouse to define the proportion of hypothalamic input to the main olfactory bulb that is orexinergic and to determine what fraction of the orexin-A population innervates the bulb. The numbers and spatial positions of all retrogradely labeled neurons and all the orexin-A-expressing neurons were quantified in sequential sections through the hypothalamus. Retrogradely labeled neurons were found in the ipsilateral hypothalamus, of which 22% expressed orexin-A. The retrogradely labeled neurons that did and did not express orexin-A could be anatomically distinguished based on their spatial position and cell body area. Remarkably, only 7% of all the orexin-A neurons were retrogradely labeled, suggesting that only a small fraction of the orexin-A population directly innervate the main olfactory bulb. These neurons spatially overlapped with the orexin-A neurons that did not innervate the bulb, although the two cell populations were differentiated based on cell body area. Overall, these results support a model in which olfactory sensory processing is influenced by orexinergic feedback at the first synapse in the olfactory processing pathway.
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Affiliation(s)
- Meizhu Qi
- Department of Biological Science, Florida State University, Tallahassee, FL
- Program in Neuroscience, Florida State University, Tallahassee, FL
| | - Debra Ann Fadool
- Department of Biological Science, Florida State University, Tallahassee, FL
- Program in Neuroscience, Florida State University, Tallahassee, FL
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL
| | - Douglas A. Storace
- Department of Biological Science, Florida State University, Tallahassee, FL
- Program in Neuroscience, Florida State University, Tallahassee, FL
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL
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9
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Miao HT, Song RX, Xin Y, Wang LY, Lv JM, Liu NN, Wu ZY, Zhang W, Li Y, Zhang DX, Zhang LM. Spautin-1 Protects Against Mild TBI-Induced Anxiety-Like Behavior in Mice via Immunologically Silent Apoptosis. Neuromolecular Med 2023; 25:336-349. [PMID: 36745326 DOI: 10.1007/s12017-023-08737-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Accepted: 01/19/2023] [Indexed: 02/07/2023]
Abstract
Anxiety is reportedly one of the most common mental changes after traumatic brain injury (TBI). Perineuronal nets (PNNs) produced by astrocytes in the lateral hypothalamus (LHA) that surround gamma-aminobutyric acid-ergic (GABAergic) neurons have been associated with anxiety. The potent anti-tumor effects of Spautin-1, a novel autophagy inhibitor, have been documented in malignant melanoma; moreover, the inhibition of autophagy is reported to mitigate anxiety disorders. However, little is known about the ability of spautin-1 to alleviate anxiety. In this study, we sought to investigate whether spautin-1 could alleviate anxiety-like behaviors post-TBI by reducing the loss of PNNs in the LHA. A mild TBI was established in mice through Feeney's weight-drop model. Then, Spautin-1 (20 mmol/2 μl) was immediately administered into the left lateral ventricle. Behavioral and pathological changes were assessed at 24 h, 7 days, 30 days, 31 days and 32 days after TBI by the neurological severity scores (NSS), open field test (OFT), elevated plus-maze (EPM) test, western blot, immunofluorescence assays and electron microscopy. Spautin-1 significantly reversed TBI-induced decreased time in the central zone during OFT and in the open-arm during the EPM test. Spautin-1 also increased PNNs around GABAergic neurons indicated by WFA- plus GAD2- positive A2-type astrocytes and attenuated M1-type microglia in the LHA 32 days after TBI compared to TBI alone. Moreover, compared to mice that only underwent TBI, spautin-1 downregulated autophagic vacuoles, abnormal organelles, the expression of Beclin 1, USP13, phospho-TBK1, and phospho-IRF3 and upregulated the levels of cleaved caspase-3, -7 and -9, but failed to increase TUNEL-positive cells in the LHA at 24 h. Spautin-1 alleviated anxiety-like behavior in mice exposed to mild TBI; this protective mechanism may be associated with decreased PNNs loss around GABAergic neurons via immunologically silent apoptosis induced by the caspase cascade.
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Affiliation(s)
- Hui-Tao Miao
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Rong-Xin Song
- Department of Anesthesiology, Cangzhou Central Hospital, Hebei Medical University, Cangzhou, China
| | - Yue Xin
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Lu-Ying Wang
- Department of Anesthesia and Trauma Research, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Jin-Meng Lv
- Department of Anesthesia and Trauma Research, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China
| | - Na-Na Liu
- Department of Pediatric, Cangzhou Central Hospital, Cangzhou, China
| | - Zhi-You Wu
- Department of Neurosurgery, Cangzhou Central Hospital, Hebei Medical University, Cangzhou, China
| | - Wei Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yan Li
- Department of Anesthesiology, Cangzhou Central Hospital, Hebei Medical University, Cangzhou, China
| | - Dong-Xue Zhang
- Department of Gerontology, Cangzhou Central Hospital, Cangzhou, China
| | - Li-Min Zhang
- Department of Anesthesiology, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, China.
- Hebei Key Laboratory of Integrated Traditional and Western Medicine in Osteoarthrosis Research (Preparing), Cangzhou, China.
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10
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Rossi MA. Control of energy homeostasis by the lateral hypothalamic area. Trends Neurosci 2023; 46:738-749. [PMID: 37353461 PMCID: PMC10524917 DOI: 10.1016/j.tins.2023.05.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 05/12/2023] [Accepted: 05/23/2023] [Indexed: 06/25/2023]
Abstract
The lateral hypothalamic area (LHA) is a subcortical brain region that exerts control over motivated behavior, feeding, and energy balance across species. Recent single-cell sequencing studies have defined at least 30 distinct LHA neuron types. Some of these influence specific aspects of energy homeostasis; however, the functions of many LHA cell types remain unclear. This review addresses the rapidly emerging evidence from cell-type-specific investigations that the LHA leverages distinct neuron populations to regulate energy balance through complex connections with other brain regions. It will highlight recent findings demonstrating that LHA control of energy balance extends beyond mere food intake and propose outstanding questions to be addressed by future research.
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Affiliation(s)
- Mark A Rossi
- Child Health Institute of New Jersey, New Brunswick, NJ, USA; Department of Psychiatry, Robert Wood Johnson Medical School, New Brunswick, NJ, USA; Brain Health Institute, Rutgers University, New Brunswick, NJ, USA.
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11
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Bouâouda H, Jha PK. Orexin and MCH neurons: regulators of sleep and metabolism. Front Neurosci 2023; 17:1230428. [PMID: 37674517 PMCID: PMC10478345 DOI: 10.3389/fnins.2023.1230428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 08/07/2023] [Indexed: 09/08/2023] Open
Abstract
Sleep-wake and fasting-feeding are tightly coupled behavioral states that require coordination between several brain regions. The mammalian lateral hypothalamus (LH) is a functionally and anatomically complex brain region harboring heterogeneous cell populations that regulate sleep, feeding, and energy metabolism. Significant attempts were made to understand the cellular and circuit bases of LH actions. Rapid advancements in genetic and electrophysiological manipulation help to understand the role of discrete LH cell populations. The opposing action of LH orexin/hypocretin and melanin-concentrating hormone (MCH) neurons on metabolic sensing and sleep-wake regulation make them the candidate to explore in detail. This review surveys the molecular, genetic, and neuronal components of orexin and MCH signaling in the regulation of sleep and metabolism.
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Affiliation(s)
- Hanan Bouâouda
- Pharmacology Institute, Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Pawan Kumar Jha
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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12
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Kniazkina M, Dyachuk V. Does EGFR Signaling Mediate Orexin System Activity in Sleep Initiation? Int J Mol Sci 2023; 24:ijms24119505. [PMID: 37298454 DOI: 10.3390/ijms24119505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/21/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Sleep-wake cycle disorders are an important symptom of many neurological diseases, including Parkinson's disease, Alzheimer's disease, and multiple sclerosis. Circadian rhythms and sleep-wake cycles play a key role in maintaining the health of organisms. To date, these processes are still poorly understood and, therefore, need more detailed elucidation. The sleep process has been extensively studied in vertebrates, such as mammals and, to a lesser extent, in invertebrates. A complex, multi-step interaction of homeostatic processes and neurotransmitters provides the sleep-wake cycle. Many other regulatory molecules are also involved in the cycle regulation, but their functions remain largely unclear. One of these signaling systems is epidermal growth factor receptor (EGFR), which regulates the activity of neurons in the modulation of the sleep-wake cycle in vertebrates. We have evaluated the possible role of the EGFR signaling pathway in the molecular regulation of sleep. Understanding the molecular mechanisms that underlie sleep-wake regulation will provide critical insight into the fundamental regulatory functions of the brain. New findings of sleep-regulatory pathways may provide new drug targets and approaches for the treatment of sleep-related diseases.
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Affiliation(s)
- Marina Kniazkina
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
| | - Vyacheslav Dyachuk
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, Vladivostok 690041, Russia
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13
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Fan BQ, Xia JM, Chen DD, Feng LL, Ding JH, Li SS, Li WX, Han Y. Medial septum glutamatergic neurons modulate nociception in chronic neuropathic pain via projections to lateral hypothalamus. Front Pharmacol 2023; 14:1171665. [PMID: 37266154 PMCID: PMC10229799 DOI: 10.3389/fphar.2023.1171665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/09/2023] [Indexed: 06/03/2023] Open
Abstract
The medial septum (MS) contributes in pain processing and regulation, especially concerning persistent nociception. However, the role of MS glutamatergic neurons in pain and the underlying neural circuit mechanisms in pain remain poorly understood. In this study, chronic constrictive injury of the sciatic nerve (CCI) surgery was performed to induce thermal and mechanical hyperalgesia in mice. The chemogenetic activation of MS glutamatergic neurons decreased pain thresholds in naïve mice. In contrast, inhibition or ablation of these neurons has improved nociception thresholds in naïve mice and relieved thermal and mechanical hyperalgesia in CCI mice. Anterograde viral tracing revealed that MS glutamatergic neurons had projections to the lateral hypothalamus (LH) and supramammillary nucleus (SuM). We further demonstrated that MS glutamatergic neurons regulate pain thresholds by projecting to LH but not SuM, because the inhibition of MS-LH glutamatergic projections suppressed pain thresholds in CCI and naïve mice, yet, optogenetic activation or inhibition of MS-SuM glutamatergic projections had no effect on pain thresholds in naïve mice. In conclusion, our results reveal that MS glutamatergic neurons play a significant role in regulating pain perception and decipher that MS glutamatergic neurons modulate nociception via projections to LH.
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Affiliation(s)
| | | | | | | | | | | | | | - Yuan Han
- *Correspondence: Yuan Han, ; Wen-Xian Li,
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14
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Shrivastava K, Swaminathan T, Barlotta A, Athreya V, Choudhry H, Rossi MA. Maternal overnutrition is associated with altered synaptic input to lateral hypothalamic area. Mol Metab 2023; 71:101702. [PMID: 36898526 PMCID: PMC10025284 DOI: 10.1016/j.molmet.2023.101702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/18/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
OBJECTIVE Maternal overnutrition is associated with adverse outcomes in offspring, including increased risk for obesity and diabetes. Here, we aim to test the effects of maternal obesity on lateral hypothalamic feeding circuit function and determine the relationship with body weight regulation. METHODS Using a mouse model of maternal obesity, we assessed how perinatal overnutrition affected food intake and body weight regulation in adult offspring. We then used channelrhodopsin-assisted circuit mapping and electrophysiological recordings to assess the synaptic connectivity within an extended amygdala-lateral hypothalamic pathway. RESULTS We show that maternal overnutrition during gestation and throughout lactation produces offspring that are heavier than controls prior to weaning. When weaned onto chow, the body weights of over-nourished offspring normalize to control levels. However, when presented with highly palatable food as adults, both male and female maternally over-nourished offspring are highly susceptible to diet-induced obesity. This is associated with altered synaptic strength in an extended amygdala-lateral hypothalamic pathway, which is predicted by developmental growth rate. Additionally, lateral hypothalamic neurons receiving synaptic input from the bed nucleus of the stria terminalis have enhanced excitatory input following maternal overnutrition which is predicted by early life growth rate. CONCLUSIONS Together, these results demonstrate one way in which maternal obesity rewires hypothalamic feeding circuits to predispose offspring to metabolic dysfunction.
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Affiliation(s)
| | | | | | | | | | - Mark A Rossi
- Child Health Institute of New Jersey, USA; Department of Psychiatry, Robert Wood Johnson Medical School, USA; Brain Health Institute, Rutgers University, New Brunswick, NJ, USA.
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15
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Hung C, Yamanaka A. The role of orexin neuron activity in sleep/wakefulness regulation. Peptides 2023; 165:171007. [PMID: 37030519 DOI: 10.1016/j.peptides.2023.171007] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 04/10/2023]
Abstract
Orexin (also known as hypocretin) is a neuropeptide exclusively synthesized in the neurons of the lateral hypothalamus (LH). Initially orexin was thought to be involved in the regulation of feeding behavior. However, it is now known to also be a critical regulator of sleep/wakefulness, especially the maintenance of wakefulness. Although the somas of orexin neurons are exclusively located in the LH, these neurons send axons throughout the brain and spinal cord. Orexin neurons integrate inputs from various brain regions and project to neurons that are involved in the regulation of sleep/wakefulness. Orexin knockout mice have a fragmentation of sleep/wakefulness and cataplexy-like behavior arrest, which is similar to the sleep disorder narcolepsy. Recent progress with manipulation of neural activity of targeted neurons, using experimental tools such as optogenetics and chemogenetics, has emphasized the role of orexin neuron activity on the regulation of sleep/wakefulness. Recording of orexin neuron activity in vivo using electrophysiological and gene-encoded calcium indicator proteins revealed that these cells have specific activity patterns across sleep/wakefulness state changes. Here, we also discuss not only the role of the orexin peptide, but also the role of other co-transmitters that are synthesized and released from orexin neurons and involved in sleep/wakefulness regulation.
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Affiliation(s)
- Chijung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan; Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Akihiro Yamanaka
- Chinese Institute for Brain Research, Beijing (CIBR), Beijing, 102206, China; National Institute for Physiological Sciences, National Institutes of Natural Sciences, Aichi 444-8585 Japan; Division of Brain Sciences Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, 160-8582, Japan.
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16
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Kaneko T, Kuwaki T. The opposite roles of orexin neurons in pain and itch neural processing. Peptides 2023; 160:170928. [PMID: 36566840 DOI: 10.1016/j.peptides.2022.170928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Revised: 12/17/2022] [Accepted: 12/20/2022] [Indexed: 12/24/2022]
Abstract
Pain and itch are antagonistically regulated sensations; pain suppresses itch, and inhibition of pain enhances itch. Understanding the central neural circuit of antagonistic regulation between pain and itch is required to develop new therapeutics better to manage these two feelings in a clinical situation. However, evidence of the neural mechanism underlying the pain-itch interaction in the central nervous system (CNS) is still insufficient. To pave the way for this research area, our laboratory has focused on orexin (ORX) producing neurons in the hypothalamus, which is known as a master switch that induces various defense responses when animals face a stressful environment. This review article summarized the previous evidence and our latest findings to argue the neural regulation between pain and itch and the bidirectional roles of ORX neurons in processing these two sensations. i.e., pain relief and itch exacerbation. Further, we discussed the possible neural circuit mechanism for the opposite controlling of pain and itch by ORX neurons. Focusing on the roles of ORX neurons would provide a new perspective to understand the antagonistic regulation of pain and itch in CNS.
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Affiliation(s)
- Tatsuroh Kaneko
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan.
| | - Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
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17
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Bigalke JA, Shan Z, Carter JR. Orexin, Sleep, Sympathetic Neural Activity, and Cardiovascular Function. Hypertension 2022; 79:2643-2655. [PMID: 36148653 PMCID: PMC9649879 DOI: 10.1161/hypertensionaha.122.19796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Inadequate sleep duration and quality are associated with reduced cardiovascular health and increased mortality. Experimental evidence points to the sympathetic nervous system as a key mediator in the observed relationship between poor sleep and cardiovascular dysfunction. However, brain mechanisms underpinning the impaired sympathetic function associated with poor sleep remain unclear. Recent evidence suggests the central orexin system, particularly orexins A and B and their receptors, have a key regulatory role for sleep in animal and human models. While orexin system activity has been observed to significantly impact sympathetic regulation in animals, the extension of these findings to humans has been difficult due to an inability to directly assess orexin system activity in humans. However, direct measures of sympathetic activity in populations with narcolepsy and chronic insomnia, 2 sleep disorders associated with deficient and excessive orexin neural activity, have allowed indirect assessment of the relationships between orexin, sleep, and sympathetic regulation. Further, the recent pharmaceutical development of dual orexin receptor antagonists for use in clinical insomnia populations offers an unprecedented opportunity to examine the mechanistic role of orexin in sleep and cardiovascular health in humans. The current review assesses the role of orexin in both sleep and sympathetic regulation from a translational perspective, spanning animal and human studies. The review concludes with future research directions necessary to fully elucidate the mechanistic role for orexin in sleep and sympathetic regulation in humans.
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Affiliation(s)
- Jeremy A. Bigalke
- Department of Health and Human Development, Montana State University, Bozeman, Montana
- Department of Psychology, Montana State University, Bozeman, Montana
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan
| | - Jason R. Carter
- Department of Health and Human Development, Montana State University, Bozeman, Montana
- Department of Psychology, Montana State University, Bozeman, Montana
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18
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Abdelmissih S. A Bitter Experience That Enlightens the Future: COVID-19 Neurological Affection and Perspectives on the Orexigenic System. Cureus 2022; 14:e30788. [DOI: 10.7759/cureus.30788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
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19
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López-Muciño LA, García-García F, Cueto-Escobedo J, Acosta-Hernández M, Venebra-Muñoz A, Rodríguez-Alba JC. Sleep loss and addiction. Neurosci Biobehav Rev 2022; 141:104832. [PMID: 35988803 DOI: 10.1016/j.neubiorev.2022.104832] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/25/2022]
Abstract
Reducing sleep hours is a risk factor for developing cardiovascular, metabolic, and psychiatric disorders. Furthermore, previous studies have shown that reduction in sleep time is a factor that favors relapse in addicted patients. Additionally, animal models have demonstrated that both sleep restriction and sleep deprivation increase the preference for alcohol, methylphenidate, and the self-administration of cocaine. Therefore, the present review discusses current knowledge about the influence of sleep hours reduction on addictivebehaviors; likewise, we discuss the neuronal basis underlying the sleep reduction-addiction relationship, like the role of the orexin and dopaminergic system and neuronal plasticity (i.e., delta FosB expression). Potentially, chronic sleep restriction could increase brain vulnerability and promote addictive behavior.
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Affiliation(s)
- Luis Angel López-Muciño
- Health Sciences Ph.D. Program, Health Sciences Institute, Veracruzana University, Xalapa, VER 91190, Mexico.
| | - Fabio García-García
- Department of Biomedicine, Health Sciences Institute, Veracruzana University, Xalapa, VER 91190, Mexico.
| | - Jonathan Cueto-Escobedo
- Department of Clinical and Translational Research, Health Sciences Institute, Veracruzana University, Xalapa, VER 91190, Mexico.
| | - Mario Acosta-Hernández
- Department of Biomedicine, Health Sciences Institute, Veracruzana University, Xalapa, VER 91190, Mexico.
| | - Arturo Venebra-Muñoz
- Laboratory of Neurobiology of Addiction and Brain Plasticity, Faculty of Science, Autonomous University of Mexico State, Edomex 50295, Mexico.
| | - Juan Carlos Rodríguez-Alba
- Department of Biomedicine, Health Sciences Institute, Veracruzana University, Xalapa, VER 91190, Mexico.
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20
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Gao XB, Horvath TL. From Molecule to Behavior: Hypocretin/orexin Revisited From a Sex-dependent Perspective. Endocr Rev 2022; 43:743-760. [PMID: 34792130 PMCID: PMC9277634 DOI: 10.1210/endrev/bnab042] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Indexed: 11/19/2022]
Abstract
The hypocretin/orexin (Hcrt/Orx) system in the perifornical lateral hypothalamus has been recognized as a critical node in a complex network of neuronal systems controlling both physiology and behavior in vertebrates. Our understanding of the Hcrt/Orx system and its array of functions and actions has grown exponentially in merely 2 decades. This review will examine the latest progress in discerning the roles played by the Hcrt/Orx system in regulating homeostatic functions and in executing instinctive and learned behaviors. Furthermore, the gaps that currently exist in our knowledge of sex-related differences in this field of study are discussed.
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Affiliation(s)
- Xiao-Bing Gao
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tamas L Horvath
- Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
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21
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Babaie F, Kourosh-Arami M, Farhadi M. Administration of Orexin-A into the Rat Thalamic Paraventricular Nucleus Enhances the Naloxone Induced Morphine Withdrawal. Drug Res (Stuttg) 2022; 72:209-214. [PMID: 35385881 DOI: 10.1055/a-1744-5868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Orexin neuropeptides are implicated in physical dependence on opioids and expression of withdrawal symptoms in drug abuse. The paraventricular nucleus of the midline thalamus (PVT) has a high expression of orexin receptors. The current research studied the effect of orexin-A in the PVT area on the development of behavioral indices produced by morphine withdrawal in rats. METHODS Male Wistar rats weighing 250-300 gr were utilised. To produce drug dependence, morphine (6, 16, 26, 36, 46, 56, and 66 mg/kg, 2 ml/kg) was injected at an interval of 24 hrs for 7 days. To assess the involvement of the orexin in withdrawal syndrome, we injected orexin-A (100 μM, 200 nl) into the PVT for 7 days before each morphine injection. On the day after the last injection of morphine, naloxone (2.5 mg/kg, i.p.) was injected to elicit the morphine withdrawal symptoms which were observed and checked for 25 min. RESULTS The results of the current research showed that the orexin-A in PVT enhances the severity of behavioral symptoms prompted by the injection of naloxone in drug-dependent rats. CONCLUSIONS These observations imply that targeting the orexin receptors in PVT might exhibit a new therapeutic strategy for the future treatment of dependence.
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Affiliation(s)
- Fatemeh Babaie
- Department of Microbiology, Karaj Branch Islamic Azad University, Karaj, Iran.,Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Masoumeh Kourosh-Arami
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mona Farhadi
- Department of Microbiology, Karaj Branch Islamic Azad University, Karaj, Iran.,Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
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22
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Sotelo MI, Tyan J, Markunas C, Sulaman BA, Horwitz L, Lee H, Morrow JG, Rothschild G, Duan B, Eban-Rothschild A. Lateral hypothalamic neuronal ensembles regulate pre-sleep nest-building behavior. Curr Biol 2022; 32:806-822.e7. [PMID: 35051354 PMCID: PMC10455050 DOI: 10.1016/j.cub.2021.12.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 11/17/2021] [Accepted: 12/21/2021] [Indexed: 01/08/2023]
Abstract
The transition from wakefulness to sleep requires striking alterations in brain activity, physiology, and behavior, yet the precise neuronal circuit elements facilitating this transition remain unclear. Prior to sleep onset, many animal species display characteristic behaviors, including finding a safe location, performing hygiene-related behaviors, and preparing a space for sleep. It has been proposed that the pre-sleep period is a transitional phase in which engaging in a specific behavioral repertoire de-arouses the brain and facilitates the wake-to-sleep transition, yet both causal evidence for this premise and an understanding of the neuronal circuit elements involved are lacking. Here, we combine detailed behavioral observations, EEG-EMG recordings, selective targeting, and activity modulation of pre-sleep-active neurons to reveal the behaviors preceding sleep initiation and their underlying neurobiological mechanisms. We show that mice engage in temporally structured behaviors with stereotypic EEG signatures prior to sleep and that nest-building and grooming become significantly more prevalent with sleep proximity. We next demonstrate that the ability to build a nest promotes the initiation and consolidation of sleep and that the lack of nesting material chronically fragments sleep. Lastly, we identify broadly projecting and predominantly glutamatergic neuronal ensembles in the lateral hypothalamus that regulate the motivation to engage in pre-sleep nest-building behavior and gate sleep initiation and intensity. Our study provides causal evidence for the facilitatory role of pre-sleep behaviors in sleep initiation and consolidation and a functional characterization of the neuronal underpinnings regulating a sleep-related and goal-directed complex behavior.
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Affiliation(s)
- Maria I Sotelo
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jean Tyan
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Chelsea Markunas
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bibi A Sulaman
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Lorraine Horwitz
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI 48109, USA; Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Hankyu Lee
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Joshua G Morrow
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gideon Rothschild
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109, USA; Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, MI 48109, USA
| | - Bo Duan
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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23
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Thomas CS, Mohammadkhani A, Rana M, Qiao M, Baimel C, Borgland SL. Optogenetic stimulation of lateral hypothalamic orexin/dynorphin inputs in the ventral tegmental area potentiates mesolimbic dopamine neurotransmission and promotes reward-seeking behaviours. Neuropsychopharmacology 2022; 47:728-740. [PMID: 34663867 PMCID: PMC8782948 DOI: 10.1038/s41386-021-01196-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 01/30/2023]
Abstract
Reward and reinforcement processes are critical for survival and propagation of genes. While numerous brain systems underlie these processes, a cardinal role is ascribed to mesolimbic dopamine. However, ventral tegmental area (VTA) dopamine neurons receive complex innervation and various neuromodulatory factors, including input from lateral hypothalamic (LH) orexin/hypocretin neurons which also express and co-release the neuropeptide, dynorphin. Dynorphin in the VTA induces aversive conditioning through the Kappa opioid receptor (KOR) and decreases dopamine when administered intra-VTA. Exogenous application of orexin or orexin 1 receptor (oxR1) antagonists in the VTA bidirectionally modulates dopamine-driven motivation and reward-seeking behaviours, including the attribution of motivational value to primary rewards and associated conditioned stimuli. However, the effect of endogenous stimulation of LH orexin/dynorphin-containing projections to the VTA and the potential contribution of co-released dynorphin on mesolimbic dopamine and reward related processes remains uncharacterised. We combined optogenetic, electrochemical, and behavioural approaches to examine this. We found that optical stimulation of LH orexin/dynorphin inputs in the VTA potentiates mesolimbic dopamine neurotransmission in the nucleus accumbens (NAc) core, produces real time and conditioned place preference, and increases the food cue-directed orientation in a Pavlovian conditioning procedure. LH orexin/dynorphin potentiation of NAc dopamine release and real time place preference was blocked by an oxR1, but not KOR antagonist. Thus, rewarding effects associated with optical stimulation of LH orexin/dynorphin inputs in the VTA are predominantly driven by orexin rather than dynorphin.
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Affiliation(s)
- Catherine S. Thomas
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
| | - Aida Mohammadkhani
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
| | - Madiha Rana
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
| | - Min Qiao
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
| | - Corey Baimel
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
| | - Stephanie L. Borgland
- grid.22072.350000 0004 1936 7697Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, 3330 Hospital Dr. NW, Calgary, AB T2N 4N1 Canada
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Miyata K, Ikoma Y, Murata K, Kusumoto-Yoshida I, Kobayashi K, Kuwaki T, Ootsuka Y. Multifaceted roles of orexin neurons in mediating methamphetamine-induced changes in body temperature and heart rate. IBRO Neurosci Rep 2022; 12:108-120. [PMID: 35128515 PMCID: PMC8804267 DOI: 10.1016/j.ibneur.2022.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 01/12/2022] [Accepted: 01/17/2022] [Indexed: 11/26/2022] Open
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25
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Transcriptional and functional divergence in lateral hypothalamic glutamate neurons projecting to the lateral habenula and ventral tegmental area. Neuron 2021; 109:3823-3837.e6. [PMID: 34624220 DOI: 10.1016/j.neuron.2021.09.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/28/2021] [Accepted: 09/10/2021] [Indexed: 01/19/2023]
Abstract
The lateral hypothalamic area (LHA) regulates feeding- and reward-related behavior, but because of its molecular and anatomical heterogeneity, the functions of defined neuronal populations are largely unclear. Glutamatergic neurons within the LHA (LHAVglut2) negatively regulate feeding and appetitive behavior. However, this population comprises transcriptionally distinct and functionally diverse neurons that project to diverse brain regions, including the lateral habenula (LHb) and ventral tegmental area (VTA). To resolve the function of distinct LHAVglut2 populations, we systematically compared projections to the LHb and VTA using viral tracing, single-cell sequencing, electrophysiology, and in vivo calcium imaging. LHAVglut2 neurons projecting to the LHb or VTA are anatomically, transcriptionally, electrophysiologically, and functionally distinct. While both populations encode appetitive and aversive stimuli, LHb projecting neurons are especially sensitive to satiety state and feeding hormones. These data illuminate the functional heterogeneity of LHAVglut2 neurons, suggesting that reward and aversion are differentially processed in divergent efferent pathways.
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26
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Spinieli RL, Ben Musa R, Kielhofner J, Cornelius-Green J, Cummings KJ. Orexin contributes to eupnea within a critical period of postnatal development. Am J Physiol Regul Integr Comp Physiol 2021; 321:R558-R571. [PMID: 34405704 PMCID: PMC8560369 DOI: 10.1152/ajpregu.00156.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 02/03/2023]
Abstract
Orexin neurons are active in wakefulness and mostly silent in sleep. In adult rats and humans, orexin facilitates the hypercapnic ventilatory response but has little effect on resting ventilation. The influence of orexin on breathing in the early postnatal period, and across states of vigilance, have not been investigated. This is relevant as the orexin system may be impaired in Sudden Infant Death Syndrome (SIDS) cases. We addressed three hypotheses: 1) orexin provides a drive to breathe in infancy; 2) the effect of orexin depends on stage of postnatal development; and 3) orexin has a greater influence on breathing in wakefulness compared with sleep. Whole body plethysmography was used to monitor breathing of infant rats at three ages: postnatal days (P) 7-8, 12-14, and 17-19. Respiratory variables were analyzed in wakefulness (W), quiet sleep (QS), and active sleep (AS), following suvorexant (5 mg/kg ip), a dual orexin receptor antagonist, or vehicle (DMSO). Effects of suvorexant on ventilatory responses to graded hypercapnia ([Formula: see text] = 0.02, 0.04, 0.06), hypoxia ([Formula: see text] = 0.10), and hyperoxia ([Formula: see text] = 1.0) at P12-14 were also tested. At P12-14, but not at other ages, suvorexant significantly reduced respiratory frequency in all states, reduced the ventilatory equivalent in QW and QS, and increased [Formula: see text] to ∼5 mmHg. Suvorexant had no effect on ventilatory responses to graded hypercapnia or hypoxia. Hyperoxia eliminated the effects of suvorexant on respiratory frequency at P12-14. Our data suggest that orexin preserves eupneic frequency and ventilation in rats, specifically at ∼2 wk of age, perhaps by facilitating tonic peripheral chemoreflex activity.
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Affiliation(s)
- Richard L Spinieli
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - Jane Kielhofner
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | | | - Kevin J Cummings
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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27
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Zhou X, Risold PY, Alvarez-Bolado G. Development of the GABAergic and glutamatergic neurons of the lateral hypothalamus. J Chem Neuroanat 2021; 116:101997. [PMID: 34182088 DOI: 10.1016/j.jchemneu.2021.101997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 11/26/2022]
Abstract
In the last few years we assist to an unexpected deluge of genomic data on hypothalamic development and structure. Perhaps most surprisingly, the Lateral Zone has received much attention too. The new information focuses first of all on transcriptional heterogeneity. Many already known and a number of hitherto unknown lateral hypothalamic neurons have been described to an enormous degree of detail. Maybe the most surprising novel discoveries are two: First, some restricted regions of the embryonic forebrain neuroepithelium generate specific LHA neurons, either GABAergic or glutamatergic. Second, evidence is mounting that supports the existence of numerous kinds of "bilingual" lateral hypothalamic neurons, expressing (and releasing) glutamate and GABA both as well as assorted neuropeptides. This is not accepted by all, and it could be that genomic researchers need a common set of rules to interpret their data (sensitivity, significance, age of analysis). In any case, some of the new results appear to confirm hypotheses about the ability of the hypothalamus and in particular its Lateral Zone to achieve physiological flexibility on a fixed connectivity ("biochemical switching"). Furthermore, the results succinctly reviewed here are the basis for future advances, since the transcriptional databases generated can now be mined e.g. for adhesion genes, to figure out the causes of the peculiar histology of the Lateral Zone; or for ion channel genes, to clarify present and future electrophysiological data. And with the specific expression data about small subpopulations of neurons, their connections can now be specifically labeled, revealing novel relations with functional significance.
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Affiliation(s)
- Xunlei Zhou
- Dept. Neuroanatomy, University of Heidelberg School of Medicine, D-69120, Heidelberg, Germany
| | - Pierre-Yves Risold
- Neurosciences Intégratives et Cliniques EA481, Université de Bourgogne Franche-Comté, 25000, Besançon, France
| | - Gonzalo Alvarez-Bolado
- Dept. Neuroanatomy, University of Heidelberg School of Medicine, D-69120, Heidelberg, Germany.
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28
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Zhao S, Li R, Li H, Wang S, Zhang X, Wang D, Guo J, Li H, Li A, Tong T, Zhong H, Yang Q, Dong H. Lateral Hypothalamic Area Glutamatergic Neurons and Their Projections to the Lateral Habenula Modulate the Anesthetic Potency of Isoflurane in Mice. Neurosci Bull 2021; 37:934-946. [PMID: 33847915 PMCID: PMC8275739 DOI: 10.1007/s12264-021-00674-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/26/2020] [Indexed: 01/19/2023] Open
Abstract
The lateral hypothalamic area (LHA) plays a pivotal role in regulating consciousness transition, in which orexinergic neurons, GABAergic neurons, and melanin-concentrating hormone neurons are involved. Glutamatergic neurons have a large population in the LHA, but their anesthesia-related effect has not been explored. Here, we found that genetic ablation of LHA glutamatergic neurons shortened the induction time and prolonged the recovery time of isoflurane anesthesia in mice. In contrast, chemogenetic activation of LHA glutamatergic neurons increased the time to anesthesia and decreased the time to recovery. Optogenetic activation of LHA glutamatergic neurons during the maintenance of anesthesia reduced the burst suppression pattern of the electroencephalogram (EEG) and shifted EEG features to an arousal pattern. Photostimulation of LHA glutamatergic projections to the lateral habenula (LHb) also facilitated the emergence from anesthesia and the transition of anesthesia depth to a lighter level. Collectively, LHA glutamatergic neurons and their projections to the LHb regulate anesthetic potency and EEG features.
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Affiliation(s)
- Shiyi Zhao
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Rui Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Huiming Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Sa Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Xinxin Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Dan Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Juan Guo
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Huihui Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Ao Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Tingting Tong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Haixing Zhong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Qianzi Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
| | - Hailong Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China.
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29
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An S, Sun H, Wu M, Xie D, Hu SW, Ding HL, Cao JL. Medial septum glutamatergic neurons control wakefulness through a septo-hypothalamic circuit. Curr Biol 2021; 31:1379-1392.e4. [DOI: 10.1016/j.cub.2021.01.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/04/2020] [Accepted: 01/07/2021] [Indexed: 02/06/2023]
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30
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Taksokhan A, Fraigne J, Peever J. Neuroscience: Glutamate neurons in the medial septum control wakefulness. Curr Biol 2021; 31:R340-R342. [PMID: 33848488 DOI: 10.1016/j.cub.2021.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Despite intensive research efforts, biologists still do not have a clear picture of the brain circuitry that controls behavioural arousal. However, new research has identified a novel septo-hypothalamic circuit that functions to promote wakefulness.
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Affiliation(s)
- Anita Taksokhan
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - Jimmy Fraigne
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada
| | - John Peever
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S 3G5, Canada; Department of Physiology, University of Toronto, Toronto, ON M5S 3G5, Canada.
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31
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Huang D, Grady FS, Peltekian L, Laing JJ, Geerling JC. Efferent projections of CGRP/Calca-expressing parabrachial neurons in mice. J Comp Neurol 2021; 529:2911-2957. [PMID: 33715169 DOI: 10.1002/cne.25136] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 03/07/2021] [Accepted: 03/08/2021] [Indexed: 12/19/2022]
Abstract
The parabrachial nucleus (PB) is composed of glutamatergic neurons at the midbrain-hindbrain junction. These neurons form many subpopulations, one of which expresses Calca, which encodes the neuropeptide calcitonin gene-related peptide (CGRP). This Calca-expressing subpopulation has been implicated in a variety of homeostatic functions, but the overall distribution of Calca-expressing neurons in this region remains unclear. Also, while previous studies in rats and mice have identified output projections from CGRP-immunoreactive or Calca-expressing neurons, we lack a comprehensive understanding of their efferent projections. We began by identifying neurons with Calca mRNA and CGRP immunoreactivity in and around the PB, including populations in the locus coeruleus and motor trigeminal nucleus. Calca-expressing neurons in the PB prominently express the mu opioid receptor (Oprm1) and are distinct from neighboring neurons that express Foxp2 and Pdyn. Next, we used Cre-dependent anterograde tracing with synaptophysin-mCherry to map the efferent projections of these neurons. Calca-expressing PB neurons heavily target subregions of the amygdala, bed nucleus of the stria terminalis, basal forebrain, thalamic intralaminar and ventral posterior parvicellular nuclei, and hindbrain, in different patterns depending on the injection site location within the PB region. Retrograde axonal tracing revealed that the previously unreported hindbrain projections arise from a rostral-ventral subset of CGRP/Calca neurons. Finally, we show that these efferent projections of Calca-expressing neurons are distinct from those of neighboring PB neurons that express Pdyn. This information provides a detailed neuroanatomical framework for interpreting experimental work involving CGRP/Calca-expressing neurons and opioid action in the PB region.
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Affiliation(s)
- Dake Huang
- Department of Neurology, University of Iowa, Iowa, USA
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32
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Wang RF, Guo H, Jiang SY, Liu ZL, Qu WM, Huang ZL, Wang L. Control of wakefulness by lateral hypothalamic glutamatergic neurons in male mice. J Neurosci Res 2021; 99:1689-1703. [PMID: 33713502 DOI: 10.1002/jnr.24828] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/21/2021] [Accepted: 03/01/2021] [Indexed: 11/10/2022]
Abstract
The lateral hypothalamus (LH) plays a key role in the maintenance of cortical activation and wakefulness. In the LH, the two main neuronal cell populations consist of excitatory glutamatergic neurons and inhibitory GABAergic neurons. Recent studies have shown that inhibitory LH GABAergic neurons are wake-promoting. However, the mechanism by which excitatory LH glutamatergic neurons contribute to sleep-wake regulation remains unclear. Using fiber photometry in male mice, we demonstrated that LH glutamatergic neurons exhibited high activities during both wakefulness and rapid eye movement sleep. Chemogenetic activation of LH glutamatergic neurons induced an increase in wakefulness that lasted for 6 hr, whereas suppression of LH glutamatergic neuronal activity caused a reduction in wakefulness. Brief optogenetic activation of LH glutamatergic neurons induced an immediate transition from slow-wave sleep to wakefulness, and long-lasting optogenetic stimulation of these neurons maintained wakefulness. Moreover, we found that LH-locus coeruleus/parabrachial nucleus and LH-basal forebrain projections mediated the wake-promoting effects of LH glutamatergic neurons. Taken together, our data indicate that LH glutamatergic neurons are essential for the induction and maintenance of wakefulness. The results presented here may advance our understanding of the role of LH in the control of wakefulness.
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Affiliation(s)
- Ren-Fei Wang
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Han Guo
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Shi-Yu Jiang
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zi-Long Liu
- Department of Pulmonary Medicine, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Wei-Min Qu
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Zhi-Li Huang
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
| | - Lu Wang
- Department of Pharmacology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Shanghai Medical College of Fudan University, Shanghai, China
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33
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Tunisi L, D'Angelo L, Fernández-Rilo AC, Forte N, Piscitelli F, Imperatore R, de Girolamo P, Di Marzo V, Cristino L. Orexin-A/Hypocretin-1 Controls the VTA-NAc Mesolimbic Pathway via Endocannabinoid-Mediated Disinhibition of Dopaminergic Neurons in Obese Mice. Front Synaptic Neurosci 2021; 13:622405. [PMID: 33613258 PMCID: PMC7890184 DOI: 10.3389/fnsyn.2021.622405] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/11/2021] [Indexed: 01/27/2023] Open
Abstract
Disinhibition of orexin-A/hypocretin-1 (OX-A) release occurs to several output areas of the lateral hypothalamus (LH) in the brain of leptin knockout obese ob/ob mice. In this study, we have investigated whether a similar increase of OX-A release occurs to the ventral tegmental area (VTA), an orexinergic LH output area with functional effects on dopaminergic signaling at the mesolimbic circuit. By confocal and correlative light and electron microscopy (CLEM) morphological studies coupled to molecular, biochemical, and pharmacological approaches, we investigated OX-A-mediated dopaminergic signaling at the LH-VTA-nucleus accumbens (NAc) pathway in obese ob/ob mice compared to wild-type (wt) lean littermates. We found an elevation of OX-A trafficking and release to the VTA of ob/ob mice and consequent orexin receptor-1 (OX1R)-mediated over-activation of dopaminergic (DA) neurons via phospholipase C (PLC)/diacylglycerol lipase (DAGL-α)-induced biosynthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG). In fact, by retrograde signaling to cannabinoid receptor type 1 (CB1R) at inhibitory inputs to DA neurons, 2-AG inhibited GABA release thus inducing an increase in DA concentration in the VTA and NAc of ob/ob mice. This effect was prevented by the OX1R antagonist SB-334867 (30 mg/Kg, i.p.), or the CB1R antagonist AM251 (10 mg/Kg, i.p.) and mimicked by OX-A injection (40 μg/Kg, i.p.) in wt lean mice. Enhanced DA signaling to the NAc in ob/ob mice, or in OX-A-injected wt mice, was accompanied by β-arrestin2-mediated desensitization of dopamine D2 receptor (D2R) in a manner prevented by SB-334867 or the D2R antagonist L741 (1.5 mg/Kg, i.p.). These results further support the role of OX-A signaling in the control of neuroadaptive responses, such as compulsive reward-seeking behavior or binge-like consumption of high palatable food, and suggest that aberrant OX-A trafficking to the DA neurons in the VTA of ob/ob mice influences the D2R response at NAc, a main target area of the mesolimbic pathway, via 2-AG/CB1-mediated retrograde signaling.
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Affiliation(s)
- Lea Tunisi
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Livia D'Angelo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Alba Clara Fernández-Rilo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Nicola Forte
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Université Laval, Québec City, QC, Canada
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
| | - Roberta Imperatore
- Department of Sciences and Technologies, University of Sannio, Benevento, Italy
| | - Paolo de Girolamo
- Department of Veterinary Medicine and Animal Productions, University of Naples Federico II, Naples, Italy
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy.,Canada Excellence Research Chair on the Microbiome-Endocannabinoidome Axis in Metabolic Health, Université Laval, Québec City, QC, Canada.,Heart and Lung Research Institute of Université Laval, and Institute for Nutrition and Functional Foods, Université Laval, Québec City, QC, Canada
| | - Luigia Cristino
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, National Research Council, Pozzuoli, Italy
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34
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Harris T, Bugescu R, Kelly J, Makela A, Sotzen M, Sisk C, Atkin G, Pratt R, Crockett E, Leinninger G. DLK1 Expressed in Mouse Orexin Neurons Modulates Anxio-Depressive Behavior but Not Energy Balance. Brain Sci 2020; 10:brainsci10120975. [PMID: 33322758 PMCID: PMC7764426 DOI: 10.3390/brainsci10120975] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 11/16/2022] Open
Abstract
Lateral hypothalamic area (LHA) neurons expressing the neuropeptide orexin (OX) are implicated in obesity and anxio-depression. However, these neurons release OX as well as a host of other proteins that might contribute to normal physiology and disease states. We hypothesized that delta-like homolog 1 (DLK1), a protein reported to be co-expressed by all OX neurons, contributes to the regulation of energy balance and/or anxio-depression. Consistent with previous reports, we found that all rat OX neurons co-express DLK1. Yet, in mice and humans only a subset of OX neurons co-expressed DLK1. Since human OX-DLK1 distribution is more similar to mice than rats, mice are a comparable model to assess the human physiologic role of DLK1. We therefore used a viral lesion strategy to selectively delete DLK1 within the LHA of adult mice (DLK1Null) to reveal its role in body weight and behavior. Adult-onset DLK1 deletion had no impact on body weight or ingestive behavior. However, DLK1Null mice engaged in more locomotor activity than control mice and had decreased anxiety and depression measured via the elevated plus maze and forced swim tests. These data suggest that DLK1 expression via DLK1-expressing OX neurons primarily contributes to anxio-depression behaviors without impacting body weight.
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Affiliation(s)
- Tatiyana Harris
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
| | - Jaylyn Kelly
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
| | - Anna Makela
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
| | - Morgan Sotzen
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
| | - Cheryl Sisk
- Neuroscience Program, Department of Psychology, Michigan State University, East Lansing, MI 48824, USA;
| | - Graham Atkin
- Department of Radiology, Michigan State University, East Lansing, MI 48824, USA;
| | - Rebecca Pratt
- Department of Foundational Medical Studies, Oakland University William Beaumont School of Medicine, Rochester, MI 48309, USA;
| | - Elahé Crockett
- Department of Medicine, Michigan State University, East Lansing, MI 48824, USA;
| | - Gina Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA; (T.H.); (R.B.); (J.K.); (A.M.); (M.S.)
- Correspondence:
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35
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Lee J, Raycraft L, Johnson AW. The dynamic regulation of appetitive behavior through lateral hypothalamic orexin and melanin concentrating hormone expressing cells. Physiol Behav 2020; 229:113234. [PMID: 33130035 DOI: 10.1016/j.physbeh.2020.113234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/20/2020] [Accepted: 10/21/2020] [Indexed: 02/07/2023]
Abstract
The lateral hypothalamic area (LHA) is a heterogeneous brain structure extensively studied for its potent role in regulating energy balance. The anatomical and molecular diversity of the LHA permits the orchestration of responses to energy sensing cues from the brain and periphery. Two of the primary cell populations within the LHA associated with integration of this information are Orexin (ORX) and Melanin Concentrating Hormone (MCH). While both of these non-overlapping populations exhibit orexigenic properties, the activities of these two systems support feeding behavior through contrasting mechanisms. We describe the anatomical and functional properties as well as interaction with other neuropeptides and brain reward and hedonic systems. Specific outputs relating to arousal, food seeking, feeding, and metabolism are coordinated through these mechanisms. We then discuss how both the ORX and MCH systems harmonize in a divergent yet overall cooperative manner to orchestrate feeding behavior through transitions between various appetitive states, and thus offer novel insights into LHA allostatic control of appetite.
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Affiliation(s)
| | | | - Alexander W Johnson
- Department of Psychology; Neuroscience Program, Michigan State University, East Lansing.
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36
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Orexin type-1 receptor inhibition in the rat lateral paragigantocellularis nucleus attenuates development of morphine dependence. Neurosci Lett 2020; 724:134875. [DOI: 10.1016/j.neulet.2020.134875] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 02/10/2020] [Accepted: 02/26/2020] [Indexed: 11/18/2022]
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37
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Simmons SJ, Gentile TA. Cocaine abuse and midbrain circuits: Functional anatomy of hypocretin/orexin transmission and therapeutic prospect. Brain Res 2020; 1731:146164. [PMID: 30796894 PMCID: PMC6702109 DOI: 10.1016/j.brainres.2019.02.026] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 01/09/2019] [Accepted: 02/12/2019] [Indexed: 12/18/2022]
Abstract
Cocaine abuse remains a pervasive public health problem, and treatments thus far have proven ineffective for long-term abstinence maintenance. Intensive research on the neurobiology underlying drug abuse has led to the consideration of many candidate transmitter systems to target for intervention. Among these, the hypocretin/orexin (hcrt/ox) neuropeptide system holds largely untapped yet clinically viable therapeutic potential. Hcrt/ox originates from the hypothalamus and projects widely across the mammalian central nervous system to produce neuroexcitatory actions via two excitatory G-protein coupled receptor subtypes. Functionally, hcrt/ox promotes arousal/wakefulness and facilitates energy homeostasis. In the early 2000s, hcrt/ox transmission was shown to underlie mating behavior in male rats suggesting a novel role in reward-seeking. Soon thereafter, hcrt/ox neurons were shown to respond to drug-associated stimuli, and hcrt/ox transmission was found to facilitate motivated responding for intravenous cocaine. Notably, blocking hcrt/ox transmission using systemic or site-directed pharmacological antagonists markedly reduced motivated drug-taking as well as drug-seeking in tests of relapse. This review will unfold the current state of knowledge implicating hcrt/ox receptor transmission in the context of cocaine abuse and provide detailed background on animal models and underlying midbrain circuits. Specifically, attention will be paid to the mesoaccumbens, tegmental, habenular, pallidal and preoptic circuits. The review will conclude with discussion of recent preclinical studies assessing utility of suvorexant - the first and only FDA-approved hcrt/ox receptor antagonist - against cocaine-associated behaviors.
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Affiliation(s)
- Steven J Simmons
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA, USA; Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA.
| | - Taylor A Gentile
- Center for Substance Abuse Research, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, USA
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Fakhoury M, Salman I, Najjar W, Merhej G, Lawand N. The Lateral Hypothalamus: An Uncharted Territory for Processing Peripheral Neurogenic Inflammation. Front Neurosci 2020; 14:101. [PMID: 32116534 PMCID: PMC7029733 DOI: 10.3389/fnins.2020.00101] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 01/24/2020] [Indexed: 12/20/2022] Open
Abstract
The roles of the hypothalamus and particularly the lateral hypothalamus (LH) in the regulation of inflammation and pain have been widely studied. The LH consists of a parasympathetic area that has connections with all the major parts of the brain. It controls the autonomic nervous system (ANS), regulates feeding behavior and wakeful cycles, and is a part of the reward system. In addition, it contains different types of neurons, most importantly the orexin neurons. These neurons, though few in number, perform critical functions such as inhibiting pain transmission and interfering with the reward system, feeding behavior and the hypothalamic pituitary axis (HPA). Recent evidence has identified a new role for orexin neurons in the modulation of pain transmission associated with several inflammatory diseases, including rheumatoid arthritis and ulcerative colitis. Here, we review recent findings on the various physiological functions of the LH with special emphasis on the orexin/receptor system and its role in mediating inflammatory pain.
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Affiliation(s)
- Marc Fakhoury
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Israa Salman
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Wassim Najjar
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - George Merhej
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Nada Lawand
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.,Department of Neurology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
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Collier AD, Min SS, Campbell SD, Roberts MY, Camidge K, Leibowitz SF. Maternal ethanol consumption before paternal fertilization: Stimulation of hypocretin neurogenesis and ethanol intake in zebrafish offspring. Prog Neuropsychopharmacol Biol Psychiatry 2020; 96:109728. [PMID: 31394141 PMCID: PMC6815720 DOI: 10.1016/j.pnpbp.2019.109728] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 08/02/2019] [Accepted: 08/03/2019] [Indexed: 12/27/2022]
Abstract
There are numerous clinical and pre-clinical studies showing that exposure of the embryo to ethanol markedly affects neuronal development and stimulates alcohol drinking and related behaviors. In rodents and zebrafish, our studies show that embryonic exposure to low-dose ethanol, in addition to increasing voluntary ethanol intake during adolescence, increases the density of hypothalamic hypocretin (hcrt) neurons, a neuropeptide known to regulate reward-related behaviors. The question addressed here in zebrafish is whether maternal ethanol intake before conception also affects neuronal and behavioral development, phenomena suggested by clinical reports but seldom investigated. To determine if preconception maternal ethanol consumption also affects these hcrt neurons and behavior in the offspring, we first standardized a method of measuring voluntary ethanol consumption in AB strain adult and larval zebrafish given gelatin meals containing 10% or 0.1% ethanol, respectively. We found the number of bites of gelatin to be an accurate measure of intake in adults and a strong predictor of blood ethanol levels, and also to be a reliable indicator of intake in larval zebrafish. We then used this feeding paradigm and live imaging to examine the effects of preconception maternal intake of 10% ethanol-gelatin compared to plain-gelatin for 14 days on neuronal development in the offspring. Whereas ethanol consumption by adult female HuC:GFP transgenic zebrafish had no impact on the number of differentiated HuC+ neurons at 28 h post-fertilization (hpf), preconception ethanol consumption by adult female hcrt:EGFP zebrafish significantly increased the number of hcrt neurons in the offspring, an effect observed at 28 hpf and confirmed at 6 and 12 days post-fertilization (dpf). This increase in hcrt neurons was primarily present on the left side of the brain, indicating asymmetry in ethanol's actions, and it was accompanied by behavioral changes in the offspring, including a significant increase in novelty-induced locomotor activity but not thigmotaxis measured at 6 dpf and also in voluntary consumption of 0.1% ethanol-gelatin at 12 dpf. Notably, these measures of ethanol intake and locomotor activity stimulated by preconception ethanol were strongly, positively correlated with the number of hcrt neurons. These findings demonstrate that preconception maternal ethanol consumption affects the brain and behavior of the offspring, producing effects similar to those caused by embryonic ethanol exposure, and they provide further evidence that the ethanol-induced increase in hcrt neurogenesis contributes to the behavioral disturbances caused by ethanol.
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Affiliation(s)
- Adam D Collier
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA
| | - Soe S Min
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA
| | - Samantha D Campbell
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA
| | - Mia Y Roberts
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA
| | - Kaylin Camidge
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA
| | - Sarah F Leibowitz
- Laboratory of Behavioral Neurobiology, The Rockefeller University, New York, NY, USA.
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The role of co-neurotransmitters in sleep and wake regulation. Mol Psychiatry 2019; 24:1284-1295. [PMID: 30377299 PMCID: PMC6491268 DOI: 10.1038/s41380-018-0291-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 12/11/2022]
Abstract
Sleep and wakefulness control in the mammalian brain requires the coordination of various discrete interconnected neurons. According to the most conventional sleep model, wake-promoting neurons (WPNs) and sleep-promoting neurons (SPNs) compete for network dominance, creating a systematic "switch" that results in either the sleep or awake state. WPNs and SPNs are ubiquitous in the brainstem and diencephalon, areas that together contain <1% of the neurons in the human brain. Interestingly, many of these WPNs and SPNs co-express and co-release various types of the neurotransmitters that often have opposing modulatory effects on the network. Co-transmission is often beneficial to structures with limited numbers of neurons because it provides increasing computational capability and flexibility. Moreover, co-transmission allows subcortical structures to bi-directionally control postsynaptic neurons, thus helping to orchestrate several complex physiological functions such as sleep. Here, we present an in-depth review of co-transmission in hypothalamic WPNs and SPNs and discuss its functional significance in the sleep-wake network.
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Grafe LA, Geng E, Corbett B, Urban K, Bhatnagar S. Sex- and Stress-Dependent Effects on Dendritic Morphology and Spine Densities in Putative Orexin Neurons. Neuroscience 2019; 418:266-278. [PMID: 31442567 DOI: 10.1016/j.neuroscience.2019.08.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/11/2019] [Accepted: 08/13/2019] [Indexed: 01/23/2023]
Abstract
We recently found that non-stressed female rats have higher basal prepro-orexin expression and activation of orexinergic neurons compared to non-stressed males, which lead to impaired habituation to repeated restraint stress at the behavioral, neural, and endocrine level. Here, we extended our study of sex differences in the orexin system by examining spine densities and dendritic morphology in putative orexin neurons in adult male and female rats that were exposed to 5 consecutive days of 30-min restraint. Analysis of spine distribution and density indicated that putative orexinergic neurons in control non-stressed females had significantly more dendritic spines than those in control males, and the majority of these were mushroom spines. This morphological finding may suggest more excitatory input onto orexin neurons in female rats. As orexin neurons are known to promote the hypothalamic-pituitary-adrenal response, this morphological change in orexin neurons could underlie the impaired habituation to repeated stress in female rats. Dendritic complexity did not differ between non-stressed males and females, however repeated restraint stress decreased total dendritic length, nodes, and branching primarily in males. Thus, reduced dendritic complexity of putative orexinergic neurons is observed in males but not in females after 5days of repeated restraint stress. This morphological change might be reflective of decreased orexin system function, which may allow males to habituate more fully to repeated restraint than females. These results extend our understanding of the role of orexin neurons in regulating habituation and demonstrate changes in putative orexin cell morphology and spines that may underlie sex differences in habituation.
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Affiliation(s)
- Laura A Grafe
- Department of Psychology, Bryn Mawr College, Bryn Mawr, PA 19010, USA
| | - Eric Geng
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Brian Corbett
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kimberly Urban
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Seema Bhatnagar
- Department of Anesthesiology and Critical Care, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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42
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Godfrey N, Borgland SL. Diversity in the lateral hypothalamic input to the ventral tegmental area. Neuropharmacology 2019; 154:4-12. [DOI: 10.1016/j.neuropharm.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/15/2019] [Accepted: 05/13/2019] [Indexed: 12/29/2022]
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43
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Hooshmand B, Azizi H, Ahmadi-Soleimani SM, Semnanian S. Synergistic effect of orexin-glutamate co-administration on spontaneous discharge rate of locus coeruleus neurons in morphine-dependent rats. Neurosci Lett 2019; 706:12-17. [DOI: 10.1016/j.neulet.2019.04.060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 12/16/2022]
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Chowdhury S, Hung CJ, Izawa S, Inutsuka A, Kawamura M, Kawashima T, Bito H, Imayoshi I, Abe M, Sakimura K, Yamanaka A. Dissociating orexin-dependent and -independent functions of orexin neurons using novel Orexin-Flp knock-in mice. eLife 2019; 8:44927. [PMID: 31159922 PMCID: PMC6548533 DOI: 10.7554/elife.44927] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
Uninterrupted arousal is important for survival during threatening situations. Activation of orexin/hypocretin neurons is implicated in sustained arousal. However, orexin neurons produce and release orexin as well as several co-transmitters including dynorphin and glutamate. To disambiguate orexin-dependent and -independent physiological functions of orexin neurons, we generated a novel Orexin-flippase (Flp) knock-in mouse line. Crossing with Flp-reporter or Cre-expressing mice showed gene expression exclusively in orexin neurons. Histological studies confirmed that orexin was knock-out in homozygous mice. Orexin neurons without orexin showed altered electrophysiological properties, as well as received decreased glutamatergic inputs. Selective chemogenetic activation revealed that both orexin and co-transmitters functioned to increase wakefulness, however, orexin was indispensable to promote sustained arousal. Surprisingly, such activation increased the total time spent in cataplexy. Taken together, orexin is essential to maintain basic membrane properties and input-output computation of orexin neurons, as well as to exert awake-sustaining aptitude of orexin neurons.
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Affiliation(s)
- Srikanta Chowdhury
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Shuntaro Izawa
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Ayumu Inutsuka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Meiko Kawamura
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Takashi Kawashima
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Itaru Imayoshi
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Manabu Abe
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Animal Model development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
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Abstract
Encoding and predicting aversive events are critical functions of circuits that support survival and emotional well-being. Maladaptive circuit changes in emotional valence processing can underlie the pathophysiology of affective disorders. The lateral habenula (LHb) has been linked to aversion and mood regulation through modulation of the dopamine and serotonin systems. We have defined the identity and function of glutamatergic (Vglut2) control of the LHb, comparing the role of inputs originating in the globus pallidus internal segment (GPi), and lateral hypothalamic area (LHA), respectively. We found that LHb-projecting LHA neurons, and not the proposed GABA/glutamate co-releasing GPi neurons, are responsible for encoding negative value. Monosynaptic rabies tracing of the presynaptic organization revealed a predominantly limbic input onto LHA Vglut2 neurons, while sensorimotor inputs were more prominent onto GABA/glutamate co-releasing GPi neurons. We further recorded the activity of LHA Vglut2 neurons, by imaging calcium dynamics in response to appetitive versus aversive events in conditioning paradigms. LHA Vglut2 neurons formed activity clusters representing distinct reward or aversion signals, including a population that responded to mild foot shocks and predicted aversive events. We found that the LHb-projecting LHA Vglut2 neurons encode negative valence and rapidly develop a prediction signal for negative events. These findings establish the glutamatergic LHA-LHb circuit as a critical node in value processing.
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46
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Hökfelt T, Barde S, Xu ZQD, Kuteeva E, Rüegg J, Le Maitre E, Risling M, Kehr J, Ihnatko R, Theodorsson E, Palkovits M, Deakin W, Bagdy G, Juhasz G, Prud’homme HJ, Mechawar N, Diaz-Heijtz R, Ögren SO. Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness. Front Neural Circuits 2018; 12:106. [PMID: 30627087 PMCID: PMC6309708 DOI: 10.3389/fncir.2018.00106] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022] Open
Abstract
Neuropeptides are auxiliary messenger molecules that always co-exist in nerve cells with one or more small molecule (classic) neurotransmitters. Neuropeptides act both as transmitters and trophic factors, and play a role particularly when the nervous system is challenged, as by injury, pain or stress. Here neuropeptides and coexistence in mammals are reviewed, but with special focus on the 29/30 amino acid galanin and its three receptors GalR1, -R2 and -R3. In particular, galanin's role as a co-transmitter in both rodent and human noradrenergic locus coeruleus (LC) neurons is addressed. Extensive experimental animal data strongly suggest a role for the galanin system in depression-like behavior. The translational potential of these results was tested by studying the galanin system in postmortem human brains, first in normal brains, and then in a comparison of five regions of brains obtained from depressed people who committed suicide, and from matched controls. The distribution of galanin and the four galanin system transcripts in the normal human brain was determined, and selective and parallel changes in levels of transcripts and DNA methylation for galanin and its three receptors were assessed in depressed patients who committed suicide: upregulation of transcripts, e.g., for galanin and GalR3 in LC, paralleled by a decrease in DNA methylation, suggesting involvement of epigenetic mechanisms. It is hypothesized that, when exposed to severe stress, the noradrenergic LC neurons fire in bursts and release galanin from their soma/dendrites. Galanin then acts on somato-dendritic, inhibitory galanin autoreceptors, opening potassium channels and inhibiting firing. The purpose of these autoreceptors is to act as a 'brake' to prevent overexcitation, a brake that is also part of resilience to stress that protects against depression. Depression then arises when the inhibition is too strong and long lasting - a maladaption, allostatic load, leading to depletion of NA levels in the forebrain. It is suggested that disinhibition by a galanin antagonist may have antidepressant activity by restoring forebrain NA levels. A role of galanin in depression is also supported by a recent candidate gene study, showing that variants in genes for galanin and its three receptors confer increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events. In summary, galanin, a neuropeptide coexisting in LC neurons, may participate in the mechanism underlying resilience against a serious and common disorder, MDD. Existing and further results may lead to an increased understanding of how this illness develops, which in turn could provide a basis for its treatment.
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Affiliation(s)
- Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Swapnali Barde
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Zhi-Qing David Xu
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neurobiology, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Laboratory of Brain Disorders (Ministry of Science and Technology), Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Eugenia Kuteeva
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Joelle Rüegg
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- The Center for Molecular Medicine, Stockholm, Sweden
- Swedish Toxicology Sciences Research Center, Swetox, Södertälje, Sweden
| | - Erwan Le Maitre
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Mårten Risling
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jan Kehr
- Pronexus Analytical AB, Solna, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Robert Ihnatko
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Elvar Theodorsson
- Department of Clinical Chemistry, Linköping University, Linköping, Sweden
- Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Miklos Palkovits
- Department of Anatomy, Histology and Embryology, Semmelweis University, Budapest, Hungary
| | - William Deakin
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- MTA-SE Neuropsychopharmacology and Neurochemistry Research Group, Hungarian Academy of Sciences, Semmelweis University, Budapest, Hungary
- NAP 2-SE New Antidepressant Target Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | - Gabriella Juhasz
- Neuroscience and Psychiatry Unit, University of Manchester, Manchester, United Kingdom
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary
- SE-NAP2 Genetic Brain Imaging Migraine Research Group, Hungarian Brain Research Program, Semmelweis University, Budapest, Hungary
| | | | - Naguib Mechawar
- Douglas Hospital Research Centre, Verdun, QC, Canada
- Department of Psychiatry, McGill University, Montreal, QC, Canada
| | | | - Sven Ove Ögren
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Rodrigues LTC, da Silva EN, Horta-Júnior JDAC, Gargaglioni LH, Dias MB. Glutamate metabotropic receptors in the lateral hypothalamus/perifornical area reduce the CO 2 chemoreflex. Respir Physiol Neurobiol 2018; 260:122-130. [PMID: 30471436 DOI: 10.1016/j.resp.2018.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/27/2018] [Accepted: 11/20/2018] [Indexed: 11/26/2022]
Abstract
It has been shown that the lateral hypothalamus/perifornical area (LH/PFA) exerts an important role on arousal-state variations of the central chemoreflex, but the mechanisms that underlie LH/PFA chemoreception are poorly understood. Here we asked whether glutamate inputs on metabotropic receptors in the LH/PFA modulate the hypercapnic ventilatory response. We studied the effects of microinjection of a glutamate metabotropic receptor (mGluR) antagonist ((+)-α-Methyl-4-carboxyphenylglycine; MCPG; 100 mM) and a selective Group II/III mGluR antagonist ((2S)-2-Amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid; LY341495; 5 mM) into the LH/PFA of conscious rats on ventilation in room air and in 7% CO2, during wakefulness and sleep, in the dark and light periods of the diurnal cycle. Microinjection of MCPG and LY341495 increased the hypercapnic ventilatory response in both the light and the dark period during wakefulness, but not during sleep, (p < 0.001). Our data suggest that glutamate, acting on Group II/III metabotropic receptors in the LH/PFA, exerts an inhibitory modulation of the hypercapnic ventilatory response in awake rats.
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Affiliation(s)
| | - Eliandra Nunes da Silva
- Department of Physiology, Institute of Bioscience, Sao Paulo State University-UNESP, Botucatu, SP, Brazil.
| | | | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University-FCAV, Jaboticabal, SP, Brazil.
| | - Mirela B Dias
- Department of Physiology, Institute of Bioscience, Sao Paulo State University-UNESP, Botucatu, SP, Brazil.
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48
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Iyer M, Essner RA, Klingenberg B, Carter ME. Identification of discrete, intermingled hypocretin neuronal populations. J Comp Neurol 2018; 526:2937-2954. [PMID: 30019757 DOI: 10.1002/cne.24490] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Revised: 06/12/2018] [Accepted: 06/14/2018] [Indexed: 01/04/2023]
Abstract
Neurons in the lateral hypothalamic area that express hypocretin (Hcrt) neuropeptides help regulate many behaviors including wakefulness and reward seeking. These neurons project throughout the brain, including to neural populations that regulate wakefulness, such as the locus coeruleus (LC) and tuberomammilary nucleus (TMN), as well as to populations that regulate reward, such as the nucleus accumbens (NAc) and ventral tegmental area (VTA). To address the roles of Hcrt neurons in seemingly disparate behaviors, it has been proposed that Hcrt neurons can be anatomically subdivided into at least two distinct subpopulations: a "medial group" that projects to the LC and TMN, and a "lateral group" that projects to the NAc and VTA. Here, we use a dual retrograde tracer strategy to test the hypotheses that Hcrt neurons can be classified based on their downstream projections and medial/lateral location within the hypothalamus. We found that individual Hcrt neurons were significantly more likely to project to both the LC and TMN or to both the VTA and NAc than would be predicted by chance. In contrast, we found that Hcrt neurons that projected to the LC or TMN were mostly distinct from Hcrt neurons that projected to the VTA or NAc. Interestingly, these two populations of Hcrt neurons are intermingled within the hypothalamus and cannot be classified into medial or lateral groups. These results suggest that Hcrt neurons can be distinguished based on their downstream projections but are intermingled within the hypothalamus.
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Affiliation(s)
- Manasi Iyer
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
| | - Rachel A Essner
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
| | - Bernhard Klingenberg
- Department of Mathematics and Statistics, Williams College, Williamstown, Massachusetts
| | - Matthew E Carter
- Department of Biology, Williams College, Williamstown, Massachusetts.,Program in Neuroscience, Williams College, Williamstown, Massachusetts
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49
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Orexinergic Modulation of Spinal Motor Activity in the Neonatal Mouse Spinal Cord. eNeuro 2018; 5:eN-NWR-0226-18. [PMID: 30417080 PMCID: PMC6223113 DOI: 10.1523/eneuro.0226-18.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 10/15/2018] [Accepted: 10/20/2018] [Indexed: 11/21/2022] Open
Abstract
The role of orexin during development, and especially in terms of spinal cord function, is not well understood. It is for this reason that we focused on the network actions of orexin during the first week of development. We found that orexinergic fibers were present in the lumbar spinal cord of postnatal day 0 (P0) to P3 mice. The fibers were expressed mainly in the dorsal horn, but occasional fibers were observed in the ventral horn. Both orexin (OX) A and OXB increased the motoneurons (MNs) tonic neurogram discharge. However, only OXA was found to significantly increase spontaneous bursting activity and the frequency of fictive locomotor bursts. We show that OXA is able to act directly on MNs. To test the contribution of the recurrent MN collaterals, we blocked the nicotinic cholinergic drive and observed that OXA retained its ability to increase fictive locomotor activity. Additionally, we recorded neurograms from ventral lateral funiculi, where OXA had no effect on population discharge. These effects were also confirmed by recording from descending commissural interneurons via patch recordings. The loci of the effects of OXA were further investigated in a dorsal horn-removed preparation where OXA also shows an increase in the discharge from ventral root neurograms but no increase in the frequency of spontaneous or fictive locomotion burst activity. In summary, multiple lines of evidence from our work demonstrate the robust effects of orexins on spinal cord networks and MNs at the time of birth.
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Abstract
The neuropeptides orexins are important in regulating the neurobiological systems that respond to stressful stimuli. Furthermore, orexins are known to play a role many of the phenotypes associated with stress-related mental illness such as changes in cognition, sleep-wake states, and appetite. Interestingly, orexins are altered in stress-related psychiatric disorders such as Major Depressive Disorder and Anxiety Disorders. Thus, orexins may be a potential target for treatment of these disorders. In this review, we will focus on what is known about the role of orexins in acute and repeated stress, in stress-induced phenotypes relevant to psychiatric illness in preclinical models, and in stress-related psychiatric illness in humans. We will also briefly discuss how orexins may contribute to sex differences in the stress response and subsequent phenotypes relevant to mental health, as many stress-related psychiatric disorders are twice as prevalent in women.
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