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Mohammadkhani A, Mitchell C, James MH, Borgland SL, Dayas CV. Contribution of hypothalamic orexin (hypocretin) circuits to pathologies of motivation. Br J Pharmacol 2024; 181:4430-4449. [PMID: 39317446 PMCID: PMC11458361 DOI: 10.1111/bph.17325] [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: 07/30/2023] [Revised: 06/17/2024] [Accepted: 06/28/2024] [Indexed: 09/26/2024] Open
Abstract
The orexin (also known as hypocretin) system, consisting of neuropeptides orexin-A and orexin-B, was discovered over 25 years ago and was immediately identified as a central regulator of sleep and wakefulness. These peptides interact with two G-protein coupled receptors, orexin 1 (OX1) and orexin 2 (OX2) receptors which are capable of coupling to all heterotrimeric G-protein subfamilies, but primarily transduce increases in calcium signalling. Orexin neurons are regulated by a variety of transmitter systems and environmental stimuli that signal reward availability, including food and drug related cues. Orexin neurons are also activated by anticipation, stress, cues predicting motivationally relevant information, including those predicting drugs of abuse, and engage neuromodulatory systems, including dopamine neurons of the ventral tegmental area (VTA) to respond to these signals. As such, orexin neurons have been characterized as motivational activators that coordinate a range of functions, including feeding and arousal, that allow the individual to respond to motivationally relevant information, critical for survival. This review focuses on the role of orexins in appetitive motivation and highlights a role for these neuropeptides in pathologies characterized by inappropriately high levels of motivated arousal (overeating, anxiety and substance use disorders) versus those in which motivation is impaired (depression).
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Affiliation(s)
- Aida Mohammadkhani
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada
| | - Caitlin Mitchell
- School of Biomedical Sciences and Pharmacy, University of Newcastle, University Drive, Callaghan, New South Wales, Australia
- The Hunter Medical Research, New Lambton Heights, New South Wales, Australia
| | - Morgan H James
- Department of Psychiatry and Brain Health Institute, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Stephanie L Borgland
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada
| | - Christopher V Dayas
- School of Biomedical Sciences and Pharmacy, University of Newcastle, University Drive, Callaghan, New South Wales, Australia
- The Hunter Medical Research, New Lambton Heights, New South Wales, Australia
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2
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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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3
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la Fleur SE, Blancas-Velazquez AS, Stenvers DJ, Kalsbeek A. Circadian influences on feeding behavior. Neuropharmacology 2024; 256:110007. [PMID: 38795953 DOI: 10.1016/j.neuropharm.2024.110007] [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: 03/07/2024] [Revised: 05/15/2024] [Accepted: 05/19/2024] [Indexed: 05/28/2024]
Abstract
Feeding, like many other biological functions, displays a daily rhythm. This daily rhythmicity is controlled by the circadian timing system of which the central master clock is located in the hypothalamic suprachiasmatic nucleus (SCN). Other brain areas and tissues throughout the body also display rhythmic functions and contain the molecular clock mechanism known as peripheral oscillators. To generate the daily feeding rhythm, the SCN signals to different hypothalamic areas with the lateral hypothalamus, paraventricular nucleus and arcuate nucleus being the most prominent. With respect to the rewarding aspects of feeding behavior, the dopaminergic system is also under circadian influence. However the SCN projects only indirectly to the different reward regions, such as the ventral tegmental area where dopamine neurons are located. In addition, high palatable, high caloric diets have the potential to disturb the normal daily rhythms of physiology and have been shown to alter for example meal patterns. Around a meal several hormones and peptides are released that are also under circadian influence. For example, the release of postprandial insulin and glucagon-like peptide following a meal depend on the time of the day. Finally, we review the effect of deletion of different clock genes on feeding behavior. The most prominent effect on feeding behavior has been observed in Clock mutants, whereas deletion of Bmal1 and Per1/2 only disrupts the day-night rhythm, but not overall intake. Data presented here focus on the rodent literature as only limited data are available on the mechanisms underlying daily rhythms in human eating behavior.
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Affiliation(s)
- 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.
| | - Aurea S Blancas-Velazquez
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Dirk Jan Stenvers
- 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
| | - 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; Amsterdam UMC, University of Amsterdam, Department of Endocrinology and Metabolism, 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
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4
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Skandalakis GP, Neudorfer C, Payne CA, Bond E, Tavakkoli AD, Barrios-Martinez J, Trutti AC, Koutsarnakis C, Coenen VA, Komaitis S, Hadjipanayis CG, Stranjalis G, Yeh FC, Banihashemi L, Hong J, Lozano AM, Kogan M, Horn A, Evans LT, Kalyvas A. Establishing connectivity through microdissections of midbrain stimulation-related neural circuits. Brain 2024; 147:3083-3098. [PMID: 38808482 PMCID: PMC11370807 DOI: 10.1093/brain/awae173] [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: 12/14/2023] [Revised: 03/15/2024] [Accepted: 04/21/2024] [Indexed: 05/30/2024] Open
Abstract
Comprehensive understanding of the neural circuits involving the ventral tegmental area is essential for elucidating the anatomofunctional mechanisms governing human behaviour, in addition to the therapeutic and adverse effects of deep brain stimulation for neuropsychiatric diseases. Although the ventral tegmental area has been targeted successfully with deep brain stimulation for different neuropsychiatric diseases, the axonal connectivity of the region is not fully understood. Here, using fibre microdissections in human cadaveric hemispheres, population-based high-definition fibre tractography and previously reported deep brain stimulation hotspots, we find that the ventral tegmental area participates in an intricate network involving the serotonergic pontine nuclei, basal ganglia, limbic system, basal forebrain and prefrontal cortex, which is implicated in the treatment of obsessive-compulsive disorder, major depressive disorder, Alzheimer's disease, cluster headaches and aggressive behaviours.
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Affiliation(s)
- Georgios P Skandalakis
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
- Department of Neurosurgery, National and Kapodistrian University of Athens Medical School, Evangelismos General Hospital, Athens 10676, Greece
| | - Clemens Neudorfer
- Center for Brain Circuit Therapeutics Department of Neurology Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- MGH Neurosurgery & Center for Neurotechnology and Neurorecovery (CNTR) at MGH Neurology Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Caitlin A Payne
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Evalina Bond
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Armin D Tavakkoli
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | | | - Anne C Trutti
- Integrative Model-Based Cognitive Neuroscience Research Unit, University of Amsterdam, Amsterdam 15926, The Netherlands
| | - Christos Koutsarnakis
- Department of Neurosurgery, National and Kapodistrian University of Athens Medical School, Evangelismos General Hospital, Athens 10676, Greece
| | - Volker A Coenen
- Department of Stereotactic and Functional Neurosurgery, Medical Center of the University of Freiburg, Freiburg 79106, Germany
- Medical Faculty of the University of Freiburg, Freiburg 79110, Germany
- Center for Deep Brain Stimulation, Medical Center of the University of Freiburg, Freiburg 79106, Germany
| | - Spyridon Komaitis
- Queens Medical Center, Nottingham University Hospitals NHS Foundation Trust, Nottingham NG7 2UH, UK
| | | | - George Stranjalis
- Department of Neurosurgery, National and Kapodistrian University of Athens Medical School, Evangelismos General Hospital, Athens 10676, Greece
| | - Fang-Cheng Yeh
- Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Layla Banihashemi
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15213, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Jennifer Hong
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Andres M Lozano
- Division of Neurosurgery, University Health Network, University of Toronto, Toronto, ON M5T 1P5, Canada
| | - Michael Kogan
- Department of Neurosurgery, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
| | - Andreas Horn
- Center for Brain Circuit Therapeutics Department of Neurology Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- MGH Neurosurgery & Center for Neurotechnology and Neurorecovery (CNTR) at MGH Neurology Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- Movement Disorder and Neuromodulation Unit, Department of Neurology, Department of Neurology, Charité—Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Linton T Evans
- Section of Neurosurgery, Dartmouth Hitchcock Medical Center, Lebanon, NH 03756, USA
| | - Aristotelis Kalyvas
- Division of Neurosurgery, University Health Network, University of Toronto, Toronto, ON M5T 1P5, Canada
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5
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Hinova-Palova D, Landzhov B, Edelstein L, Fakih K, Alexandrov A, Kiriakova T, Radeva E, Gaydarski L, Denaro F, Paloff A. Identification of degenerated synaptic boutons in the dorsal claustrum of the cat after electrolytic lesions of the intralaminar thalamic nuclei. J Histotechnol 2024; 47:117-125. [PMID: 38564246 DOI: 10.1080/01478885.2024.2335827] [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: 05/18/2023] [Accepted: 03/23/2024] [Indexed: 04/04/2024]
Abstract
The aim of this study is to investigate whether the dorsal claustrum receives afferent input from the intralaminar thalamic nuclei - centromedian nucleus, central lateral nucleus and paracentral nucleus. The intralaminar thalamic nuclei of eight cats were electrolytically lesioned. We obtained samples from the dorsal claustrum for electron microscopic analysis from the second to the seventh post-procedural day. Two types of degenerated synaptic boutons were observed: electron-dense which formed the majority of boutons, and electron-lucent comprising the remaining samples. Between the second and seventh post-procedural day, we observed a steady increase in the number of electron-dense boutons which were diffusely distributed throughout the dorsal claustrum. Electron-dense degenerated boutons formed asymmetrical contacts with dendritic spines as well as with small and medium-sized dendrites. In contrast, electron-lucent degenerated boutons were observed in earlier post-procedural periods and formed symmetrical axodendritic contacts.
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Affiliation(s)
- Dimka Hinova-Palova
- Department of Anatomy, Histology and Embryology, Medical University of Sofia, Sofia, Bulgaria
| | - Boycho Landzhov
- Department of Anatomy, Histology and Embryology, Medical University of Sofia, Sofia, Bulgaria
| | - Lawrence Edelstein
- Department of Experimental Neuroanatomy, Medimark Corporation, Del Mar, CA, USA
| | - Khodor Fakih
- Department of Oral and Maxillofacial Surgery, Medical University of Sofia, Sofia, Bulgaria
| | - Alexandar Alexandrov
- Department of Forensic Medicine and Deontology, Medical University of Sofia, Sofia, Bulgaria
| | - Teodora Kiriakova
- Department of Forensic Medicine and Deontology, Medical University of Sofia, Sofia, Bulgaria
| | - Elka Radeva
- Department of Conservative Dentistry, Faculty of Dental Medicine, Medical University Sofia, Sofia, Bulgaria
| | - Lyubomir Gaydarski
- Department of Anatomy, Histology and Embryology, Medical University of Sofia, Sofia, Bulgaria
| | - Frank Denaro
- Department of Biology, Morgan State University, Baltimore, MD, USA
| | - Adrian Paloff
- Department of Anatomy, Histology and Embryology, Medical University of Sofia, Sofia, Bulgaria
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6
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Schoukroun F, Befort K, Bourdy R. The rostromedial tegmental nucleus gates fat overconsumption through ventral tegmental area output in male rats. Neuropsychopharmacology 2024; 49:1569-1579. [PMID: 38570645 PMCID: PMC11319719 DOI: 10.1038/s41386-024-01855-w] [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: 11/30/2023] [Revised: 02/27/2024] [Accepted: 03/22/2024] [Indexed: 04/05/2024]
Abstract
Excessive consumption of palatable foods that are rich in fats and sugars has contributed to the increasing prevalence of obesity worldwide. Similar to addictive drugs, such foods activate the brain's reward circuit, involving mesolimbic dopaminergic projections from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) and the prefrontal cortex. Neuroadaptations occurring in this circuit are hypothesized to contribute to uncontrolled consumption of such foods, a common feature of most of eating disorders and obesity. The rostromedial tegmental nucleus (RMTg), also named tail of the VTA (tVTA), is an inhibitory structure projecting to the VTA and the lateral hypothalamus (LH), two key brain regions in food intake regulation. Prior research has demonstrated that the RMTg responds to addictive drugs and influences their impact on mesolimbic activity and reward-related behaviors. However, the role of the RMTg in food intake regulation remains largely unexplored. The present study aimed to investigate the role of the RMTg and its projections to the VTA and the LH in regulating food intake in rats. To do so, we examined eating patterns of rats with either bilateral excitotoxic lesions of the RMTg or specific lesions of RMTg-VTA and RMTg-LH pathways. Rats were exposed to a 6-week 'free choice high-fat and high-sugar' diet, followed by a 4-week palatable food forced abstinence and a 24 h re-access period. Our results indicate that an RMTg-VTA pathway lesion increases fat consumption following 6 weeks of diet and at time of re-access. The RMTg-LH pathway lesion produces a milder effect with a decrease in global calorie intake. These findings suggest that the RMTg influences palatable food consumption and relapse through its projections to the VTA.
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Affiliation(s)
- Florian Schoukroun
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, UMR7364, CNRS, 12 Rue Goethe, 67000, Strasbourg, France
| | - Katia Befort
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, UMR7364, CNRS, 12 Rue Goethe, 67000, Strasbourg, France.
| | - Romain Bourdy
- Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Université de Strasbourg, UMR7364, CNRS, 12 Rue Goethe, 67000, Strasbourg, France.
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7
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Lipiec-Borowicz A, Pałasz A, Suszka-Świtek A, Filipczyk Ł, Della Vecchia A, Worthington JJ, Piwowarczyk-Nowak A. Neuropeptides in the rat claustrum - An immunohistochemical detection. Acta Histochem 2024; 126:152156. [PMID: 38518508 DOI: 10.1016/j.acthis.2024.152156] [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: 12/17/2023] [Revised: 03/16/2024] [Accepted: 03/18/2024] [Indexed: 03/24/2024]
Abstract
Neuropeptides are involved in numerous brain activities and are responsible for a wide spectrum of higher mental functions. The main purpose of this outline structural qualitative study was to identify the possible immunoreactivity of classical neuropeptides, as well as novel ones such as nesfatin-1, phoenixin (PNX), spexin (SPX), neuromedin U (NMU) and respective receptors within the rat claustrum for the first time. The study shows the novel identification of peptidergic neurotransmission in the rat claustrum which potentially implicates a contribution of this neuropeptide to numerous central neurosecretory mechanisms.
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Affiliation(s)
- Anna Lipiec-Borowicz
- Department of Histology, School of Medical Sciences in Katowice, Medical University of Silesia, ul. Medyków 18, Katowice 40-752, Poland.
| | - Artur Pałasz
- Department of Histology, School of Medical Sciences in Katowice, Medical University of Silesia, ul. Medyków 18, Katowice 40-752, Poland.
| | - Aleksandra Suszka-Świtek
- Department of Histology, School of Medical Sciences in Katowice, Medical University of Silesia, ul. Medyków 18, Katowice 40-752, Poland
| | - Łukasz Filipczyk
- Department of Histology, School of Medical Sciences in Katowice, Medical University of Silesia, ul. Medyków 18, Katowice 40-752, Poland
| | - Alessandra Della Vecchia
- Department of Clinical and Experimental Medicine, Section of Psychiatry, University of Pisa, 67, Via Roma, Pisa 56100, Italy
| | - John J Worthington
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, LA1 4YQ, UK
| | - Aneta Piwowarczyk-Nowak
- Department of Anatomy, School of Medical Sciences in Katowice, Medical University of Silesia, ul. Medyków 18, Katowice 40-752, Poland
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8
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Kim WJ, Kim HS. Emerging and upcoming therapies in insomnia. Transl Clin Pharmacol 2024; 32:1-17. [PMID: 38586124 PMCID: PMC10990727 DOI: 10.12793/tcp.2024.32.e5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 04/09/2024] Open
Abstract
Insomnia, commonly treated with benzodiazepine (BZD) receptor agonists, presents challenges due to associated serious side effects such as abuse and dependence. To address these concerns, many researches have been conducted to develop and advance both pharmacological and non-pharmacological interventions. Dual orexin receptor antagonists (DORAs), which include suvorexant, daridorexant and lemborexant, have recently been approved by United States Food and Drug Administration (US FDA) as a novel pharmacotherapeutic alternative. Unlike BZD receptor agonists that act as positive allosteric modulators of the gamma-aminobutyric acid type A subunit alpha 1 receptor, DORAs function by binding to both orexin receptor types 1 and 2, and inhibiting the action of the wake-promoting orexin neuropeptide. These drugs induce normal sleep without sleep stage change, do not impair attention and memory performance, and facilitate easier awakening. However, more real-world safety information is needed. Selective orexin-2 receptor antagonists (2-SORAs) is under clinical developments. This review provides an overview of the mechanism of action in relation to insomnia, pharmacokinetics, efficacy and safety information of DORAs and SORA. According to insomnia management guidelines, the first-line treatment for chronic insomnia is cognitive behavioral therapy for insomnia (CBT-I). Although it has proven effective in improving sleep-related quality of life, it has several restrictions limitations due to a face-to-face format. Recently, prescription digital therapy such as Somryst® was approved by US FDA. Somryst®, a smartphone app-based CBT-I, demonstrated meaningful responses in patients. However, digital limitations may impact scalability. Overall, these developments offer promising alternatives for insomnia treatment, emphasizing safety, efficacy, and accessibility.
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Affiliation(s)
- Woo-Ju Kim
- Inje University College of Medicine, Busan, Korea
| | - Ho-Sook Kim
- Department of Pharmacology and PharmacoGenomics Research Center, Inje University College of Medicine, Busan, Korea
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9
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Narai E, Yoshimura Y, Honaga T, Mizoguchi H, Yamanaka A, Hiyama TY, Watanabe T, Koba S. Orexinergic neurons contribute to autonomic cardiovascular regulation for locomotor exercise. J Physiol 2024. [PMID: 38380995 DOI: 10.1113/jp285791] [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: 12/01/2023] [Accepted: 01/26/2024] [Indexed: 02/22/2024] Open
Abstract
While the hypothalamic orexinergic nervous system is established as having a pivotal role in the long-term regulation of various organismic functions, including wakefulness, metabolism and hypertensive states, whether this system contributes to the rapid autonomic cardiovascular regulation during physical activity remains elusive. This study aimed to elucidate the role of the orexinergic nervous system in transmitting volitional motor signals, i.e. central command, to drive somatomotor and sympathetic cardiovascular responses. We first found that this system is activated by voluntary locomotor exercise as evidenced by an increased expression of Fos, a marker of neural activation, in the orexinergic neurons of Sprague-Dawley rats engaged in spontaneous wheel running. Next, using transgenic Orexin-Cre rats for optogenetic manipulation of orexinergic neurons, we found that optogenetic excitation of orexinergic neurons caused sympathoexcitation on a subsecond timescale under anaesthesia. In freely moving conscious rats, this excitatory stimulation rapidly elicited exploration-like behaviours, predominantly locomotor activity, along with pressor and tachycardiac responses. Meanwhile, optogenetic inhibition of orexinergic neurons during spontaneous wheel running immediately suppressed locomotor activities and blood pressure elevation without affecting basal cardiovascular homeostasis. Taken together, these findings demonstrate the essential role of the orexinergic nervous system in the central circuitry that transmits central command signals for locomotor exercise. This study not only offers insights into the brain circuit mechanisms precisely regulating autonomic cardiovascular systems during voluntary exercise but also likely contributes to our understanding of brain mechanisms underlying abnormal cardiovascular adjustments to exercise in pathological conditions, such as hypertension. KEY POINTS: The hypothalamic orexinergic nervous system plays various roles in the long-term regulation of autonomic and endocrine functions, as well as motivated behaviours. We present a novel, rapid role of the orexinergic nervous system, revealing its significance as a crucial substrate in the brain circuit mechanisms that coordinate somatomotor and autonomic cardiovascular controls for locomotor exercise. Our data demonstrate that orexinergic neurons relay volitional motor signals, playing a necessary and sufficient role in the autonomic cardiovascular regulation required for locomotor exercise in rats. The findings contribute to our understanding of how the brain precisely regulates autonomic cardiovascular systems during voluntary exercise, providing insights into the central neural mechanisms that enhance physical performance moment-by-moment during exercise.
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Affiliation(s)
- Emi Narai
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Yuki Yoshimura
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Takaho Honaga
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Hiroyuki Mizoguchi
- Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Akihiro Yamanaka
- Chinese Institute for Brain Research, Beijing (CIBR), Beijing, China
| | - Takeshi Y Hiyama
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Tatsuo Watanabe
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Satoshi Koba
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
- Division of Veterinary Physiology, Tottori University Faculty of Agriculture, Tottori, Japan
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10
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Jászberényi M, Thurzó B, Bagosi Z, Vécsei L, Tanaka M. The Orexin/Hypocretin System, the Peptidergic Regulator of Vigilance, Orchestrates Adaptation to Stress. Biomedicines 2024; 12:448. [PMID: 38398050 PMCID: PMC10886661 DOI: 10.3390/biomedicines12020448] [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: 01/18/2024] [Revised: 02/10/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
The orexin/hypocretin neuropeptide family has emerged as a focal point of neuroscientific research following the discovery that this family plays a crucial role in a variety of physiological and behavioral processes. These neuropeptides serve as powerful neuromodulators, intricately shaping autonomic, endocrine, and behavioral responses across species. Notably, they serve as master regulators of vigilance and stress responses; however, their roles in food intake, metabolism, and thermoregulation appear complementary and warrant further investigation. This narrative review provides a journey through the evolution of our understanding of the orexin system, from its initial discovery to the promising progress made in developing orexin derivatives. It goes beyond conventional boundaries, striving to synthesize the multifaceted activities of orexins. Special emphasis is placed on domains such as stress response, fear, anxiety, and learning, in which the authors have contributed to the literature with original publications. This paper also overviews the advancement of orexin pharmacology, which has already yielded some promising successes, particularly in the treatment of sleep disorders.
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Affiliation(s)
- Miklós Jászberényi
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
| | - Balázs Thurzó
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
- Emergency Patient Care Unit, Albert Szent-Györgyi Health Centre, University of Szeged, H-6725 Szeged, Hungary
| | - Zsolt Bagosi
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
| | - László Vécsei
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary;
- HUN-REN-SZTE Neuroscience Research Group, Hungarian Research Network, University of Szeged (HUN-REN-SZTE), Danube Neuroscience Research Laboratory, Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Masaru Tanaka
- HUN-REN-SZTE Neuroscience Research Group, Hungarian Research Network, University of Szeged (HUN-REN-SZTE), Danube Neuroscience Research Laboratory, Tisza Lajos krt. 113, H-6725 Szeged, Hungary
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11
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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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12
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Fernandez FX, Perlis ML. Animal models of human insomnia. J Sleep Res 2023; 32:e13845. [PMID: 36748845 PMCID: PMC10404637 DOI: 10.1111/jsr.13845] [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: 12/16/2022] [Accepted: 01/20/2023] [Indexed: 02/08/2023]
Abstract
Insomnia disorder (chronic sleep continuity disturbance) is a debilitating condition affecting 5%-10% of the adult population worldwide. To date, researchers have attempted to model insomnia in animals through breeding strategies that create pathologically short-sleeping individuals or with drugs and environmental contexts that directly impose sleeplessness. While these approaches have been invaluable for identifying insomnia susceptibility genes and mapping the neural networks that underpin sleep-wake regulation, they fail to capture concurrently several of the core clinical diagnostic features of insomnia disorder in humans, where sleep continuity disturbance is self-perpetuating, occurs despite adequate sleep opportunity, and is often not accompanied by significant changes in sleep duration or architecture. In the present review, we discuss these issues and then outline ways animal models can be used to develop approaches that are more ecologically valid in their recapitulation of chronic insomnia's natural aetiology and pathophysiology. Conditioning of self-generated sleep loss with these methods promises to create a better understanding of the neuroadaptations that maintain insomnia, including potentially within the infralimbic cortex, a substrate at the crossroads of threat habituation and sleep.
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Affiliation(s)
| | - Michael L. Perlis
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, USA
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13
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Somach RT, Jean ID, Farrugia AM, Cohen AS. Mild Traumatic Brain Injury Affects Orexin/Hypocretin Physiology Differently in Male and Female Mice. J Neurotrauma 2023; 40:2146-2163. [PMID: 37476962 PMCID: PMC10701510 DOI: 10.1089/neu.2023.0125] [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: 07/22/2023] Open
Abstract
Traumatic brain injury (TBI) is known to affect the physiology of neural circuits in several brain regions, which can contribute to behavioral changes after injury. Disordered sleep is a behavior that is often seen after TBI, but there is little research into how injury affects the circuitry that contributes to disrupted sleep regulation. Orexin/hypocretin neurons (hereafter referred to as orexin neurons) located in the lateral hypothalamus normally stabilize wakefulness in healthy animals and have been suggested as a source of dysregulated sleep behavior. Despite this, few studies have examined how TBI affects orexin neuron circuitry. Further, almost no animal studies of orexin neurons after TBI have included female animals. Here, we address these gaps by studying changes to orexin physiology using ex vivo acute brain slices and whole-cell patch clamp recording. We hypothesized that orexin neurons would have reduced afferent excitatory activity after injury. Ultimately, this hypothesis was supported but there were additional physiological changes that occurred that we did not originally hypothesize. We studied physiological properties in orexin neurons approximately 1 week after mild traumatic brain injury (mTBI) in 6-8-week-old male and female mice. mTBI was performed with a lateral fluid percussion injury between 1.4 and 1.6 atmospheres. Mild TBI increased the size of action potential afterhyperpolarization in orexin neurons from female mice, but not male mice and reduced the action potential threshold in male mice, but not in female mice. Mild TBI reduced afferent excitatory activity and increased afferent inhibitory activity onto orexin neurons. Alterations in afferent excitatory activity occurred in different parameters in male and female animals. The increased afferent inhibitory activity after injury is more pronounced in recordings from female animals. Our results indicate that mTBI changes the physiology of orexin neuron circuitry and that these changes are not the same in male and female animals.
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Affiliation(s)
- Rebecca T. Somach
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian D. Jean
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Anthony M. Farrugia
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Akiva S. Cohen
- Department of Anesthesiology and Critical Care Medicine, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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14
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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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15
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Berteotti C, Calvello C, Liguori C. Role of the orexin system in the bidirectional relation between sleep and epilepsy: New chances for patients with epilepsy by the antagonism to orexin receptors? Epilepsia 2023; 64:1991-2005. [PMID: 37212716 DOI: 10.1111/epi.17661] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 05/19/2023] [Accepted: 05/19/2023] [Indexed: 05/23/2023]
Abstract
Epilepsy is a common neurological disorder, affecting patients of all ages, reducing the quality of life, and associated with several comorbidities. Sleep impairment is a frequent condition in patients with epilepsy (PWE), and the relation between sleep and epilepsy has been considered bidirectional, as one can significantly influence the other, and vice versa. The orexin system was described more than 20 years ago and is implicated in several neurobiological functions other than in controlling the sleep-wake cycle. Considering the relation between epilepsy and sleep, and the significant contribution of the orexin system in regulating the sleep-wake cycle, it is conceivable that the orexin system may be affected in PWE. Preclinical studies investigated the impact of the orexin system on epileptogenesis and the effect of orexin antagonism on seizures in animal models. Conversely, clinical studies are few and propose heterogeneous results also considering the different methodological approaches to orexin levels quantification (cerebrospinal-fluid or blood samples). Because orexin system activity can be modulated by sleep, and considering the sleep impairment documented in PWE, the recently approved dual orexin receptor antagonists (DORAs) have been suggested for treating sleep impairment and insomnia in PWE. Accordingly, sleep improvement can be a therapeutic strategy for reducing seizures and better managing epilepsy. The present review analyzes the preclinical and clinical evidence linking the orexin system to epilepsy, and hypothesizes a model in which the antagonism to the orexin system by DORAs can improve epilepsy by both a direct and a sleep-mediated (indirect) effect.
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Affiliation(s)
- Chiara Berteotti
- Physiological Regulation in Sleeping Mice Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Carmen Calvello
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Claudio Liguori
- Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
- Epilepsy Center, Neurology Unit, University Hospital Tor Vergata, Rome, Italy
- Sleep Medicine Center, Neurology Unit, University Hospital Tor Vergata, Rome, Italy
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16
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Saitoh T, Sakurai T. The Present and Future of Synthetic Orexin Receptor Agonists. Peptides 2023:171051. [PMID: 37422012 DOI: 10.1016/j.peptides.2023.171051] [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: 05/03/2023] [Revised: 06/16/2023] [Accepted: 07/02/2023] [Indexed: 07/10/2023]
Abstract
The neuropeptide orexin/hypocretin plays a crucial role in various physiological processes, including the regulation of sleep/wakefulness, appetite, emotion and the reward system. Dysregulation of orexin signaling has been implicated in hypersomnia, especially in narcolepsy, which is a chronic neurological disorder characterized by excessive daytime sleepiness (EDS), sudden loss of muscle tone while awake (cataplexy), sleep paralysis, and hallucinations. Small-molecule orexin receptor agonists have emerged as promising therapeutics for these disorders, and significant progress has been made in this field in the past decade. This review summarizes recent advances in the design and synthesis of orexin receptor agonists, with a focus on peptidic and small-molecule OX2R-selective, dual, and OX1R-selective agonists. The review discusses the key structural features and pharmacological properties of these agonists, as well as their potential therapeutic applications. DATA AVAILABILITY: No data was used for the research described in the article.
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Affiliation(s)
- Tsuyoshi Saitoh
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; International Institute for Integrative Sleep Medicine (IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
| | - Takeshi Sakurai
- Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan; International Institute for Integrative Sleep Medicine (IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8575, Japan
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17
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Prokofeva K, Saito YC, Niwa Y, Mizuno S, Takahashi S, Hirano A, Sakurai T. Structure and Function of Neuronal Circuits Linking Ventrolateral Preoptic Nucleus and Lateral Hypothalamic Area. J Neurosci 2023; 43:4075-4092. [PMID: 37117013 PMCID: PMC10255079 DOI: 10.1523/jneurosci.1913-22.2023] [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: 10/04/2022] [Revised: 04/19/2023] [Accepted: 04/21/2023] [Indexed: 04/30/2023] Open
Abstract
To understand how sleep-wakefulness cycles are regulated, it is essential to disentangle structural and functional relationships between the preoptic area (POA) and lateral hypothalamic area (LHA), since these regions play important yet opposing roles in the sleep-wakefulness regulation. GABA- and galanin (GAL)-producing neurons in the ventrolateral preoptic nucleus (VLPO) of the POA (VLPOGABA and VLPOGAL neurons) are responsible for the maintenance of sleep, while the LHA contains orexin-producing neurons (orexin neurons) that are crucial for maintenance of wakefulness. Through the use of rabies virus-mediated neural tracing combined with in situ hybridization (ISH) in male and female orexin-iCre mice, we revealed that the vesicular GABA transporter (Vgat, Slc32a1)- and galanin (Gal)-expressing neurons in the VLPO directly synapse with orexin neurons in the LHA. A majority (56.3 ± 8.1%) of all VLPO input neurons connecting to orexin neurons were double-positive for Vgat and Gal Using projection-specific rabies virus-mediated tracing in male and female Vgat-ires-Cre and Gal-Cre mice, we discovered that VLPOGABA and VLPOGAL neurons that send projections to the LHA received innervations from similarly distributed input neurons in many brain regions, with the POA and LHA being among the main upstream areas. Additionally, we found that acute optogenetic excitation of axons of VLPOGABA neurons, but not VLPOGAL neurons, in the LHA of male Vgat-ires-Cre mice induced wakefulness. This study deciphers the connectivity between the VLPO and LHA, provides a large-scale map of upstream neuronal populations of VLPO→LHA neurons, and reveals a previously uncovered function of the VLPOGABA→LHA pathway in the regulation of sleep and wakefulness.SIGNIFICANCE STATEMENT We identified neurons in the ventrolateral preoptic nucleus (VLPO) that are positive for vesicular GABA transporter (Vgat) and/or galanin (Gal) and serve as presynaptic partners of orexin-producing neurons in the lateral hypothalamic area (LHA). We depicted monosynaptic input neurons of GABA- and galanin-producing neurons in the VLPO that send projections to the LHA throughout the entire brain. Their input neurons largely overlap, suggesting that they comprise a common neuronal population. However, acute excitatory optogenetic manipulation of the VLPOGABA→LHA pathway, but not the VLPOGAL→LHA pathway, evoked wakefulness. This study shows the connectivity of major components of the sleep/wake circuitry in the hypothalamus and unveils a previously unrecognized function of the VLPOGABA→LHA pathway in sleep-wakefulness regulation. Furthermore, we suggest the existence of subpopulations of VLPOGABA neurons that innervate LHA.
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Affiliation(s)
- Kseniia Prokofeva
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Yuki C Saito
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Yasutaka Niwa
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Seiya Mizuno
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Satoru Takahashi
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Arisa Hirano
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Takeshi Sakurai
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Institute of Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
- Life Science Center for Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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18
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Maruyama T, Ueta Y. Internal and external modulation factors of the orexin system (REVIEW). Peptides 2023; 165:171009. [PMID: 37054895 DOI: 10.1016/j.peptides.2023.171009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 04/15/2023]
Abstract
Orexin-A and -B (identical to hypocretin-1 and -2) are neuropeptides synthesized in the lateral hypothalamus and perifornical area, and orexin neurons project their axon terminals broadly throughout the entire central nervous system (CNS). The activity of orexins is mediated by two specific G protein-coupled receptors (GPCRs), termed orexin type1 receptor (OX1R) and orexin type2 receptor (OX2R). The orexin system plays a relevant role in various physiological functions, including arousal, feeding, reward, and thermogenesis, and is key to human health. Orexin neurons receive various signals related to environmental, physiological, and emotional stimuli. Previous studies have reported that several neurotransmitters and neuromodulators influence the activation or inhibition of orexin neuron activity. In this review, we summarize the modulating factors of orexin neurons in the sleep/wake rhythm and feeding behavior, particularly in the context of the modulation of appetite, body fluids, and circadian signaling. We also describe the effects of life activity, behavior, and diet on the orexin system. Some studies have observed phenomena that have been verified in animal experiments, revealing the detailed mechanism and neural pathway, while their applications to humans is expected in future research.
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Affiliation(s)
- Takashi Maruyama
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan.
| | - Yoichi Ueta
- Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Japan
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19
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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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20
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Krohn F, Novello M, van der Giessen RS, De Zeeuw CI, Pel JJM, Bosman LWJ. The integrated brain network that controls respiration. eLife 2023; 12:83654. [PMID: 36884287 PMCID: PMC9995121 DOI: 10.7554/elife.83654] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 01/29/2023] [Indexed: 03/09/2023] Open
Abstract
Respiration is a brain function on which our lives essentially depend. Control of respiration ensures that the frequency and depth of breathing adapt continuously to metabolic needs. In addition, the respiratory control network of the brain has to organize muscular synergies that integrate ventilation with posture and body movement. Finally, respiration is coupled to cardiovascular function and emotion. Here, we argue that the brain can handle this all by integrating a brainstem central pattern generator circuit in a larger network that also comprises the cerebellum. Although currently not generally recognized as a respiratory control center, the cerebellum is well known for its coordinating and modulating role in motor behavior, as well as for its role in the autonomic nervous system. In this review, we discuss the role of brain regions involved in the control of respiration, and their anatomical and functional interactions. We discuss how sensory feedback can result in adaptation of respiration, and how these mechanisms can be compromised by various neurological and psychological disorders. Finally, we demonstrate how the respiratory pattern generators are part of a larger and integrated network of respiratory brain regions.
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Affiliation(s)
- Friedrich Krohn
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | - Manuele Novello
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
| | | | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Johan J M Pel
- Department of Neuroscience, Erasmus MC, Rotterdam, Netherlands
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21
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Sex-dependent role of orexin deficiency in feeding behavior and affective state of mice following intermittent access to a Western diet - Implications for binge-like eating behavior. Physiol Behav 2023; 260:114069. [PMID: 36572152 DOI: 10.1016/j.physbeh.2022.114069] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/02/2022] [Accepted: 12/22/2022] [Indexed: 12/24/2022]
Abstract
Binge eating disorder is a debilitating disease characterized by recurrent episodes of excessive food consumption and associated with psychiatric comorbidities. Despite a growing body of research investigating the neurobiological underpinnings of eating disorders, specific treatments are lacking. Given its fundamental role in feeding behaviors, we investigated the role of the orexin (hypocretin) neuropeptide system in binge-like eating and associated phenotypes. Specifically, we submitted female and male orexin-deficient mice to a paradigm of intermittent access (once weekly for 24 h) to a Western diet (WD) to induce binge-like eating. Additionally, we measured their anxiety-like behavior and plasma corticosterone levels. All mice showed binge-like eating in response to the intermittent WD access, but females did so to a greater extent than males. While orexin deficiency did not affect binge-like eating in this paradigm, we found that female orexin-deficient mice generally weighed more, and they expressed increased hypophagia and stress levels compared to wild-type mice following binge-like eating episodes. These detrimental effects of orexin deficiency were marginal or absent in males. Moreover, male wild-type mice expressed post-binge anxiety, but orexin-deficient mice did not. In conclusion, these results extend our knowledge of orexin's role in dysregulated eating and associated negative affective states, and contribute to the growing body of evidence indicating a sexual dimorphism of the orexin system. Considering that many human disorders, and especially eating disorders, have a strong sex bias, our findings further emphasize the importance of testing both female and male subjects.
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22
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Ben Musa R, Cornelius-Green J, Hasser EM, Cummings KJ. The effect of orexin on the hypoxic ventilatory response of female rats is greatest in the active phase during diestrus. J Appl Physiol (1985) 2023; 134:638-648. [PMID: 36656978 PMCID: PMC10010922 DOI: 10.1152/japplphysiol.00661.2022] [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: 11/02/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
We recently showed that in male rats, orexin contributes to the hypoxic ventilatory response (HVR), with a stronger effect in the active phase. The effect of orexin on the HVR in females has not been investigated. As estrogen can inhibit orexin neurons, here we hypothesized that orexin neurons are activated by hypoxia and facilitate the HVR only in diestrus, when estrogen is low. We exposed female rats (n = 10) to near-isocapnic hypoxia ([Formula: see text] from 0.21 to 0.09) over ∼5 min, after vehicle and again after suvorexant (a dual OxR antagonist; 20 mg/kg ip), with ventilation measured using whole body plethysmography. Each rat was tested in proestrus or estrus (p/estrus), and again in diestrus, during both inactive and active phases. We also performed immunohistochemistry (IHC) to determine the proportion of orexin neurons activated by acute hypoxia during diestrus (n = 6) or proestrus/estrus (n = 6) in the active phase. In the inactive phase, the HVR was unaffected by OxR blockade, irrespective of estrus stage. In the active phase, the effect of OxR blockade depended on stage: the slope of the HVR was significantly reduced by OxR blockade only during diestrus. IHC revealed that hypoxia activated more orexin neurons during diestrus compared with p/estrus. We conclude that in females, orexin neurons are activated by hypoxia and contribute to the HVR only in diestrus when estrogen levels are low. Stage of the estrus cycle should be considered when examining the physiological function of orexin neurons in females.NEW & NOTEWORTHY We previously showed that orexin facilitates the hypoxic ventilatory response (HVR) of adult male rats during the active phase. Others have shown that estrogen inhibits orexin neurons. Here we show that orexin neurons are activated by hypoxia and facilitate the HVR of adult female rats during the active phase, but only in diestrus. These data suggest that orexin neurons facilitate the HVR in females when they are free from the inhibitory effects of estrogen.
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Affiliation(s)
- Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
| | - Jennifer Cornelius-Green
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
| | - Eileen M Hasser
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
| | - Kevin J Cummings
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, United States
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Plaza-Briceño W, Velásquez VB, Silva-Olivares F, Ceballo K, Céspedes R, Jorquera G, Cruz G, Martínez-Pinto J, Bonansco C, Sotomayor-Zárate R. Chronic Exposure to High Fat Diet Affects the Synaptic Transmission That Regulates the Dopamine Release in the Nucleus Accumbens of Adolescent Male Rats. Int J Mol Sci 2023; 24:ijms24054703. [PMID: 36902133 PMCID: PMC10003643 DOI: 10.3390/ijms24054703] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/21/2022] [Accepted: 12/23/2022] [Indexed: 03/05/2023] Open
Abstract
Obesity is a pandemic caused by many factors, including a chronic excess in hypercaloric and high-palatable food intake. In addition, the global prevalence of obesity has increased in all age categories, such as children, adolescents, and adults. However, at the neurobiological level, how neural circuits regulate the hedonic consumption of food intake and how the reward circuit is modified under hypercaloric diet consumption are still being unraveled. We aimed to determine the molecular and functional changes of dopaminergic and glutamatergic modulation of nucleus accumbens (NAcc) in male rats exposed to chronic consumption of a high-fat diet (HFD). Male Sprague-Dawley rats were fed a chow diet or HFD from postnatal day (PND) 21 to 62, increasing obesity markers. In addition, in HFD rats, the frequency but not amplitude of the spontaneous excitatory postsynaptic current is increased in NAcc medium spiny neurons (MSNs). Moreover, only MSNs expressing dopamine (DA) receptor type 2 (D2) increase the amplitude and glutamate release in response to amphetamine, downregulating the indirect pathway. Furthermore, NAcc gene expression of inflammasome components is increased by chronic exposure to HFD. At the neurochemical level, DOPAC content and tonic dopamine (DA) release are reduced in NAcc, while phasic DA release is increased in HFD-fed rats. In conclusion, our model of childhood and adolescent obesity functionally affects the NAcc, a brain nucleus involved in the hedonic control of feeding, which might trigger addictive-like behaviors for obesogenic foods and, through positive feedback, maintain the obese phenotype.
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Affiliation(s)
- Wladimir Plaza-Briceño
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Programa de Doctorado en Ciencias Mención Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Victoria B. Velásquez
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Programa de Doctorado en Ciencias Mención Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Francisco Silva-Olivares
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Programa de Doctorado en Ciencias Mención Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Instituto de Ciencias Naturales, Facultad de Medicina Veterinaria y Agronomía, Universidad de las Américas, Viña del Mar 2520000, Chile
| | - Karina Ceballo
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Programa de Doctorado en Ciencias Mención Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Ricardo Céspedes
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Programa de Doctorado en Ciencias Mención Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Gonzalo Jorquera
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Gonzalo Cruz
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Jonathan Martínez-Pinto
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Christian Bonansco
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Correspondence: (C.B.); (R.S.-Z.)
| | - Ramón Sotomayor-Zárate
- Centro de Neurobiología y Fisiopatología Integrativa (CENFI), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso 2360102, Chile
- Correspondence: (C.B.); (R.S.-Z.)
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He X, Ji P, Guo R, Ming X, Zhang H, Yu L, Chen Z, Gao S, Guo F. Regulation of the central amygdala on intestinal motility and behavior via the lateral hypothalamus in irritable bowel syndrome model mice. Neurogastroenterol Motil 2023; 35:e14498. [PMID: 36408759 DOI: 10.1111/nmo.14498] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/28/2022] [Accepted: 10/18/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Impaired bidirectional communication between the gastrointestinal tract and the central nervous system (CNS) is closely related to the development of irritable bowel syndrome (IBS). Studies in patients with IBS have also shown significant activation of the hypothalamus and amygdala. However, how neural circuits of the CNS participate in and process the emotional and intestinal disorders of IBS remains unclear. METHODS The GABAergic neural pathway projecting from the central amygdala (CeA) to the lateral hypothalamus (LHA) in mice was investigated by retrograde tracking combined with fluorescence immunohistochemistry. Anxiety, depression-like behavior, and intestinal motility were observed in the water-immersion restraint stress group and the control group. Furthermore, the effects of the chemogenetic activation of the GABAergic neural pathway of CeA-LHA on behavior and intestinal motility, as well as the co-expression of orexin-A and c-Fos in the LHA, were explored. KEY RESULTS In our study, Fluoro-Gold retrograde tracking combined with fluorescence immunohistochemistry showed that GABAergic neurons in the CeA were projected to the LHA. The microinjection of the gamma-aminobutyric acid (GABA) receptor antagonist into the LHA relieved anxiety, depression-like behavior, and intestinal motility disorder in the IBS mice. The chemogenetic activation of GABAergic neurons in the CeA-LHA pathway led to anxiety, depression-like behavior, and intestinal motility disorder. In addition, GABAergic neurons in the CeA-LHA pathway inhibited the expression of orexin-A in the LHA, and orexin-A was co-expressed with GABAA receptors. CONCLUSIONS & INFERENCES The CeA-LHA GABAergic pathway might participate in the occurrence and development of IBS by regulating orexin-A neurons.
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Affiliation(s)
- Xiaoman He
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Pengfei Ji
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Ruixiao Guo
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xing Ming
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Hongfei Zhang
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Lizheng Yu
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Ziyi Chen
- Qingdao Medical College, Qingdao University, Qingdao, China
| | - Shengli Gao
- Biomedical Center, Qingdao Medical College, Qingdao University, Qingdao, China
| | - Feifei Guo
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
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Narcolepsy and emotions: Is there a place for a theory of mind approach? Sleep Med 2023; 102:84-89. [PMID: 36634602 DOI: 10.1016/j.sleep.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/10/2022] [Accepted: 12/18/2022] [Indexed: 12/24/2022]
Abstract
Narcolepsy type 1 is a central disorder of hypersomnolence characterized by excessive daytime sleepiness, rapid eye movement sleep-related manifestations, and cataplexy. In the current literature there is general agreement regarding neural correlates of Narcolepsy type 1 that appear to be related to anatomical and functional abnormalities in the hypothalamic region. In the last two decades, researchers shed light on the neurological bases of cataplexy by focusing on the neurobiological correlates of emotions. Although the results of these studies differ, they all point to an impairment in the amygdala and hypothalamus functions that are known to be involved in emotional processing, suggesting an impairment in this domain in narcoleptic patients. Indeed, despite heterogeneous results, several studies showed that narcoleptic patients differed from healthy controls in processing emotional stimuli. From a behavioral point of view, these findings suggest that alterations in emotional processing may be driven, at least in part, by compensatory strategies to avoid or reduce the frequency of cataplexy attacks. Surprisingly, the only study exploring in NT1 the behavioural performances in emotional facial recognition found no differences between NT1 adults and controls. We hypothesize that narcoleptic patients may present an alteration in a more complex socio-cognitive ability that is related to emotional processing, namely Theory of Mind. This review aims to investigate the literature supporting this hypothesis and to propose possible future developments on this topic.
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Mogavero MP, Silvani A, Lanza G, DelRosso LM, Ferini-Strambi L, Ferri R. Targeting Orexin Receptors for the Treatment of Insomnia: From Physiological Mechanisms to Current Clinical Evidence and Recommendations. Nat Sci Sleep 2023; 15:17-38. [PMID: 36713640 PMCID: PMC9879039 DOI: 10.2147/nss.s201994] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/08/2023] [Indexed: 01/23/2023] Open
Abstract
After a detailed description of orexins and their roles in sleep and other medical disorders, we discuss here the current clinical evidence on the effects of dual (DORAs) or selective (SORAs) orexin receptor antagonists on insomnia with the aim to provide recommendations for their further assessment in a context of personalized and precision medicine. In the last decade, many trials have been conducted with orexin receptor antagonists, which represent an innovative and valid therapeutic option based on the multiple mechanisms of action of orexins on different biological circuits, both centrally and peripherally, and their role in a wide range of medical conditions which are often associated with insomnia. A very interesting aspect of this new category of drugs is that they have limited abuse liability and their discontinuation does not seem associated with significant rebound effects. Further studies on the efficacy of DORAs are required, especially on children and adolescents and in particular conditions, such as menopause. Which DORA is most suitable for each patient, based on comorbidities and/or concomitant treatments, should be the focus of further careful research. On the contrary, studies on SORAs, some of which seem to be appropriate also in insomnia in patients with psychiatric diseases, are still at an early stage and, therefore, do not allow to draw definite conclusions.
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Affiliation(s)
- Maria P Mogavero
- Vita-Salute San Raffaele University, Milan, Italy
- Sleep Disorders Center, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Silvani
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Giuseppe Lanza
- Sleep Research Centre, Oasi Research Institute - IRCCS, Troina, Italy
- Department of Surgery and Medical-Surgical Specialties, University of Catania, Catania, Italy
| | - Lourdes M DelRosso
- Pulmonary and Sleep Medicine, University of California San Francisco-Fresno, Fresno, CA, USA
| | - Luigi Ferini-Strambi
- Vita-Salute San Raffaele University, Milan, Italy
- Sleep Disorders Center, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Raffaele Ferri
- Sleep Research Centre, Oasi Research Institute - IRCCS, Troina, Italy
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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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CO 2 exposure enhances Fos expression in hypothalamic neurons in rats during the light and dark phases of the diurnal cycle. Brain Struct Funct 2022; 227:2667-2679. [PMID: 36109371 DOI: 10.1007/s00429-022-02562-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/29/2022] [Indexed: 12/30/2022]
Abstract
Orexinergic (OX) neurons in the lateral hypothalamus (LH), perifornical area (PFA) and dorsomedial hypothalamus (DMH) play a role in the hypercapnic ventilatory response, presumably through direct inputs to central pattern generator sites and/or through interactions with other chemosensitive regions. OX neurons can produce and release orexins, excitatory neuropeptides involved in many functions, including physiological responses to changes in CO2/pH. Thus, in the present study, we tested the hypothesis that different nuclei (LH, PFA and DMH) where the orexinergic neurons are located, show distinct activation by CO2 during the light-dark cycle phases. For this purpose, we evaluated the Fos and OXA expression by immunohistochemistry to identify neurons that co-localize Fos + OXA in the LH, LPeF, MPeF and DMH in the light-inactive and dark-active phase in Wistar rats subjected to 3 h of normocapnia or hypercapnia (7% CO2). Quantitative analyses of immunoreactive neurons show that hypercapnia caused an increase in the number of neurons expressing Fos in the LH, LPeF, MPeF and DMH in the light and dark phases. In addition, the number of Fos + OXA neurons increased in the LPeF and DMH independently of the phases of the diurnal cycle; whereas in the MPeF, this increase was observed exclusively in the light phase. Thus, we suggest that OX neurons are selectively activated by hypercapnia throughout the diurnal cycle, reinforcing the differential role of nuclei in the hypothalamus during central chemosensitivity.
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López JM, Carballeira P, Pozo J, León-Espinosa G, Muñoz A. Hypothalamic orexinergic neuron changes during the hibernation of the Syrian hamster. Front Neuroanat 2022; 16:993421. [PMID: 36157325 PMCID: PMC9501701 DOI: 10.3389/fnana.2022.993421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Hibernation in small mammals is a highly regulated process with periods of torpor involving drops in body temperature and metabolic rate, as well as a general decrease in neural activity, all of which proceed alongside complex brain adaptive changes that appear to protect the brain from extreme hypoxia and low temperatures. All these changes are rapidly reversed, with no apparent brain damage occurring, during the short periods of arousal, interspersed during torpor—characterized by transitory and partial rewarming and activity, including sleep activation, and feeding in some species. The orexins are neuropeptides synthesized in hypothalamic neurons that project to multiple brain regions and are known to participate in the regulation of a variety of processes including feeding behavior, the sleep-wake cycle, and autonomic functions such as brown adipose tissue thermogenesis. Using multiple immunohistochemical techniques and quantitative analysis, we have characterized the orexinergic system in the brain of the Syrian hamster—a facultative hibernator. Our results revealed that orexinergic neurons in this species consisted of a neuronal population restricted to the lateral hypothalamic area, whereas orexinergic fibers distribute throughout the rostrocaudal extent of the brain, particularly innervating catecholaminergic and serotonergic neuronal populations. We characterized the changes of orexinergic cells in the different phases of hibernation based on the intensity of immunostaining for the neuronal activity marker C-Fos and orexin A (OXA). During torpor, we found an increase in C-Fos immunostaining intensity in orexinergic neurons, accompanied by a decrease in OXA immunostaining. These changes were accompanied by a volume reduction and a fragmentation of the Golgi apparatus (GA) as well as a decrease in the colocalization of OXA and the GA marker GM-130. Importantly, during arousal, C-Fos and OXA expression in orexinergic neurons was highest and the structural appearance and the volume of the GA along with the colocalization of OXA/GM-130 reverted to euthermic levels. We discuss the involvement of orexinergic cells in the regulation of mammalian hibernation and, in particular, the possibility that the high activation of orexinergic cells during the arousal stage guides the rewarming as well as the feeding and sleep behaviors characteristic of this phase.
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Affiliation(s)
- Jesús M. López
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Paula Carballeira
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Javier Pozo
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Gonzalo León-Espinosa
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-Centro de Estudios Universitarios (CEU), Madrid, Spain
| | - Alberto Muñoz
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica (CTB), Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- *Correspondence: Alberto Muñoz,
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Bingul A, Merlin S, Carrive P, Killcross S, Furlong TM. Targeting the lateral hypothalamus with short hairpin RNAs reduces habitual behaviour following extended instrumental training in rats. Neurobiol Learn Mem 2022; 193:107657. [DOI: 10.1016/j.nlm.2022.107657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/23/2022] [Accepted: 06/28/2022] [Indexed: 10/17/2022]
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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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Villano I, La Marra M, Di Maio G, Monda V, Chieffi S, Guatteo E, Messina G, Moscatelli F, Monda M, Messina A. Physiological Role of Orexinergic System for Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:8353. [PMID: 35886210 PMCID: PMC9323672 DOI: 10.3390/ijerph19148353] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/03/2022] [Accepted: 07/05/2022] [Indexed: 02/06/2023]
Abstract
Orexins, or hypocretins, are excitatory neuropeptides involved in the regulation of feeding behavior and the sleep and wakefulness states. Since their discovery, several lines of evidence have highlighted that orexin neurons regulate a great range of physiological functions, giving it the definition of a multitasking system. In the present review, we firstly describe the mechanisms underlining the orexin system and their interactions with the central nervous system (CNS). Then, the system's involvement in goal-directed behaviors, sleep/wakefulness state regulation, feeding behavior and energy homeostasis, reward system, and aging and neurodegenerative diseases are described. Advanced evidence suggests that the orexin system is crucial for regulating many physiological functions and could represent a promising target for therapeutical approaches to obesity, drug addiction, and emotional stress.
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Affiliation(s)
- Ines Villano
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Marco La Marra
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Girolamo Di Maio
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Vincenzo Monda
- Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80138 Naples, Italy; (V.M.); (E.G.)
| | - Sergio Chieffi
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Ezia Guatteo
- Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80138 Naples, Italy; (V.M.); (E.G.)
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, 71100 Foggia, Italy; (G.M.); (F.M.)
| | - Fiorenzo Moscatelli
- Department of Clinical and Experimental Medicine, University of Foggia, 71100 Foggia, Italy; (G.M.); (F.M.)
| | - Marcellino Monda
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
| | - Antonietta Messina
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.L.M.); (G.D.M.); (S.C.); (M.M.); (A.M.)
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Gołyszny M, Zieliński M, Paul-Samojedny M, Filipczyk Ł, Pałasz A, Obuchowicz E. Escitalopram alters the hypothalamic OX system but does not affect its up-regulation induced by early-life stress in adult rats. Neurosci Res 2022; 180:58-71. [PMID: 35219722 DOI: 10.1016/j.neures.2022.02.005] [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: 07/21/2021] [Revised: 02/07/2022] [Accepted: 02/23/2022] [Indexed: 01/06/2023]
Abstract
We hypothesized that there is a relationship between the orexinergic system (OX) alterations and changes elicited by escitalopram or venlafaxine in adult rats subjected to maternal separation (MS). This animal model of childhood adversity induces long-lasting consequences in adult physiology and behavior. Male Wistar rats from the control and MS groups were injected with escitalopram or venlafaxine (10 mg/kg) IP from postnatal day (PND) 69-89. Adult rats were subjected to behavioral assessment, estimation of hypothalamic-pituitary-adrenal (HPA) axis activity and analysis of the OX system (quantitative PCR and immunohistochemistry) in the hypothalamus and amygdala. MS caused anxiety- and depressive-like behavior, endocrine stress-related response, and up-regulation of the OX system in the hypothalamus. Escitalopram, but not venlafaxine, increased the activity of hypothalamic OX system in the control rats and both drugs had no effect on OXs in the MS group. The disturbed signaling of the OX pathway may be significant for harmful long-term consequences of early-life stress. Our data show that the normal brain and brain altered by MS respond differently to escitalopram. Presumably, anti-anxiety and antidepressant effects of this drug do not depend on the activity of hypothalamic OX system.
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Affiliation(s)
- Miłosz Gołyszny
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland.
| | - Michał Zieliński
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Monika Paul-Samojedny
- Department of Medical Genetics, Faculty of Pharmacy with the Division of Laboratory Medicine in Sosnowiec, Medical University of Silesia, Jedności 8, Sosnowiec 41-200, Poland
| | - Łukasz Filipczyk
- Department of Histology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Artur Pałasz
- Department of Histology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
| | - Ewa Obuchowicz
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 street, Katowice 40-752, Poland
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Demidova A, Kahl E, Fendt M. Orexin deficiency affects sensorimotor gating and its amphetamine-induced impairment. Prog Neuropsychopharmacol Biol Psychiatry 2022; 116:110517. [PMID: 35101602 DOI: 10.1016/j.pnpbp.2022.110517] [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: 12/16/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 11/17/2022]
Abstract
The orexin neuropeptides have an important role in the regulation of the sleep/wake cycle and foraging, as well as in reward processing and emotions. Furthermore, recent research implicates the orexin system in different behavioral endophenotypes of neuropsychiatric diseases such as social avoidance and cognitive flexibility. Utilizing orexin-deficient mice, the present study tested the hypothesis that orexin is involved in two further mouse behavioral endophenotypes of neuropsychiatric disorders, i.e., sensorimotor gating and amphetamine sensitivity. The data revealed that orexin-deficient mice expressed a deficit in sensorimotor gating, measured by prepulse inhibition of the startle response. Amphetamine treatment impaired prepulse inhibition in wildtype and heterozygous orexin-deficient mice, but had no effects in homozygous orexin-deficient mice. Furthermore, locomotor activity and center time in the open field was not affected by orexin deficiency but was similarly increased or decreased, respectively, by amphetamine treatment in all genotypes. These data indicate that the orexin system modulates prepulse inhibition and is involved in mediating amphetamine's effect on prepulse inhibition. Future studies should investigate whether pharmacological manipulations of the orexin system can be used to treat neuropsychiatric diseases associated with deficits in sensorimotor gating, such as schizophrenia or attention deficit hyperactivity disorder.
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Affiliation(s)
- Alexandrina Demidova
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany; Psychology Master Program, Otto-von-Guericke University Magdeburg, Germany
| | - Evelyn Kahl
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University Magdeburg, Germany; Psychology Master Program, Otto-von-Guericke University Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke University Magdeburg, Germany.
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Spinieli RL, Ben Musa R, Cornelius-Green J, Hasser EM, Cummings KJ. Orexin facilitates the ventilatory and behavioral responses of rats to hypoxia. Am J Physiol Regul Integr Comp Physiol 2022; 322:R581-R596. [PMID: 35380477 PMCID: PMC9109809 DOI: 10.1152/ajpregu.00334.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/22/2022] [Accepted: 03/30/2022] [Indexed: 02/03/2023]
Abstract
Orexin neurons are sensitive to CO2 and contribute to cardiorespiratory homeostasis as well as sensorimotor control. Whether orexin facilitates respiratory and behavioral responses to acute hypoxia is unclear. We hypothesized that orexin neurons are activated by acute hypoxia and that orexin facilitates the hypoxic ventilatory response (HVR), as well as the arterial blood pressure (ABP) and behavioral (movement) responses to acute hypoxia. We further hypothesized that orexin has greater effects in the active phase of the rat circadian cycle, when orexin neurons have high activity. Using whole body plethysmography with EEG, EMG, and the dual-orexin receptor (OxR) antagonist suvorexant (20 mg/kg ip), we determined the effect of OxR blockade on the respiratory, ABP, and behavioral responses of adult rats to acute, graded hypoxia ([Formula: see text]= 0.15, 0.13, 0.11, and 0.09) and hyperoxic hypercapnia ([Formula: see text]= 0.05; [Formula: see text]= 0.95). OxR blockade had no effect on eupnea. OxR blockade significantly reduced the HVR in both inactive and active phases, with a stronger effect in the active phase. OxR blockade reduced the behavioral response to acute hypoxia in the active phase. The central component of the ventilatory and the ABP responses to hypercapnia were reduced by OxR blockade solely in the inactive phase. In the inactive phase, hypoxia activated ∼10% of orexin neurons in the perifornical hypothalamus. These data suggest that orexin neurons participate in the peripheral chemoreflex to facilitate the ventilatory and behavioral responses to acute hypoxia in rats, particularly in the active phase. Orexin also facilitates central chemoreflex responses to CO2 in the inactive phase.
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Affiliation(s)
- Richard L Spinieli
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Jennifer Cornelius-Green
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Eileen M Hasser
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Kevin J Cummings
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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Mavanji V, Georgopoulos AP, Kotz CM. Orexin enhances neuronal synchronization in adult rat hypothalamic culture: a model to study hypothalamic function. J Neurophysiol 2022; 127:1221-1229. [PMID: 35353632 PMCID: PMC9054260 DOI: 10.1152/jn.00041.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/28/2022] [Indexed: 11/22/2022] Open
Abstract
The regulation of sleep/wake behavior and energy homeostasis is maintained in part by the hypothalamic neuropeptide orexin A (OXA, hypocretin). Reduction in orexin signaling is associated with sleep disorders and obesity, whereas higher lateral hypothalamic (LH) orexin signaling and sensitivity promotes obesity resistance. Similarly, dysregulation of hypothalamic neural networks is associated with onset of age-related diseases, including obesity and several neurological diseases. Despite the association of obesity and aging, and that adult populations are the target for the majority of pharmaceutical and obesity studies, conventional models for neuronal networks utilize embryonic neural cultures rather than adult neurons. Synchronous activity describes correlated changes in neuronal activity between neurons and is a feature of normal brain function, and is a measure of functional connectivity and final output from a given neural structure. Earlier studies show alterations in hypothalamic synchronicity following behavioral perturbations in embryonic neurons obtained from obesity-resistant rats and following application of orexin onto embryonic hypothalamic cultures. Synchronous network dynamics in adult hypothalamic neurons remain largely undescribed. To address this, we established an adult rat hypothalamic culture in multi-electrode-array (MEA) dishes and recorded the field potentials. Then we studied the effect of exogenous orexin on network synchronization of these adult hypothalamic cultures. In addition, we studied the wake promoting effects of orexin in vivo when directly injected into the lateral hypothalamus (LH). Our results showed that the adult hypothalamic cultures are viable for nearly 3 mo in vitro, good quality MEA recordings can be obtained from these cultures in vitro, and finally, that cultured adult hypothalamus is responsive to orexin. These results support that adult rat hypothalamic cultures could be used as a model to study the neural mechanisms underlying obesity. In addition, LH administration of OXA enhanced wakefulness in rats, indicating that OXA enhances wakefulness partly by promoting neural synchrony in the hypothalamus.NEW & NOTEWORTHY This study, for the first time, demonstrates that adult hypothalamic cultures are viable in vitro for a prolonged duration and are electrophysiologically active. In addition, the study shows that orexin enhances neural synchronization in adult hypothalamic cultures.
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Affiliation(s)
- Vijayakumar Mavanji
- Research Service, Veterans Affairs Health Care System, Minneapolis, Minnesota
| | - Apostolos P Georgopoulos
- Research Service, Veterans Affairs Health Care System, Minneapolis, Minnesota
- Brain Sciences Center, Veterans Affairs Health Care System, Minneapolis, Minnesota
- Department of Neuroscience, University of Minnesota Medical School, Minneapolis, Minnesota
- Department of Psychiatry, University of Minnesota Medical School, Minneapolis, Minnesota
- Center for Cognitive Sciences, University of Minnesota, Minneapolis, Minnesota
- Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Catherine M Kotz
- Research Service, Veterans Affairs Health Care System, Minneapolis, Minnesota
- Minnesota Nutrition and Obesity Research Center, St. Paul, Minnesota
- Geriatric Research Education Clinical Center, Veterans Affairs Health Care System, Minneapolis, Minnesota
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, Minnesota
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Gugula A, Trenk A, Celary A, Cizio K, Tylko G, Blasiak A, Hess G. Early-life stress modifies the reactivity of neurons in the ventral tegmental area and lateral hypothalamus to acute stress in female rats. Neuroscience 2022; 490:49-65. [DOI: 10.1016/j.neuroscience.2022.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/29/2022] [Accepted: 02/14/2022] [Indexed: 10/19/2022]
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Agee LA, Nemchek V, Malone CA, Lee HJ, Monfils MH. Appetitive Behavior in the Social Transmission of Food Preference Paradigm Predicts Activation of Orexin-A producing Neurons in a Sex-Dependent Manner. Neuroscience 2022; 481:30-46. [PMID: 34843892 PMCID: PMC9246717 DOI: 10.1016/j.neuroscience.2021.11.032] [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: 06/12/2021] [Revised: 11/17/2021] [Accepted: 11/20/2021] [Indexed: 11/22/2022]
Abstract
Orexin-producing cells in the lateral hypothalamic area have been shown to be involved in a wide variety of behavioral and cognitive functions, including the recall of appetitive associations and a variety of social behaviors. Here, we investigated the role of orexin in the acquisition and recall of socially transmitted food preferences in the rat. Rats were euthanized following either acquisition, short-term recall, or long-term recall of a socially transmitted food preference and their brains were processed for orexin-A and c-Fos expression. We found that while there were no significant differences in c-Fos expression between control and experimental subjects at any of the tested timepoints, females displayed significantly more activity in both orexinergic and non-orexinergic cells in the lateral hypothalamus. In the infralimbic cortex, we found that social behavior was significantly predictive of c-Fos expression, with social behaviors related to olfactory exploration appearing to be particularly influential. We additionally found that appetitive behavior was significantly predictive of orexin-A activity in a sex-dependent matter, with the total amount eaten correlating negatively with orexin-A/c-Fos colocalization in male rats but not female rats. These findings suggest a potential sex-specific role for the orexin system in balancing the stimulation of feeding behavior with the sleep/wake cycle.
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Affiliation(s)
- Laura A Agee
- The University of Texas at Austin, Department of Psychology, Austin, TX, USA
| | - Victoria Nemchek
- The University of Texas at Austin, Department of Psychology, Austin, TX, USA
| | - Cassidy A Malone
- The University of Texas at Austin, Department of Psychology, Austin, TX, USA
| | - Hongjoo J Lee
- The University of Texas at Austin, Department of Psychology, Austin, TX, USA; Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Marie-H Monfils
- The University of Texas at Austin, Department of Psychology, Austin, TX, USA; Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA.
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Lo Y, Yi PL, Hsiao YT, Chang FC. Hypocretin in locus coeruleus and dorsal raphe nucleus mediates inescapable footshock stimulation (IFS)-induced REM sleep alteration. Sleep 2021; 45:6490200. [PMID: 34969120 DOI: 10.1093/sleep/zsab301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/12/2021] [Indexed: 11/14/2022] Open
Abstract
Hypocretin (hcrt) is a stress-reacting neuropeptide mediating arousal and energy homeostasis. An inescapable footshock stimulation (IFS) could initiate the hcrt release from the lateral hypothalamus (LHA) and suppresses rapid eye movement (REM) sleep in rodents. However, the effects of the IFS-induced hcrts on REM-off nuclei, the locus coeruleus (LC) and dorsal raphe nucleus (DRN), remained unclear. We hypothesized that the hcrt projections from the LHA to LC or DRN mediate IFS-induced sleep disruption. Our results demonstrated that the IFS increased hcrt expression and the neuronal activities in the LHA, hypothalamus, brainstem, thalamus, and amygdala. Suppressions of REM sleep and slow wave activity during non-REM (NREM) sleep caused by the high expression of hcrts were blocked when a non-specific and dual hcrt receptor antagonist was administered into the LC or DRN. Furthermore, the IFS also caused an elevated innate anxiety, but was limitedly influenced by the hcrt antagonist. This result suggests that the increased hcrt concentrations in the LC and DRN mediate stress-induced sleep disruptions and might partially involve IFS-induced anxiety.
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Affiliation(s)
- Yun Lo
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan, University, Taipei, Taiwan
| | - Pei-Lu Yi
- Department of Sport Management, College of Tourism, Leisure and Sports, Aletheia, University, New Taipei City, Taiwan
| | - Yi-Tse Hsiao
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan, University, Taipei, Taiwan
| | - Fang-Chia Chang
- Department of Veterinary Medicine, School of Veterinary Medicine, National Taiwan, University, Taipei, Taiwan.,Graduate Institute of Brain & Mind Sciences, College of Medicine, National Taiwan, University, Taipei, Taiwan.,Graduate Institute of Acupuncture Science, College of Chinese Medicine, China, Medical University, Taichung, Taiwan.,Department of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
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40
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Matsumoto S, Tsunematsu T. Association between Sleep, Alzheimer's, and Parkinson's Disease. BIOLOGY 2021; 10:1127. [PMID: 34827122 PMCID: PMC8614785 DOI: 10.3390/biology10111127] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/28/2021] [Accepted: 10/30/2021] [Indexed: 01/09/2023]
Abstract
The majority of neurodegenerative diseases are pathologically associated with protein misfolding and aggregation. Alzheimer's disease (AD) is a type of dementia that slowly affects memory and cognitive function, and is characterized by the aggregation of the β-amyloid protein and tau neurofibrillary tangles in the brain. Parkinson's disease (PD) is a movement disorder typically resulting in rigidity and tremor, which is pathologically linked to the aggregation of α-synuclein, particularly in dopaminergic neurons in the midbrain. Sleep disorders commonly occur in AD and PD patients, and it can precede the onset of these diseases. For example, cognitively normal older individuals who have highly fragmented sleep had a 1.5-fold increased risk of subsequently developing AD. This suggests that sleep abnormalities may be a potential biomarker of these diseases. In this review, we describe the alterations of sleep in AD and PD, and discuss their potential in the early diagnosis of these diseases. We further discuss whether sleep disturbance could be a target for the treatment of these diseases.
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Affiliation(s)
- Sumire Matsumoto
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan;
| | - Tomomi Tsunematsu
- Advanced Interdisciplinary Research Division, Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai 980-8578, Japan;
- Super-Network Brain Physiology, Graduate School of Life Sciences, Tohoku University, Sendai 980-8577, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi 332-0012, Japan
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Kousi C, Lampri E, Voulgaris S, Vougiouklakis T, Galani V, Mitselou A. Expression of orexin-A (hypocretin-A) in the hypothalamus after traumatic brain injury: A postmortem evaluation. Forensic Sci Int 2021; 327:110961. [PMID: 34454377 DOI: 10.1016/j.forsciint.2021.110961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/16/2021] [Accepted: 08/17/2021] [Indexed: 01/01/2023]
Abstract
Traumatic brain injury (TBI) is one of the leading causes of mortality and morbidity. The key component of TBI pathophysiology is traumatic axonal injury (TAI), commonly referred to as diffuse axonal injury (DAI). Coma is a serious complication which can occur following traumatic brain injury (TBI). Recently, studies have shown that the central orexinergic/ hypocretinergic system exhibit prominent arousal promoting actions. Therefore, the purpose of this study is to investigate by immunohistochemistry the expression of beta-amyloid precursor protein (β-APP) in white matter of parasagittal region, corpus callosum and brainstem and the expression of orexin-A (ORXA) in the hypothalamus after traumatic brain injury. RESULTS: DAI was found in 26 (53.06%) cases, assessed with β-APP immunohistochemical staining in parasagittal white matter, corpus callosum and brainstem. Orexin-A immunoreactivity in hypothalamus was completely absent in 5 (10.2%) of the cases; moderate reduction of ORXA was observed in 9 (18.4%) of the cases; and severe reduction was observed in 7 (14.3%) of the cases. A statistically significant correlation was found between β-APP immunostaining in white matter, corpus callosum and brainstem in relation to survival time (p < 0.002, p < 0.003 and p < 0.005 respectively). A statistically positive correlation was noted between ORX-A immunoreactivity in hypothalamus to survival time (p < 0.003). An inverse correlation was noted between the expression of β-APP in the regions of brain studied to the expression of ORX-A in the hypothalamus of the cases studied (p < 0.005). CONCLUSIONS: The present study demonstrated by immunohistochemistry that reduction of orexin-A neurons in the hypothalamus, involved in coma status and arousal, enhanced the immunoexpression of β-APP in parasagital white matter, corpus callosum and brainstem.
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Affiliation(s)
- Chrysavgi Kousi
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Evangeli Lampri
- Department of Pathology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Spyridon Voulgaris
- Department of Neurosurgery, Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Theodoros Vougiouklakis
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
| | - Vassiliki Galani
- Department of Anatomy-Histology-Embryology, University of Ioannina, Greece.
| | - Antigony Mitselou
- Department of Forensic Medicine and Toxicology Health Sciences, School of Medicine, University of Ioannina, Greece
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Han D, Shi Y, Han F. The effects of orexin-A and orexin receptors on anxiety- and depression-related behaviors in a male rat model of post-traumatic stress disorder. J Comp Neurol 2021; 530:592-606. [PMID: 34387361 DOI: 10.1002/cne.25231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 08/08/2021] [Accepted: 08/09/2021] [Indexed: 12/14/2022]
Abstract
Orexin neurons play an important role in stress-related mental disorders including post-traumatic stress disorder (PTSD). Anxiety- and depression-related symptoms commonly occur in combination with PTSD. However, the role of the orexin system in mediating alterations in these affective symptoms remains unclear. The medial prefrontal cortex (mPFC) is implicated in both cognitive and emotional processing. In the present study, we investigated anxiety- and depression-related behavioral changes using the elevated plus maze, the sucrose preference test, and the open field test in male rats with single prolonged stress (SPS) induced-PTSD. The expression of orexin-A in the hypothalamus and orexin receptors (OX1R and OX2R) in the mPFC was detected and quantified by immunohistochemistry, western blotting, and real-time polymerase chain reaction. We found that the SPS rats exhibited enhanced levels of anxiety, reduced exploratory activities, and anhedonia. Furthermore, SPS resulted in reductions in the expression of orexin-A in the hypothalamus and the increased the expression of OX1R in the mPFC. The intracerebroventricular administration of orexin-A alleviated behavioral changes in SPS rats and partly restored the increased levels of OX1R in the mPFC. These results suggest that the orexin system plays a role in the anxiety- and depression-related symptoms observed in PTSD.
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Affiliation(s)
- Dan Han
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical Sciences College, China Medical University, Shenyang, China.,Department of Neonatology, The First Hospital of China Medical University, Shenyang, China
| | - Yuxiu Shi
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical Sciences College, China Medical University, Shenyang, China
| | - Fang Han
- PTSD Laboratory, Department of Histology and Embryology, Basic Medical Sciences College, China Medical University, Shenyang, China
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Agustí A, Campillo I, Balzano T, Benítez-Páez A, López-Almela I, Romaní-Pérez M, Forteza J, Felipo V, Avena NM, Sanz Y. Bacteroides uniformis CECT 7771 Modulates the Brain Reward Response to Reduce Binge Eating and Anxiety-Like Behavior in Rat. Mol Neurobiol 2021; 58:4959-4979. [PMID: 34228269 PMCID: PMC8497301 DOI: 10.1007/s12035-021-02462-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 06/17/2021] [Indexed: 12/18/2022]
Abstract
Food addiction (FA) is characterized by behavioral and neurochemical changes linked to loss of food intake control. Gut microbiota may influence appetite and food intake via endocrine and neural routes. The gut microbiota is known to impact homeostatic energy mechanisms, but its role in regulating the reward system is less certain. We show that the administration of Bacteroides uniformis CECT 7771 (B. uniformis) in a rat FA model impacts on the brain reward response, ameliorating binge eating and decreasing anxiety-like behavior. These effects are mediated, at least in part, by changes in the levels of dopamine, serotonin, and noradrenaline in the nucleus accumbens and in the expression of dopamine D1 and D2 receptors in the prefrontal cortex and intestine. B. uniformis reverses the fasting-induced microbiota changes and increases the abundance of species linked to healthy metabolotypes. Our data indicate that microbiota-based interventions might help to control compulsive overeating by modulating the reward response.
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Affiliation(s)
- Ana Agustí
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain.
| | - Isabel Campillo
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain
| | - Tiziano Balzano
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Alfonso Benítez-Páez
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain
| | - Inmaculada López-Almela
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain
| | - Marina Romaní-Pérez
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain
| | - Jerónimo Forteza
- Instituto Valenciano de Patología Unidad Mixta de Patología Molecular, Centro Investigación Príncipe Felipe/Universidad Católica de Valencia, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, Valencia, Spain
| | - Nicole M Avena
- Department of Neuroscience, Icahn School of Medicine, Mount Sinai, New York, NY, USA
| | - Yolanda Sanz
- Microbial Ecology, Nutrition and Health. Research Unit, Institute of Agrochemistry and Food Technology, Spanish Council for Scientific Research(IATA-CSIC), Valencia, Spain.
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Ballotta D, Talami F, Pizza F, Vaudano AE, Benuzzi F, Plazzi G, Meletti S. Hypothalamus and amygdala functional connectivity at rest in narcolepsy type 1. Neuroimage Clin 2021; 31:102748. [PMID: 34252875 PMCID: PMC8278207 DOI: 10.1016/j.nicl.2021.102748] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 06/23/2021] [Accepted: 06/26/2021] [Indexed: 01/20/2023]
Abstract
INTRODUCTION functional and structural MRI studies suggest that the orexin (hypocretin) deficiency in the dorso-lateral hypothalamus of narcoleptic patients would influence both brain metabolism and perfusion and would cause reduction in cortical grey matter. Previous fMRI studies have mainly focused on cerebral functioning during emotional processing. The aim of the present study was to explore the hemodynamic behaviour of spontaneous BOLD fluctuation at rest in patients with Narcolepsy type 1 (NT1) close to disease onset. METHODS Fifteen drug naïve children/adolescents with NT1 (9 males; mean age 11.7 ± 3 years) and fifteen healthy children/adolescents (9 males; mean age 12.4 ± 2.8 years) participated in an EEG-fMRI study in order to investigate the resting-state functional connectivity of hypothalamus and amygdala. Functional images were acquired on a 3 T system. Seed-based functional connectivity analyses were performed using SPM12. Regions of Interest were the lateral hypothalamus and the amygdala. RESULTS compared to controls, NT1 patients showed decreased functional connectivity between the lateral hypothalamus and the left superior parietal lobule, the hippocampus and the parahippocampal gyrus. Decreased functional connectivity was detected between the amygdala and the post-central gyrus and several occipital regions, whereas it was increased between the amygdala and the inferior frontal gyrus, claustrum, insula, and putamen. CONCLUSION in NT1 patients the abnormal connectivity between the hypothalamus and brain regions involved in memory consolidation during sleep, such as the hippocampus, may be linked to the loss of orexin containing neurons in the dorsolateral hypothalamus. Moreover, also functional connectivity of the amygdala seems to be influenced by the loss of orexin-containing neurons. Therefore, we can hypothesize that dysfunctional interactions between regions subserving the maintenance of arousal, memory and emotional processing may contribute to the main symptom of narcolepsy.
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Affiliation(s)
- Daniela Ballotta
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Italy
| | - Francesca Talami
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Italy
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche, AUSL of Bologna, Italy
| | | | - Francesca Benuzzi
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Italy
| | - Giuseppe Plazzi
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Italy; IRCCS Istituto delle Scienze Neurologiche, AUSL of Bologna, Italy
| | - Stefano Meletti
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Italy; Center for Neuroscience and Neurotechnology, University of Modena and Reggio Emilia, Italy; Neurology Unit, OCB Hospital, AOU Modena, Italy.
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Gao HR, Wu ZJ, Wu SB, Gao HY, Wang J, Zhang JL, Zhou MQ. Roles of central orexinergic system on cardiovascular function and acupuncture on intervention of cardiovascular risk: Orexinergic system mediate the role of acupuncture? Neuropeptides 2021; 87:102132. [PMID: 33636511 DOI: 10.1016/j.npep.2021.102132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 01/09/2021] [Accepted: 02/11/2021] [Indexed: 12/26/2022]
Abstract
Central orexinergic system contributes to the regulation of cardiovascular function. Orexinergic neurons receiving projections of nerve fibers from multiple structures of brain which involved in control and regulation of cardiovascular function locate in hypothalamus, and their axon terminals widely project to various central structures where orexins receptors are expressed. Here, we summarize the present knowledge that describes the influence of central orexinergic system on cardiovascular activity, the relevance of dysfunction in central orexinergic system with hypertension and psychological stress induced cardiovascular reactivity which are serious risk factors for cardiovascular disease and cardiovascular death. We propose that central orexinergic system may be potentially important targets for the prevention of cardiovascular disease and cardiovascular death, and different orexinergic system involved neuronal circuits may be involved in distinct cardiovascular functions. Acupuncture having bidirectional regulatory ability and a much lower incidence of side effects can prevent disease. We review the improvement of acupuncture on hypertension and psychological stress induced cardiovascular reactivity. We think that acupuncture intervenes hypertension and psychological stress induced cardiovascular reactivity to prevent cardiovascular disease and cardiovascular death. We also summarize relation between acupuncture and central orexinergic system. We propose a hypothesis that acupuncture improve hypertension and psychological stress induced cardiovascular reactivity through regulating central orexinergic system. The knowledge is beneficial for the development of potential therapeutic targets and methods to prevent cardiovascular disease and cardiovascular death.
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Affiliation(s)
- He-Ren Gao
- Key Laboratory of Acupuncture and Moxibustion Foundation and Technology of Anhui Province, Research Institute of Acupuncture and Meridian, College of Acupuncture and Tuina, Anhui Academy of Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China.
| | - Zi-Jian Wu
- Key Laboratory of Acupuncture and Moxibustion Foundation and Technology of Anhui Province, Research Institute of Acupuncture and Meridian, College of Acupuncture and Tuina, Anhui Academy of Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Sheng-Bing Wu
- Key Laboratory of Acupuncture and Moxibustion Foundation and Technology of Anhui Province, Research Institute of Acupuncture and Meridian, College of Acupuncture and Tuina, Anhui Academy of Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China; Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China
| | - He-Yuan Gao
- Department of Pediatrics, The First Hospital of Qinhuangdao, Qinhuangdao, China
| | - Jie Wang
- Key Laboratory of Acupuncture and Moxibustion Foundation and Technology of Anhui Province, Research Institute of Acupuncture and Meridian, College of Acupuncture and Tuina, Anhui Academy of Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China
| | - Jin-Li Zhang
- Anhui Vocational College of Grain Engineering, Hefei, China
| | - Mei-Qi Zhou
- Key Laboratory of Acupuncture and Moxibustion Foundation and Technology of Anhui Province, Research Institute of Acupuncture and Meridian, College of Acupuncture and Tuina, Anhui Academy of Chinese Medicine, Anhui University of Chinese Medicine, Hefei, China; Key Laboratory of Xin'an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei, China; Bozhou Institute of Traditional Chinese Medicine, Anhui Academy of Chinese Medicine, Bozhou, China.
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46
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Zhu J, Tang S, Zhao D, Zeng Z, Mo H, Hu K. Orexin A improves the cognitive impairment induced by chronic intermittent hypoxia in mice. Brain Res Bull 2021; 173:203-210. [PMID: 34051297 DOI: 10.1016/j.brainresbull.2021.05.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 05/09/2021] [Accepted: 05/24/2021] [Indexed: 01/04/2023]
Abstract
The orexin neuron in lateral hypothalamus (LH) was involved in the regulation of sleep-wake cycle. However, the effect of orexin A (OXA) on cognitive impairment resulting from diverse diseases remains controversial. In this study, we investigated the effect of OXA on cognitive impairment induced by chronic intermittent hypoxia (CIH) in mice. Adult (10 weeks old) male C57BL/6 mice were randomly divided into the following four groups: normoxia control (NC)+normal saline (NS), NC + OXA, CIH + NS and CIH + OXA group. Following the CIH mice models establishment, OXA was injected into the right lateral ventricles of mice by a micro-injection system. Water maze test was used to assess spatial memory abilities of the mice. The expression of OXA and c-Fos in LH were analyzed by immunofluorescence staining. Apoptotic cell death and oxidative stress in hippocampus were evaluated using multiple methods including TUNEL, western blot and biochemical analysis. Behavioral tests revealed that CIH significantly increased the escape latency and time of arriving platform, of which were markedly decreased by OXA treatment. Similarly, the CIH + NS group was worse than NC + NS group in terms of the number of platform crossing and time in the target quadrant, of which were also significantly improved by OXA treatment. The number of OXA + neuron in LH was decreased, but the percentage of c-Fos+/OXA + neuron in LH was remarkably increased by CIH. Furthermore, we found that micro-injection of OXA attenuated CIH-induced apoptotic cell death and oxidative stress in the hippocampus. Our results suggested that OXA might improve cognitive impairment induced by CIH through inhibiting hippocampal apoptosis and oxidative stress.
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Affiliation(s)
- Jing Zhu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China; Department of Respiratory and Critical Care Medicine, the People's Hospital of China Three Gorges University, Yichang, Hubei, China
| | - Si Tang
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Dong Zhao
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Zhaofu Zeng
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Huaheng Mo
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Ke Hu
- Department of Respiratory and Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, China.
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Kuwaki T. Orexin (hypocretin) participates in central autonomic regulation during fight-or-flight response. Peptides 2021; 139:170530. [PMID: 33741478 DOI: 10.1016/j.peptides.2021.170530] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/12/2021] [Accepted: 03/12/2021] [Indexed: 12/25/2022]
Abstract
Our daily life does not only involve a calm resting state but is rather full of perturbations that induce active states such as moving, eating, and communicating. During such active conditions, cardiorespiratory regulation should be adjusted according to bodily demand, which differs from that during the resting state, by modulating or resetting the operating point. To explore neural mechanisms in the state-dependent adjustment of central autonomic regulation, my research group has recently focused on the fight-or-flight response because the stressor induces not only cognitive, emotional, and behavioral changes but also autonomic changes. In this brief review, I will summarize our discovery using orexin knockout mice and orexin neuron-ablated mice for the possible contribution of orexin, a hypothalamic neuropeptide, to the state-dependent adjustment of the central autonomic regulation. In addition, I will introduce some recent discovery using optogenetic manipulation of the orexin and related systems. The diversity of synaptic control of the cardiovascular and respiratory neurons appears necessary for animals to adapt themselves to ever-changing life circumstances and behavioral states. The orexin system is likely to function as one of the essential modulators for coordinating the circuits controlling autonomic functions and behaviors.
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Affiliation(s)
- Tomoyuki Kuwaki
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka 8-35-1, Kagoshima, 890-8544, Japan.
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48
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Pang TY, Yaeger JDW, Summers CH, Mitra R. Cardinal role of the environment in stress induced changes across life stages and generations. Neurosci Biobehav Rev 2021; 124:137-150. [PMID: 33549740 PMCID: PMC9286069 DOI: 10.1016/j.neubiorev.2021.01.012] [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: 03/15/2020] [Revised: 11/20/2020] [Accepted: 01/08/2021] [Indexed: 12/21/2022]
Abstract
The stress response in rodents and humans is exquisitely dependent on the environmental context. The interactive element of the environment is typically studied by creating laboratory models of stress-induced plasticity manifested in behavior or the underlying neuroendocrine mediators of the behavior. Here, we discuss three representative sets of studies where the role of the environment in mediating stress sensitivity or stress resilience is considered across varying windows of time. Collectively, these studies testify that environmental variation at an earlier time point modifies the relationship between stressor and stress response at a later stage. The metaplastic effects of the environment on the stress response remain possible across various endpoints, including behavior, neuroendocrine regulation, region-specific neural plasticity, and regulation of receptors. The timescale of such variation spans adulthood, across stages of life history and generational boundaries. Thus, environmental variables are powerful determinants of the observed diversity in stress response. The predominant role of the environment suggests that it is possible to promote stress resilience through purposeful modification of the environment.
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Affiliation(s)
- Terence Y Pang
- Florey Institute of Neuroscience and Mental Health, Parkville, 3052, VIC, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, 3010, VIC, Australia
| | - Jazmine D W Yaeger
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA; Veterans Affairs Research Service, Sioux Falls VA Health Care System, Sioux Falls, SD, 57105, USA
| | - Cliff H Summers
- Department of Biology, University of South Dakota, Vermillion, SD, 57069, USA; Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA; Veterans Affairs Research Service, Sioux Falls VA Health Care System, Sioux Falls, SD, 57105, USA
| | - Rupshi Mitra
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
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49
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Lonstein JS, Linning-Duffy K, Tang Y, Moody A, Yan L. Impact of daytime light intensity on the central orexin (hypocretin) system of a diurnal rodent (Arvicanthis niloticus). Eur J Neurosci 2021; 54:4167-4181. [PMID: 33899987 DOI: 10.1111/ejn.15248] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/14/2021] [Accepted: 04/17/2021] [Indexed: 11/29/2022]
Abstract
The neuropeptide orexin/hypocretin is implicated in sleep and arousal, energy expenditure, reward, affective state and cognition. Our previous work using diurnal Nile grass rats (Arvicanthis niloticus) found that orexin mediates the effects of environmental light, particularly daytime light intensity, on affective and cognitive behaviours. The present study further investigated how daytime light intensity affects the central orexin system in male and female grass rats. Subjects were housed for 4 weeks in 12:12 hr dim light:dark (50 lux, dimLD) or in 12:12 hr bright light:dark cycle (1000 lux, brightLD). Day/night fluctuations in some orexin measures were also assessed. Despite similar hypothalamic prepro-orexin mRNA expression across all conditions, there were significantly more orexin-immunoreactive neurons, larger somata, greater optical density or higher orexin A content at night (ZT14) than during the day (ZT2), and/or in animals housed in brightLD compared to dimLD. Grass rats in brightLD also had higher cisternal CSF levels of orexin A. Furthermore, orexin receptor OX1R and OX2R proteins in the medial prefrontal cortex were higher in brightLD than dimLD males, but lower in brightLD than dimLD females. In the CA1 and dorsal raphe nucleus, females had higher OX1R than males without any significant effects of light condition, and OX2R levels were unaffected by sex or light. These results reveal that daytime light intensity alters the central orexin system of both male and female diurnal grass rats, sometimes sex-specifically, and provides insight into the mechanisms underlying how daytime light intensity impacts orexin-regulated functions.
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Affiliation(s)
- Joseph S Lonstein
- Department of Psychology, Michigan State University, East Lansing, MI, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Katrina Linning-Duffy
- Department of Psychology, Michigan State University, East Lansing, MI, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Yuping Tang
- Department of Psychology, Michigan State University, East Lansing, MI, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
| | - Anna Moody
- Department of Psychology, Michigan State University, East Lansing, MI, USA
| | - Lily Yan
- Department of Psychology, Michigan State University, East Lansing, MI, USA
- Neuroscience Program, Michigan State University, East Lansing, MI, USA
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50
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Adamantidis AR, Schmidt MH, Carter ME, Burdakov D, Peyron C, Scammell TE. A circuit perspective on narcolepsy. Sleep 2021; 43:5699663. [PMID: 31919524 PMCID: PMC7215265 DOI: 10.1093/sleep/zsz296] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/13/2019] [Indexed: 01/25/2023] Open
Abstract
The sleep disorder narcolepsy is associated with symptoms related to either boundary state control that include excessive daytime sleepiness and sleep fragmentation, or rapid eye movement (REM) sleep features including cataplexy, sleep paralysis, hallucinations, and sleep-onset REM sleep events (SOREMs). Although the loss of Hypocretin/Orexin (Hcrt/Ox) peptides or their receptors have been associated with the disease, here we propose a circuit perspective of the pathophysiological mechanisms of these narcolepsy symptoms that encompasses brain regions, neuronal circuits, cell types, and transmitters beyond the Hcrt/Ox system. We further discuss future experimental strategies to investigate brain-wide mechanisms of narcolepsy that will be essential for a better understanding and treatment of the disease.
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Affiliation(s)
- A R Adamantidis
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Biomedical Research, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
| | - M H Schmidt
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Ohio Sleep Medicine Institute, Dublin, OH
| | - M E Carter
- Department of Biology, Program in Neuroscience, Williams College, Williamstown, MA
| | - D Burdakov
- Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - C Peyron
- Center for Research in Neuroscience of Lyon, SLEEP team, CNRS UMR5292, INSERM U1028, University Lyon 1, Bron, France
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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