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Park I, Yoshitake R, Kioka K, Ishihara A, Yajima K, Kawana F, Kokubo T, Matsuzaki I, Kanbayashi T, Yanagisawa M, Tokuyama K. Orexin receptor antagonist increases fat oxidation and suppresses protein catabolism during sleep in humans. iScience 2024; 27:110212. [PMID: 38993665 PMCID: PMC11238128 DOI: 10.1016/j.isci.2024.110212] [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: 11/07/2023] [Revised: 04/17/2024] [Accepted: 06/04/2024] [Indexed: 07/13/2024] Open
Abstract
Suvorexant is an orexin receptor antagonist that targets the wake-promoting system. Orexin is also known to regulate energy metabolism in rodents, but its role in humans remains largely unknown. Here, we assessed the effect of suvorexant (20 mg) on energy metabolism during sleep and shortly after awakening in a randomized, double-blind, placebo-controlled, crossover study in 14 healthy men. Suvorexant increased rapid eye movement (REM) but decreased nonrapid eye movement (NREM) stage 1. Energy expenditure during wake after sleep onset (WASO) was higher than that during NREM and REM sleep in the placebo but not in the suvorexant trial, suggesting that the increase in energy expenditure during WASO was due to an activation of the orexin system. Fat oxidation during sleep increased, and its effect remained after waking the next morning. Suvorexant decreased protein catabolism but did not affect overall energy expenditure. The orexin system may affect fat oxidation independent of its roles in sleep regulation in humans.
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Affiliation(s)
- Insung Park
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Rikako Yoshitake
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan
| | - Kazuki Kioka
- Faculty of Health and Sports Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8574, Japan
| | - Asuka Ishihara
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Katsuhiko Yajima
- Faculty of Pharmaceutical Sciences, Josai University, Sakado, Saitama 350-0295, Japan
| | - Fusae Kawana
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Toshio Kokubo
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Ichiyo Matsuzaki
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Takashi Kanbayashi
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Kumpei Tokuyama
- International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
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Su L, Li G, Chow BKC, Cardoso JCR. Neuropeptides and receptors in the cephalochordate: A crucial model for understanding the origin and evolution of vertebrate neuropeptide systems. Mol Cell Endocrinol 2024; 592:112324. [PMID: 38944371 DOI: 10.1016/j.mce.2024.112324] [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: 03/15/2024] [Revised: 05/26/2024] [Accepted: 06/25/2024] [Indexed: 07/01/2024]
Abstract
Genomes and transcriptomes from diverse organisms are providing a wealth of data to explore the evolution and origin of neuropeptides and their receptors in metazoans. While most neuropeptide-receptor systems have been extensively studied in vertebrates, there is still a considerable lack of understanding regarding their functions in invertebrates, an extraordinarily diverse group that account for the majority of animal species on Earth. Cephalochordates, commonly known as amphioxus or lancelets, serve as the evolutionary proxy of the chordate ancestor. Their key evolutionary position, bridging the invertebrate to vertebrate transition, has been explored to uncover the origin, evolution, and function of vertebrate neuropeptide systems. Amphioxus genomes exhibit a high degree of sequence and structural conservation with vertebrates, and sequence and functional homologues of several vertebrate neuropeptide families are present in cephalochordates. This review aims to provide a comprehensively overview of the recent findings on neuropeptides and their receptors in cephalochordates, highlighting their significance as a model for understanding the complex evolution of neuropeptide signaling in vertebrates.
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Affiliation(s)
- Liuru Su
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Guang Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China.
| | - Billy K C Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
| | - João C R Cardoso
- Comparative Endocrinology and Integrative Biology, Centre of Marine Sciences, Universidade do Algarve, 8005-139, Faro, Portugal.
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Metha J, Ji Y, Braun C, Nicholson JR, De Lecea L, Murawski C, Hoyer D, Jacobson LH. Hypocretin-1 receptor antagonism improves inhibitory control during the Go/No-Go task in highly motivated, impulsive male mice. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06628-3. [PMID: 38886189 DOI: 10.1007/s00213-024-06628-3] [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: 04/21/2024] [Accepted: 05/28/2024] [Indexed: 06/20/2024]
Abstract
RATIONALE Motivation and inhibitory control are dominantly regulated by the dopaminergic (DA) and noradrenergic (NA) systems, respectively. Hypothalamic hypocretin (orexin) neurons provide afferent inputs to DA and NA nuclei and hypocretin-1 receptors (HcrtR1) are implicated in reward and addiction. However, the role of the HcrtR1 in inhibitory control is not well understood. OBJECTIVES To determine the effects of HcrtR1 antagonism and motivational state in inhibitory control using the go/no-go task in mice. METHODS n = 23 male C57Bl/6JArc mice were trained in a go/no-go task. Decision tree dendrogram analysis of training data identified more and less impulsive clusters of animals. A HcrtR1 antagonist (BI001, 12.5 mg/kg, per os) or vehicle were then administered 30 min before go/no-go testing, once daily for 5 days, under high (food-restricted) and low (free-feeding) motivational states in a latin-square crossover design. Compound exposure levels were assessed in a satellite group of animals. RESULTS HcrtR1 antagonism increased go accuracy and decreased no-go accuracy in free-feeding animals overall, whereas it decreased go accuracy and increased no-go accuracy only in more impulsive, food restricted mice. HcrtR1 antagonism also showed differential effects in premature responding, which was increased in response to the antagonist in free-feeding, less impulsive animals, and decreased in food restricted, more impulsive animals. HcrtR1 receptor occupancy by BI001 was estimated at ~ 66% during the task. CONCLUSIONS These data indicate that hypocretin signalling plays roles in goal-directed behaviour and inhibitory control in a motivational state-dependant manner. While likely not useful in all settings, HcrtR1 antagonism may be beneficial in improving inhibitory control in impulsive subpopulations.
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Affiliation(s)
- Jeremy Metha
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
- Department of Finance, The University of Melbourne, Parkville, VIC, 3052, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Yijun Ji
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3052, Australia
- Circadian Misalignment and Shift Work Laboratory, Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Notting Hill, VIC, 3162, Australia
| | - Clemens Braun
- Drug Discovery Sciences, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Janet R Nicholson
- CNS Diseases Research, Boehringer Ingelheim Pharma GmbH & Co. KG, 88397 Biberach, Germany
| | - Luis De Lecea
- Department of Psychiatry and Behavioural Sciences, Stanford University, Stanford, CA, 94305, USA
| | - Carsten Murawski
- Department of Finance, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3052, Australia
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Laura H Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, 3052, Australia.
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3052, Australia.
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Pagh-Berendtsen N, Pavlovskyi A, Flores Téllez D, Egebjerg C, Kolmos MG, Justinussen J, Kornum BR. Downregulation of hypocretin/orexin after H1N1 Pandemrix vaccination of adolescent mice. Sleep 2024; 47:zsae014. [PMID: 38227834 DOI: 10.1093/sleep/zsae014] [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: 09/27/2023] [Revised: 11/07/2023] [Indexed: 01/18/2024] Open
Abstract
Narcolepsy type 1 (NT1), characterized by the loss of hypocretin/orexin (HCRT) production in the lateral hypothalamus, has been linked to Pandemrix vaccination during the 2009 H1N1 pandemic, especially in children and adolescents. It is still unknown why this vaccination increased the risk of developing NT1. This study investigated the effects of Pandemrix vaccination during adolescence on Hcrt mRNA expression in mice. Mice received a primary vaccination (50 µL i.m.) during prepubescence and a booster vaccination during peri-adolescence. Hcrt expression was measured at three-time points after the vaccinations. Control groups included both a saline group and an undisturbed group of mice. Hcrt expression was decreased after both Pandemrix and saline injections, but 21 days after the second injection, the saline group no longer showed decreased Hcrt expression, while the Pandemrix group still exhibited a significant reduction of about 60% compared to the undisturbed control group. This finding suggests that Pandemrix vaccination during adolescence influences Hcrt expression in mice into early adulthood. The Hcrt mRNA level did not reach the low levels known to induce NT1 symptoms, instead, our finding supports the multiple-hit hypothesis of NT1 that states that several insults to the HCRT system may be needed to induce NT1 and that Pandemrix could be one such insult.
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Affiliation(s)
- Nicolai Pagh-Berendtsen
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Artem Pavlovskyi
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Daniel Flores Téllez
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Christine Egebjerg
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Mie Gunni Kolmos
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Jessica Justinussen
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
| | - Birgitte Rahbek Kornum
- Faculty of Health and Medical Sciences, Department of Neuroscience, University of Copenhagen, Denmark
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Cavalu S, Saber S, Hamad RS, Abdel-Reheim MA, Elmorsy EA, Youssef ME. Orexins in apoptosis: a dual regulatory role. Front Cell Neurosci 2024; 18:1336145. [PMID: 38699177 PMCID: PMC11064656 DOI: 10.3389/fncel.2024.1336145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/03/2024] [Indexed: 05/05/2024] Open
Abstract
The orexins, also referred to as hypocretins, are neuropeptides that originate from the lateral hypothalamus (LH) region of the brain. They are composed of two small peptides, orexin-A, and orexin-B, which are broadly distributed throughout the central and peripheral nervous systems. Orexins are recognized to regulate diverse functions, involving energy homeostasis, the sleep-wake cycle, stress responses, and reward-seeking behaviors. Additionally, it is suggested that orexin-A deficiency is linked to sleepiness and narcolepsy. The orexins bind to their respective receptors, the orexin receptor type 1 (OX1R) and type 2 (OX2R), and activate different signaling pathways, which results in the mediation of various physiological functions. Orexin receptors are widely expressed in different parts of the body, including the skin, muscles, lungs, and bone marrow. The expression levels of orexins and their receptors play a crucial role in apoptosis, which makes them a potential target for clinical treatment of various disorders. This article delves into the significance of orexins and orexin receptors in the process of apoptosis, highlighting their expression levels and their potential contributions to different diseases. The article offers an overview of the existing understanding of the orexin/receptor system and how it influences the regulation of apoptosis.
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Affiliation(s)
- Simona Cavalu
- Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
| | - Sameh Saber
- Department of Pharmacology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
| | - Rabab S. Hamad
- Biological Sciences Department, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
- Central Laboratory, Theodor Bilharz Research Institute, Giza, Egypt
| | - Mustafa Ahmed Abdel-Reheim
- Department of Pharmaceutical Sciences, College of Pharmacy, Shaqra University, Shaqra, Saudi Arabia
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Beni-Suef University, Beni Suef, Egypt
| | - Elsayed A. Elmorsy
- Department of Pharmacology and Therapeutics, College of Medicine, Qassim University, Buraidah, Saudi Arabia
- Department of Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Mahmoud E. Youssef
- Department of Pharmacology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
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Hovi M, Roine U, Autti T, Heiskala H, Roine T, Kirjavainen T. Microstructural White Matter Abnormalities in Children and Adolescents With Narcolepsy Type 1. Pediatr Neurol 2024; 153:56-64. [PMID: 38320459 DOI: 10.1016/j.pediatrneurol.2024.01.015] [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: 09/12/2022] [Revised: 01/06/2024] [Accepted: 01/08/2024] [Indexed: 02/08/2024]
Abstract
BACKGROUND In 2010, the H1N1 Pandemrix vaccination campaign was followed by a sudden increase in narcolepsy type 1 (NT1). We investigated the brain white matter microstructure in children with onset of NT1 within two years after the Pandemrix vaccination. METHODS We performed diffusion-weighted magnetic resonance imaging (MRI) on 19 children and adolescents with NT1 and 19 healthy controls. Imaging was performed at a median of 4 years after the diagnosis at a median age of 16 years. For the MRI, we used whole-brain tractography and tract-based spatial statistics (TBSS). We compared these results with medical records and questionnaire data. RESULTS Narcoleptic children showed a global decrease in mean, axial, and radial diffusivity and an increase in planarity coefficient in the white matter TBSS skeleton and tractography. These differences were widespread, and there was an increased asymmetry of the mean diffusivity in children with NT1. The global microstructural metrics were reflected in behavior, and especially the axial diffusion levels correlated with anxiety and depression symptoms and social and behavioral problems. CONCLUSIONS In pediatric patients with Pandemrix-associated NT1, several global changes in the brain white matter network skeleton were observed within five years after the onset of NT1. The degree of changes correlates with behavioral problems.
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Affiliation(s)
- Marita Hovi
- Children's Hospital, and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki, University Hospital, Helsinki, Finland
| | - Ulrika Roine
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki, University Hospital, Helsinki, Finland; HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Taina Autti
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Hannu Heiskala
- Department of Pediatric Neurology, Children's Hospital, University of Helsinki and Helsinki, University Hospital, Helsinki, Finland
| | - Timo Roine
- HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Department of Neuroscience and Biomedical Engineering, Aalto University School of Science, Espoo, Finland; Turku Brain and Mind Center, University of Turku, Turku, Finland
| | - Turkka Kirjavainen
- Children's Hospital, and Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.
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Glen A, Bürli RW, Livermore D, Buffham W, Merison S, Rowland AE, Newman R, Fieldhouse C, Miller DJ, Dawson LA, Matthews K, Carlton MB, Brice NL. Discovery and first-time disclosure of CVN766, an exquisitely selective orexin 1 receptor antagonist. Bioorg Med Chem Lett 2024; 100:129629. [PMID: 38295907 DOI: 10.1016/j.bmcl.2024.129629] [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: 09/08/2023] [Revised: 01/15/2024] [Accepted: 01/26/2024] [Indexed: 02/10/2024]
Abstract
Modulators of orexin receptors are being developed for neurological illnesses such as sleep disorders, addictive behaviours and other psychiatric diseases. We herein describe the discovery of CVN766, a potent orexin 1 receptor antagonist that has greater than 1000-fold selectivity for the orexin 1 receptor over the orexin 2 receptor and demonstrates low off target hits in a diversity screen. In agreement with its in vitro ADME data, CVN766 demonstrated moderate in vivo clearance in rodents and displayed good brain permeability and target occupancy. This drug candidate is currently being investigated in clinical trials for schizophrenia and related psychiatric conditions.
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Affiliation(s)
- Angela Glen
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Roland W Bürli
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - David Livermore
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - William Buffham
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Stephanie Merison
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Anna E Rowland
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK; Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Robert Newman
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK; Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Charlotte Fieldhouse
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - David J Miller
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Lee A Dawson
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Kim Matthews
- Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Mark B Carlton
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK; Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK
| | - Nicola L Brice
- Takeda Cambridge Ltd., 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK; Cerevance Ltd, 418 Cambridge Science Park, Milton Road, Cambridge CB4 0PZ, UK.
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8
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Kobayashi I, Forcelli PA. The effects of a dual orexin receptor antagonist on fear extinction memory and sleep in mice: Implications for exposure therapy. Behav Brain Res 2024; 458:114741. [PMID: 37931704 PMCID: PMC10841840 DOI: 10.1016/j.bbr.2023.114741] [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: 08/07/2023] [Revised: 10/18/2023] [Accepted: 11/01/2023] [Indexed: 11/08/2023]
Abstract
Extinction of conditioned fear is considered a fundamental process in the recovery from posttraumatic stress disorder and anxiety disorders. Sleep, especially rapid-eye-movement (REM) sleep, has been implicated in promoting extinction memory. The orexin system contributes to the regulation of sleep and wakefulness and emotional behaviors. In rodents, administrations of an orexin receptor antagonist following fear extinction training enhanced consolidation of extinction memory. Although orexin antagonists increase sleep, including REM sleep, the possible contribution of sleep to the effects of orexin antagonists on extinction memory has not been examined. Therefore, this study examined the effects of suvorexant, a dual orexin receptor antagonist, on extinction memory and sleep and their associations in mice. C57BL/6 mice underwent sleep recording for 24 h before and after contextual fear conditioning with footshocks and extinction learning during the early light phase or early dark phase. Mice were systemically injected with either 25 mg/kg of suvorexant or vehicle immediately after the extinction session. We found that suvorexant neither altered sleep nor improved extinction memory recall compared with vehicle. The higher percentages of REM sleep during the post-extinction dark phase were associated with lower extinction memory recall and greater freezing responses to the fear context. Results also indicate that animals did not reach complete extinction of fear with the fear extinction training protocol used in this study. These findings suggest that promoting REM sleep may not enhance fear extinction memory when extinction of fear is incomplete.
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Affiliation(s)
- Ihori Kobayashi
- Howard University College of Medicine, 520 W St. NW, Washington, DC 20059, USA.
| | - Patrick A Forcelli
- Georgetown University School of Medicine, 3970 Reservoir Rd NW, Washington, DC 20007, USA
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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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10
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Tsuneki H, Honda K, Sekine Y, Yahata K, Yasue M, Fujishima M, Takeda R, Wada T, Sasaoka T. C-terminal peptide of preproorexin enhances brain-derived neurotrophic factor expression in rat cerebrocortical cells and recognition memory in mice. Eur J Pharmacol 2024; 964:176306. [PMID: 38145647 DOI: 10.1016/j.ejphar.2023.176306] [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: 07/24/2023] [Revised: 12/08/2023] [Accepted: 12/21/2023] [Indexed: 12/27/2023]
Abstract
During the production of orexin A and B from preproorexin, a common precursor protein, in hypothalamic orexin neurons, C-terminal peptide (herein called preproorexin C-peptide) is concomitantly produced via post-translational processing. The predicted three-dimensional structure of preproorexin C-peptide is similar among mammalian species, suggestive of a conserved function in the mammalian brain. However, C-peptide has long been regarded as a non-functional peptide. We herein examined the effects of rat and/or mouse preproorexin C-peptide on gene expression and cell viability in cultured rat cerebrocortical cells and on memory behavior in C57BL/6J mice. Rat and mouse C-peptides both increased brain-derived neurotrophic factor (Bdnf) mRNA levels. Moreover, C-peptide enhanced high K+-, glutamate-, and BDNF-induced increases in Bdnf mRNA levels without affecting forskolin-induced Bdnf expression. H-89, a protein kinase A inhibitor, blocked C-peptide-induced Bdnf expression, whereas rolipram, a phosphodiesterase inhibitor, enhanced this effect. Intracellular cyclic AMP concentrations were elevated by C-peptide. These results demonstrate that preproorexin C-peptide promoted Bdnf mRNA expression by a cyclic AMP-dependent mechanism. Eleven amino acids at the N terminus of rat preproorexin C-peptide exerted similar effects on Bdnf expression as full-length preproorexin C-peptide. Preproorexin C-peptide also exerted protective effects against CoCl2-induced neuronal cell death. An intracerebroventricular injection of mouse preproorexin C-peptide induced c-fos and Bdnf expression in the cerebral cortex and hippocampus and enhanced novel object recognition memory in mice. Collectively, the present results show that preproorexin C-peptide is a functional substance, at least in some pharmacological and neuronal settings.
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Affiliation(s)
- Hiroshi Tsuneki
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan; Department of Integrative Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Kosuke Honda
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Yurika Sekine
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Koji Yahata
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Moeka Yasue
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Masashi Fujishima
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Ryuta Takeda
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Tsutomu Wada
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
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11
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Kron JOZJ, Keenan RJ, Hoyer D, Jacobson LH. Orexin Receptor Antagonism: Normalizing Sleep Architecture in Old Age and Disease. Annu Rev Pharmacol Toxicol 2024; 64:359-386. [PMID: 37708433 DOI: 10.1146/annurev-pharmtox-040323-031929] [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] [Indexed: 09/16/2023]
Abstract
Sleep is essential for human well-being, yet the quality and quantity of sleep reduce as age advances. Older persons (>65 years old) are more at risk of disorders accompanied and/or exacerbated by poor sleep. Furthermore, evidence supports a bidirectional relationship between disrupted sleep and Alzheimer's disease (AD) or related dementias. Orexin/hypocretin neuropeptides stabilize wakefulness, and several orexin receptor antagonists (ORAs) are approved for the treatment of insomnia in adults. Dysregulation of the orexin system occurs in aging and AD, positioning ORAs as advantageous for these populations. Indeed, several clinical studies indicate that ORAs are efficacious hypnotics in older persons and dementia patients and, as in adults, are generally well tolerated. ORAs are likely to be more effective when administered early in sleep/wake dysregulation to reestablish good sleep/wake-related behaviors and reduce the accumulation of dementia-associated proteinopathic substrates. Improving sleep in aging and dementia represents a tremendous opportunity to benefit patients, caregivers, and health systems.
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Affiliation(s)
- Jarrah O-Z J Kron
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia;
| | - Ryan J Keenan
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia;
- Department of Physiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Daniel Hoyer
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia;
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia;
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Laura H Jacobson
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia;
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia;
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12
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Steiner MA, Toeroek-Schafroth M, Giusepponi ME, Dacome L, Tessari M. Abuse potential assessment of the dual orexin receptor antagonist daridorexant in rats. J Psychopharmacol 2023; 37:1249-1260. [PMID: 38059356 PMCID: PMC10714714 DOI: 10.1177/02698811231215415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
BACKGROUND Drugs that act on the central nervous system (CNS) and have sedative effects can lead to abuse in humans. New CNS-active drugs often require evaluation of their abuse potential in dedicated animal models before marketing approval. Daridorexant is a new dual orexin receptor antagonist (DORA) with sleep-promoting properties in animals and humans. It was approved in 2022 in the United States and Europe for the treatment of insomnia disorder. AIMS Nonclinical evaluation of abuse potential of daridorexant using three specific rat models assessing reinforcement, interoception, and withdrawal. METHODS Reinforcing effects of daridorexant were assessed in an operant rat model of intravenous drug self-administration. Similarity of interoceptive effects to those of the commonly used sleep medication zolpidem was tested in an operant drug discrimination task. Withdrawal signs indicative of physical dependence were evaluated upon sudden termination of chronic daridorexant treatment. Rat experiments were conducted at a dose range resulting in daridorexant plasma concentrations equaling or exceeding those achieved at the clinically recommended dose of 50 mg in humans. RESULTS Daridorexant had no reinforcing effects, was dissimilar to zolpidem in the drug discrimination task, and did not induce any withdrawal-related signs upon treatment discontinuation that would be indicative of physical dependence. OUTCOMES Daridorexant showed no signs of abuse or dependence potential in rats. Our data indicate that daridorexant, like other DORAs, has a low potential for abuse in humans.
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Affiliation(s)
| | - Michael Toeroek-Schafroth
- Idorsia Pharmaceuticals Ltd, Allschwil, Switzerland
- Current affiliation: Galapagos GmbH, Basel, Switzerland
| | | | - Lisa Dacome
- Aptuit Srl, An Evotec Company, Verona, Italy
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13
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Cohen H, Matar MA, Todder D, Cohen C, Zohar J, Hawlena H, Abramsky Z. Sounds of danger and post-traumatic stress responses in wild rodents: ecological validity of a translational model of post-traumatic stress disorder. Mol Psychiatry 2023; 28:4719-4728. [PMID: 37674017 PMCID: PMC10914612 DOI: 10.1038/s41380-023-02240-7] [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: 02/01/2023] [Revised: 08/17/2023] [Accepted: 08/24/2023] [Indexed: 09/08/2023]
Abstract
In the wild, animals face a highly variable world full of predators. Most predator attacks are unsuccessful, and the prey survives. According to the conventional perspective, the fear responses elicited by predators are acute and transient in nature. However, the long-term, non-lethal effects of predator exposure on prey behavioral stress sequelae, such as anxiety and post-traumatic symptoms, remain poorly understood. Most experiments on animal models of anxiety-related behavior or post-traumatic stress disorder have been carried out using commercial strains of rats and mice. A fundamental question is whether laboratory rodents appropriately express the behavioral responses of wild species in their natural environment; in other words, whether behavioral responses to stress observed in the laboratory can be generalized to natural behavior. To further elucidate the relative contributions of the natural selection pressures influences, this study investigated the bio-behavioral and morphological effects of auditory predator cues (owl territorial calls) in males and females of three wild rodent species in a laboratory set-up: Acomys cahirinus; Gerbillus henleyi; and Gerbillus gerbillus. Our results indicate that owl territorial calls elicited not only "fight or flight" behavioral responses but caused PTSD-like behavioral responses in wild rodents that have never encountered owls in nature and could cause, in some individuals, enduring physiological and morphological responses that parallel those seen in laboratory rodents or traumatized people. In all rodent species, the PTSD phenotype was characterized by a blunting of fecal cortisol metabolite response early after exposure and by a lower hypothalamic orexin-A level and lower total dendritic length and number in the dentate gyrus granule cells eight days after predator exposure. Phenotypically, this refers to a significant functional impairment that could affect reproduction and survival and thus fitness and population dynamics.
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Affiliation(s)
- Hagit Cohen
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel & Ministry of Health, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Beer-Sheva, Israel.
- Department of Psychology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
| | - Michael A Matar
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel & Ministry of Health, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Beer-Sheva, Israel
| | - Doron Todder
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel & Ministry of Health, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Beer-Sheva, Israel
| | - Carmit Cohen
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel & Ministry of Health, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Beer-Sheva, Israel
| | - Joseph Zohar
- Post-Trauma Center, Sheba Medical Center, Tel Aviv University, Tel Aviv, 52621, Israel
| | - Hadas Hawlena
- Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion Israel, Sde Boker, 8499000, Israel
| | - Zvika Abramsky
- Department of Life Sciences and Ramon Science Center, Ben-Gurion University of the Negev, Beer-Sheva, 84105, Israel
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14
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Santin MDN, Tempier N, Belaid H, Zenoni M, Dumas S, Wallén-Mackenzie Å, Bardinet E, Destrieux C, François C, Karachi C. Anatomical characterisation of three different psychosurgical targets in the subthalamic area: from the basal ganglia to the limbic system. Brain Struct Funct 2023; 228:1977-1992. [PMID: 37668733 DOI: 10.1007/s00429-023-02691-2] [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: 02/03/2023] [Accepted: 07/24/2023] [Indexed: 09/06/2023]
Abstract
Effective neural stimulation for the treatment of severe psychiatric disorders needs accurate characterisation of surgical targets. This is especially true for the medial subthalamic region (MSR) which contains three targets: the anteromedial STN for obsessive compulsive disorder (OCD), the medial forebrain bundle (MFB) for depression and OCD, and the "Sano triangle" for pathological aggressiveness. Blocks containing the subthalamic area were obtained from two human brains. After obtaining 11.7-Tesla MRI, blocks were cut in regular sections for immunohistochemistry. Fluorescent in situ hybridisation was performed on the macaque MSR. Electron microscopic observation for synaptic specialisation was performed on human and macaque subthalamic fresh samples. Images of human brain sections were reconstructed in a cryoblock which was registered on the MRI and histological slices were then registered. The STN contains glutamatergic and fewer GABAergic neurons and has no strict boundary with the adjacent MSR. The anteromedial STN has abundant dopaminergic and serotoninergic innervation with very sparse dopaminergic neurons. The MFB is composed of dense anterior dopaminergic and posterior serotoninergic fibres, and fewer cholinergic and glutamatergic fibres. Medially, the Sano triangle presumably contains orexinergic terminals from the hypothalamus, and neurons with strong nuclear oestrogen receptor-alpha staining with a decreased anteroposterior and mediolateral gradient of staining. These findings provide new insight regarding MSR cells and their fibre specialisation, forming a transition zone between the basal ganglia and the limbic systems. Our 3D reconstruction enabled us to visualize the main histological features of the three targets which should enable better targeting and understanding of neuromodulatory stimulation results in severe psychiatric conditions.
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Affiliation(s)
- Marie des Neiges Santin
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | - Nicolas Tempier
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | - Hayat Belaid
- Service de Neurochirurgie, Hôpital Fondation Adolphe de Rothschild, 29 rue Manin, Paris, France
| | - Matthieu Zenoni
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | | | - Åsa Wallén-Mackenzie
- Department of Organismal Biology, Unit of Comparative Physiology, Uppsala University, S-756 32, Uppsala, Sweden
| | - Eric Bardinet
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | - Christophe Destrieux
- UMR Inserm U1253, IBrain, Université de Tours, Tours, France
- Laboratoire d'Anatomie, Faculté de Médecine, Université François Rabelais, Tours, France
| | - Chantal François
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France
| | - Carine Karachi
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute- ICM, Inserm, CNRS, APHP, Hôpital de la Pitié Salpêtrière, 75013, Paris, France.
- AP-HP, Hôpital de la Pitié-Salpêtrière, Service de Neurochirurgie, Paris, France.
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15
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Li S, Liu M, Cao S, Liu B, Li D, Wang Z, Sun H, Cui Y, Shi Y. The Mechanism of the Gut-Brain Axis in Regulating Food Intake. Nutrients 2023; 15:3728. [PMID: 37686760 PMCID: PMC10490484 DOI: 10.3390/nu15173728] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/16/2023] [Accepted: 08/23/2023] [Indexed: 09/10/2023] Open
Abstract
With the increasing prevalence of energy metabolism disorders such as diabetes, cardiovascular disease, obesity, and anorexia, the regulation of feeding has become the focus of global attention. The gastrointestinal tract is not only the site of food digestion and absorption but also contains a variety of appetite-regulating signals such as gut-brain peptides, short-chain fatty acids (SCFAs), bile acids (BAs), bacterial proteins, and cellular components produced by gut microbes. While the central nervous system (CNS), as the core of appetite regulation, can receive and integrate these appetite signals and send instructions to downstream effector organs to promote or inhibit the body's feeding behaviour. This review will focus on the gut-brain axis mechanism of feeding behaviour, discussing how the peripheral appetite signal is sensed by the CNS via the gut-brain axis and the role of the central "first order neural nuclei" in the process of appetite regulation. Here, elucidation of the gut-brain axis mechanism of feeding regulation may provide new strategies for future production practises and the treatment of diseases such as anorexia and obesity.
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Affiliation(s)
- Shouren Li
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
| | - Mengqi Liu
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
| | - Shixi Cao
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
| | - Boshuai Liu
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
| | - Defeng Li
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
| | - Zhichang Wang
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
| | - Hao Sun
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
| | - Yalei Cui
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
| | - Yinghua Shi
- College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450002, China; (S.L.); (M.L.)
- Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou 450002, China
- Henan Forage Engineering Technology Research Center, Zhengzhou 450002, China
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16
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Zhu M, Huang H. The Underlying Mechanisms of Sleep Deprivation Exacerbating Neuropathic Pain. Nat Sci Sleep 2023; 15:579-591. [PMID: 37533626 PMCID: PMC10392808 DOI: 10.2147/nss.s414174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 07/25/2023] [Indexed: 08/04/2023] Open
Abstract
Pain disrupts sleep, and sleep deprivation or interference can alter pain perception in animals and humans, for example by increasing sensitivity to pain. However, the mechanism by which sleep affects neuropathic pain remains unclear. In this review, we discuss the available evidence from the epidemiologic, clinical, and human, as well as laboratory studies. In previous studies, we have found that sleep deprivation affects various injurious systems, including opioids, dopaminergic, immune, orexins, hypothalamic-pituitary-adrenal axis, and adenosine. At the same time, these systems play a crucial role in neuropathic pain regulation. In the complex interactions between these neurobiological systems, there may be potential regulatory pathways through which sleep deprivation amplifies neuropathic pain. Because of the impact sleep problems and neuropathic pain can have on the patients' quality of life, studying the link between sleep and neuropathic pain is important for neuropathic pain prevention and public health.
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Affiliation(s)
- Manmin Zhu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Guizhou, People’s Republic of China
| | - Hao Huang
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Guizhou, People’s Republic of China
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17
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Costello A, Linning-Duffy K, Vandenbrook C, Donohue K, O'Hara BF, Kim A, Lonstein JS, Yan L. Effects of light therapy on sleep/wakefulness, daily rhythms, and the central orexin system in a diurnal rodent model of seasonal affective disorder. J Affect Disord 2023; 332:299-308. [PMID: 37060954 PMCID: PMC10161688 DOI: 10.1016/j.jad.2023.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/31/2023] [Accepted: 04/07/2023] [Indexed: 04/17/2023]
Abstract
BACKGROUND Bright light therapy (BLT) is the first-line treatment for seasonal affective disorder. However, the neural mechanisms underlying BLT are unclear. To begin filling this gap, the present study examined the impact of BLT on sleep/wakefulness, daily rhythms, and the wakefulness-promoting orexin/hypocretin system in a diurnal rodent, Nile grass rats (Arvicanthis niloticus). METHODS Male and female grass rats were housed under a 12:12 h light/dark cycle with dim light (50 lx) during the day. The experimental group received daily 1-h early morning BLT (full-spectrum white light, 10,000 lx), while the control group received narrowband red light for 4 weeks. Sleep/wakefulness and in-cage locomotor activity were monitored, followed by examination of hypothalamic prepro-orexin and orexin receptors OX1R and OX2R expression in corticolimbic brain regions. RESULTS The BLT group had higher wakefulness during light treatment, better nighttime sleep quality, and improved daily rhythm entrainment compared to controls. The impact of BLT on the orexin system was sex- and brain region-specific, with males showing higher OX1R and OX2R in the CA1, while females showed higher prepro-orexin but lower OX1R and OX2R in the BLA, compared to same-sex controls. LIMITATIONS The present study focused on the orexin system in a limited number of brain regions at a single time point. Sex wasn't a statistical factor, as male and female cohorts were run independently. CONCLUSIONS The diurnal grass rats show similar behavioral responses to BLT as humans, thus could be a good model for further elucidating the neural mechanisms underlying the therapeutic effects of BLT.
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Affiliation(s)
- Allison Costello
- Department of Psychology, Michigan State University, United States of America.
| | | | | | - Kevin Donohue
- Department of Electrical and Computer Engineering, Michigan State University, United States of America
| | - Bruce F O'Hara
- Department of Biology, University of Kentucky, United States of America
| | - Antony Kim
- Department of Architecture, UC Berkeley, United States of America
| | - Joseph S Lonstein
- Department of Psychology, Michigan State University, United States of America; Neuroscience Program, Michigan State University, United States of America
| | - Lily Yan
- Department of Psychology, Michigan State University, United States of America; Neuroscience Program, Michigan State University, United States of America
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18
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Xia L, Liu HY, Wang BY, Lin HN, Wang MC, Ren JX. A review of physiological functions of orexin: From instinctive responses to subjective cognition. Medicine (Baltimore) 2023; 102:e34206. [PMID: 37390267 PMCID: PMC10313292 DOI: 10.1097/md.0000000000034206] [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: 03/13/2023] [Accepted: 06/14/2023] [Indexed: 07/02/2023] Open
Abstract
Orexin, also known as hypocretin, is an excitatory neuropeptide secreted by the hypothalamus. Orexin is divided into orexin-A (OXA) and orexin-B (OXB), which are derived from a common precursor secreted by hypothalamic neurons. Orexin acts on orexin receptor-1 (OX1R) and orexin receptor-2 (OX2R). Orexin neurons, as well as receptors, are widely distributed in various regions of the brain as well as in the peripheral system and have a wider range of functions. This paper reviews the latest research results of orexin in the aspects of food intake, sleep, addiction, depression and anxiety. Because orexin has certain physiological functions in many systems, we further explored the possibility of orexin as a new target for the treatment of bulimia, anorexia nervosa, insomnia, lethargy, anxiety and depression. It is precisely because orexin has physiological functions in multiple systems that orexin, as a new target for the treatment of the above diseases, has potential contradictions. For example, it promotes the function of 1 system and may inhibit the function of another system. How to study a new drug, which can not only treat the diseases of this system, but also do not affect other system functions, is what we need to focus on.
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Affiliation(s)
- LiBo Xia
- Department of Encephalopathy, Jilin Provincial Hospital of Chinese Medicine, Changchun, China
| | - Hai Yan Liu
- Department of Medical Section, Changchun Second Hospital, Changchun, China
| | - Bi Yan Wang
- Department of Encephalopathy, Jilin Provincial Hospital of Chinese Medicine, Changchun, China
| | - Hai Ning Lin
- Department of Encephalopathy, Jilin Provincial Hospital of Chinese Medicine, Changchun, China
| | - Meng Chen Wang
- Department of Encephalopathy, Jilin Provincial Hospital of Chinese Medicine, Changchun, China
| | - Ji-Xiang Ren
- Department of Encephalopathy, Jilin Provincial Hospital of Chinese Medicine, Changchun, China
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19
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Christensen J, MacPherson N, Li C, Yamakawa GR, Mychasiuk R. Repeat mild traumatic brain injuries (RmTBI) modify nociception and disrupt orexinergic connectivity within the descending pain pathway. J Headache Pain 2023; 24:72. [PMID: 37316796 DOI: 10.1186/s10194-023-01608-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023] Open
Abstract
Repeat mild traumatic brain injuries (RmTBI) result in substantial burden to the public health system given their association with chronic post-injury pathologies, such as chronic pain and post-traumatic headache. Although this may relate to dysfunctional descending pain modulation (DPM), it is uncertain what mechanisms drive changes within this pathway. One possibility is altered orexinergic system functioning, as orexin is a potent anti-nociceptive neuromodulator. Orexin is exclusively produced by the lateral hypothalamus (LH) and receives excitatory innervation from the lateral parabrachial nucleus (lPBN). Therefore, we used neuronal tract-tracing to investigate the relationship between RmTBI and connectivity between lPBN and the LH, as well as orexinergic projections to a key site within the DPM, the periaqueductal gray (PAG). Prior to injury induction, retrograde and anterograde tract-tracing surgery was performed on 70 young-adult male Sprague Dawley rats, targeting the lPBN and PAG. Rodents were then randomly assigned to receive RmTBIs or sham injuries before undergoing testing for anxiety-like behaviour and nociceptive sensitivity. Immunohistochemical analysis identified distinct and co-localized orexin and tract-tracing cell bodies and projections within the LH. The RmTBI group exhibited altered nociception and reduced anxiety as well as a loss of orexin cell bodies and a reduction of hypothalamic projections to the ventrolateral nucleus of the PAG. However, there was no significant effect of injury on neuronal connectivity between the lPBN and orexinergic cell bodies within the LH. Our identification of structural losses and the resulting physiological changes in the orexinergic system following RmTBI begins to clarify acute post-injury mechanistic changes that drive may drive the development of post-traumatic headache and the chronification of pain.
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Affiliation(s)
- Jennaya Christensen
- Department of Neuroscience, Central Clinical School, 99 Commercial Road, VIC, 3004, Melbourne, Australia
| | - Naomi MacPherson
- Department of Neuroscience, Central Clinical School, 99 Commercial Road, VIC, 3004, Melbourne, Australia
| | - Crystal Li
- Department of Neuroscience, Central Clinical School, 99 Commercial Road, VIC, 3004, Melbourne, Australia
| | - Glenn R Yamakawa
- Department of Neuroscience, Central Clinical School, 99 Commercial Road, VIC, 3004, Melbourne, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, 99 Commercial Road, VIC, 3004, Melbourne, Australia.
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20
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Pandey P, Wall PK, Lopez SR, Dubuisson OS, Zunica ERM, Dantas WS, Kirwan JP, Axelrod CL, Johnson AE. A familial natural short sleep mutation promotes healthy aging and extends lifespan in Drosophila. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.25.538137. [PMID: 37163058 PMCID: PMC10168263 DOI: 10.1101/2023.04.25.538137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Sleep loss typically imposes negative effects on animal health. However, humans with a rare genetic mutation in the dec2 gene ( dec2 P384R ) present an exception; these individuals sleep less without the usual effects associated with sleep deprivation. Thus, it has been suggested that the dec2 P384R mutation activates compensatory mechanisms that allows these individuals to thrive with less sleep. To test this directly, we used a Drosophila model to study the effects of the dec2 P384R mutation on animal health. Expression of human dec2 P384R in fly sleep neurons was sufficient to mimic the short sleep phenotype and, remarkably, dec2 P384R mutants lived significantly longer with improved health despite sleeping less. The improved physiological effects were enabled, in part, by enhanced mitochondrial fitness and upregulation of multiple stress response pathways. Moreover, we provide evidence that upregulation of pro-health pathways also contributes to the short sleep phenotype, and this phenomenon may extend to other pro-longevity models.
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21
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Moline M, Asakura S, Beuckman C, Landry I, Setnik B, Ashworth J, Henningfield JE. The abuse potential of lemborexant, a dual orexin receptor antagonist, according to the 8 factors of the Controlled Substances Act. Psychopharmacology (Berl) 2023; 240:699-711. [PMID: 36749354 PMCID: PMC10006052 DOI: 10.1007/s00213-023-06320-y] [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: 06/27/2022] [Accepted: 01/17/2023] [Indexed: 02/08/2023]
Abstract
RATIONALE Lemborexant (LEM) is a dual orexin receptor antagonist (DORA) approved in multiple countries including the USA, Japan, Canada, Australia, and several Asian countries for the treatment of insomnia in adults. As a compound with central nervous system activity, it is important to understand the abuse potential of LEM with respect to public health. OBJECTIVES This review discusses data for LEM relevant to each of the 8 factors of the United States Controlled Substances Act. RESULTS LEM did not demonstrate abuse potential in nonclinical testing and was associated with a low incidence of abuse-related adverse events in clinical study participants with insomnia disorder. Similar to other DORAs that have been evaluated (eg., almorexant, suvorexant (SUV), and daridorexant), LEM and the positive controls (zolpidem and SUV) also showed drug liking in a phase 1 abuse potential study that enrolled subjects who used sedatives recreationally. However, internet surveillance of SUV and the FDA Adverse Events Reporting System suggests that drugs in the DORA class display very low abuse-related risks in the community. Additionally, as described in FDA-approved labeling, it does not carry physical dependence and withdrawal risks. CONCLUSIONS LEM, similar to most other prescription insomnia medications, was placed into Schedule IV. However, LEM and other drugs in the DORA class may have a lower potential for abuse as suggested by real-world postmarketing data from federal surveys and internet surveillance, and thus may have lower risks to public health than Schedule IV benzodiazepines and nonbenzodiazepine hypnotics that potentiate GABA signaling.
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Affiliation(s)
- Margaret Moline
- Eisai Inc., 200 Metro Boulevard, Nutley, Jersey, NJ, 07110, USA.
| | | | | | | | - Beatrice Setnik
- Altasciences, Laval, Quebec, Canada and the Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | | | - Jack E Henningfield
- Pinney Associates, Inc., Bethesda, MD, USA.,The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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22
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Beckenstrom AC, Coloma PM, Dawson GR, Finlayson AK, Malik A, Post A, Steiner MA, Potenza MN. Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation. Neurosci Biobehav Rev 2023; 147:105107. [PMID: 36828161 PMCID: PMC10165155 DOI: 10.1016/j.neubiorev.2023.105107] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/08/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023]
Abstract
Despite progress in understanding the pathological mechanisms underlying psychiatric disorders, translation from animal models into clinical use remains a significant bottleneck. Preclinical studies have implicated the orexin neuropeptide system as a potential target for psychiatric disorders through its role in regulating emotional, cognitive, and behavioral processes. Clinical studies are investigating orexin modulation in addiction and mood disorders. Here we review performance-outcome measures (POMs) arising from experimental medicine research methods which may show promise as markers of efficacy of orexin receptor modulators in humans. POMs provide objective measures of brain function, complementing patient-reported or clinician-observed symptom evaluation, and aid the translation from preclinical to clinical research. Significant challenges include the development, validation, and operationalization of these measures. We suggest that collaborative networks comprising clinical practitioners, academics, individuals working in the pharmaceutical industry, drug regulators, patients, patient advocacy groups, and other relevant stakeholders may provide infrastructure to facilitate validation of experimental medicine approaches in translational research and in the implementation of these approaches in real-world clinical practice.
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Affiliation(s)
- Amy C Beckenstrom
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK.
| | - Preciosa M Coloma
- Idorsia Pharmaceuticals Ltd, Hegenheimermattweg 91, Allschwil 4123, Switzerland
| | - Gerard R Dawson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Ailidh K Finlayson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK; Department of Psychology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Asad Malik
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Anke Post
- Corlieve Therapeutics, Swiss Innovation Park, Hegenheimermattweg 167A, 4123 Allschwil, Switzerland
| | | | - Marc N Potenza
- Departments of Psychiatry and Neuroscience and the Child Study Center, Yale School of Medicine, 1 Church Street, Room 726, New Haven, CT 06510, USA; Connecticut Mental Health Center, 34 Park Street, New Haven, CT 06519, USA; Connecticut Council on Problem Gambling, Wethersfield, CT, USA; The Wu Tsai Institute, Yale University, 100 College St, New Haven, CT 06510, USA
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23
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Vraka K, Mytilinaios D, Katsenos AP, Serbis A, Baloyiannis S, Bellos S, Simos YV, Tzavellas NP, Konitsiotis S, Vezyraki P, Peschos D, Tsamis KI. Cellular Localization of Orexin 1 Receptor in Human Hypothalamus and Morphological Analysis of Neurons Expressing the Receptor. Biomolecules 2023; 13:biom13040592. [PMID: 37189339 DOI: 10.3390/biom13040592] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
The orexin system is related to food behavior, energy balance, wakefulness and the reward system. It consists of the neuropeptides orexin A and B, and their receptors, orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R). OX1R has selective affinity for orexin A, and is implicated in multiple functions, such as reward, emotions, and autonomic regulation. This study provides information about the OX1R distribution in human hypothalamus. The human hypothalamus, despite its small size, demonstrates a remarkable complexity in terms of cell populations and cellular morphology. Numerous studies have focused on various neurotransmitters and neuropeptides in the hypothalamus, both in animals and humans, however, there is limited experimental data on the morphological characteristics of neurons. The immunohistochemical analysis of the human hypothalamus revealed that OX1R is mainly found in the lateral hypothalamic area, the lateral preoptic nucleus, the supraoptic nucleus, the dorsomedial nucleus, the ventromedial nucleus, and the paraventricular nucleus. The rest of the hypothalamic nuclei do not express the receptor, except for a very low number of neurons in the mammillary bodies. After identifying the nuclei and neuronal groups that were immunopositive for OX1R, a morphological and morphometric analysis of those neurons was conducted using the Golgi method. The analysis revealed that the neurons in the lateral hypothalamic area were uniform in terms of their morphological characteristics, often forming small groups of three to four neurons. A high proportion of neurons in this area (over 80%) expressed the OX1R, with particularly high expression in the lateral tuberal nucleus (over 95% of neurons). These results were analyzed, and shown to represent, at the cellular level, the distribution of OX1R, and we discuss the regulatory role of orexin A in the intra-hypothalamic areas, such as its special role in the plasticity of neurons, as well as in neuronal networks of the human hypothalamus.
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24
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Ball HL, Said H, Chapman K, Fu R, Xiong Y, Burk JA, Rosenbaum D, Veneziano R, Cotten ML. Orexin A, an amphipathic α-helical neuropeptide involved in pleiotropic functions in the nervous and immune systems: Synthetic approach and biophysical studies of the membrane-bound state. Biophys Chem 2023; 297:107007. [PMID: 37037119 DOI: 10.1016/j.bpc.2023.107007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/11/2023] [Accepted: 03/12/2023] [Indexed: 03/16/2023]
Abstract
This research reports on the membrane interactions of orexin A (OXA), an α-helical and amphipathic neuropeptide that contains 33 residues and two disulfide bonds in the N-terminal region. OXA, which activates the orexins 1 and 2 receptors in neural and immune cell membranes, has essential pleiotropic physiological effects, including at the levels of arousal, sleep/wakefulness, energy balance, neuroprotection, lipid signaling, the inflammatory response, and pain. As a result, the orexin system has become a prominent target to treat diseases such as sleep disorders, drug addiction, and inflammation. While the high-resolution structure of OXA has been investigated in water and bound to micelles, there is a lack of information about its conformation bound to phospholipid membranes and its receptors. NMR is a powerful method to investigate peptide structures in a membrane environment. To facilitate the NMR structural studies of OXA exposed to membranes, we present a novel synthetic scheme, leading to the production of isotopically-labeled material at high purity. A receptor activation assay shows that the 15N-labeled peptide is biologically active. Biophysical studies are performed using surface plasmon resonance, circular dichroism, and NMR to investigate the interactions of OXA with phospholipid bilayers. The results demonstrate a strong interaction between the peptide and phospholipids, an increase in α-helical content upon membrane binding, and an in-plane orientation of the C-terminal region critical to function. This new knowledge about structure-activity relationships in OXA could inspire the design of novel therapeutics that leverage the anti-inflammatory and neuro-protective functions of OXA, and therefore could help address neuroinflammation, a major issue associated with neurological disorders such as Alzheimer's disease.
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Affiliation(s)
- Haydn L Ball
- Department of Chemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Hooda Said
- Department of Bioengineering, College of Engineering and Computing, George Mason University, Fairfax, VA 22030, USA
| | - Karen Chapman
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Riqiang Fu
- National High Magnetic Field Laboratory, Tallahassee, FL 32310, USA
| | - Yawei Xiong
- Department of Applied Science, William & Mary, Williamsburg, VA 23185, USA
| | - Joshua A Burk
- Department of Psychological Sciences, William & Mary, Williamsburg, VA 23185, USA
| | - Daniel Rosenbaum
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Remi Veneziano
- Department of Bioengineering, College of Engineering and Computing, George Mason University, Fairfax, VA 22030, USA
| | - Myriam L Cotten
- Department of Applied Science, William & Mary, Williamsburg, VA 23185, USA.
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25
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Gao WR, Hu XH, Yu KY, Cai HY, Wang ZJ, Wang L, Wu MN. Selective orexin 1 receptor antagonist SB-334867 aggravated cognitive dysfunction in 3xTg-AD mice. Behav Brain Res 2023; 438:114171. [PMID: 36280008 DOI: 10.1016/j.bbr.2022.114171] [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: 07/18/2022] [Revised: 10/09/2022] [Accepted: 10/20/2022] [Indexed: 11/05/2022]
Abstract
Cognitive dysfunction is the main clinical manifestation of Alzheimer's disease (AD). Previous research found that elevated orexin level in the cerebrospinal fluid was closely related to the course of AD, and orexin-A treatment could increase amyloid β protein (Aβ) deposition and aggravate spatial memory impairment in APP/PS1 mice. Furthermore, recent research found that dual orexin receptor (OXR) antagonist might affect Aβ level and cognitive dysfunction in AD, but the effects of OX1R or OX2R alone is unreported until now. Considering that OX1R is highly expressed in the hippocampus and plays important roles in learning and memory, the effects of OX1R in AD cognitive dysfunction and its possible mechanism should be investigated. In the present study, selective OX1R antagonist SB-334867 was used to block OX1R. Then, different behavioral tests were performed to observe the effects of OX1R blockade on cognitive function of 3xTg-AD mice exhibited both Aβ and tau pathology, in vivo electrophysiological recording and western blot were used to investigate the potential mechanism. The results showed that chronic OX1R blockade aggravated the impairments of short-term working memory, long-term spatial memory and synaptic plasticity in 9-month-old female 3xTg-AD mice, increased levels of soluble Aβ oligomers and p-tau, and decreased PSD-95 expression in the hippocampus of 3xTg-AD mice. These results indicate that the detrimental effects of SB-334867 on cognitive behaviors in 3xTg-AD mice are closely related to the decrease of PSD-95 and depression of in vivo long-term potentiation (LTP) caused by increased Aβ oligomers and p-tau.
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Affiliation(s)
- Wen-Rui Gao
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Xiao-Hong Hu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Kai-Yue Yu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Hong-Yan Cai
- Department of Microbiology and Immunology, Shanxi Medical University, Taiyuan 030001, China
| | - Zhao-Jun Wang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China
| | - Lei Wang
- Department of Geriatrics, Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Taiyuan 030032, China.
| | - Mei-Na Wu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan 030001, China.
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26
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Zhou F, Wang D, Li H, Wang S, Zhang X, Li A, Tong T, Zhong H, Yang Q, Dong H. Orexinergic innervations at GABAergic neurons of the lateral habenula mediates the anesthetic potency of sevoflurane. CNS Neurosci Ther 2023; 29:1332-1344. [PMID: 36740262 PMCID: PMC10068468 DOI: 10.1111/cns.14106] [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: 08/03/2022] [Revised: 01/17/2023] [Accepted: 01/18/2023] [Indexed: 02/07/2023] Open
Abstract
AIMS The circuitry mechanism associated with anesthesia-induced unconsciousness is still largely unknown. It has been reported that orexinergic neurons of the lateral hypothalamus (LHA) facilitate the emergence from anesthesia through their neuronal projections to the arousal-promoting brain areas. However, the lateral habenula (LHb), as one of the orexin downstream targets, is known for its anesthesia-promoting effect. Therefore, the current study aimed to explore whether and how the orexinergic projections from the LHA to the LHb have a regulatory effect on unconsciousness induced by general anesthesia. METHODS We applied optogenetic, chemogenetic, or pharmacological approaches to regulate the orexinergicLHA-LHb pathway. Fiber photometry was used to assess neuronal activity. Loss or recovery of the righting reflex was used to evaluate the induction or emergence time of general anesthesia. The burst-suppression ratio and electroencephalography spectra were used to measure the anesthetic depth. RESULTS We found that activation of the orexinergicLHA-LHb pathway promoted emergence and reduced anesthetic depth during sevoflurane anesthesia. Surprisingly, the arousal-promoting effect of the orexinergicLHA-LHb pathway was mediated by excitation of glutamate decarboxylase (GAD2)-expressing neurons, but not glutamatergic neurons in the LHb. CONCLUSION The orexinergicLHA-LHb pathway facilitates emergence from sevoflurane anesthesia, and this effect was mediated by OxR2 in GAD2-expressing GABA neurons.
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Affiliation(s)
- Fang Zhou
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Dan Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Huiming Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Sa Wang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xinxin Zhang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ao Li
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China.,Anesthesia and Operation Center, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Tingting Tong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Haixing Zhong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Qianzi Yang
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China.,Department of Anesthesiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hailong Dong
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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27
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Muacevic A, Adler JR. Physiological Role of Orexin/Hypocretin in the Human Body in Motivated Behavior: A Comprehensive Review. Cureus 2023; 15:e34009. [PMID: 36814741 PMCID: PMC9939734 DOI: 10.7759/cureus.34009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 01/20/2023] [Indexed: 01/22/2023] Open
Abstract
Neurohormones are neurosecretory materials released by neurosecretory cells that serve both as neuromodulators in the brain and spinal cord and as circulating regulatory hormones. They serve a wide range of functions, including homeostasis, development, and modulation of neuronal and muscle activity. In the hypothalamus, neurohormones called hypocretins are created that were discovered in the late nineties. Orexin receptors (OXRs) have been shown to enhance synaptic signaling in the central nervous system at the cellular level. The orexins improve stimulated neural activity in the hippocampus, which, in turn, aids with spatial memory, learning, and mood. They present themselves as mediators for the hypothalamic functions. They have been shown to regulate sleep-wake cycles, arousal mechanisms, addiction, sympathetic nerve activity (SNA), blood pressure, and thermogenesis. Its role in storing brown adipose tissue has implications for thermal homeostasis. The significant role of orexins is seen in tumorigenesis when orexin A (OrxA) and orexin B (OrxB) induce apoptosis in fast-growing tumor cells. Orexin-null subjects show clinical narcolepsy, indicating that orexins were responsible for keeping them awake. Orexin microinjections in mice brains stimulated increased physical activity, thus possibly countering diet-induced obesity. Physical activity significantly increased plasma orexin-A levels, which facilitated the process of energy homeostasis. The amount of adrenocorticotropic hormone (ACTH) increases in stress conditions, which further facilitates the release of the stress hormone cortisol. No increase in the ACTH hormone is seen in stressed mice administered with orexin receptor 2 (OX2R) antagonists thus showing orexin's role in stress reaction. As a result of linking hypocretin/orexin to various physiological procedures, increased research into the medicinal potential of drugs targeting these receptors is emerging. We summed up in this review the recent advances in our understanding of how orexin and its receptor system play an essential role in clinical and pathological functions. This research summarizes a new area for research in human medicine, providing the possibility of controlling a vast array of physiological functions through intra-cerebroventricular injections of a single neuropeptide.
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28
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Estradiol-dependent hypocretinergic/orexinergic behaviors throughout the estrous cycle. Psychopharmacology (Berl) 2023; 240:15-25. [PMID: 36571628 PMCID: PMC9816302 DOI: 10.1007/s00213-022-06296-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/12/2022] [Indexed: 12/27/2022]
Abstract
RATIONALE The female menstrual or estrous cycle and its associated fluctuations in circulating estradiol (E2), progesterone, and other gonadal hormones alter orexin or hypocretin peptide production and receptor activity. Depending on the estrous cycle phase, the transcription of prepro-orexin mRNA, post-translational modification of orexin peptide, and abundance of orexin receptors change in a brain region-specific manner. The most dramatic changes occur in the hypothalamus, which is considered the starting point of the hypothalamic-pituitary-gonadal axis as well as the hub of orexin-producing neurons. Thus, hypothalamus-regulated behaviors, including arousal, feeding, reward processing, and the stress response depend on coordinated efforts between E2, progesterone, and the orexin system. Given the rise of orexin therapeutics for various neuropsychiatric conditions including insomnia and affective disorders, it is important to delineate the behavioral outcomes of this drug class in both sexes, as well as within different time points of the female reproductive cycle. OBJECTIVES Summarize how the menstrual or estrous cycle affects orexin system functionality in animal models in order to predict how orexin pharmacotherapies exert varying degrees of behavioral effects across the dynamic hormonal milieu.
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29
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Oddes D, Ngwenya A, Malungo IB, Burkevica A, Hård T, Bertelsen MF, Spocter MA, Scantlebury DM, Manger PR. Orexinergic neurons in the hypothalami of an Asiatic lion, an African lion, and a Southeast African cheetah. J Comp Neurol 2022; 531:366-389. [PMID: 36354959 PMCID: PMC10099269 DOI: 10.1002/cne.25431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/12/2022]
Abstract
Employing orexin-A immunohistochemistry, we describe the distribution, morphology, and nuclear parcellation of orexinergic neurons within the hypothalami of an Asiatic lion (Panthera leo subsp. persica), an African lion (Panthera leo subsp. melanochaita), and a Southeast African cheetah (Acinonyx jubatus subsp. jubatus). In all three felids, the clustering of large, bipolar, and multipolar hypothalamic orexinergic neurons primarily follows the pattern observed in other mammals. The orexinergic neurons were found, primarily, to form three distinct clusters-the main, zona incerta, and optic tract clusters. In addition, large orexinergic neurons were observed in the ventromedial supraoptic region of the hypothalamus, where they are not typically observed in other species. As has been observed in cetartiodactyls and the African elephant, a cluster of small, multipolar orexinergic neurons, the parvocellular cluster, was observed in the medial zone of the hypothalamus in all three felids, although this parvocellular cluster has not been reported in other carnivores. In both subspecies of lions, but not the cheetah, potential orexin-immunopositive neurons were observed in the paraventricular hypothalamic nucleus, supraoptic nucleus, the lateral part of the retrochiasmatic area, and the inner layer of the median eminence. The distribution and parcellation of orexinergic neurons in the hypothalami of the three felids studied appear to be more complex than observed in many other mammals and for the two subspecies of lion may be even more complex. These findings are discussed in terms of potential technical concerns, phylogenetic variations of this system, and potentially associated functional aspects of the orexinergic system.
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Affiliation(s)
- Demi Oddes
- School of Anatomical Sciences, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
| | - Ayanda Ngwenya
- School of Anatomical Sciences, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
| | - Illke B. Malungo
- School of Anatomical Sciences, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
| | | | | | - Mads. F. Bertelsen
- Centre for Zoo and Wild Animal Health Copenhagen Zoo Frederiksberg Denmark
| | - Muhammad A. Spocter
- School of Anatomical Sciences, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
- Department of Anatomy Des Moines University Des Moines Iowa USA
| | | | - Paul R. Manger
- School of Anatomical Sciences, Faculty of Health Sciences University of the Witwatersrand Johannesburg South Africa
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30
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Suzuki H, Yamamoto T. Orexin‐A
and
orexin‐B
are differently localized in the pars nervosa and pars distalis of the white‐spotted conger and Japanese eel pituitaries. ACTA ZOOL-STOCKHOLM 2022. [DOI: 10.1111/azo.12442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hirohumi Suzuki
- Department of Biology University of Teacher Education Fukuoka Munakata Japan
| | - Toshiharu Yamamoto
- Brain Functions and Neuroscience Unit, Department of Oral Science, Graduate School of Dentistry Kanagawa Dental University Yokosuka Japan
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31
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Carrera-Cañas C, de Andrés I, Callejo M, Garzón M. Plasticity of the hypocretinergic/orexinergic system after a chronic treatment with suvorexant in rats. Role of the hypocretinergic/orexinergic receptor 1 as an autoreceptor. Front Mol Neurosci 2022; 15:1013182. [PMID: 36277486 PMCID: PMC9581150 DOI: 10.3389/fnmol.2022.1013182] [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: 08/06/2022] [Accepted: 09/13/2022] [Indexed: 12/02/2022] Open
Abstract
The hypothalamic hypocretinergic/orexinergic (Hcrt/Ox) system is involved in many physiological and pathophysiological processes. Malfunction of Hcrt/Ox transmission results in narcolepsy, a sleep disease caused in humans by progressive neurodegeneration of hypothalamic neurons containing Hcrt/Ox. To explore the Hcrt/Ox system plasticity we systemically administered suvorexant (a dual Hcrt/Ox receptor antagonist) in rats to chronically block Hcrt/Ox transmission without damaging Hcrt/Ox cells. Three groups of eight rats (four males and four females) received daily i.p. injections of suvorexant (10 or 30 mg/kg) or vehicle (DMSO) over a period of 7 days in which the body weight was monitored. After the treatments cerebrospinal fluid (CSF) Hcrt1/OxA concentration was measured by ELISA, and hypothalamic Hcrt/OxR1 and Hcrt/OxR2 levels by western blot. The systemic blockade of the Hcrt/Ox transmission with the suvorexant high dose produced a significant increase in body weight at the end of the treatment, and a significant decrease in CSF Hcrt1/OxA levels, both features typical in human narcolepsy type 1. Besides, a significant overexpression of hypothalamic Hcrt/OxR1 occurred. For the Hcrt/OxR2 two very close bands were detected, but they did not show significant changes with the treatment. Thus, the plastic changes observed in the Hcrt/Ox system after the chronic blockade of its transmission were a decrease in CSF Hcrt1/OXA levels and an overexpression of hypothalamic Hcrt/OxR1. These findings support an autoregulatory role of Hcrt/OxR1 within the hypothalamus, which would induce the synthesis/release of Hcrt/Ox, but also decrease its own availability at the plasma membrane after binding Hcrt1/OxA to preserve Hcrt/Ox system homeostasis.
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32
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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:ijerph19148353. [PMID: 35886210 PMCID: PMC9323672 DOI: 10.3390/ijerph19148353] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [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.)
- Correspondence:
| | - 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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Yaeger JDW, Krupp KT, Summers TR, Summers CH. Contextual generalization of social stress learning is modulated by orexin receptors in basolateral amygdala. Neuropharmacology 2022; 215:109168. [PMID: 35724928 PMCID: PMC9285878 DOI: 10.1016/j.neuropharm.2022.109168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/07/2022] [Accepted: 06/14/2022] [Indexed: 01/22/2023]
Abstract
Fear-associated memories and behavior are often expressed in contexts/environments distinctively different from those in which they are created. This generalization process contributes to psychological disorders, particularly PTSD. Stress-related neurocircuits in the basolateral amygdala (BLA) receive inputs from hypothalamic orexin (Orx) neurons, which mediate neuronal activity by targeting orexin 1 (Orx1R) and orexin 2 (Orx2R) receptors via opposing functions. In BLA, inhibition of Orx1R or activation of Orx2R ameliorate stress responsiveness and behavior. We discovered that most Orx1R+ cells also express CamKIIα, while a majority of Orx2R+ cells are colocalized with GAD67. Further, Orx1R gene Hcrtr1 expression was positively correlated, and Orx2R gene Hcrtr2 expression was negatively correlated, with freezing in a phenotype-dependent fashion (Escape vs Stay) in the Stress Alternatives Model (SAM). The SAM consists of 4-days of social interaction between test mice and novel larger aggressors. Exits positioned at opposite ends of the SAM oval arena provide opportunities to actively avoid aggression. By Day 2, mice commit to behavioral phenotypes: Escape or Stay. Pharmacologically manipulating Orx receptor activity in the BLA, before Day 3 of the SAM, was followed with standard tests of anxiety: Open Field (OF) and Elevated Plus Maze (EPM). In Stay mice, freezing in response to social conflict and locomotion during SAM interaction (not home cage locomotion) were generalized to OF, and blocked by intra-BLA Orx1R antagonism, but not Orx2R antagonism. Moreover, patterns of social avoidance for Escape and Stay mice were recapitulated in OF, with generalization mediated by Orx1R and Orx2R antagonism, plus Orx2R stimulation.
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Affiliation(s)
- 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; Pediatrics and Rare Diseases Group, Sanford Research, Sioux Falls, SD, 57104, USA
| | - Kevin T Krupp
- 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
| | - Tangi R 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
| | - 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.
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Elahdadi Salmani M, Sarfi M, Goudarzi I. Hippocampal orexin receptors: Localization and function. VITAMINS AND HORMONES 2022; 118:393-421. [PMID: 35180935 DOI: 10.1016/bs.vh.2021.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Orexin (hypocretin) is secreted from the perifornical/lateral hypothalamus and is well known for sleep regulation. Orexin has two, orexin A and B, transcripts and two receptors, type 1 and 2 (OX1R and OX2R), located in the plasma membrane of neurons in different brain areas, including the hippocampus involved in learning, memory, seizures, and epilepsy, as physiologic and pathologic phenomena. OX1R is expressed in the dentate gyrus and CA1 and the OX2R in the CA3 areas. Orexin enhances learning and memory as well as reward, stress, seizures, and epilepsy, partly through OX1Rs, while either aggravating or alleviating those phenomena via OX2Rs. OX1Rs activation induces long-term changes of synaptic responses in the hippocampus, an age and concentration-dependent manner. Briefly, we will review the localization and functions of hippocampal orexin receptors, their role in learning, memory, stress, reward, seizures, epilepsy, and hippocampal synaptic plasticity.
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Affiliation(s)
| | | | - Iran Goudarzi
- School of Biology, Damghan University, Damghan, Iran
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Ramser A, Dridi S. Avian Orexin: Feed Intake Regulator or Something Else? Vet Sci 2022; 9:vetsci9030112. [PMID: 35324840 PMCID: PMC8950792 DOI: 10.3390/vetsci9030112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 02/25/2022] [Accepted: 03/02/2022] [Indexed: 02/04/2023] Open
Abstract
Originally named for its expression in the posterior hypothalamus in rats and after the Greek word for “appetite”, hypocretin, or orexin, as it is known today, gained notoriety as a neuropeptide regulating feeding behavior, energy homeostasis, and sleep. Orexin has been proven to be involved in both central and peripheral control of neuroendocrine functions, energy balance, and metabolism. Since its discovery, its ability to increase appetite as well as regulate feeding behavior has been widely explored in mammalian food production animals such as cattle, pigs, and sheep. It is also linked to neurological disorders, leading to its intensive investigation in humans regarding narcolepsy, depression, and Alzheimer’s disease. However, in non-mammalian species, research is limited. In the case of avian species, orexin has been shown to have no central effect on feed-intake, however it was found to be involved in muscle energy metabolism and hepatic lipogenesis. This review provides current knowledge and summarizes orexin’s physiological roles in livestock and pinpoints the present lacuna to facilitate further investigations.
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Affiliation(s)
- Alison Ramser
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA;
- Cell and Molecular Biology Program, Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
| | - Sami Dridi
- Center of Excellence for Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA;
- Cell and Molecular Biology Program, Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701, USA
- Correspondence: ; Tel.: +1-(479)-575-2583; Fax: +1-(479)-575-7139
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DeCarlo AA, Hammes N, Johnson PL, Shekhar A, Samuels BC. Dual Orexin Receptor Antagonist Attenuates Increases in IOP, ICP, and Translaminar Pressure Difference After Stimulation of the Hypothalamus in Rats. Invest Ophthalmol Vis Sci 2022; 63:1. [PMID: 35234838 PMCID: PMC8899853 DOI: 10.1167/iovs.63.3.1] [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] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma progression. Our previous discovery that stimulation of nuclei within the hypothalamus can modulate IOP, intracranial pressure (ICP), and translaminar pressure difference (TLPD) fluctuations led us to investigate this pathway further. Our purpose was to determine the role of orexin neurons, primarily located in the dorsomedial hypothalamus (DMH) and perifornical (PeF) regions of the hypothalamus, in modulating these pressures. METHODS Sprague Dawley rats were pretreated systemically with a dual orexin receptor antagonist (DORA-12) at 30 mg/Kg (n = 8), 10 mg/Kg (n = 8), or vehicle control (n = 8). The IOP, ICP, heart rate (HR), and mean arterial pressure (MAP) were recorded prior to and following excitation of the DMH/PeF using microinjection of the gamma-aminobutyric acid (GABA)A receptor antagonist bicuculline methiodide (BMI). RESULTS Administration of the DORA at 30 mg/Kg significantly attenuated peak IOP by 5.2 ± 3.6 mm Hg (P = 0.007). During the peak response period (8-40 minutes), the area under the curve (AUC) for the 30 mg/Kg DORA cohort was significantly lower than the control cohort during the same period (P = 0.04). IOP responses for peak AUC versus DORA dose, from 0 to 30 mg/Kg, were linear (R2 = 0.18, P = 0.04). The ICP responses during the peak response period (4-16 minutes) versus DORA dose were also linear (R2 = 0.24, P = 0.014). Pretreatment with DORA significantly decreased AUC for the TLPD following stimulation of the DMH/PeF (10 mg/kg, P = 0.045 and 30 mg/kg, P = 0.015). CONCLUSIONS DORAs have the potential to attenuate asynchronous changes in IOP and in ICP and to lessen the extent of TLPDs that may result from central nervous system (CNS) activation.
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Affiliation(s)
- Arthur A. DeCarlo
- University of Alabama at Birmingham, Department of Ophthalmology and Visual Sciences, Birmingham, Alabama, United States
| | - Nathan Hammes
- Indiana University School of Medicine, Department of Ophthalmology, Indianapolis, Indiana, United States,Microsoft Corporation, Redmond, Washington, United States
| | - Philip L. Johnson
- Indiana University School of Medicine, Department of Anatomy, Cell Biology, and Physiology, Indianapolis, Indiana, United States
| | - Anantha Shekhar
- University of Pittsburgh, Department of Psychiatry, Pittsburgh, Pennsylvania, United States
| | - Brian C. Samuels
- University of Alabama at Birmingham, Department of Ophthalmology and Visual Sciences, Birmingham, Alabama, United States
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Characterization of Hypothalamic MCH Neuron Development in a 3D Differentiation System of Mouse Embryonic Stem Cells. eNeuro 2022; 9:ENEURO.0442-21.2022. [PMID: 35437265 PMCID: PMC9047030 DOI: 10.1523/eneuro.0442-21.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 04/05/2022] [Accepted: 04/11/2022] [Indexed: 01/20/2023] Open
Abstract
Hypothalamic melanin-concentrating hormone (MCH) neurons are important regulators of multiple physiological processes, such as sleep, feeding, and memory. Despite the increasing interest in their neuronal functions, the molecular mechanism underlying MCH neuron development remains poorly understood. We report that a three-dimensional culture of mouse embryonic stem cells (mESCs) can generate hypothalamic-like tissues containing MCH-positive neurons, which reproduce morphologic maturation, neuronal connectivity, and neuropeptide/neurotransmitter phenotype of native MCH neurons. Using this in vitro system, we demonstrate that Hedgehog (Hh) signaling serves to produce major neurochemical subtypes of MCH neurons characterized by the presence or absence of cocaine- and amphetamine-regulated transcript (CART). Without exogenous Hh signals, mESCs initially differentiated into dorsal hypothalamic/prethalamic progenitors and finally into MCH+CART+ neurons through a specific intermediate progenitor state. Conversely, activation of the Hh pathway specified ventral hypothalamic progenitors that generate both MCH+CART− and MCH+CART+ neurons. These results suggest that in vivo MCH neurons may originate from multiple cell lineages that arise through early dorsoventral patterning of the hypothalamus. Additionally, we found that Hh signaling supports the differentiation of mESCs into orexin/hypocretin neurons, a well-defined cell group intermingled with MCH neurons in the lateral hypothalamic area (LHA). The present study highlights and improves the utility of mESC culture in the analysis of the developmental programs of specific hypothalamic cell types.
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Effects of the selective orexin-2 receptor antagonist JNJ-48816274 on sleep initiated in the circadian wake maintenance zone: a randomised trial. Neuropsychopharmacology 2022; 47:719-727. [PMID: 34628482 PMCID: PMC8782905 DOI: 10.1038/s41386-021-01175-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/23/2021] [Accepted: 08/30/2021] [Indexed: 12/13/2022]
Abstract
The effects of orexinergic peptides are diverse and are mediated by orexin-1 and orexin-2 receptors. Antagonists that target both receptors have been shown to promote sleep initiation and maintenance. Here, we investigated the role of the orexin-2 receptor in sleep regulation in a randomised, double-blind, placebo-controlled, three-period crossover clinical trial using two doses (20 and 50 mg) of a highly selective orexin-2 receptor antagonist (2-SORA) (JNJ-48816274). We used a phase advance model of sleep disruption where sleep initiation is scheduled in the circadian wake maintenance zone. We assessed objective and subjective sleep parameters, pharmacokinetic profiles and residual effects on cognitive performance in 18 healthy male participants without sleep disorders. The phase advance model alone (placebo condition) resulted in disruption of sleep at the beginning of the sleep period compared to baseline sleep (scheduled at habitual time). Compared to placebo, both doses of JNJ-48816274 significantly increased total sleep time, REM sleep duration and sleep efficiency, and reduced latency to persistent sleep, sleep onset latency, and REM latency. All night EEG spectral power density for both NREM and REM sleep were unaffected by either dose. Participants reported significantly better quality of sleep and feeling more refreshed upon awakening following JNJ-48816274 compared to placebo. No significant residual effects on objective performance measures were observed and the compound was well tolerated. In conclusion, the selective orexin-2 receptor antagonist JNJ-48816274 rapidly induced sleep when sleep was scheduled earlier in the circadian cycle and improved self-reported sleep quality without impact on waking performance.
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Neurobiology of the Orexin System and Its Potential Role in the Regulation of Hedonic Tone. Brain Sci 2022; 12:brainsci12020150. [PMID: 35203914 PMCID: PMC8870430 DOI: 10.3390/brainsci12020150] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 01/13/2023] Open
Abstract
Orexin peptides comprise two neuropeptides, orexin A and orexin B, that bind two G-protein coupled receptors (GPCRs), orexin receptor 1 (OXR1) and orexin receptor 2 (OXR2). Although cell bodies that produce orexin peptides are localized in a small area comprising the lateral hypothalamus and adjacent regions, orexin-containing fibres project throughout the neuraxis. Although orexins were initially described as peptides that regulate feeding behaviour, research has shown that orexins are involved in diverse functions that range from the modulation of autonomic functions to higher cognitive functions, including reward-seeking, behaviour, attention, cognition, and mood. Furthermore, disruption in orexin signalling has been shown in mood disorders that are associated with low hedonic tone or anhedonia, including depression, anxiety, attention deficit hyperactivity disorder, and addiction. Notably, projections of orexin neurons overlap circuits involved in the modulation of hedonic tone. Evidence shows that orexins may potentiate hedonic behaviours by increasing the feeling of pleasure or reward to various signalling, whereas dysregulation of orexin signalling may underlie low hedonic tone or anhedonia. Further, orexin appears to play a key role in regulating behaviours in motivationally charged situations, such as food-seeking during hunger, or drug-seeking during withdrawal. Therefore, it would be expected that dysregulation of orexin expression or signalling is associated with changes in hedonic tone. Further studies investigating this association are warranted.
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Matzeu A, Martin-Fardon R. Understanding the Role of Orexin Neuropeptides in Drug Addiction: Preclinical Studies and Translational Value. Front Behav Neurosci 2022; 15:787595. [PMID: 35126069 PMCID: PMC8811192 DOI: 10.3389/fnbeh.2021.787595] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/29/2021] [Indexed: 12/22/2022] Open
Abstract
Orexins (also known as hypocretins) are neuropeptides that participate in the regulation of energy metabolism, homeostasis, sleep, feeding, stress responses, arousal, and reward. Particularly relevant to the scope of the present review is the involvement of the orexin system in brain mechanisms that regulate motivation, especially highly motivated behavior, arousal, and stress, making it an ideal target for studying addiction and discovering treatments. Drug abuse and misuse are thought to induce maladaptive changes in the orexin system, and these changes might promote and maintain uncontrolled drug intake and contribute to relapse. Dysfunctional changes in this neuropeptidergic system that are caused by drug use might also be responsible for alterations of feeding behavior and the sleep-wake cycle that are commonly disrupted in subjects with substance use disorder. Drug addiction has often been associated with an increase in activity of the orexin system, suggesting that orexin receptor antagonists may be a promising pharmacological treatment for substance use disorder. Substantial evidence has shown that single orexin receptor antagonists that are specific to either orexin receptor 1 or 2 can be beneficial against drug intake and relapse. Interest in the efficacy of dual orexin receptor antagonists, which were primarily developed to treat insomnia, has grown in the field of drug addiction. Treatments that target the orexin system may be a promising strategy to reduce drug intake, mitigate relapse vulnerability, and restore “normal” physiological functions, including feeding and sleep. The present review discusses preclinical and clinical evidence of the involvement of orexins in drug addiction and possible beneficial pharmacotherapeutic effects of orexin receptor antagonists to treat substance use disorder.
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Couvineau A, Nicole P, Gratio V, Voisin T. The Orexin receptors: Structural and anti-tumoral properties. Front Endocrinol (Lausanne) 2022; 13:931970. [PMID: 35966051 PMCID: PMC9365956 DOI: 10.3389/fendo.2022.931970] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/11/2022] [Indexed: 12/12/2022] Open
Abstract
At the end of the 20th century, two new neuropeptides (Orexin-A/hypocretin-1 and Orexin-B/hypocretins-2) expressed in hypothalamus as a prepro-orexins precursor, were discovered. These two neuropeptides interacted with two G protein-coupled receptor isoforms named OX1R and OX2R. The orexins/OX receptors system play an important role in the central and peripheral nervous system where it controls wakefulness, addiction, reward seeking, stress, motivation, memory, energy homeostasis, food intake, blood pressure, hormone secretions, reproduction, gut motility and lipolysis. Orexins and their receptors are involved in pathologies including narcolepsy type I, neuro- and chronic inflammation, neurodegenerative diseases, metabolic syndrome, and cancers. Associated with these physiopathological roles, the extensive development of pharmacological molecules including OXR antagonists, has emerged in association with the determination of the structural properties of orexins and their receptors. Moreover, the identification of OX1R expression in digestive cancers encompassing colon, pancreas and liver cancers and its ability to trigger mitochondrial apoptosis in tumoral cells, indicate a new putative therapeutical action of orexins and paradoxically OXR antagonists. The present review focuses on structural and anti-tumoral aspects of orexins and their receptors.
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Kobayashi I, Mellman TA, Cannon A, Brown I, Boadi L, Howell MK, Lavela P, Sandhu I. Blocking the orexin system following therapeutic exposure promoted between session habituation, but not PTSD symptom reduction. J Psychiatr Res 2021; 145:222-229. [PMID: 34933185 PMCID: PMC9192822 DOI: 10.1016/j.jpsychires.2021.12.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 12/06/2021] [Accepted: 12/11/2021] [Indexed: 11/24/2022]
Abstract
There is a need to identify strategies to increase the effectiveness of treatments for posttraumatic stress disorder (PTSD). Sleep is often disturbed in PTSD and has been implicated in learning processes that underlie recovery from PTSD, including extinction of conditioned fear. Our prior study suggested that diminished arousal during sleep may enhance benefits of therapeutic exposure for PTSD. The orexin system regulates arousal, and blocking the system diminishes arousal and promotes sleep. We, therefore, examined whether a dual orexin receptor antagonist, suvorexant, administered following evening exposure sessions, would enhance their therapeutic effectiveness for PTSD. In this randomized double-blind placebo-controlled trial, adults with PTSD completed four written narrative exposure (WNE) sessions, two of which took place in the evening, and two the next morning. Participants received either suvorexant or placebo after each evening WNE. We found that suvorexant increased N3 sleep and decreased N2 sleep and rapid-eye-movement latency measured by polysomnography. Between session habituation indexed by subjective distress ratings was greater with suvorexant, but there was no group difference in the reduction of PTSD severity from baseline to 1-week follow-up. No safety concerns emerged. The present findings provide preliminary support for enhancement of an effect of therapeutic exposure for PTSD by suvorexant. Further studies with larger samples are needed to translate the present findings into clinical applications, including studies to develop optimal suvorexant administration and exposure session schedules to achieve persistent benefits to sleep and possibly greater treatment augmentation.
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Affiliation(s)
- Ihori Kobayashi
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA.
| | - Thomas A Mellman
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
| | - Ashley Cannon
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
| | - Imani Brown
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
| | - Linda Boadi
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
| | | | - Pewu Lavela
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
| | - Ishaan Sandhu
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington, DC, USA
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Bhat US, Shahi N, Surendran S, Babu K. Neuropeptides and Behaviors: How Small Peptides Regulate Nervous System Function and Behavioral Outputs. Front Mol Neurosci 2021; 14:786471. [PMID: 34924955 PMCID: PMC8674661 DOI: 10.3389/fnmol.2021.786471] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
One of the reasons that most multicellular animals survive and thrive is because of the adaptable and plastic nature of their nervous systems. For an organism to survive, it is essential for the animal to respond and adapt to environmental changes. This is achieved by sensing external cues and translating them into behaviors through changes in synaptic activity. The nervous system plays a crucial role in constantly evaluating environmental cues and allowing for behavioral plasticity in the organism. Multiple neurotransmitters and neuropeptides have been implicated as key players for integrating sensory information to produce the desired output. Because of its simple nervous system and well-established neuronal connectome, C. elegans acts as an excellent model to understand the mechanisms underlying behavioral plasticity. Here, we critically review how neuropeptides modulate a wide range of behaviors by allowing for changes in neuronal and synaptic signaling. This review will have a specific focus on feeding, mating, sleep, addiction, learning and locomotory behaviors in C. elegans. With a view to understand evolutionary relationships, we explore the functions and associated pathophysiology of C. elegans neuropeptides that are conserved across different phyla. Further, we discuss the mechanisms of neuropeptidergic signaling and how these signals are regulated in different behaviors. Finally, we attempt to provide insight into developing potential therapeutics for neuropeptide-related disorders.
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Affiliation(s)
- Umer Saleem Bhat
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, India
| | - Navneet Shahi
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
| | - Siju Surendran
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
| | - Kavita Babu
- Centre for Neuroscience, Indian Institute of Science, Bengaluru, India
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Couvineau A, Voisin T, Nicole P, Gratio V, Blais A. Orexins: A promising target to digestive cancers, inflammation, obesity and metabolism dysfunctions. World J Gastroenterol 2021; 27:7582-7596. [PMID: 34908800 PMCID: PMC8641057 DOI: 10.3748/wjg.v27.i44.7582] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/22/2021] [Accepted: 11/18/2021] [Indexed: 02/06/2023] Open
Abstract
Hypothalamic neuropeptides named hypocretin/orexins which were identified in 1998 regulate critical functions such as wakefulness in the central nervous system. These past 20 years had revealed that orexins/receptors system was also present in the peripheral nervous system where they participated to the regulation of multiple functions including blood pressure regulation, intestinal motility, hormone secretion, lipolyze and reproduction functions. Associated to these peripheral functions, it was found that orexins and their receptors were involved in various diseases such as acute/chronic inflammation, metabolic syndrome and cancers. The present review suggests that orexins or the orexin neural circuitry represent potential therapeutic targets for the treatment of multiple pathologies related to inflammation including intestinal bowel disease, multiple sclerosis and septic shock, obesity and digestive cancers.
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Affiliation(s)
- Alain Couvineau
- INSERM UMR1149/Inflammation Research Center, Team “From inflammation to cancer in digestive diseases” labeled by “la Ligue Nationale contre le Cancer”, University of Paris, DHU UNITY, Paris 75018, France
| | - Thierry Voisin
- INSERM UMR1149/Inflammation Research Center, Team “From inflammation to cancer in digestive diseases” labeled by “la Ligue Nationale contre le Cancer”, University of Paris, DHU UNITY, Paris 75018, France
| | - Pascal Nicole
- INSERM UMR1149/Inflammation Research Center, Team “From inflammation to cancer in digestive diseases” labeled by “la Ligue Nationale contre le Cancer”, University of Paris, DHU UNITY, Paris 75018, France
| | - Valerie Gratio
- INSERM UMR1149/Inflammation Research Center, Team “From inflammation to cancer in digestive diseases” labeled by “la Ligue Nationale contre le Cancer”, University of Paris, DHU UNITY, Paris 75018, France
| | - Anne Blais
- UMR PNCA, AgroParisTech, INRA, Université Paris-Saclay, Paris 75005, France
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Brain Clocks, Sleep, and Mood. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 34773227 DOI: 10.1007/978-3-030-81147-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
The suprachiasmatic nucleus houses the master clock, but the genes which encode the circadian clock components are also expressed throughout the brain. Here, we review how circadian clock transcription factors regulate neuromodulator systems such as histamine, dopamine, and orexin that promote arousal. These circadian transcription factors all lead to repression of the histamine, dopamine, and orexin systems during the sleep period, so ensuring integration with the ecology of the animal. If these transcription factors are deleted or mutated, in addition to the global disturbances in circadian rhythms, this causes a chronic up-regulation of neuromodulators leading to hyperactivity, elevated mood, and reduced sleep, which have been suggested to be states resembling mania.
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Azeez IA, Igado OO, Olopade JO. An overview of the orexinergic system in different animal species. Metab Brain Dis 2021; 36:1419-1444. [PMID: 34224065 DOI: 10.1007/s11011-021-00761-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 06/06/2021] [Indexed: 01/13/2023]
Abstract
Orexin (hypocretin), is a neuropeptide produced by a subset of neurons in the lateral hypothalamus. From the lateral hypothalamus, the orexin-containing neurons project their fibres extensively to other brain structures, and the spinal cord constituting the central orexinergic system. Generally, the term ''orexinergic system'' usually refers to the orexin peptides and their receptors, as well as to the orexin neurons and their projections to different parts of the central nervous system. The extensive networks of orexin axonal fibres and their terminals allow these neuropeptidergic neurons to exert great influence on their target regions. The hypothalamic neurons containing the orexin neuropeptides have been implicated in diverse functions, especially related to the control of a variety of homeostatic functions including feeding behaviour, arousal, wakefulness stability and energy expenditure. The broad range of functions regulated by the orexinergic system has led to its description as ''physiological integrator''. In the last two decades, the orexinergic system has been a topic of great interest to the scientific community with many reports in the public domain. From the documentations, variations exist in the neuroanatomical profile of the orexinergic neuron soma, fibres and their receptors from animal to animal. Hence, this review highlights the distinct variabilities in the morphophysiological aspects of the orexinergic system in the vertebrate animals, mammals and non-mammals, its presence in other brain-related structures, including its involvement in ageing and neurodegenerative diseases. The presence of the neuropeptide in the cerebrospinal fluid and peripheral tissues, as well as its alteration in different animal models and conditions are also reviewed.
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Affiliation(s)
- Idris A Azeez
- Department of Veterinary Anatomy, University of Jos, Jos, Nigeria
| | - Olumayowa O Igado
- Department of Veterinary Anatomy, University of Ibadan, Ibadan, Nigeria
| | - James O Olopade
- Department of Veterinary Anatomy, University of Ibadan, Ibadan, Nigeria.
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Xu YX, Liu GY, Jiang Q, Bi HQ, Wang SC, Zhang PP, Gao CB, Chen GH, Cheng WH, Chen GJ, Zhu DF, Zhong MK, Xu Q. Effect of Restricted Feeding on Metabolic Health and Sleep-Wake Rhythms in Aging Mice. Front Neurosci 2021; 15:745227. [PMID: 34557073 PMCID: PMC8453873 DOI: 10.3389/fnins.2021.745227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 08/17/2021] [Indexed: 12/25/2022] Open
Abstract
Aging, an irreversible and unavoidable physiological process in all organisms, is often accompanied by obesity, diabetes, cardiovascular diseases, sleep disorders, and fatigue. Thus, older adults are more likely to experience metabolic symptoms and sleep disturbances than are younger adults. Restricted feeding (RF) is a dietary regimen aimed at improving metabolic health and extending longevity, as well as reorganizing sleep-wake cycles. However, the potential of RF to improve metabolic health and sleep quality in older adults who are known to show a tendency toward increased weight gain and decreased sleep is unknown. To elucidate this issue, aged mice were assigned to an RF protocol during the active phase for 2 h per day for 2 weeks. Sleep-wake cycles were recorded during the RF regime in RF group and control mice. At the end of this period, body weight and blood biochemistry profiles, including blood glucose, cholesterol, and enzyme activity, in addition to dopamine concentrations in the brain, were measured in the RF group and age-matched controls. RF for 2 weeks improved the metabolic health of aged mice by reducing their body weights and blood glucose and cholesterol levels. At the beginning of the RF regime, sleep decreased in the dark period but not in the light period. After stable food entrainment was achieved (7 days post-RF commencement), the amount of time spent in wakefulness during the light period dramatically increased for 2 h before food availability, thereby increasing the mean duration of awake episodes and decreasing the number of wakefulness episodes. There was no significant difference in the sleep-wake time during the dark period in the RF group, with similar total amounts of wakefulness and sleep in a 24-h period to those of the controls. During the RF regime, dopamine levels in the midbrain increased in the RF group, pointing to its potential as the mechanism mediating metabolic symptoms and sleep-wake regulation during RF. In conclusion, our study suggested that RF during aging might prohibit or delay the onset of age-related diseases by improving metabolic health, without having a severe deleterious effect on sleep.
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Affiliation(s)
- Yong-Xia Xu
- Department of Geriatric Endocrinology, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Guo-Ying Liu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qian Jiang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Han-Qi Bi
- Department of Geriatric Endocrinology, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Shi-Chan Wang
- Department of Geriatric Endocrinology, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ping-Ping Zhang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Chao-Bing Gao
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Gui-Hai Chen
- Department of Sleep Disorders and Neurology, The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Wen-Hui Cheng
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.,Laboratory Animal Research Center, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Guan-Jun Chen
- Center for Scientific Research, Anhui Medical University, Hefei, China
| | - De-Fa Zhu
- Department of Geriatric Endocrinology, Anhui Geriatric Institute, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Ming-Kui Zhong
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Qi Xu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
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Wang Q, Cao F, Wu Y. Orexinergic System in Neurodegenerative Diseases. Front Aging Neurosci 2021; 13:713201. [PMID: 34483883 PMCID: PMC8416170 DOI: 10.3389/fnagi.2021.713201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 07/20/2021] [Indexed: 01/16/2023] Open
Abstract
Orexinergic system consisting of orexins and orexin receptors plays an essential role in regulating sleep–wake states, whereas sleep disruption is a common symptom of a number of neurodegenerative diseases. Emerging evidence reveals that the orexinergic system is disturbed in various neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), and multiple sclerosis (MS), whereas the dysregulation of orexins and/or orexin receptors contributes to the pathogenesis of these diseases. In this review, we summarized advanced knowledge of the orexinergic system and its role in sleep, and reviewed the dysregulation of the orexinergic system and its role in the pathogenesis of AD, PD, HD, and MS. Moreover, the therapeutic potential of targeting the orexinergic system for the treatment of these diseases was discussed.
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Affiliation(s)
- Qinqin Wang
- Shandong Collaborative Innovation Center for Diagnosis, Treatment & Behavioral Interventions of Mental Disorders, Institute of Mental Health, Jining Medical University, Jining, China.,Shandong Key Laboratory of Behavioral Medicine, School of Mental Health, Jining Medical University, Jining, China
| | - Fei Cao
- Shandong Collaborative Innovation Center for Diagnosis, Treatment & Behavioral Interventions of Mental Disorders, Institute of Mental Health, Jining Medical University, Jining, China
| | - Yili Wu
- Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, School of Mental Health and The Affiliated Kangning Hospital, Wenzhou Medical University, Wenzhou, China.,Oujiang Laboratory, Wenzhou, China
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Orexin receptors 1 and 2 in serotonergic neurons differentially regulate peripheral glucose metabolism in obesity. Nat Commun 2021; 12:5249. [PMID: 34475397 PMCID: PMC8413382 DOI: 10.1038/s41467-021-25380-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 08/05/2021] [Indexed: 12/02/2022] Open
Abstract
The wake-active orexin system plays a central role in the dynamic regulation of glucose homeostasis. Here we show orexin receptor type 1 and 2 are predominantly expressed in dorsal raphe nucleus-dorsal and -ventral, respectively. Serotonergic neurons in ventral median raphe nucleus and raphe pallidus selectively express orexin receptor type 1. Inactivation of orexin receptor type 1 in serotonin transporter-expressing cells of mice reduced insulin sensitivity in diet-induced obesity, mainly by decreasing glucose utilization in brown adipose tissue and skeletal muscle. Selective inactivation of orexin receptor type 2 improved glucose tolerance and insulin sensitivity in obese mice, mainly through a decrease in hepatic gluconeogenesis. Optogenetic activation of orexin neurons in lateral hypothalamus or orexinergic fibers innervating raphe pallidus impaired or improved glucose tolerance, respectively. Collectively, the present study assigns orexin signaling in serotonergic neurons critical, yet differential orexin receptor type 1- and 2-dependent functions in the regulation of systemic glucose homeostasis. The wake-active orexin system plays a central role in the dynamic regulation of glucose homeostasis. Here the authors report that inactivation of the orexin receptor type 1 or 2 in serotonergic neurons differentially regulate systemic glucose homeostasis in the context of diet induced obesity.
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Alain C, Pascal N, Valérie G, Thierry V. Orexins/Hypocretins and Cancer: A Neuropeptide as Emerging Target. Molecules 2021; 26:molecules26164849. [PMID: 34443437 PMCID: PMC8398691 DOI: 10.3390/molecules26164849] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 02/05/2023] Open
Abstract
Over 20 years ago, orexin neuropeptides (Orexin-A/hypocretin-1 and Orexin-B/hypocretins-2) produced from the same precursor in hypothalamus were identified. These two neurotransmitters and their receptors (OX1R and OX1R), present in the central and peripheral nervous system, play a major role in wakefulness but also in drug addiction, food consumption, homeostasis, hormone secretion, reproductive function, lipolysis and blood pressure regulation. With respect to these biological functions, orexins were involved in various pathologies encompassing narcolepsy, neurodegenerative diseases, chronic inflammations, metabolic syndrome and cancers. The expression of OX1R in various cancers including colon, pancreas and prostate cancers associated with its ability to induce a proapoptotic activity in tumor cells, suggested that the orexins/OX1R system could have a promising therapeutic role. The present review summarizes the relationship between cancers and orexins/OX1R system as an emerging target.
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Affiliation(s)
- Couvineau Alain
- INSERM UMR1149/Inflammation Research Center (CRI), Team "From Inflammation to Cancer in Digestive Diseases" Labeled by "la Ligue Nationale Contre le Cancer", University of Paris, DHU UNITY, 75018 Paris, France
| | - Nicole Pascal
- INSERM UMR1149/Inflammation Research Center (CRI), Team "From Inflammation to Cancer in Digestive Diseases" Labeled by "la Ligue Nationale Contre le Cancer", University of Paris, DHU UNITY, 75018 Paris, France
| | - Gratio Valérie
- INSERM UMR1149/Inflammation Research Center (CRI), Team "From Inflammation to Cancer in Digestive Diseases" Labeled by "la Ligue Nationale Contre le Cancer", University of Paris, DHU UNITY, 75018 Paris, France
| | - Voisin Thierry
- INSERM UMR1149/Inflammation Research Center (CRI), Team "From Inflammation to Cancer in Digestive Diseases" Labeled by "la Ligue Nationale Contre le Cancer", University of Paris, DHU UNITY, 75018 Paris, France
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