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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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2
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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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3
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Keenan RJ, Daykin H, Metha J, Cornthwaite-Duncan L, Wright DK, Clarke K, Oberrauch S, Brian M, Stephenson S, Nowell CJ, Allocca G, Barnham KJ, Hoyer D, Jacobson LH. Orexin 2 receptor antagonism sex-dependently improves sleep/wakefulness and cognitive performance in tau transgenic mice. Br J Pharmacol 2024; 181:87-106. [PMID: 37553894 DOI: 10.1111/bph.16212] [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: 02/08/2023] [Revised: 07/25/2023] [Accepted: 08/01/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Tau pathology contributes to a bidirectional relationship between sleep disruption and neurodegenerative disease. Tau transgenic rTg4510 mice model tauopathy symptoms, including sleep/wake disturbances, which manifest as marked hyperarousal. This phenotype can be prevented by early transgene suppression; however, whether hyperarousal can be rescued after onset is unknown. EXPERIMENTAL APPROACH Three 8-week experiments were conducted with wild-type and rTg4510 mice after age of onset of hyperarousal (4.5 months): (1) Tau transgene suppression with doxycycline (200 ppm); (2) inactive phase rapid eye movement (REM) sleep enhancement with the dual orexin receptor antagonist suvorexant (50 mg·kg-1 ·day-1 ); or (3) Active phase non-NREM (NREM) and REM sleep enhancement using the selective orexin 2 (OX2 ) receptor antagonist MK-1064 (40 mg·kg-1 ·day-1 ). Sleep was assessed using polysomnography, cognition using the Barnes maze, and tau pathology using immunoblotting and/or immunohistochemistry. KEY RESULTS Tau transgene suppression improved tauopathy and hippocampal-dependent spatial memory, but did not modify hyperarousal. Pharmacological rescue of REM sleep deficits did not improve spatial memory or tau pathology. In contrast, normalising hyperarousal by increasing both NREM and REM sleep via OX2 receptor antagonism restored spatial memory, independently of tauopathy, but only in male rTg4510 mice. OX2 receptor antagonism induced only short-lived hypnotic responses in female rTg4510 mice and did not improve spatial memory, indicating a tau- and sex-dependent disruption of OX2 receptor signalling. CONCLUSIONS AND IMPLICATIONS Pharmacologically reducing hyperarousal corrects tau-induced sleep/wake and cognitive deficits. Tauopathy causes sex-dependent disruptions of OX2 receptor signalling/function, which may have implications for choice of hypnotic therapeutics in tauopathies.
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Affiliation(s)
- Ryan J Keenan
- 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
| | - Heather Daykin
- 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
| | - Jeremy Metha
- 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 Finance, Faculty of Business and Economics, The University of Melbourne, Parkville, Victoria, Australia
| | - Linda Cornthwaite-Duncan
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - David K Wright
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Kyra Clarke
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Sara Oberrauch
- 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
| | - Maddison Brian
- 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
| | - Sarah Stephenson
- Bruce Lefroy Centre, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - Cameron J Nowell
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
| | - Giancarlo Allocca
- 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
- Somnivore Inc. Ltd Pty, Bacchus Marsh, Victoria, Australia
| | - Kevin J Barnham
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia
| | - Daniel Hoyer
- 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
- 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
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health and The University of Melbourne, Parkville, Victoria, Australia
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Dale NC, Hoyer D, Jacobson LH, Pfleger KDG, Johnstone EKM. Orexin Signaling: A Complex, Multifaceted Process. Front Cell Neurosci 2022; 16:812359. [PMID: 35496914 PMCID: PMC9044999 DOI: 10.3389/fncel.2022.812359] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 03/07/2022] [Indexed: 11/15/2022] Open
Abstract
The orexin system comprises two G protein-coupled receptors, OX1 and OX2 receptors (OX1R and OX2R, respectively), along with two endogenous agonists cleaved from a common precursor (prepro-orexin), orexin-A (OX-A) and orexin-B (OX-B). For the receptors, a complex array of signaling behaviors has been reported. In particular, it becomes obvious that orexin receptor coupling is very diverse and can be tissue-, cell- and context-dependent. Here, the early signal transduction interactions of the orexin receptors will be discussed in depth, with particular emphasis on the direct G protein interactions of each receptor. In doing so, it is evident that ligands, additional receptor-protein interactions and cellular environment all play important roles in the G protein coupling profiles of the orexin receptors. This has potential implications for our understanding of the orexin system's function in vivo in both central and peripheral environments, as well as the development of novel agonists, antagonists and possibly allosteric modulators targeting the orexin system.
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Affiliation(s)
- Natasha C. Dale
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
| | - Daniel Hoyer
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Laura H. Jacobson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
- Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
| | - Kevin D. G. Pfleger
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- Dimerix Limited, Nedlands, WA, Australia
| | - Elizabeth K. M. Johnstone
- Molecular Endocrinology and Pharmacology, Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Melbourne, VIC, Australia
- Australian Research Council Centre for Personalised Therapeutics Technologies, Perth, WA, Australia
- School of Biomedical Sciences, The University of Western Australia, Nedlands, WA, Australia
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5
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Keenan RJ, Daykin H, Chu J, Cornthwaite-Duncan L, Allocca G, Hoyer D, Jacobson LH. Differential sleep/wake response and sex effects following acute suvorexant, MK-1064 and zolpidem administration in the rTg4510 mouse model of tauopathy. Br J Pharmacol 2022; 179:3403-3417. [PMID: 35112344 PMCID: PMC9302982 DOI: 10.1111/bph.15813] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 01/06/2022] [Accepted: 01/28/2022] [Indexed: 12/02/2022] Open
Abstract
Background and Purpose Transgenic mouse models of tauopathy display prominent sleep/wake disturbances which manifest primarily as a hyperarousal phenotype during the active phase, suggesting that tau pathology contributes to sleep/wake changes. However, no study has yet investigated the effect of sleep‐promoting compounds in these models. Such information has implications for the use of hypnotics as potential therapeutic tools in tauopathy‐related disorders. Experimental Approach This study examined polysomnographic recordings in 6‐6.5‐month‐old male and female rTg4510 mice following acute administration of suvorexant (50 mg·kg−1), MK‐1064 (30 mg·kg−1) or zolpidem (10 mg·kg−1), administered at the commencement of the active phase. Key Results Suvorexant, a dual OX receptor antagonist, promoted REM sleep in rTg4510 mice, without affecting wake or NREM sleep. MK‐1064, a selective OX2 receptor antagonist, reduced wake and increased NREM and total sleep time. MK‐1064 normalised the hyperarousal phenotype of male rTg4510 mice, whereas female rTg4510 mice exhibited a more transient response. Zolpidem, a GABAA receptor positive allosteric modulator, decreased wake and increased NREM sleep in both male and female rTg4510 mice. Of the three compounds, the OX2 receptor antagonist MK‐1064 promoted and normalised physiologically normal sleep, especially in male rTg4510 mice. Conclusions and Implications Our findings indicate that hyperphosphorylated tau accumulation and associated hyperarousal does not significantly alter the responses of tauopathy mouse models to hypnotics. However, the sex differences observed in the sleep/wake response of rTg4510 mice to MK‐1064, but not suvorexant or zolpidem, raise questions about therapeutic implications for the use of OX2 receptor antagonists in human neurodegenerative disorders.
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Affiliation(s)
- Ryan J Keenan
- 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
| | - Heather Daykin
- 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
| | - Jiahui Chu
- 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
| | - Linda Cornthwaite-Duncan
- Department of Biochemistry and Pharmacology, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Giancarlo Allocca
- 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.,Somnivore Inc. Ltd. Pty, Bacchus Marsh, Victoria, Australia
| | - Daniel Hoyer
- 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
- 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.,Melbourne Dementia Research Centre, Florey Institute of Neuroscience and Mental Health and The University of Melbourne, Parkville, Victoria, Australia
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6
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Clark JW, Daykin H, Metha JA, Allocca G, Hoyer D, Drummond SPA, Jacobson LH. Manipulation of REM sleep via orexin and GABAA receptor modulators differentially affects fear extinction in mice: effect of stable versus disrupted circadian rhythm. Sleep 2021; 44:6171207. [PMID: 33720375 DOI: 10.1093/sleep/zsab068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 01/22/2021] [Indexed: 12/18/2022] Open
Abstract
Sleep disruption, and especially REM sleep disruption, is associated with fear inhibition impairment in animals and humans. The REM sleep-fear inhibition relationship raises concern for individuals with PTSD, whose sleep disturbance is commonly treated with hypnotics which disrupt and/or decrease REM sleep, such as benzodiazepines or 'Z-drugs'. Here, we examined the effects of the Z-drug zolpidem, a GABAA receptor positive allosteric modulator, as well as suvorexant, an orexin receptor antagonist (hypnotics which decrease and increase REM sleep, respectively) in the context of circadian disruption in murine models of fear inhibition-related processes (i.e., fear extinction and safety learning). Adult male C57Bl/6J mice completed fear and safety conditioning before undergoing shifts in the light-dark (LD) cycle or maintaining a consistent LD schedule. Fear extinction and recall of conditioned safety were thereafter tested daily. Immediately prior to onset of the light phase between testing sessions, mice were treated with zolpidem, suvorexant, or vehicle (methylcellulose). EEG/EMG analysis showed temporal distribution of REM sleep was misaligned during LD cycle-shifts, while REM sleep duration was preserved. Suvorexant increased REM sleep and improved fear extinction rate, relative to zolpidem, which decreased REM sleep. Survival analysis demonstrated LD shifted mice treated with suvorexant were faster to achieve complete extinction than vehicle and zolpidem-treated mice in the LD shifted condition. By contrast, retention of conditioned safety memory was not influenced by either treatment. This study thus provides preclinical evidence for the potential clinical utility of hypnotics which increase REM sleep for fear extinction after PTSD-relevant sleep disturbance.
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Affiliation(s)
- Jacob W Clark
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, VIC, Australia.,Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia
| | - Heather Daykin
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia
| | - Jeremy A Metha
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia.,Brain, Mind and Markets Laboratory, Department of Finance, The University of Melbourne, VIC, Australia
| | - Giancarlo Allocca
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia.,Somnivore Pty. Ltd., Bacchus Marsh, Victoria, Australia
| | - Daniel Hoyer
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia.,Department of Molecular Medicine, The Scripps Research Institute, CA, The United States of America
| | - Sean P A Drummond
- School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, VIC, Australia
| | - Laura H Jacobson
- Department of Pharmacology and Therapeutics, The University of Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, VIC, Australia
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Boss C, Gatfield J, Brotschi C, Heidmann B, Sifferlen T, von Raumer M, Schmidt G, Williams JT, Treiber A, Roch C. The Quest for the Best Dual Orexin Receptor Antagonist (Daridorexant) for the Treatment of Insomnia Disorders. ChemMedChem 2020; 15:2286-2305. [PMID: 32937014 DOI: 10.1002/cmdc.202000453] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/06/2020] [Indexed: 02/06/2023]
Abstract
Since its discovery in 1998, the orexin system has been of interest to the research community as a potential therapeutic target for the treatment of sleep/wake disorders, stress and anxiety disorders, addiction or eating disorders. It consists of two G protein-coupled receptors, the orexin 1 and orexin 2 receptors, and two neuropeptides with agonistic effects, the orexin A and orexin B peptides. Herein we describe our efforts leading to the identification of a promising set of dual orexin receptor antagonists (DORAs) which subsequently went through physiology-based pharmacokinetic and pharmacodynamic modelling>[1] and finally led to the selection of daridorexant, currently in phase 3 clinical trials for the treatment of insomnia disorders.
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Affiliation(s)
- Christoph Boss
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - John Gatfield
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Christine Brotschi
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Bibia Heidmann
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Thierry Sifferlen
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Markus von Raumer
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Gunther Schmidt
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Jodi T Williams
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Alexander Treiber
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
| | - Catherine Roch
- Drug Discovery and Preclinical Research & Development, Idorsia Pharmaceuticals Ltd., Hegenheimermattweg 91, 4123, Allschwil, BL, Switzerland
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8
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Sanchez-Alavez M, Benedict J, Wills DN, Ehlers CL. Effect of suvorexant on event-related oscillations and EEG sleep in rats exposed to chronic intermittent ethanol vapor and protracted withdrawal. Sleep 2020; 42:5304584. [PMID: 30715515 DOI: 10.1093/sleep/zsz020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/07/2018] [Indexed: 01/27/2023] Open
Abstract
STUDY OBJECTIVES Insomnia is a prominent complaint in patients with alcohol use disorders (AUD). However, despite the importance of sleep in the maintenance of sobriety, treatment options for sleep disturbance associated with a history of AUD are currently limited. Recent clinical trials have demonstrated that suvorexant, a dual Hct/OX receptor antagonist, normalizes sleep in patients with primary insomnia; yet, its potential for the treatment of sleep pathology associated with AUD has not been investigated in either preclinical or clinical studies. METHODS This study employed a model whereby ethanol vapor exposure or control conditions were administered for 8 weeks to adult rats. Waking event-related oscillations (EROs) and EEG sleep were evaluated at baseline before exposure and again following 24 hr of withdrawal from the exposure. Subsequently, the ability of vehicle (VEH) and two doses (10, 30 mg/kg IP) of suvorexant to modify EROs, sleep, and the sleep EEG was investigated. RESULTS After 24 hr following EtOH withdrawal, the ethanol-treated group had increases in waking ERO θ and β activity, more fragmented sleep (shorter duration and increased frequency of slow wave (SW) and rapid eye movement [REM] sleep episodes), and increased θ and β power in REM and SW sleep. Suvorexant induced a dose-dependent decrease in the latency to REM and SW sleep onsets but also produced REM and SW sleep fragmentation and increased β energy in waking EROs when compared with VEH. CONCLUSIONS Taken together, these studies suggest that suvorexant has overall sleep-promoting effects, but it may exacerbate some aspects of sleep and EEG pathology.
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Affiliation(s)
| | - Jessica Benedict
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
| | - Derek N Wills
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
| | - Cindy L Ehlers
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
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9
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Han Y, Yuan K, Zheng Y, Lu L. Orexin Receptor Antagonists as Emerging Treatments for Psychiatric Disorders. Neurosci Bull 2020; 36:432-448. [PMID: 31782044 PMCID: PMC7142186 DOI: 10.1007/s12264-019-00447-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022] Open
Abstract
Orexins comprise two neuropeptides produced by orexin neurons in the lateral hypothalamus and are released by extensive projections of these neurons throughout the central nervous system. Orexins bind and activate their associated G protein-coupled orexin type 1 receptors (OX1Rs) and OX2Rs and act on numerous physiological processes, such as sleep-wake regulation, feeding, reward, emotion, and motivation. Research on the development of orexin receptor antagonists has dramatically increased with the approval of suvorexant for the treatment of primary insomnia. In the present review, we discuss recent findings on the involvement of the orexin system in the pathophysiology of psychiatric disorders, including sleep disorders, depression, anxiety, and drug addiction. We discuss the actions of orexin receptor antagonists, including selective OX1R antagonists (SORA1s), selective OX2R antagonists (SORA2s), and dual OX1/2R antagonists (DORAs), in the treatment of these disorders based on both preclinical and clinical evidence. SORA2s and DORAs have more pronounced efficacy in the treatment of sleep disorders, whereas SORA1s may be promising for the treatment of anxiety and drug addiction. We also discuss potential challenges and opportunities for the application of orexin receptor antagonists to clinical interventions.
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Affiliation(s)
- Ying Han
- National Institute of Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, 100191, China
| | - Kai Yuan
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, 100191, China
- Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China
| | - Yongbo Zheng
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, 100191, China
| | - Lin Lu
- National Institute of Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, 100191, China.
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, 100191, China.
- Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
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Hoyer D, Allen A, Jacobson LH. Hypnotics with novel modes of action. Br J Clin Pharmacol 2020; 86:244-249. [PMID: 31756268 PMCID: PMC7015741 DOI: 10.1111/bcp.14180] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 10/25/2019] [Accepted: 11/01/2019] [Indexed: 12/19/2022] Open
Abstract
Insomnia and, more generally, lack of sleep are on the rise. Traditionally treated by classical hypnotics, such as benzodiazepines and Z drugs, which both act on the GABAA receptor, and other modalities, including nondrug therapies, such as cognitive behavioural therapy, there is a range of new hypnotics which are being developed or have recently received market approval. Suvorexant and the like target the orexin/hypocretin system: they should have less side effects in terms of drug-drug interactions with e.g. alcohol, less memory impairment and dependence potential compared to classical hypnotics.
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Affiliation(s)
- Daniel Hoyer
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health SciencesThe University of MelbourneParkvilleVictoriaAustralia
- The Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleAustralia
- Department of Molecular MedicineThe Scripps Research InstituteLa JollaCAUSA
| | - Andrew Allen
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health SciencesThe University of MelbourneParkvilleVictoriaAustralia
| | - Laura H. Jacobson
- Department of Pharmacology & Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health SciencesThe University of MelbourneParkvilleVictoriaAustralia
- The Florey Institute of Neuroscience and Mental HealthUniversity of MelbourneParkvilleAustralia
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11
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Atkin T, Comai S, Gobbi G. Drugs for Insomnia beyond Benzodiazepines: Pharmacology, Clinical Applications, and Discovery. Pharmacol Rev 2018; 70:197-245. [PMID: 29487083 DOI: 10.1124/pr.117.014381] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Although the GABAergic benzodiazepines (BZDs) and Z-drugs (zolpidem, zopiclone, and zaleplon) are FDA-approved for insomnia disorders with a strong evidence base, they have many side effects, including cognitive impairment, tolerance, rebound insomnia upon discontinuation, car accidents/falls, abuse, and dependence liability. Consequently, the clinical use of off-label drugs and novel drugs that do not target the GABAergic system is increasing. The purpose of this review is to analyze the neurobiological and clinical evidence of pharmacological treatments of insomnia, excluding the BZDs and Z-drugs. We analyzed the melatonergic agonist drugs, agomelatine, prolonged-release melatonin, ramelteon, and tasimelteon; the dual orexin receptor antagonist suvorexant; the modulators of the α2δ subunit of voltage-sensitive calcium channels, gabapentin and pregabalin; the H1 antagonist, low-dose doxepin; and the histamine and serotonin receptor antagonists, amitriptyline, mirtazapine, trazodone, olanzapine, and quetiapine. The pharmacology and mechanism of action of these treatments and the evidence-base for the use of these drugs in clinical practice is outlined along with novel pipelines. There is evidence to recommend suvorexant and low-dose doxepin for sleep maintenance insomnia; there is also sufficient evidence to recommend ramelteon for sleep onset insomnia. Although there is limited evidence for the use of the quetiapine, trazodone, mirtazapine, amitriptyline, pregabalin, gabapentin, agomelatine, and olanzapine as treatments for insomnia disorder, these drugs may improve sleep while successfully treating comorbid disorders, with a different side effect profile than the BZDs and Z-drugs. The unique mechanism of action of each drug allows for a more personalized and targeted medical management of insomnia.
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Affiliation(s)
- Tobias Atkin
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University Health Center, McGill University, Montreal, Quebec, Canada (T.A., S.C., G.G.); and Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy (S.C.)
| | - Stefano Comai
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University Health Center, McGill University, Montreal, Quebec, Canada (T.A., S.C., G.G.); and Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy (S.C.)
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University Health Center, McGill University, Montreal, Quebec, Canada (T.A., S.C., G.G.); and Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy (S.C.)
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12
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Li SB, Nevárez N, Giardino WJ, de Lecea L. Optical probing of orexin/hypocretin receptor antagonists. Sleep 2018; 41:5060288. [PMID: 30060151 PMCID: PMC6454482 DOI: 10.1093/sleep/zsy141] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/10/2018] [Indexed: 01/17/2023] Open
Abstract
Study Objectives The present study investigated the function of Hypocretin (Hcrt or Orexin/OX) receptor antagonists in sleep modulation and memory function with optical methods in transgenic mice. Methods We used Hcrt-IRES-Cre knock-in mice and AAV vectors expressing channelrhodopsin-2 (ChR2) to render Hcrt neurons sensitive to blue light stimulation. We optogenetically stimulated Hcrt neurons and measured latencies to wakefulness in the presence or absence of OX1/2R antagonists and Zolpidem. We also examined endogenous Hcrt neuronal activity with fiber photometry. Changes in memory after optogenetic sleep disruption were evaluated by the novel object recognition test (NOR) and compared for groups treated with vehicle, OX1/2R antagonists, or Zolpidem. We also analyzed electroencephalogram (EEG) power spectra of wakefulness, rapid eye movement (REM) sleep, and non-REM (NREM) sleep following the injections of vehicle, OX1/2R antagonists, and Zolpidem in young adult mice. Results Acute optogenetic stimulation of Hcrt neurons at different frequencies resulted in wakefulness. Treatment with dual OX1/2R antagonists (DORAs) DORA12 and MK6096, as well as selective OX2R antagonist MK1064 and Zolpidem, but not selective OX1R antagonist 1SORA1, significantly reduced the bout length of optogenetic stimulation-evoked wakefulness episode. Fiber photometry recordings of GCaMP6f signals showed that Hcrt neurons are active during wakefulness, even in the presence of OXR antagonists. Treatment with dual OX1/2R antagonists improved memory function despite optogenetic sleep fragmentation caused impaired memory function in a NOR test. Conclusions Our results show DORAs and selective OX2R antagonists stabilize sleep and improve sleep-dependent cognitive processes even when challenged by optogenetic stimulation mimicking highly arousing stimuli.
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Affiliation(s)
- Shi-Bin Li
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Natalie Nevárez
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - William J Giardino
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA
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13
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Campbell EJ, Marchant NJ, Lawrence AJ. A sleeping giant: Suvorexant for the treatment of alcohol use disorder? Brain Res 2018; 1731:145902. [PMID: 30081035 DOI: 10.1016/j.brainres.2018.08.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/23/2018] [Accepted: 08/01/2018] [Indexed: 01/12/2023]
Abstract
There are currently 3 FDA approved treatments for alcohol use disorder (AUD) in the USA, opioid receptor antagonists such as naltrexone, disulfiram and acamprosate. To date, these have been largely inadequate at preventing relapse at a population level and this may be because they only target certain aspects of AUD. Recently, suvorexant, a dual orexin receptor antagonist, has been FDA approved for the treatment of insomnia. Importantly, sleep disruptions occur during both acute and prolonged alcohol exposure and sleep deprivation is a potent factor promoting relapse to alcohol use. In this mini review article, we explore the therapeutic potential of suvorexant for the treatment of AUD. In particular, we highlight that in addition to altering the motivational properties of alcohol, suvorexant may also address key physiological components associated with alcohol withdrawal and abstinence, such as sleep disruptions, which should in turn help reduce or prevent relapse.
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Affiliation(s)
- Erin J Campbell
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia
| | - Nathan J Marchant
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia; Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, Parkville, Victoria 3052, Australia; Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010, Australia.
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14
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Jaggard JB, Stahl BA, Lloyd E, Prober DA, Duboue ER, Keene AC. Hypocretin underlies the evolution of sleep loss in the Mexican cavefish. eLife 2018; 7:32637. [PMID: 29405117 PMCID: PMC5800846 DOI: 10.7554/elife.32637] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/25/2017] [Indexed: 01/09/2023] Open
Abstract
The duration of sleep varies dramatically between species, yet little is known about the genetic basis or evolutionary factors driving this variation in behavior. The Mexican cavefish, Astyanax mexicanus, exists as surface populations that inhabit rivers, and multiple cave populations with convergent evolution on sleep loss. The number of Hypocretin/Orexin (HCRT)-positive hypothalamic neurons is increased significantly in cavefish, and HCRT is upregulated at both the transcript and protein levels. Pharmacological or genetic inhibition of HCRT signaling increases sleep in cavefish, suggesting enhanced HCRT signaling underlies the evolution of sleep loss. Ablation of the lateral line or starvation, manipulations that selectively promote sleep in cavefish, inhibit hcrt expression in cavefish while having little effect on surface fish. These findings provide the first evidence of genetic and neuronal changes that contribute to the evolution of sleep loss, and support a conserved role for HCRT in sleep regulation.
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Affiliation(s)
- James B Jaggard
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - Bethany A Stahl
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - Evan Lloyd
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
| | - David A Prober
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Erik R Duboue
- Department of Embryology, Carnegie Institution for Science, Baltimore, United States.,Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, United States
| | - Alex C Keene
- Department of Biological Sciences, Florida Atlantic University, Jupiter, United States
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15
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16
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Abstract
The discovery of the orexin system represents the single major progress in the sleep field of the last three to four decades. The two orexin peptides and their two receptors play a major role in arousal and sleep/wake cycles. Defects in the orexin system lead to narcolepsy with cataplexy in humans and dogs and can be experimentally reproduced in rodents. At least six orexin receptor antagonists have reached Phase II or Phase III clinical trials in insomnia, five of which are dual orexin receptor antagonists (DORAs) that target both OX1 and OX2 receptors (OX2Rs). All clinically tested DORAs induce and maintain sleep: suvorexant, recently registered in the USA and Japan for insomnia, represents the first hypnotic principle that acts in a completely different manner from the current standard medications. It is clear, however, that in the clinic, all DORAs promote sleep primarily by increasing rapid eye movement (REM) and are almost devoid of effects on slow-wave (SWS) sleep. At present, there is no consensus on whether the sole promotion of REM sleep has a negative impact in patients suffering from insomnia. However, sleep onset REM (SOREM), which has been documented with DORAs, is clearly an undesirable effect, especially for narcoleptic patients and also in fragile populations (e.g. elderly patients) where REM-associated loss of muscle tone may promote an elevated risk of falls. Debate thus remains as to the ideal orexin agent to achieve a balanced increase in REM and non-rapid eye movement (NREM) sleep. Here, we review the evidence that an OX2R antagonist should be at least equivalent, or perhaps superior, to a DORA for the treatment of insomnia. An OX2R antagonist may produce more balanced sleep than a DORA. Rodent sleep experiments show that the OX2R is the primary target of orexin receptor antagonists in sleep modulation. Furthermore, an OX2R antagonist should, in theory, have a lower narcoleptic/cataplexic potential. In the clinic, the situation remains equivocal, since OX2R antagonists are in early stages: MK-1064 has completed Phase I, and MIN202 is currently in clinical Phase II/III trials. However, data from insomnia patients have not yet been released. Promotional material suggests that balanced sleep is indeed induced by MIN-202, whereas in volunteers MK-1064 has been reported to act similarly to DORAs.
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Affiliation(s)
- Laura H Jacobson
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sui Chen
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Sanjida Mir
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Daniel Hoyer
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, 30 Royal Parade, Parkville, VIC, 3052, Australia.
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
- Department of Chemical Physiology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA, 92037, USA.
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17
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Liu K, Kim J, Kim DW, Zhang YS, Bao H, Denaxa M, Lim SA, Kim E, Liu C, Wickersham IR, Pachnis V, Hattar S, Song J, Brown SP, Blackshaw S. Lhx6-positive GABA-releasing neurons of the zona incerta promote sleep. Nature 2017; 548:582-587. [PMID: 28847002 DOI: 10.1038/nature23663] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 07/19/2017] [Indexed: 01/21/2023]
Abstract
Multiple populations of wake-promoting neurons have been characterized in mammals, but few sleep-promoting neurons have been identified. Wake-promoting cell types include hypocretin and GABA (γ-aminobutyric-acid)-releasing neurons of the lateral hypothalamus, which promote the transition to wakefulness from non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Here we show that a subset of GABAergic neurons in the mouse ventral zona incerta, which express the LIM homeodomain factor Lhx6 and are activated by sleep pressure, both directly inhibit wake-active hypocretin and GABAergic cells in the lateral hypothalamus and receive inputs from multiple sleep-wake-regulating neurons. Conditional deletion of Lhx6 from the developing diencephalon leads to decreases in both NREM and REM sleep. Furthermore, selective activation and inhibition of Lhx6-positive neurons in the ventral zona incerta bidirectionally regulate sleep time in adult mice, in part through hypocretin-dependent mechanisms. These studies identify a GABAergic subpopulation of neurons in the ventral zona incerta that promote sleep.
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Affiliation(s)
- Kai Liu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Juhyun Kim
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Dong Won Kim
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yi Stephanie Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hechen Bao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | | | - Szu-Aun Lim
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Eileen Kim
- Department of Biology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Chang Liu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ian R Wickersham
- The McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | | | - Samer Hattar
- National Institute of Mental Health, Bethesda, Maryland, USA
| | - Juan Song
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
| | - Solange P Brown
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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18
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Mieda M. The roles of orexins in sleep/wake regulation. Neurosci Res 2017; 118:56-65. [DOI: 10.1016/j.neures.2017.03.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/07/2017] [Accepted: 03/07/2017] [Indexed: 10/25/2022]
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19
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Gotter AL, Forman MS, Harrell CM, Stevens J, Svetnik V, Yee KL, Li X, Roecker AJ, Fox SV, Tannenbaum PL, Garson SL, Lepeleire ID, Calder N, Rosen L, Struyk A, Coleman PJ, Herring WJ, Renger JJ, Winrow CJ. Orexin 2 Receptor Antagonism is Sufficient to Promote NREM and REM Sleep from Mouse to Man. Sci Rep 2016; 6:27147. [PMID: 27256922 PMCID: PMC4891657 DOI: 10.1038/srep27147] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022] Open
Abstract
Orexin neuropeptides regulate sleep/wake through orexin receptors (OX1R, OX2R); OX2R is the predominant mediator of arousal promotion. The potential for single OX2R antagonism to effectively promote sleep has yet to be demonstrated in humans. MK-1064 is an OX2R-single antagonist. Preclinically, MK-1064 promotes sleep and increases both rapid eye movement (REM) and non-REM (NREM) sleep in rats at OX2R occupancies higher than the range observed for dual orexin receptor antagonists. Similar to dual antagonists, MK-1064 increases NREM and REM sleep in dogs without inducing cataplexy. Two Phase I studies in healthy human subjects evaluated safety, tolerability, pharmacokinetics and sleep-promoting effects of MK-1064, and demonstrated dose-dependent increases in subjective somnolence (via Karolinska Sleepiness Scale and Visual Analogue Scale measures) and sleep (via polysomnography), including increased REM and NREM sleep. Thus, selective OX2R antagonism is sufficient to promote REM and NREM sleep across species, similarly to that seen with dual orexin receptor antagonism.
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Affiliation(s)
| | - Mark S. Forman
- Department of Translational Medicine, Merck & Co. Inc., Kenilworth, NJ, USA
| | | | - Joanne Stevens
- Department of in vivo Pharmacology, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Vladimir Svetnik
- Department of Biostatistics and Research Decision Sciences, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Ka Lai Yee
- Department of Pharmacokinetics Pharmacodynamics and Drug Metabolism, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Xiaodong Li
- Department of Pharmacokinetics Pharmacodynamics and Drug Metabolism, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Anthony J. Roecker
- Department of Medicinal Chemistry, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Steven V. Fox
- Department of in vivo Pharmacology, Merck & Co. Inc., Kenilworth, NJ, USA
| | | | - Susan L. Garson
- Department of Neuroscience, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Inge De Lepeleire
- Department of Translational Medicine, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Nicole Calder
- Department of Clinical Neuroscience, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Laura Rosen
- Department of Clinical Neuroscience, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Arie Struyk
- Department of Translational Medicine, Merck & Co. Inc., Kenilworth, NJ, USA
| | - Paul J. Coleman
- Department of Medicinal Chemistry, Merck & Co. Inc., Kenilworth, NJ, USA
| | - W. Joseph Herring
- Department of Clinical Neuroscience, Merck & Co. Inc., Kenilworth, NJ, USA
| | - John J. Renger
- Department of Neuroscience, Merck & Co. Inc., Kenilworth, NJ, USA
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20
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Hazra A, Corbett BF, You JC, Aschmies S, Zhao L, Li K, Lepore AC, Marsh ED, Chin J. Corticothalamic network dysfunction and behavioral deficits in a mouse model of Alzheimer's disease. Neurobiol Aging 2016; 44:96-107. [PMID: 27318137 DOI: 10.1016/j.neurobiolaging.2016.04.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 10/21/2022]
Abstract
Alzheimer's disease is associated with cognitive decline and seizures. Growing evidence indicates that seizures contribute to cognitive deficits early in disease, but how they develop and impact cognition are unclear. To investigate potential mechanisms, we studied a mouse model that overexpresses mutant human amyloid precursor protein with high levels of amyloid beta (Aβ). These mice develop generalized epileptiform activity, including nonconvulsive seizures, consistent with alterations in corticothalamic network activity. Amyloid precursor protein mice exhibited reduced activity marker expression in the reticular thalamic nucleus, a key inhibitory regulatory nucleus, and increased activity marker expression in downstream thalamic relay targets that project to cortex and limbic structures. Slice recordings revealed impaired cortical inputs to the reticular thalamic nucleus that may contribute to corticothalamic dysfunction. These results are consistent with our findings of impaired sleep maintenance in amyloid precursor protein mice. Finally, the severity of sleep impairments predicted the severity of deficits in Morris water maze, suggesting corticothalamic dysfunction may relate to hippocampal dysfunction, and may be a pathophysiological mechanism underlying multiple behavioral and cognitive alterations in Alzheimer's disease.
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Affiliation(s)
- Anupam Hazra
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Brian F Corbett
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Jason C You
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Suzan Aschmies
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Lijuan Zhao
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Ke Li
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Angelo C Lepore
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107
| | - Eric D Marsh
- Departments of Pediatrics and Neurology, Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104
| | - Jeannie Chin
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107.,Farber Institute for Neurosciences, Thomas Jefferson University, Philadelphia, PA 19107.,Memory & Brain Research Center, Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030
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21
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Locus Coeruleus and Tuberomammillary Nuclei Ablations Attenuate Hypocretin/Orexin Antagonist-Mediated REM Sleep. eNeuro 2016; 3:eN-NWR-0018-16. [PMID: 27022631 PMCID: PMC4801942 DOI: 10.1523/eneuro.0018-16.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 01/13/2023] Open
Abstract
Hypocretin 1 and 2 (Hcrts; also known as orexin A and B), excitatory neuropeptides synthesized in cells located in the tuberal hypothalamus, play a central role in the control of arousal. Hcrt inputs to the locus coeruleus norepinephrine (LC NE) system and the posterior hypothalamic histaminergic tuberomammillary nuclei (TMN HA) are important efferent pathways for Hcrt-induced wakefulness. The LC expresses Hcrt receptor 1 (HcrtR1), whereas HcrtR2 is found in the TMN. Although the dual Hcrt/orexin receptor antagonist almorexant (ALM) decreases wakefulness and increases NREM and REM sleep time, the neural circuitry that mediates these effects is currently unknown. To test the hypothesis that ALM induces sleep by selectively disfacilitating subcortical wake-promoting populations, we ablated LC NE neurons (LCx) or TMN HA neurons (TMNx) in rats using cell-type-specific saporin conjugates and evaluated sleep/wake following treatment with ALM and the GABAA receptor modulator zolpidem (ZOL). Both LCx and TMNx attenuated the promotion of REM sleep by ALM without affecting ALM-mediated increases in NREM sleep. Thus, eliminating either HcrtR1 signaling in the LC or HcrtR2 signaling in the TMN yields similar effects on ALM-induced REM sleep without affecting NREM sleep time. In contrast, neither lesion altered ZOL efficacy on any measure of sleep–wake regulation. These results contrast with those of a previous study in which ablation of basal forebrain cholinergic neurons attenuated ALM-induced increases in NREM sleep time without affecting REM sleep, indicating that Hcrt neurotransmission influences distinct aspects of NREM and REM sleep at different locations in the sleep–wake regulatory network.
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Abstract
The hypocretins (Hcrts), also known as orexins, have been among the most intensely studied neuropeptide systems since their discovery about two decades ago. Anatomical evidence shows that the hypothalamic neurons that produce hypocretins/orexins project widely throughout the entire brain, innervating the noradrenergic locus coeruleus, the cholinergic basal forebrain, the dopaminergic ventral tegmental area, the serotonergic raphe nuclei, the histaminergic tuberomammillary nucleus, and many other brain regions. By interacting with other neural systems, the Hcrt system profoundly modulates versatile physiological processes including arousal, food intake, emotion, attention, and reward. Importantly, interruption of the interactions between these systems has the potential to cause neurological and psychiatric diseases. Here, we review the modulation of diverse neural systems by Hcrts and summarize potential therapeutic strategies based on our understanding of the Hcrt system's role in physiology and pathophysiological processes.
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23
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Recent trends in orexin research—2010 to 2015. Bioorg Med Chem Lett 2015; 25:2875-87. [DOI: 10.1016/j.bmcl.2015.05.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 05/08/2015] [Accepted: 05/09/2015] [Indexed: 12/31/2022]
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Abstract
Suvorexant (Belsorma(®)) is the first orexin receptor antagonist approved by the US FDA (August 2014) for insomnia treatment. Following comprehensive Phase II/III studies, with up to 12 months of treatment in adult and elderly patients, there is little doubt that suvorexant induces and maintains sleep. However, the FDA and sponsor disagreed about effective versus safe doses (November 2012). The FDA considered that 5-15 mg were efficient and probably safe, whereas the sponsors had proposed 15-40 mg. The final approved doses are 5, 10, 15 and 20 mg. The major issues are next-morning somnolence and safety as seen in driving tests, with possible signs of muscle weakness, weird dreams, sleep walking, other nighttime behaviors and suicidal ideation. Despite its limitations, suvorexant's market entry offers a truly novel treatment for insomnia, paving the way for follow-up compounds and opening therapeutic avenues in other disorders for orexin receptor modulating compounds.
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Affiliation(s)
- Laura H Jacobson
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia
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25
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Gotter AL, Garson SL, Stevens J, Munden RL, Fox SV, Tannenbaum PL, Yao L, Kuduk SD, McDonald T, Uslaner JM, Tye SJ, Coleman PJ, Winrow CJ, Renger JJ. Differential sleep-promoting effects of dual orexin receptor antagonists and GABAA receptor modulators. BMC Neurosci 2014; 15:109. [PMID: 25242351 PMCID: PMC4261741 DOI: 10.1186/1471-2202-15-109] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 09/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The current standard of care for insomnia includes gamma-aminobutyric acid receptor A (GABAA) activators, which promote sleep as well as general central nervous system depression. Dual orexin receptor antagonists (DORAs) represent an alternative mechanism for insomnia treatment that induces somnolence by blocking the wake-promoting effects of orexin neuropeptides. The current study compares the role and interdependence of these two mechanisms on their ability to influence sleep architecture and quantitative electroencephalography (qEEG) spectral profiles across preclinical species. RESULTS Active-phase dosing of DORA-22 induced consistent effects on sleep architecture in mice, rats, dogs, and rhesus monkeys; attenuation of active wake was accompanied by increases in both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. Eszopiclone, a representative GABAA receptor modulator, promoted sleep in rats and rhesus monkeys that was marked by REM sleep suppression, but had inconsistent effects in mice and paradoxically promoted wakefulness in dogs. Active-phase treatment of rats with DORA-12 similarly promoted NREM and REM sleep to magnitudes nearly identical to those seen during normal resting-phase sleep following vehicle treatment, whereas eszopiclone suppressed REM even to levels below those seen during the active phase. The qEEG changes induced by DORA-12 in rats also resembled normal resting-phase patterns, whereas eszopiclone induced changes distinct from normal active- or inactive-phase spectra. Co-dosing experiments, as well as studies in transgenic rats lacking orexin neurons, indicated partial overlap in the mechanism of sleep promotion by orexin and GABA modulation with the exception of the REM suppression exclusive to GABAA receptor modulation. Following REM deprivation in mice, eszopiclone further suppressed REM sleep while DORA-22 facilitated recovery including increased REM sleep. CONCLUSION DORAs promote NREM and importantly REM sleep that is similar in proportion and magnitude to that seen during the normal resting phase across mammalian animal models. While limited overlap exists between therapeutic mechanisms, orexin signaling does not appear involved in the REM suppression exhibited by GABAA receptor modulators. The ability of DORAs to promote proportional NREM and REM sleep following sleep deprivation suggests that this mechanism may be effective in alleviating recovery from sleep disturbance.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - John J Renger
- Department of Neuroscience, Merck Research Laboratories, 770 Sumneytown Pike, PO Box 4, West Point, PA 19486-0004, USA.
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26
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Abstract
Addiction is a chronic relapsing disorder which presents a significant global health burden and unmet medical need. The orexin/hypocretin system is an attractive potential therapeutic target as demonstrated by the successful clinical trials of antagonist medications like Suvorexant for insomnia. It is composed of two neuropeptides, orexin-A and orexin-B and two excitatory and promiscuous G-protein coupled receptors, OX1 and OX2. Orexins are known to have a variety of functions, most notably in regulating arousal, appetite and reward. The orexins have been shown to have a role in mediating the effects of several drugs of abuse, such as cocaine, morphine and alcohol via projections to key brain regions such as the ventral tegmental area, nucleus accumbens and prefrontal cortex. However, it has not yet been demonstrated whether the dual orexin receptor antagonists (DORAs) under development for insomnia are ideal drugs for the treatment of addiction. The question of whether to use a DORA or single orexin receptor antagonist (SORA) for the treatment of addiction is a key question that will need to be answered in order to maximize the clinical utility of orexin receptor antagonists. This review will examine the role of the orexin/hypocretin system in addiction, orexin-based pharmacotherapies under development and factors affecting the selection of one or both orexin receptors as drug targets for the treatment of addiction.
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Chen Q, de Lecea L, Hu Z, Gao D. The hypocretin/orexin system: an increasingly important role in neuropsychiatry. Med Res Rev 2014; 35:152-97. [PMID: 25044006 DOI: 10.1002/med.21326] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Hypocretins, also named as orexins, are excitatory neuropeptides secreted by neurons specifically located in lateral hypothalamus and perifornical areas. Orexinergic fibers are extensively distributed in various brain regions and involved in a number of physiological functions, such as arousal, cognition, stress, appetite, and metabolism. Arousal is the most important function of orexin system as dysfunction of orexin signaling leads to narcolepsy. In addition to narcolepsy, orexin dysfunction is associated with serious neural disorders, including addiction, depression, and anxiety. However, some results linking orexin with these disorders are still contradictory, which may result from differences of detection methods or the precision of tools used in measurements; strategies targeted to orexin system (e.g., antagonists to orexin receptors, gene delivery, and cell transplantation) are promising new tools for treatment of neuropsychiatric disorders, though studies are still in a stage of preclinical or clinical research.
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Affiliation(s)
- Quanhui Chen
- Department of Physiology, Third Military Medical University, Chongqing 400038, China; Department of Sleep and Psychology, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400038, China
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28
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Steiner MA, Winrow CJ. Opportunities and perspectives for developing orexin receptor antagonists. Front Neurosci 2014; 8:158. [PMID: 24971050 PMCID: PMC4054497 DOI: 10.3389/fnins.2014.00158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/26/2014] [Indexed: 12/16/2022] Open
Affiliation(s)
- Michel A Steiner
- Actelion Pharmaceuticals Ltd., Department of Central Nervous System (CNS) Pharmacology Allschwil, Switzerland
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Callander GE, Olorunda M, Monna D, Schuepbach E, Langenegger D, Betschart C, Hintermann S, Behnke D, Cotesta S, Fendt M, Laue G, Ofner S, Briard E, Gee CE, Jacobson LH, Hoyer D. Kinetic properties of "dual" orexin receptor antagonists at OX1R and OX2R orexin receptors. Front Neurosci 2013; 7:230. [PMID: 24376396 PMCID: PMC3847553 DOI: 10.3389/fnins.2013.00230] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 11/15/2013] [Indexed: 12/28/2022] Open
Abstract
Orexin receptor antagonists represent attractive targets for the development of drugs for the treatment of insomnia. Both efficacy and safety are crucial in clinical settings and thorough investigations of pharmacokinetics and pharmacodynamics can predict contributing factors such as duration of action and undesirable effects. To this end, we studied the interactions between various “dual” orexin receptor antagonists and the orexin receptors, OX1R and OX2R, over time using saturation and competition radioligand binding with [3H]-BBAC ((S)-N-([1,1′-biphenyl]-2-yl)-1-(2-((1-methyl-1H-benzo[d]imidazol-2-yl)thio)acetyl)pyrrolidine-2-carboxamide). In addition, the kinetics of these compounds were investigated in cells expressing human, mouse and rat OX1R and OX2R using FLIPR® assays for calcium accumulation. We demonstrate that almorexant reaches equilibrium very slowly at OX2R, whereas SB-649868, suvorexant, and filorexant may take hours to reach steady state at both orexin receptors. By contrast, compounds such as BBAC or the selective OX2R antagonist IPSU ((2-((1H-Indol-3-yl)methyl)-9-(4-methoxypyrimidin-2-yl)-2,9-diazaspiro[5.5]undecan-1-one) bind rapidly and reach equilibrium very quickly in binding and/or functional assays. Overall, the “dual” antagonists tested here tend to be rather unselective under non-equilibrium conditions and reach equilibrium very slowly. Once equilibrium is reached, each ligand demonstrates a selectivity profile that is however, distinct from the non-equilibrium condition. The slow kinetics of the “dual” antagonists tested suggest that in vitro receptor occupancy may be longer lasting than would be predicted. This raises questions as to whether pharmacokinetic studies measuring plasma or brain levels of these antagonists are accurate reflections of receptor occupancy in vivo.
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Affiliation(s)
- Gabrielle E Callander
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Dentistry and Health Sciences, School of Medicine, The University of Melbourne Parkville, VIC, Australia ; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, VIC, Australia
| | - Morenike Olorunda
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Dominique Monna
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Edi Schuepbach
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Daniel Langenegger
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Claudia Betschart
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Samuel Hintermann
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Dirk Behnke
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Simona Cotesta
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Markus Fendt
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Grit Laue
- Metabolism and Pharmacokinetics, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Silvio Ofner
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Emmanuelle Briard
- Global Discovery Chemistry, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Christine E Gee
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland ; Centre for Neurobiology Hamburg, Institute for Synaptic Physiology Hamburg, Germany
| | - Laura H Jacobson
- Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
| | - Daniel Hoyer
- Department of Pharmacology and Therapeutics, Faculty of Medicine, Dentistry and Health Sciences, School of Medicine, The University of Melbourne Parkville, VIC, Australia ; The Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, VIC, Australia ; Department of Neuroscience, Novartis Institutes for Biomedical Research Basel, Switzerland
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