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Bandarabadi M, Prouvot Bouvier PH, Corsi G, Tafti M. The paradox of REM sleep: Seven decades of evolution. Sleep Med Rev 2024; 74:101918. [PMID: 38457935 DOI: 10.1016/j.smrv.2024.101918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/10/2024]
Affiliation(s)
- Mojtaba Bandarabadi
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
| | | | - Giorgio Corsi
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Mehdi Tafti
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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2
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Bandarabadi M, Li S, Aeschlimann L, Colombo G, Tzanoulinou S, Tafti M, Becchetti A, Boutrel B, Vassalli A. Inactivation of hypocretin receptor-2 signaling in dopaminergic neurons induces hyperarousal and enhanced cognition but impaired inhibitory control. Mol Psychiatry 2024; 29:327-341. [PMID: 38123729 PMCID: PMC11116111 DOI: 10.1038/s41380-023-02329-z] [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: 05/15/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 12/23/2023]
Abstract
Hypocretin/Orexin (HCRT/OX) and dopamine (DA) are both key effectors of salience processing, reward and stress-related behaviors and motivational states, yet their respective roles and interactions are poorly delineated. We inactivated HCRT-to-DA connectivity by genetic disruption of Hypocretin receptor-1 (Hcrtr1), Hypocretin receptor-2 (Hcrtr2), or both receptors (Hcrtr1&2) in DA neurons and analyzed the consequences on vigilance states, brain oscillations and cognitive performance in freely behaving mice. Unexpectedly, loss of Hcrtr2, but not Hcrtr1 or Hcrtr1&2, induced a dramatic increase in theta (7-11 Hz) electroencephalographic (EEG) activity in both wakefulness and rapid-eye-movement sleep (REMS). DAHcrtr2-deficient mice spent more time in an active (or theta activity-enriched) substate of wakefulness, and exhibited prolonged REMS. Additionally, both wake and REMS displayed enhanced theta-gamma phase-amplitude coupling. The baseline waking EEG of DAHcrtr2-deficient mice exhibited diminished infra-theta, but increased theta power, two hallmarks of EEG hyperarousal, that were however uncoupled from locomotor activity. Upon exposure to novel, either rewarding or stress-inducing environments, DAHcrtr2-deficient mice featured more pronounced waking theta and fast-gamma (52-80 Hz) EEG activity surges compared to littermate controls, further suggesting increased alertness. Cognitive performance was evaluated in an operant conditioning paradigm, which revealed that DAHcrtr2-ablated mice manifest faster task acquisition and higher choice accuracy under increasingly demanding task contingencies. However, the mice concurrently displayed maladaptive patterns of reward-seeking, with behavioral indices of enhanced impulsivity and compulsivity. None of the EEG changes observed in DAHcrtr2-deficient mice were seen in DAHcrtr1-ablated mice, which tended to show opposite EEG phenotypes. Our findings establish a clear genetically-defined link between monosynaptic HCRT-to-DA neurotransmission and theta oscillations, with a differential and novel role of HCRTR2 in theta-gamma cross-frequency coupling, attentional processes, and executive functions, relevant to disorders including narcolepsy, attention-deficit/hyperactivity disorder, and Parkinson's disease.
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Affiliation(s)
- Mojtaba Bandarabadi
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Sha Li
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Lea Aeschlimann
- Centre for Psychiatric Neuroscience, Department of Psychiatry, The Lausanne University Hospital, Lausanne, Switzerland
| | - Giulia Colombo
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | | | - Mehdi Tafti
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | - Benjamin Boutrel
- Centre for Psychiatric Neuroscience, Department of Psychiatry, The Lausanne University Hospital, Lausanne, Switzerland
| | - Anne Vassalli
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
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Todd RC. A Dynamic Foundation: Aberrations of Sleep Architecture and Its Association With Clinical and Sub-clinical Psychopathology. Cureus 2024; 16:e55262. [PMID: 38425327 PMCID: PMC10903967 DOI: 10.7759/cureus.55262] [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] [Accepted: 02/29/2024] [Indexed: 03/02/2024] Open
Abstract
This investigation centered on the hypnagogic and hypnopompic wake-sleep/sleep-wake transition states and the associated exploration of hypnagogic and hypnopompic experiences (HHEs), and sleep paralysis (SP) on psychiatric exacerbation and paradoxical masking. The study aims to discern causality by examining how these sleep-related experiences may contribute to the emergence or exacerbation of psychiatric and neurodegenerative conditions, particularly, pertaining to the clinical or sub-clinical demographic of Schizotypal Personality Disorder (STPD), Mood Disorders, Schizophrenia, Post-Traumatic Stress Disorder (PTSD), Generalized Anxiety Disorder (GAD), Narcolepsy, Panic Disorder, specific phobias, or heightened psychotic sensitivity. Methodologically, this study employed a comprehensive literature review, drawing from a range of studies across sleep medicine, psychiatry, and psychology, utilizing PubMed-indexed peer-reviewed scientific literature, sourcing from academic institutions, Google Scholar, and open-access publications. This interdisciplinary approach allowed for a nuanced and systematic understanding of the potential links between specific sleep-wake/wake-sleep aberrations and their masking or exacerbation of clinical/sub-clinical psychiatric symptomatology in this particular demographic. Insights gained from the outcome of this study hold promise for advancing understanding of the interrelationship between sleep neurobiology and psychiatric disorders. Additionally, the findings may inform targeted therapeutic interventions tailored to mitigate the impact of sleep-wake disruptions on vulnerable populations. The overarching objective is to bridge current gaps in knowledge, cultivating a more profound understanding with direct implications for both clinical practice and ongoing research endeavors. The study outcomes provide an intriguing understanding of the complex relationship between sleep neurobiology and psychiatric disorders, paving the way for targeted therapeutic interventions to alleviate the effects of sleep-wake disruptions, and addressing critical gaps in knowledge with direct implications for clinical practice and ongoing research.
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Affiliation(s)
- Richard C Todd
- Psychiatry, International European University School of Medicine, Kiev, UKR
- Research, Trinity Medical Sciences University, Warner Robins, USA
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Koyama Y. The role of orexinergic system in the regulation of cataplexy. Peptides 2023; 169:171080. [PMID: 37598758 DOI: 10.1016/j.peptides.2023.171080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 08/06/2023] [Accepted: 08/18/2023] [Indexed: 08/22/2023]
Abstract
Loss of orexin/hypocretin causes serious sleep disorder; narcolepsy. Cataplexy is the most striking symptom of narcolepsy, characterized by abrupt muscle paralysis induced by emotional stimuli, and has been considered pathological activation of REM sleep atonia system. Clinical treatments for cataplexy/narcolepsy and early pharmacological studies in narcoleptic dogs tell us about the involvement of monoaminergic and cholinergic systems in the control of cataplexy/narcolepsy. Muscle atonia may be induced by activation of REM sleep-atonia generating system in the brainstem. Emotional stimuli may be processed in the limbic systems including the amygdala, nucleus accumbens, and medial prefrontal cortex. It is now considered that orexin/hypocretin prevents cataplexy by modulating the activity of different points of cataplexy-inducing circuit, including monoaminergic/cholinergic systems, muscle atonia-generating systems, and emotion-related systems. This review will describe the recent advances in understanding the neural mechanisms controlling cataplexy, with a focus on the involvement of orexin/hypocretin system, and will discuss future experimental strategies that will lead to further understanding and treatment of this disease.
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Affiliation(s)
- Yoshimasa Koyama
- Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanaya-gawa, Fukushima 960-1296, Japan..
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Ito H, Fukatsu N, Rahaman SM, Mukai Y, Izawa S, Ono D, Kilduff TS, Yamanaka A. Deficiency of orexin signaling during sleep is involved in abnormal REM sleep architecture in narcolepsy. Proc Natl Acad Sci U S A 2023; 120:e2301951120. [PMID: 37796986 PMCID: PMC10576136 DOI: 10.1073/pnas.2301951120] [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: 02/03/2023] [Accepted: 07/10/2023] [Indexed: 10/07/2023] Open
Abstract
Narcolepsy is a sleep disorder caused by deficiency of orexin signaling. However, the neural mechanisms by which deficient orexin signaling causes the abnormal rapid eye movement (REM) sleep characteristics of narcolepsy, such as cataplexy and frequent transitions to REM states, are not fully understood. Here, we determined the activity dynamics of orexin neurons during sleep that suppress the abnormal REM sleep architecture of narcolepsy. Orexin neurons were highly active during wakefulness, showed intermittent synchronous activity during non-REM (NREM) sleep, were quiescent prior to the transition from NREM to REM sleep, and a small subpopulation of these cells was active during REM sleep. Orexin neurons that lacked orexin peptides were less active during REM sleep and were mostly silent during cataplexy. Optogenetic inhibition of orexin neurons established that the activity dynamics of these cells during NREM sleep regulate NREM-REM sleep transitions. Inhibition of orexin neurons during REM sleep increased subsequent REM sleep in "orexin intact" mice and subsequent cataplexy in mice lacking orexin peptides, indicating that the activity of a subpopulation of orexin neurons during the preceding REM sleep suppresses subsequent REM sleep and cataplexy. Thus, these results identify how deficient orexin signaling during sleep results in the abnormal REM sleep architecture characteristic of narcolepsy.
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Affiliation(s)
- Hiroto Ito
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Japan Society for the Promotion of Science Research Fellowship for Young Scientists, Tokyo102-0083, Japan
| | - Noriaki Fukatsu
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Sheikh Mizanur Rahaman
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Yasutaka Mukai
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Shuntaro Izawa
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
| | - Thomas S. Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, CA94025
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya464-8601, Japan
- Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya466-8550, Japan
- Chinese Institute for Brain Research, Beijing102206, China
- National Institute for Physiological Sciences, Aichi444-8585, Japan
- National Institutes of Natural Sciences, Aichi444-8585, Japan
- Division of Brain Sciences Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo160-8582, Japan
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Toth BA, Chang KS, Fechtali S, Burgess CR. Dopamine release in the nucleus accumbens promotes REM sleep and cataplexy. iScience 2023; 26:107613. [PMID: 37664637 PMCID: PMC10470413 DOI: 10.1016/j.isci.2023.107613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/21/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023] Open
Abstract
Patients with the sleep disorder narcolepsy suffer from excessive daytime sleepiness, disrupted nighttime sleep, and cataplexy-the abrupt loss of postural muscle tone during wakefulness, often triggered by strong emotion. The dopamine (DA) system is implicated in both sleep-wake states and cataplexy, but little is known about the function of DA release in the striatum and sleep disorders. Recording DA release in the ventral striatum revealed orexin-independent changes across sleep-wake states as well as striking increases in DA release in the ventral, but not dorsal, striatum prior to cataplexy onset. Tonic low-frequency stimulation of ventral tegmental efferents in the ventral striatum suppressed both cataplexy and rapid eye movement (REM) sleep, while phasic high-frequency stimulation increased cataplexy propensity and decreased the latency to REM sleep. Together, our findings demonstrate a functional role of DA release in the striatum in regulating cataplexy and REM sleep.
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Affiliation(s)
- Brandon A. Toth
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Katie S. Chang
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
| | - Sarah Fechtali
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Christian R. Burgess
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
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Toth BA, Chang KS, Burgess CR. Striatal dopamine regulates sleep states and narcolepsy-cataplexy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542872. [PMID: 37397994 PMCID: PMC10312558 DOI: 10.1101/2023.05.30.542872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Disruptions to sleep can be debilitating and have a severe effect on daily life. Patients with the sleep disorder narcolepsy suffer from excessive daytime sleepiness, disrupted nighttime sleep, and cataplexy - the abrupt loss of postural muscle tone (atonia) during wakefulness, often triggered by strong emotion. The dopamine (DA) system is implicated in both sleep-wake states and cataplexy, but little is known about the function of DA release in the striatum - a major output region of midbrain DA neurons - and sleep disorders. To better characterize the function and pattern of DA release in sleepiness and cataplexy, we combined optogenetics, fiber photometry, and sleep recordings in a murine model of narcolepsy (orexin-/-; OX KO) and in wildtype mice. Recording DA release in the ventral striatum revealed OX-independent changes across sleep-wake states as well as striking increases in DA release in the ventral, but not dorsal, striatum prior to cataplexy onset. Tonic low frequency stimulation of ventral tegmental efferents in the ventral striatum suppressed both cataplexy and REM sleep, while phasic high frequency stimulation increased cataplexy propensity and decreased the latency to rapid eye movement (REM) sleep. Together, our findings demonstrate a functional role of DA release in the striatum in regulating cataplexy and REM sleep.
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Affiliation(s)
- Brandon A. Toth
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI USA
| | - Katie S. Chang
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
| | - Christian R. Burgess
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
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Szabo ST, Hopkins SC, Lew R, Loebel A, Roth T, Koblan KS. A multicenter, double-blind, placebo-controlled, randomized, Phase 1b crossover trial comparing two doses of ulotaront with placebo in the treatment of narcolepsy-cataplexy. Sleep Med 2023; 107:202-211. [PMID: 37209427 DOI: 10.1016/j.sleep.2023.04.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 03/09/2023] [Accepted: 04/16/2023] [Indexed: 05/22/2023]
Abstract
BACKGROUND Ulotaront (SEP-363856) is a novel agonist at trace amine-associated receptor 1 and serotonin 5-HT1A receptors in clinical development for the treatment of schizophrenia. Previous studies demonstrated ulotaront suppresses rapid eye movement (REM) sleep in both rodents and healthy volunteers. We assessed acute and sustained treatments of ulotaront on REM sleep and symptoms of cataplexy and alertness in subjects with narcolepsy-cataplexy. METHODS In a multicenter, double-blind, placebo-controlled, randomized, 3-way crossover study, ulotaront was evaluated in 16 adults with narcolepsy-cataplexy. Two oral doses of ulotaront (25 mg and 50 mg) were administered daily for 2 weeks and compared with matching placebo (6-treatment sequence, 3-period, 3-treatment). RESULTS Acute treatment with both 25 mg and 50 mg of ulotaront reduced minutes spent in nighttime REM compared to placebo. A sustained 2-week administration of both doses of ulotaront reduced the mean number of short-onset REM periods (SOREMPs) during daytime multiple sleep latency test (MSLT) compared to placebo. Although cataplexy events decreased from the overall mean baseline during the 2-week treatment period, neither dose of ulotaront statistically separated from placebo (p = 0.76, 25 mg; p = 0.82, 50 mg), and no significant improvement in patient and clinician measures of sleepiness from baseline to end of the 2-week treatment period occurred in any treatment group. CONCLUSIONS Acute and sustained treatment with ulotaront reduced nighttime REM duration and daytime SOREMPs, respectively. The effect of ulotaront on suppression of REM did not demonstrate a statistical or clinically meaningful effect in narcolepsy-cataplexy. REGISTRATION ClinicalTrials.gov identifier: NCT05015673.
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Affiliation(s)
- Steven T Szabo
- Sunovion Pharmaceuticals Inc., 84 Waterford Drive, Marlborough, MA, 01752, USA.
| | - Seth C Hopkins
- Sunovion Pharmaceuticals Inc., 84 Waterford Drive, Marlborough, MA, 01752, USA.
| | - Robert Lew
- Sunovion Pharmaceuticals Inc., 84 Waterford Drive, Marlborough, MA, 01752, USA.
| | - Antony Loebel
- Sunovion Pharmaceuticals Inc., 84 Waterford Drive, Marlborough, MA, 01752, USA.
| | - Thomas Roth
- Sleep Disorders and Research Center, Henry Ford Hospital, 2799 West Grand Boulevard Detroit, MI, 48202, USA.
| | - Kenneth S Koblan
- Sunovion Pharmaceuticals Inc., 84 Waterford Drive, Marlborough, MA, 01752, USA.
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Potter LE, Burgess CR. The melanin-concentrating hormone system as a target for the treatment of sleep disorders. Front Neurosci 2022; 16:952275. [PMID: 36177357 PMCID: PMC9513178 DOI: 10.3389/fnins.2022.952275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Given the widespread prevalence of sleep disorders and their impacts on health, it is critical that researchers continue to identify and evaluate novel avenues of treatment. Recently the melanin-concentrating hormone (MCH) system has attracted commercial and scientific interest as a potential target of pharmacotherapy for sleep disorders. This interest emerges from basic scientific research demonstrating a role for MCH in regulating sleep, and particularly REM sleep. In addition to this role in sleep regulation, the MCH system and the MCH receptor 1 (MCHR1) have been implicated in a wide variety of other physiological functions and behaviors, including feeding/metabolism, reward, anxiety, depression, and learning. The basic research literature on sleep and the MCH system, and the history of MCH drug development, provide cause for both skepticism and cautious optimism about the prospects of MCH-targeting drugs in sleep disorders. Extensive efforts have focused on developing MCHR1 antagonists for use in obesity, however, few of these drugs have advanced to clinical trials, and none have gained regulatory approval. Additional basic research will be needed to fully characterize the MCH system’s role in sleep regulation, for example, to fully differentiate between MCH-neuron and peptide/receptor-mediated functions. Additionally, a number of issues relating to drug design will continue to pose a practical challenge for novel pharmacotherapies targeting the MCH system.
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Affiliation(s)
- Liam E. Potter
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Liam E. Potter,
| | - Christian R. Burgess
- Department of Molecular and Integrative Physiology, Michigan Medicine, Ann Arbor, MI, United States
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, United States
- Christian R. Burgess,
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Meskill GJ, Kallweit U, Zarycranski D, Caussé C, Finance O, Ligneau X, Davis CW. Pitolisant for the treatment of cataplexy in adults with narcolepsy. Expert Opin Orphan Drugs 2022. [DOI: 10.1080/21678707.2021.2022472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Gerard J. Meskill
- Tricoastal Narcolepsy and Sleep Disorders Center, Sugar Land, Texas, USA
| | - Ulf Kallweit
- Center for Narcolepsy, Hypersomnias and Daytime Sleepiness, Universität Witten/Herdecke, Witten, Germany
| | | | | | | | | | - Craig W. Davis
- Harmony Biosciences, Plymouth Meeting, Pennsylvania, USA
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11
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Carli G, Farabollini F. Neuromediators and defensive responses including tonic immobility (TI): Brain areas and circuits involved. PROGRESS IN BRAIN RESEARCH 2022; 271:167-189. [DOI: 10.1016/bs.pbr.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Wang YQ, Liu WY, Li L, Qu WM, Huang ZL. Neural circuitry underlying REM sleep: A review of the literature and current concepts. Prog Neurobiol 2021; 204:102106. [PMID: 34144122 DOI: 10.1016/j.pneurobio.2021.102106] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 04/25/2021] [Accepted: 06/09/2021] [Indexed: 01/09/2023]
Abstract
As one of the fundamental sleep states, rapid eye movement (REM) sleep is believed to be associated with dreaming and is characterized by low-voltage, fast electroencephalographic activity and loss of muscle tone. However, the mechanisms of REM sleep generation have remained unclear despite decades of research. Several models of REM sleep have been established, including a reciprocal interaction model, limit-cycle model, flip-flop model, and a model involving γ-aminobutyric acid, glutamate, and aminergic/orexin/melanin-concentrating hormone neurons. In the present review, we discuss these models and summarize two typical disorders related to REM sleep, namely REM sleep behavior disorder and narcolepsy. REM sleep behavior disorder is a sleep muscle-tone-related disorder and can be treated with clonazepam and melatonin. Narcolepsy, with core symptoms of excessive daytime sleepiness and cataplexy, is strongly connected with orexin in early adulthood.
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Affiliation(s)
- Yi-Qun Wang
- Department of Pharmacology, School of Basic Medical Sciences and State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Wen-Ying Liu
- Department of Pharmacology, School of Basic Medical Sciences and State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Lei Li
- Department of Pharmacology, School of Basic Medical Sciences and State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Wei-Min Qu
- Department of Pharmacology, School of Basic Medical Sciences and State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhi-Li Huang
- Department of Pharmacology, School of Basic Medical Sciences and State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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Samelisant (SUVN-G3031), a potent, selective and orally active histamine H3 receptor inverse agonist for the potential treatment of narcolepsy: pharmacological and neurochemical characterisation. Psychopharmacology (Berl) 2021; 238:1495-1511. [PMID: 33550481 DOI: 10.1007/s00213-021-05779-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023]
Abstract
RATIONALE Samelisant (SUVN-G3031) is a potent and selective histamine H3 receptor (H3R) inverse agonist with good brain penetration and oral bioavailability. OBJECTIVES Pharmacological and neurochemical characterisation to support the utility of Samelisant (SUVN-G3031) in the treatment of sleep-related disorders like narcolepsy. METHODS Samelisant (SUVN-G3031) was tested in rat brain microdialysis studies for evaluation of modulation in histamine, dopamine and norepinephrine. Sleep EEG studies were carried out in orexin knockout mice to study the effects of Samelisant (SUVN-G3031) on the sleep-wake cycle and cataplexy. RESULTS Samelisant (SUVN-G3031) has a similar binding affinity towards human (hH3R; Ki = 8.7 nM) and rat (rH3R; Ki = 9.8 nM) H3R indicating no inter-species differences. Samelisant (SUVN-G3031) displays inverse agonist activity and it exhibits very high selectivity towards H3R. Samelisant (SUVN-G3031) treatment in mice produced a dose-dependent increase in tele-methylhistamine levels indicating the activation of histaminergic neurotransmission. Apart from increasing the levels of histamine, Samelisant (SUVN-G3031) also modulates dopamine and norepinephrine levels in the cerebral cortex while it has no effects on dopamine levels in the striatum or nucleus accumbens. Treatment with Samelisant (SUVN-G3031; 10 and 30 mg/kg, p.o.) produced a significant increase in wakefulness with a concomitant decrease in NREM sleep in orexin knockout mice subjected to sleep EEG. Samelisant (SUVN-G3031) also produced a significant decrease in Direct REM sleep onset (DREM) episodes, demonstrating its anticataplectic effects in an animal model relevant to narcolepsy. Modulation in cortical levels of histamine, norepinephrine and dopamine provides the neurochemical basis for wake-promoting and anticataplectic effects observed in orexin knockout mice. CONCLUSIONS Pre-clinical studies of Samelisant (SUVN-G3031) provide a strong support for utility in the treatment of sleep-related disorders related to EDS and is currently being evaluated in a phase 2 proof of concept study in the USA for the treatment of narcolepsy with and without cataplexy.
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Adamantidis AR, Schmidt MH, Carter ME, Burdakov D, Peyron C, Scammell TE. A circuit perspective on narcolepsy. Sleep 2021; 43:5699663. [PMID: 31919524 PMCID: PMC7215265 DOI: 10.1093/sleep/zsz296] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/13/2019] [Indexed: 01/25/2023] Open
Abstract
The sleep disorder narcolepsy is associated with symptoms related to either boundary state control that include excessive daytime sleepiness and sleep fragmentation, or rapid eye movement (REM) sleep features including cataplexy, sleep paralysis, hallucinations, and sleep-onset REM sleep events (SOREMs). Although the loss of Hypocretin/Orexin (Hcrt/Ox) peptides or their receptors have been associated with the disease, here we propose a circuit perspective of the pathophysiological mechanisms of these narcolepsy symptoms that encompasses brain regions, neuronal circuits, cell types, and transmitters beyond the Hcrt/Ox system. We further discuss future experimental strategies to investigate brain-wide mechanisms of narcolepsy that will be essential for a better understanding and treatment of the disease.
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Affiliation(s)
- A R Adamantidis
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Department of Biomedical Research, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland
| | - M H Schmidt
- Department of Neurology, Centre for Experimental Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.,Ohio Sleep Medicine Institute, Dublin, OH
| | - M E Carter
- Department of Biology, Program in Neuroscience, Williams College, Williamstown, MA
| | - D Burdakov
- Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - C Peyron
- Center for Research in Neuroscience of Lyon, SLEEP team, CNRS UMR5292, INSERM U1028, University Lyon 1, Bron, France
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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15
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Mamelak M. Sleep, Narcolepsy, and Sodium Oxybate. Curr Neuropharmacol 2021; 20:272-291. [PMID: 33827411 PMCID: PMC9413790 DOI: 10.2174/1570159x19666210407151227] [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: 01/17/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 11/23/2022] Open
Abstract
Sodium oxybate (SO) has been in use for many decades to treat narcolepsy with cataplexy. It functions as a weak GABAB agonist but also as an energy source for the brain as a result of its metabolism to succinate and as a powerful antioxidant because of its capacity to induce the formation of NADPH. Its actions at thalamic GABAB receptors can induce slow-wave activity, while its actions at GABAB receptors on monoaminergic neurons can induce or delay REM sleep. By altering the balance between monoaminergic and cholinergic neuronal activity, SO uniquely can induce and prevent cataplexy. The formation of NADPH may enhance sleep’s restorative process by accelerating the removal of the reactive oxygen species (ROS), which accumulate during wakefulness. SO improves alertness in normal subjects and in patients with narcolepsy. SO may allay severe psychological stress - an inflammatory state triggered by increased levels of ROS and characterized by cholinergic supersensitivity and monoaminergic deficiency. SO may be able to eliminate the inflammatory state and correct the cholinergic/ monoaminergic imbalance.
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Affiliation(s)
- Mortimer Mamelak
- Department of Psychiatry, Baycrest Hospital, University of Toronto, Toronto, Ontario. Canada
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16
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Shiromani PJ, Blanco-Centurion C, Vidal-Ortiz A. Mapping Network Activity in Sleep. Front Neurosci 2021; 15:646468. [PMID: 33828453 PMCID: PMC8019804 DOI: 10.3389/fnins.2021.646468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 03/04/2021] [Indexed: 11/22/2022] Open
Abstract
It was in the influenza pandemic of 1918 that von Economo identified specific brain regions regulating sleep and wake. Since then researchers have used a variety of tools to determine how the brain shifts between states of consciousness. In every enterprise new tools have validated existing data, corrected errors and made new discoveries to advance science. The brain is a challenge but new tools can disentangle the brain network. We summarize the newest tool, a miniature microscope, that provides unprecedented view of activity of glia and neurons in freely behaving mice. With this tool we have observed that the activity of a majority of GABA and MCH neurons in the lateral hypothalamus is heavily biased toward sleep. We suggest that miniscope data identifies activity at the cellular level in normal versus diseased brains, and also in response to specific hypnotics. Shifts in activity in small networks across the brain will help identify point of criticality that switches the brain from wake to sleep.
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Affiliation(s)
- Priyattam J Shiromani
- Ralph H. Johnson VA Medical Center, Charleston, SC, United States.,Department of Psychiatry and Biobehavioral Science, Medical University of South Carolina, Charleston, SC, United States
| | - Carlos Blanco-Centurion
- Department of Psychiatry and Biobehavioral Science, Medical University of South Carolina, Charleston, SC, United States
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17
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Sleep Disorders in dogs: A Pathophysiological and Clinical Review. Top Companion Anim Med 2021; 43:100516. [PMID: 33556640 DOI: 10.1016/j.tcam.2021.100516] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 01/22/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022]
Abstract
Sleep is a fundamental process in mammals, including domestic dogs. Disturbances in sleep affect physiological functions like cognitive and physical performance, immune response, pain sensation and increase the risk of diseases. In dogs, sleep can be affected by several conditions, with narcolepsy, REM sleep behavior disorder and sleep breathing disorders being the most frequent causes. Furthermore, sleep disturbances can be a symptom of other primary diseases where they can contribute to the worsening of clinical signs. This review describes reciprocally interacting sleep and wakefulness promoting systems and how their dysfunction can explain the pathophysiological mechanisms of sleep disorders. Additionally, this work discusses the clinical characteristics, diagnostic tools and available treatments for these disorders while highlighting areas in where further studies are needed so as to improve their treatment and prevention.
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18
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Time to Onset of Response to Pitolisant for the Treatment of Excessive Daytime Sleepiness and Cataplexy in Patients With Narcolepsy: An Analysis of Randomized, Placebo-Controlled Trials. CNS Drugs 2021; 35:1303-1315. [PMID: 34822113 PMCID: PMC8642365 DOI: 10.1007/s40263-021-00866-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/26/2021] [Indexed: 11/07/2022]
Abstract
BACKGROUND Pitolisant is approved in the USA and Europe for the treatment of excessive daytime sleepiness or cataplexy in adults with narcolepsy. OBJECTIVE Analyses evaluated the time to onset of clinical response during treatment with pitolisant. METHODS Data were obtained from two randomized, double-blind, 7-week or 8-week, placebo-controlled studies (HARMONY 1, HARMONY CTP). Study medication was individually titrated to a maximum dose of pitolisant 35.6 mg/day and then remained stable. Efficacy assessments included the Epworth Sleepiness Scale and weekly rate of cataplexy (calculated from patient diaries). Onset of clinical response was defined as the first timepoint at which there was statistical separation between pitolisant and placebo. RESULTS The analysis included 61 patients in HARMONY 1 (pitolisant, n = 31; placebo, n = 30) and 105 patients in HARMONY CTP (pitolisant, n = 54; placebo, n = 51). Onset of clinical response began at week 2 (HARMONY 1) or week 3 (HARMONY CTP) for the mean change in Epworth Sleepiness Scale score, and week 2 (HARMONY CTP) or week 5 (HARMONY 1) for the mean change in weekly rate of cataplexy, with further improvements observed in pitolisant-treated patients through the end of treatment. The percentage of treatment responders was significantly greater with pitolisant vs placebo beginning at week 3 for excessive daytime sleepiness (defined as an Epworth Sleepiness Scale score reduction ≥ 3) and week 2 for cataplexy (defined as a ≥ 50% reduction in weekly rate of cataplexy [HARMONY CTP]). CONCLUSIONS Onset of clinical response for excessive daytime sleepiness and/or cataplexy was generally observed within the first 2-3 weeks of pitolisant treatment in patients with narcolepsy. CLINICALTRIALS. GOV IDENTIFIER NCT01067222 (February 2010), NCT01800045 (February 2013).
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19
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Durairaja A, Fendt M. Orexin deficiency modulates cognitive flexibility in a sex-dependent manner. GENES BRAIN AND BEHAVIOR 2020; 20:e12707. [PMID: 33070452 DOI: 10.1111/gbb.12707] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/01/2020] [Accepted: 10/14/2020] [Indexed: 12/18/2022]
Abstract
Cognitive flexibility is an important executive function and refers to the ability to adapt behaviors in response to changes in the environment. Of note, many brain disorders are associated with impairments in cognitive flexibility. Several classical neurotransmitter systems including dopamine, acetylcholine and noradrenaline are shown to be important for cognitive flexibility, however, there is not much known about the role of neuropeptides. The neuropeptide orexin, which is brain-widely released by neurons in the lateral hypothalamus, is a major player in maintaining sleep/wake cycle, feeding behavior, arousal, and motivational behavior. Recent studies showed a role of orexin in attention, cognition and stress-induced attenuation of cognitive flexibility by disrupting orexin signaling locally or systemically. However, it is not known so far whether brain-wide reduction or loss of orexin affects cognitive flexibility. We investigated this question by testing male and female orexin-deficient mice in the attentional set shifting task (ASST), an established paradigm of cognitive flexibility. We found that orexin deficiency impaired the intra-dimensional shift phase of the ASST selectively in female homozygous orexin-deficient mice and improved the first reversal learning phase selectively in male homozygous orexin-deficient mice. We also found that these orexin-mediated sex-based modulations of cognitive flexibility were not correlated with trait anxiety, narcoleptic episodes, and reward consumption. Our findings highlight a sexually dimorphic role of orexin in regulating cognitive flexibility and the need for further investigations of sex-specific functions of the orexin circuitry.
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Affiliation(s)
- Archana Durairaja
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany.,Center of Behavioral Brain Sciences, Otto-von-Guericke University, Magdeburg, Germany
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20
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Bandaru SS, Khanday MA, Ibrahim N, Naganuma F, Vetrivelan R. Sleep-Wake Control by Melanin-Concentrating Hormone (MCH) Neurons: a Review of Recent Findings. Curr Neurol Neurosci Rep 2020; 20:55. [PMID: 33006677 DOI: 10.1007/s11910-020-01075-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE OF THE REVIEW Melanin-concentrating hormone (MCH)-expressing neurons located in the lateral hypothalamus are considered as an integral component of sleep-wake circuitry. However, the precise role of MCH neurons in sleep-wake regulation has remained unclear, despite several years of research employing a wide range of techniques. We review recent data on this aspect, which are mostly inconsistent, and propose a novel role for MCH neurons in sleep regulation. RECENT FINDINGS While almost all studies using "gain-of-function" approaches show an increase in rapid eye movement sleep (or paradoxical sleep; PS), loss-of-function approaches have not shown reductions in PS. Similarly, the reported changes in wakefulness or non-rapid eye movement sleep (slow-wave sleep; SWS) with manipulation of the MCH system using conditional genetic methods are inconsistent. Currently available data do not support a role for MCH neurons in spontaneous sleep-wake but imply a crucial role for them in orchestrating sleep-wake responses to changes in external and internal environments.
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Affiliation(s)
- Sathyajit S Bandaru
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA
| | - Mudasir A Khanday
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Nazifa Ibrahim
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Department of Public Health Sciences, University of Massachusetts, Amherst, MA, USA
| | - Fumito Naganuma
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA.,Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai, Japan
| | - Ramalingam Vetrivelan
- Department of Neurology, Beth Israel Deaconess Medical Center, 3 Blackfan Circle, Center for Life Science # 711, Boston, MA, USA. .,Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
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21
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Hung CJ, Ono D, Kilduff TS, Yamanaka A. Dual orexin and MCH neuron-ablated mice display severe sleep attacks and cataplexy. eLife 2020; 9:54275. [PMID: 32314734 PMCID: PMC7173968 DOI: 10.7554/elife.54275] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 04/03/2020] [Indexed: 12/25/2022] Open
Abstract
Orexin/hypocretin-producing and melanin-concentrating hormone-producing (MCH) neurons are co-extensive in the hypothalamus and project throughout the brain to regulate sleep/wakefulness. Ablation of orexin neurons decreases wakefulness and results in a narcolepsy-like phenotype, whereas ablation of MCH neurons increases wakefulness. Since it is unclear how orexin and MCH neurons interact to regulate sleep/wakefulness, we generated transgenic mice in which both orexin and MCH neurons could be ablated. Double-ablated mice exhibited increased wakefulness and decreased both rapid eye movement (REM) and non-REM (NREM) sleep. Double-ablated mice showed severe cataplexy compared with orexin neuron-ablated mice, suggesting that MCH neurons normally suppress cataplexy. Double-ablated mice also showed frequent sleep attacks with elevated spectral power in the delta and theta range, a unique state that we call 'delta-theta sleep'. Together, these results indicate a functional interaction between orexin and MCH neurons in vivo that suggests the synergistic involvement of these neuronal populations in the sleep/wakefulness cycle.
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Affiliation(s)
- Chi Jung Hung
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Daisuke Ono
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
| | - Thomas S Kilduff
- Center for Neuroscience, Biosciences Division, SRI International, Menlo Park, United States
| | - Akihiro Yamanaka
- Department of Neuroscience II, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.,Department of Neural Regulation, Nagoya University Graduate School of Medicine, Nagoya, Japan.,CREST, JST, Honcho Kawaguchi, Saitama, Japan
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22
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Matsuura W, Nakamoto K, Tokuyama S. Involvement of descending pain control system regulated by orexin receptor signaling in the induction of central post-stroke pain in mice. Eur J Pharmacol 2020; 874:173029. [PMID: 32084419 DOI: 10.1016/j.ejphar.2020.173029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 02/06/2023]
Abstract
Central post-stroke pain (CPSP) is a type of neuropathic pain for which the mechanism and relevant drug pathways remain unknown. Recently, it was reported that intracerebroventricular (ICV) administration of orexin-A suppresses pain and ischemia. In this study, we tested the role of orexin-A in CPSP induction in mice. Male ddY mice were subjected to 30 min of bilateral carotid artery occlusion (BCAO). CPSP was assessed by von Frey test. Colocalization of orexin 1 receptor (OX1R) with various neuron markers were determined by double-immunofluorescence. The hindpaw withdrawal responses to mechanical stimuli were significantly increased 3 days post-BCAO compared with those of sham groups. ICV injection of orexin-A dose-dependently suppressed BCAO-induced mechanical allodynia. These effects were inhibited by pre-treatment with SB334867 (an OX1R antagonist; ICV injection), yohimbine (a noradrenaline α2 receptor antagonist; intrathecal (IT) injection), and WAY100635 (a serotonin 5-HT1A receptor antagonist; IT injection), but not TCS OX2 29 (an OX2R antagonist; ICV injection). OX1R colocalized with TH (a noradrenergic neuron marker) and TPH (a serotonergic neuron marker) in the locus ceruleus (LC) and the rostral ventromedial medulla (RVM), respectively. The number of c-Fos positive cells in the LC and the RVM of BCAO mice was increased at 90 min after ICV injection of orexin-A compared to saline group. These results indicate that orexin-A/OX1R signaling plays an important role through activation of the descending pain control system in the induction of CPSP in mice.
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Affiliation(s)
- Wataru Matsuura
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Kazuo Nakamoto
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan
| | - Shogo Tokuyama
- Department of Clinical Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, 1-1-3 Minatojima, Chuo-ku, Kobe, 650-8586, Japan.
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23
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Li SB, de Lecea L. The hypocretin (orexin) system: from a neural circuitry perspective. Neuropharmacology 2020; 167:107993. [PMID: 32135427 DOI: 10.1016/j.neuropharm.2020.107993] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/23/2020] [Accepted: 02/05/2020] [Indexed: 12/11/2022]
Abstract
Hypocretin/orexin neurons are distributed restrictively in the hypothalamus, a brain region known to orchestrate diverse functions including sleep, reward processing, food intake, thermogenesis, and mood. Since the hypocretins/orexins were discovered more than two decades ago, extensive studies have accumulated concrete evidence showing the pivotal role of hypocretin/orexin in diverse neural modulation. New method of viral-mediated tracing system offers the possibility to map the monosynaptic inputs and detailed anatomical connectivity of Hcrt neurons. With the development of powerful research techniques including optogenetics, fiber-photometry, cell-type/pathway specific manipulation and neuronal activity monitoring, as well as single-cell RNA sequencing, the details of how hypocretinergic system execute functional modulation of various behaviors are coming to light. In this review, we focus on the function of neural pathways from hypocretin neurons to target brain regions. Anatomical and functional inputs to hypocretin neurons are also discussed. We further briefly summarize the development of pharmaceutical compounds targeting hypocretin signaling. This article is part of the special issue on Neuropeptides.
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Affiliation(s)
- Shi-Bin Li
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA, 94305, USA.
| | - Luis de Lecea
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, 1201 Welch Road, Stanford, CA, 94305, USA.
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24
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Calva CB, Fayyaz H, Fadel JR. Effects of Intranasal Orexin-A (Hypocretin-1) Administration on Neuronal Activation, Neurochemistry, and Attention in Aged Rats. Front Aging Neurosci 2020; 11:362. [PMID: 32038222 PMCID: PMC6987046 DOI: 10.3389/fnagi.2019.00362] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022] Open
Abstract
Cognitive function represents a key determinative factor for independent functioning among the elderly, especially among those with age-related cognitive disorders. However; existing pharmacotherapeutic tactics for treating these disorders provide only modest benefits on cognition. The hypothalamic orexin (hypocretin) system is uniquely positioned, anatomically and functionally, to integrate physiological functions that support proper cognition. The ongoing paucity of orexin receptor agonists has mired the ability to study their potential as cognitive enhancers. Fortunately, intranasal administration of native orexin peptides circumvents this issue and others concerning peptide transport into the central nervous system (CNS). To investigate the ability of intranasal orexin-A (OxA) administration to improve the anatomical, neurochemical, and behavioral substrates of age-related cognitive dysfunction, these studies utilized a rodent model of aging combined with acute intranasal administration of saline or OxA. Here, intranasal OxA increases c-Fos expression in several telencephalic brain regions that mediate important cognitive functions, increases prefrontal cortical acetylcholine efflux, and alters set-shifting-mediated attentional function in rats. Ultimately, these studies provide a framework for the possible mechanisms and therapeutic potential of intranasal OxA in treating age-related cognitive dysfunction.
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Affiliation(s)
- Coleman B Calva
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Habiba Fayyaz
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Jim R Fadel
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
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25
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Thorpy MJ, Bogan RK. Update on the pharmacologic management of narcolepsy: mechanisms of action and clinical implications. Sleep Med 2019; 68:97-109. [PMID: 32032921 DOI: 10.1016/j.sleep.2019.09.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 08/29/2019] [Accepted: 09/03/2019] [Indexed: 12/21/2022]
Abstract
Narcolepsy is a chronic, debilitating neurological disorder of sleep-wake state instability. This instability underlies all narcolepsy symptoms, including excessive daytime sleepiness (EDS), symptoms of rapid eye movement (REM) sleep dysregulation (ie, cataplexy, hypnagogic/hypnopompic hallucinations, sleep paralysis), and disrupted nighttime sleep. Several neurotransmitter systems promote wakefulness, and various neural pathways are involved in regulating REM sleep-related muscle atonia, providing multiple targets for pharmacologic intervention to reduce EDS and cataplexy. Medications approved by the US Food and Drug Administration (FDA) for the treatment of EDS in narcolepsy include traditional stimulants (eg, amphetamines, methylphenidate), wake-promoting agents (eg, modafinil, armodafinil), and solriamfetol, which mainly act on dopaminergic and noradrenergic pathways. Sodium oxybate (thought to act via GABAB receptors) is FDA-approved for the treatment of EDS and cataplexy. Pitolisant, a histamine 3 (H3)-receptor antagonist/inverse agonist, is approved by the European Medicines Agency (EMA) for the treatment of narcolepsy with or without cataplexy in adults and by the FDA for the treatment of EDS in adults with narcolepsy. Pitolisant increases the synthesis and release of histamine in the brain and modulates the release of other neurotransmitters (eg, norepinephrine, dopamine). Antidepressants that inhibit reuptake of serotonin and/or norepinephrine are widely used off label to manage cataplexy. In many patients with narcolepsy, combination treatment with medications that act via different neural pathways is necessary for optimal symptom management. Mechanism of action, pharmacokinetics, and abuse potential are important considerations in treatment selection and subsequent medication adjustments to maximize efficacy and mitigate adverse effects in the treatment of patients with narcolepsy.
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Affiliation(s)
- Michael J Thorpy
- Sleep-Wake Disorders Center, Montefiore Medical Center, Albert Einstein College of Medicine, 3411 Wayne Ave, Bronx, NY, 10467, USA.
| | - Richard K Bogan
- SleepMed Inc., Bogan Sleep Consultants, LLC, 1333 Taylor Street, Columbia, SC, USA.
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26
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Miguel SRPDS, Ligabue-Braun R. Hypothesis: Compulsive hoarding as an atavism. Med Hypotheses 2019; 130:109273. [PMID: 31383336 DOI: 10.1016/j.mehy.2019.109273] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 06/06/2019] [Accepted: 06/10/2019] [Indexed: 01/07/2023]
Abstract
In this hypothesis paper, we propose that hoarding disorder may be an ancestral mammalian behavior, possibly hard-wired but dormant in present-day humans, that can be activated by traumatic experiences. To support this claim, we describe hoarding in ancestral mammals and provide examples of recurrence of traits, or atavisms, in humans and other mammals, highlighting its implications for neuropsychiatric diseases. We highlight the potential of using shrews as animal models for hoarding behavior and, considering the current knowledge on the molecular underpinnings of the disorder, we also point to limitations of the proposed connection.
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Affiliation(s)
| | - Rodrigo Ligabue-Braun
- Graduate Program in Biological Sciences (PPGBio) and Department of Pharmaceutical Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, RS, Brazil.
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27
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Narcolepsy — clinical spectrum, aetiopathophysiology, diagnosis and treatment. Nat Rev Neurol 2019; 15:519-539. [DOI: 10.1038/s41582-019-0226-9] [Citation(s) in RCA: 204] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/04/2019] [Indexed: 12/15/2022]
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28
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Hypocretin and the Regulation of Sleep-Wake Transitions. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/b978-0-12-813743-7.00006-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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29
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Naganuma F, Bandaru SS, Absi G, Mahoney CE, Scammell TE, Vetrivelan R. Melanin-concentrating hormone neurons contribute to dysregulation of rapid eye movement sleep in narcolepsy. Neurobiol Dis 2018; 120:12-20. [PMID: 30149182 PMCID: PMC6195361 DOI: 10.1016/j.nbd.2018.08.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 08/02/2018] [Accepted: 08/23/2018] [Indexed: 12/22/2022] Open
Abstract
The lateral hypothalamus contains neurons producing orexins that promote wakefulness and suppress REM sleep as well as neurons producing melanin-concentrating hormone (MCH) that likely promote REM sleep. Narcolepsy with cataplexy is caused by selective loss of the orexin neurons, and the MCH neurons appear unaffected. As the orexin and MCH systems exert opposing effects on REM sleep, we hypothesized that imbalance in this REM sleep-regulating system due to activity in the MCH neurons may contribute to the striking REM sleep dysfunction characteristic of narcolepsy. To test this hypothesis, we chemogenetically activated the MCH neurons and pharmacologically blocked MCH signaling in a murine model of narcolepsy and studied the effects on sleep-wake behavior and cataplexy. To chemoactivate MCH neurons, we injected an adeno-associated viral vector containing the hM3Dq stimulatory DREADD into the lateral hypothalamus of orexin null mice that also express Cre recombinase in the MCH neurons (MCH-Cre::OX-KO mice) and into control MCH-Cre mice with normal orexin expression. In both lines of mice, activation of MCH neurons by clozapine-N-oxide (CNO) increased rapid eye movement (REM) sleep without altering other states. In mice lacking orexins, activation of the MCH neurons also increased abnormal intrusions of REM sleep manifest as cataplexy and short latency transitions into REM sleep (SLREM). Conversely, a MCH receptor 1 antagonist, SNAP 94847, almost completely eliminated SLREM and cataplexy in OX-KO mice. These findings affirm that MCH neurons promote REM sleep under normal circumstances, and their activity in mice lacking orexins likely triggers abnormal intrusions of REM sleep into non-REM sleep and wake, resulting in the SLREM and cataplexy characteristic of narcolepsy.
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Affiliation(s)
- Fumito Naganuma
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA; Division of Pharmacology, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, 1-15-1, Fukumuro, Miyagino-ku, Sendai 983-8536, Japan
| | - Sathyajit S Bandaru
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA
| | - Gianna Absi
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA
| | - Carrie E Mahoney
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA
| | - Ramalingam Vetrivelan
- Department of Neurology, Beth Israel Deaconess Medical Center and Division of Sleep Medicine, Harvard Medical School, Boston MA-02215, USA.
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Arrigoni E, Chee MJS, Fuller PM. To eat or to sleep: That is a lateral hypothalamic question. Neuropharmacology 2018; 154:34-49. [PMID: 30503993 DOI: 10.1016/j.neuropharm.2018.11.017] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/08/2018] [Accepted: 11/12/2018] [Indexed: 12/15/2022]
Abstract
The lateral hypothalamus (LH) is a functionally and anatomically complex brain region that is involved in the regulation of many behavioral and physiological processes including feeding, arousal, energy balance, stress, reward and motivated behaviors, pain perception, body temperature regulation, digestive functions and blood pressure. Despite noteworthy experimental efforts over the past decades, the circuit, cellular and synaptic bases by which these different processes are regulated by the LH remains incompletely understood. This knowledge gap links in large part to the high cellular heterogeneity of the LH. Fortunately, the rapid evolution of newer genetic and electrophysiological tools is now permitting the selective manipulation, typically genetically-driven, of discrete LH cell populations. This, in turn, permits not only assignment of function to discrete cell groups, but also reveals that considerable synergistic and antagonistic interactions exist between key LH cell populations that regulate feeding and arousal. For example, we now know that while LH melanin-concentrating hormone (MCH) and orexin/hypocretin neurons both function as sensors of the internal metabolic environment, their roles regulating sleep and arousal are actually opposing. Additional studies have uncovered similarly important roles for subpopulations of LH GABAergic cells in the regulation of both feeding and arousal. Herein we review the role of LH MCH, orexin/hypocretin and GABAergic cell populations in the regulation of energy homeostasis (including feeding) and sleep-wake and discuss how these three cell populations, and their subpopulations, may interact to optimize and coordinate metabolism, sleep and arousal. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.
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Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA.
| | - Melissa J S Chee
- Department of Neuroscience, Carleton University, Ottawa, ON, K1S 5B6, Canada
| | - Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA
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Lippert J, Young P, Gross C, Meuth SG, Dräger B, Schirmacher A, Heidbreder A. Specific T-cell activation in peripheral blood and cerebrospinal fluid in central disorders of hypersomnolence. Sleep 2018; 42:5185207. [DOI: 10.1093/sleep/zsy223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Julian Lippert
- Institute for Sleep Medicine and Neuromuscular Disorders, University of Muenster, Germany
- Department of Neurology, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - Peter Young
- Institute for Sleep Medicine and Neuromuscular Disorders, University of Muenster, Germany
| | - Catharina Gross
- Clinic of Neurology with Institute for Translational Neurology, University of Muenster, Germany
| | - Sven G Meuth
- Clinic of Neurology with Institute for Translational Neurology, University of Muenster, Germany
| | - Bianca Dräger
- Institute for Sleep Medicine and Neuromuscular Disorders, University of Muenster, Germany
| | - Anja Schirmacher
- Institute for Sleep Medicine and Neuromuscular Disorders, University of Muenster, Germany
| | - Anna Heidbreder
- Institute for Sleep Medicine and Neuromuscular Disorders, University of Muenster, Germany
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Nevárez N, de Lecea L. Recent advances in understanding the roles of hypocretin/orexin in arousal, affect, and motivation. F1000Res 2018; 7. [PMID: 30254737 PMCID: PMC6127742 DOI: 10.12688/f1000research.15097.1] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/24/2018] [Indexed: 12/11/2022] Open
Abstract
The hypocretins (Hcrts) are two alternatively spliced neuropeptides (Hcrt1/Ox-A and Hcrt2/Ox-B) that are synthesized exclusively in the hypothalamus. Data collected in the 20 years since their discovery have supported the view that the Hcrts play a broad role in the control of arousal with a particularly important role in the maintenance of wakefulness and sleep-to-wake transitions. While this latter point has received an overwhelming amount of research attention, a growing literature has begun to broaden our understanding of the many diverse roles that the Hcrts play in physiology and behavior. Here, we review recent advances in the neurobiology of Hcrt in three sections. We begin by surveying findings on Hcrt function within normal sleep/wake states as well as situations of aberrant sleep (that is, narcolepsy). In the second section, we discuss research establishing a role for Hcrt in mood and affect (that is, anxiety, stress, and motivation). Finally, in the third section, we briefly discuss future directions for the field and place an emphasis on analytical modeling of Hcrt neural activity. We hope that the data discussed here provide a broad overview of recent progress in the field and make clear the diversity of roles played by these neuromodulators.
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Affiliation(s)
- Natalie Nevárez
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, California, USA
| | - Luis de Lecea
- Department of Psychiatry & Behavioral Sciences, Stanford University, Stanford, California, USA
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Abstract
PURPOSE OF REVIEW This article focuses on the clinical presentation, pathophysiology, diagnosis, differential diagnosis, and management of narcolepsy type 1 and narcolepsy type 2, idiopathic hypersomnia, Kleine-Levin syndrome, and other central disorders of hypersomnolence, as defined in the International Classification of Sleep Disorders, Third Edition (ICSD-3). RECENT FINDINGS In ICSD-3, the names of some central disorders of hypersomnolence have been changed: narcolepsy with cataplexy and narcolepsy without cataplexy have been renamed narcolepsy type 1 and narcolepsy type 2, respectively. A low level of hypocretin-1/orexin-A in the CSF is now theoretically sufficient to diagnose narcolepsy type 1, as it is a highly specific and sensitive biomarker. Conversely, other central hypersomnias are less well-defined disorders with variability in the phenotype, and few reliable biomarkers have been discovered so far. The epidemiologic observation that influenza A (H1N1) infection and vaccination are potential triggering factors of narcolepsy type 1 (discovered during the 2009 H1N1 pandemic) has increased interest in this rare disease, and progress is being made to better understand the process (highly suspected to be autoimmune) responsible for the destruction of hypocretin neurons. Treatment of narcolepsy remains largely symptomatic, usually initially with modafinil or armodafinil or with higher-potency stimulants such as methylphenidate or amphetamines. Several newer wake-promoting agents and psychostimulants have also been developed, including sodium oxybate, which has a role in the treatment of cataplexy and as an adjunctive wake-promoting agent, and pitolisant, a selective histamine H3 receptor inverse agonist that is currently only available in Europe. SUMMARY Although far less common than many other sleep disorders, central hypersomnias are among the most severe and disabling diseases in the field of sleep medicine, and their early recognition is of major importance for patients, especially children, to maximize their quality of life and functioning in activities of daily living.
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Internet of Things for Sensing: A Case Study in the Healthcare System. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8040508] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Elliott JE, De Luche SE, Churchill MJ, Moore C, Cohen AS, Meshul CK, Lim MM. Dietary therapy restores glutamatergic input to orexin/hypocretin neurons after traumatic brain injury in mice. Sleep 2018; 41:4791165. [PMID: 29315422 PMCID: PMC6454530 DOI: 10.1093/sleep/zsx212] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 10/27/2017] [Indexed: 02/06/2023] Open
Abstract
Study Objectives In previous work, dietary branched-chain amino acid (BCAA) supplementation, precursors to de novo glutamate and γ-aminobutyric acid (GABA) synthesis, restored impaired sleep-wake regulation and orexin neuronal activity following traumatic brain injury (TBI) in mice. TBI was speculated to reduce orexin neuronal activity through decreased regional excitatory (glutamate) and/or increased inhibitory (GABA) input. Therefore, we hypothesized that TBI would decrease synaptic glutamate and/or increase synaptic GABA in nerve terminals contacting orexin neurons, and BCAA supplementation would restore TBI-induced changes in synaptic glutamate and/or GABA. Methods Brain tissue was processed for orexin pre-embed diaminobenzidine labeling and glutamate or GABA postembed immunogold labeling. The density of glutamate and GABA immunogold within presynaptic nerve terminals contacting orexin-positive lateral hypothalamic neurons was quantified using electron microscopy in three groups of mice (n = 8 per group): Sham/noninjured controls, TBI without BCAA supplementation, and TBI with BCAA supplementation (given for 5 days, 48 hr post-TBI). Glutamate and GABA were also quantified within the cortical penumbral region (layer VIb) adjacent to the TBI lesion. Results In the hypothalamus and cortex, TBI decreased relative glutamate density in presynaptic terminals making axodendritic contacts. However, BCAA supplementation only restored relative glutamate density within presynaptic terminals contacting orexin-positive hypothalamic neurons. BCAA supplementation did not change relative glutamate density in presynaptic terminals making axosomatic contacts, or relative GABA density in presynaptic terminals making axosomatic or axodendritic contacts, within either the hypothalamus or cortex. Conclusions These results suggest TBI compromises orexin neuron function via decreased glutamate density and highlight BCAA supplementation as a potential therapy to restore glutamate density to orexin neurons.
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Affiliation(s)
- Jonathan E Elliott
- VA Portland Health Care System, Portland, OR
- Department of Neurology, Oregon Health and Science University, Portland, OR
| | | | | | - Cindy Moore
- VA Portland Health Care System, Portland, OR
| | - Akiva S Cohen
- Department of Anesthesiology and Critical Care Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
- Department of Anesthesiology, Joseph Stokes Research Institute, Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Charles K Meshul
- VA Portland Health Care System, Portland, OR
- Department of Behavioral Neuroscience and Pathology, Oregon Health and Science University, Portland, OR
| | - Miranda M Lim
- VA Portland Health Care System, Portland, OR
- Department of Neurology, Oregon Health and Science University, Portland, OR
- Department of Medicine and Behavioral Neuroscience, Oregon Institute of Occupational Health Sciences, Oregon Health and Science University, Portland, OR
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Trace Amine-Associated Receptor 1 Agonists as Narcolepsy Therapeutics. Biol Psychiatry 2017; 82:623-633. [PMID: 27919403 PMCID: PMC5395352 DOI: 10.1016/j.biopsych.2016.10.012] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 09/23/2016] [Accepted: 10/12/2016] [Indexed: 02/01/2023]
Abstract
BACKGROUND Narcolepsy, a disorder of rapid eye movement (REM) sleep, is characterized by excessive daytime sleepiness and cataplexy, a loss of muscle tone triggered by emotional stimulation. Current narcolepsy pharmacotherapeutics include controlled substances with abuse potential or drugs with undesirable side effects. As partial agonists at trace amine-associated receptor 1 (TAAR1) promote wakefulness in mice and rats, we evaluated whether TAAR1 agonism had beneficial effects in two mouse models of narcolepsy. METHODS In the first experiment, male homozygous B6-Taar1tm1(NLSLacZ)Blt (Taar1 knockout) and wild-type mice were surgically implanted to record electroencephalogram, electromyogram, locomotor activity, and body temperature, and the efficacy of the TAAR1 agonist, RO5256390, on sleep/wake and physiological parameters was determined. In the second experiment, the effects of the TAAR1 full agonist RO5256390 and partial agonist RO5263397 on sleep/wake, locomotor activity, body temperature, and cataplexy were assessed in two mouse narcolepsy models. RESULTS RO5256390 profoundly reduced rapid eye movement sleep in wild-type mice; these effects were eliminated in Taar1 knockout mice. The TAAR1 partial agonist RO5263397 also promoted wakefulness and suppressed nonrapid eye movement sleep. Both compounds reduced body temperature in the two narcolepsy models at the highest doses tested. Both TAAR1 compounds also mitigated cataplexy, the pathognomonic symptom of this disorder, in the narcolepsy models. The therapeutic benefit was mediated through a reduction in number of cataplexy episodes and time spent in cataplexy. CONCLUSIONS These results suggest TAAR1 agonism as a new therapeutic pathway for treatment of this orphan disease. The common underlying mechanism may be the suppression of rapid eye movement sleep.
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Lai JB, Han MM, Xu Y, Hu SH. Effective treatment of narcolepsy-like symptoms with high-frequency repetitive transcranial magnetic stimulation: A case report. Medicine (Baltimore) 2017; 96:e8645. [PMID: 29145290 PMCID: PMC5704835 DOI: 10.1097/md.0000000000008645] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
RATIONALE Narcolepsy is a rare sleep disorder with disrupted sleep-architecture. Clinical management of narcolepsy lies dominantly on symptom-driven pharmacotherapy. The treatment role of repetitive transcranial magnetic stimulation (rTMS) for narcolepsy remains unexplored. PATIENT CONCERNS In this paper, we present a case of a 14-year-old young girl with excessive daytime sleepiness (EDS), cataplexy and hypnagogic hallucinations. DIAGNOSES After excluding other possible medical conditions, this patient was primarily diagnosed with narcolepsy. INTERVENTIONS The patient received 25 sessions of high-frequency rTMS over the left dorsolateral prefrontal cortex (DLPFC). OUTCOMES The symptoms of EDS and cataplexy significantly improved after rTMS treatment. Meanwhile, her score in the Epworth sleep scale (ESS) also remarkably decreased. LESSONS This case indicates that rTMS may be selected as a safe and effective alternative strategy for treating narcolepsy-like symptoms. Well-designed researches are warranted in future investigations on this topic.
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Affiliation(s)
- Jian-bo Lai
- Department of Psychiatry, First Affiliated Hospital, Zhejiang University School of Medicine
- The Key Laboratory of Mental Disorder's Management in Zhejiang Province
| | - Mao-mao Han
- Department of VIP, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Xu
- Department of Psychiatry, First Affiliated Hospital, Zhejiang University School of Medicine
- The Key Laboratory of Mental Disorder's Management in Zhejiang Province
| | - Shao-hua Hu
- Department of Psychiatry, First Affiliated Hospital, Zhejiang University School of Medicine
- The Key Laboratory of Mental Disorder's Management in Zhejiang Province
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Baimel C, Borgland SL. Hypocretin/Orexin and Plastic Adaptations Associated with Drug Abuse. Curr Top Behav Neurosci 2017; 33:283-304. [PMID: 28303403 DOI: 10.1007/7854_2016_44] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dopamine neurons in the ventral tegmental area (VTA) are a critical part of the neural circuits that underlie reward learning and motivation. Dopamine neurons send dense projections throughout the brain and recent observations suggest that both the intrinsic properties and the functional output of dopamine neurons are dependent on projection target and are subject to neuromodulatory influences. Lateral hypothalamic hypocretin (also termed orexin) neurons project to the VTA and contain both hypocretin and dynorphin peptides in the same dense core vesicles suggesting they may be co-released. Hypocretin peptides act at excitatory Gαq protein-coupled receptors and dynorphin acts at inhibitory Gαi/o protein-coupled receptors, which are both expressed on subpopulations of dopamine neurons. This review describes a role for neuromodulation of dopamine neurons and the influence on motivated behaviour in response to natural and drug rewards.
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Affiliation(s)
- Corey Baimel
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2176 Health Sciences Mall, Vancouver, BC, Canada, V6T 1Z3
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada, T2N 4N1
| | - Stephanie L Borgland
- Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Dr. NW, Calgary, AB, Canada, T2N 4N1.
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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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Cardiovascular fitness in narcolepsy is inversely related to sleepiness and the number of cataplexy episodes. Sleep Med 2017; 34:7-12. [DOI: 10.1016/j.sleep.2017.02.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 11/17/2016] [Accepted: 02/16/2017] [Indexed: 12/11/2022]
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Pintwala S, Peever J. Circuit mechanisms of sleepiness and cataplexy in narcolepsy. Curr Opin Neurobiol 2017; 44:50-58. [DOI: 10.1016/j.conb.2017.02.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/07/2017] [Indexed: 12/23/2022]
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Pillen S, Pizza F, Dhondt K, Scammell TE, Overeem S. Cataplexy and Its Mimics: Clinical Recognition and Management. Curr Treat Options Neurol 2017; 19:23. [PMID: 28478511 DOI: 10.1007/s11940-017-0459-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OPINION STATEMENT This review describes the diagnosis and management of cataplexy: attacks of bilateral loss of muscle tone, triggered by emotions and with preserved consciousness. Although cataplexy is rare, its recognition is important as in most cases, it leads to a diagnosis of narcolepsy, a disorder that still takes a median of 9 years to be diagnosed. The expression of cataplexy varies widely, from partial episodes affecting only the neck muscles to generalized attacks leading to falls. Moreover, childhood cataplexy differs from the presentation in adults, with a prominent facial involvement, already evident without clear emotional triggers ('cataplectic facies') and 'active' motor phenomena especially of the tongue and perioral muscles. Next to narcolepsy, cataplexy can sometimes be caused by other diseases, such as Niemann-Pick type C, Prader Willi Syndrome, or lesions in the hypothalamic or pontomedullary region. Cataplexy mimics include syncope, epilepsy, hyperekplexia, drop attacks and pseudocataplexy. They can be differentiated from cataplexy using thorough history taking, supplemented with (home)video recordings whenever possible. Childhood narcolepsy, with its profound facial hypotonia, can be confused with neuromuscular disorders, and the active motor phenomenona resemble those found in childhood movement disorders such as Sydenham's chorea. Currently, the diagnosis of cataplexy is made almost solely on clinical grounds, based on history taking and (home) videos. Cataplexy shows remarkable differences in childhood compared to adults, with profound facial hypotonia and complex active motor phenomena. Over time, these severe symptoms evolve to the milder adult phenotype, and this pattern is crucial to recognize when assessing the outcome of uncontrolled case series with potential treatments such as immunomodulation. Symptomatic treatment is possible with antidepressants and sodium oxybate. Importantly, management also needs to involve sleep hygiene advice, safety measures whenever applicable and guidance with regard to the social sequelae of cataplexy.
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Affiliation(s)
- Sigrid Pillen
- Sleep Medicine Center Kempenhaeghe, P.O. Box 61, , 5590 AB, Heeze, The Netherlands.
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences (DIBINEM), University of Bologna, Bologna, Italy.,IRCCS Institute of the Neurological SciencesAUSL di Bologna, Bologna, Italy
| | - Karlien Dhondt
- Department Pediatrics, Division of Child Neurology & Metabolism, Pediatric Sleep Center, Ghent University Hospital, Ghent, Belgium
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston Children's Hospital, Boston, MA, USA
| | - Sebastiaan Overeem
- Sleep Medicine Center Kempenhaeghe, P.O. Box 61, , 5590 AB, Heeze, The Netherlands.,Eindhoven University of Technology, Eindhoven, The Netherlands
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Cairns A, Bogan R. Underutilization of the MSLT in sleepy patients with a short onset REM period (SOREMP) in the sleep clinic. Sleep Med 2017; 32:150-156. [PMID: 28366327 DOI: 10.1016/j.sleep.2016.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/01/2016] [Accepted: 11/08/2016] [Indexed: 12/30/2022]
Abstract
OBJECTIVE/BACKGROUND A nocturnal sleep onset REM period (defined as REM onset latency ≤ 15 min; SOREMP) occurs rarely and research has shown that the phenomenon is specific for type 1 and 2 narcolepsy. However, little is known about the meaningfulness of the phenotype in general sleep clinic patients because those that exhibit the phenomenon often present with few traditional narcolepsy symptoms. As such, this study aimed to (1) evaluate the rate of eventual MSLT testing for those with a SOREMP on routine PSG when the phenomenon occurred in the absence of potential explanatory factors and (2) quantify the stability of the SOREMP phenotype. PATIENTS/METHODS This was a retrospective analysis of a large repository of de-identified PSG and MSLT test results from 2008 to 2015. Patient records were retrieved from a repository of studies completed at a variety of sleep laboratories across the USA. A total of 118,046 baseline polysomnograms were evaluated for a PSG SOREMP (occurred in 0.7% of the sample). Patients were excluded if they indicated working either shift or night work at the time of the SOREMP or if their self-reported habitual weekday time in bed was less than 7 h. A final sample of 391 cases with a SOREMP were sequestered and previous or consecutive studies were searched for each individual. RESULTS The vast majority of patients (n = 347/391; 89%) with a PSG SOREMP never received MSLT testing. Patients that were evaluated by MSLT (n = 44; 11%) were typically very sleepy and 82% ended up with a diagnosis of narcolepsy or had MSLTs consistent with current narcolepsy criteria (ie, including the nocturnal SOREMP). Only seven of the 140 patients (n = 5%) that with OSA that first underwent one or more PAP titrations were subsequently seen for an MSLT. Compared to those that eventually received an MSLT, patients that did not receive MSLT testing were older (52 vs. 41 years, p < 0.001), more likely to have moderate to severe OSA (AHI ≥ 15; 39% vs. 16%, p < 0.001), and were generally less likely to report severe sleepiness (ESS ≥ 16; 25% vs. 55%, p < 0.001) and vehicle or workplace accidents or injuries. However, 12% of those that never received an MSLT reported such extreme sleepiness that they endorsed a near-miss car accident due to sleepiness, almost twice as prevalent than that found in a random sample of matched moderate-to-severe OSA patients (p < 0.01). Overall, the reliability of the SOREMP phenotype was low at 9.8%, but was much higher for those diagnosed with type 2 narcolepsy (31%) compared to those without narcolepsy (IH or normal MSLTs; 0%; p < 0.01) or where narcolepsy status was unknown because an MSLT was not conducted (7%; p < 0.01). CONCLUSIONS The MSLT has been historically underutilized for those exhibiting a SOREMP on diagnostic PSG, a potential marker of narcolepsy. This is presumably because patients with a PSG SOREMP reported variable levels of sleepiness (although some severe) and many had some degree of OSA, which may either be a partial factor in symptomology or even obscure true narcolepsy. Some patients with a PSG SOREMP were very sleepy and most, when an MSLT was conducted, received a diagnosis of type 2 narcolepsy despite few presenting with some of the associated features of narcolepsy. Well-controlled longitudinal studies with high quality data on cataplexy and hypocretin status are needed to understand where the PSG SOREMP phenomenon falls on the hypersomnolence spectrum and to establish which comorbidities share variance with and/or potentially mask narcolepsy. However because untreated narcolepsy can have high social, functional, and financial burden, until such studies are done, physicians should consider a narcolepsy workup when a SOREMP is observed (especially if multiple are seen) as well as close follow-up for symptom resolution when, for example, a patient is treated for sleep apnea.
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Affiliation(s)
| | - Richard Bogan
- SleepMed, Inc., Columbia, SC, United States; The University of South Carolina Medical School, Columbia, SC, United States; The Medical University of South Carolina, Charleston, SC, United States
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GABAergic Neurons of the Central Amygdala Promote Cataplexy. J Neurosci 2017; 37:3995-4006. [PMID: 28235898 DOI: 10.1523/jneurosci.4065-15.2017] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 02/03/2017] [Accepted: 02/07/2017] [Indexed: 11/21/2022] Open
Abstract
Narcolepsy is characterized by chronic sleepiness and cataplexy-sudden muscle paralysis triggered by strong, positive emotions. This condition is caused by a lack of orexin (hypocretin) signaling, but little is known about the neural mechanisms that mediate cataplexy. The amygdala regulates responses to rewarding stimuli and contains neurons active during cataplexy. In addition, lesions of the amygdala reduce cataplexy. Because GABAergic neurons of the central nucleus of the amygdala (CeA) target brainstem regions known to regulate muscle tone, we hypothesized that these cells promote emotion-triggered cataplexy. We injected adeno-associated viral vectors coding for Cre-dependent DREADDs or a control vector into the CeA of orexin knock-out mice crossed with vGAT-Cre mice, resulting in selective expression of the excitatory hM3 receptor or the inhibitory hM4 receptor in GABAergic neurons of the CeA. We measured sleep/wake behavior and cataplexy after injection of saline or the hM3/hM4 ligand clozapine-N-oxide (CNO) under baseline conditions and under conditions that should elicit positive emotions. In mice expressing hM3, CNO approximately doubled the amount of cataplexy in the first 3 h after dosing under baseline conditions. Rewarding stimuli (chocolate or running wheels) also increased cataplexy, but CNO produced no further increase. In mice expressing hM4, CNO reduced cataplexy in the presence of chocolate or running wheels. These results demonstrate that GABAergic neurons of the CeA are sufficient and necessary for the production of cataplexy in mice, and they likely are a key part of the mechanism through which positive emotions trigger cataplexy.SIGNIFICANCE STATEMENT Cataplexy is one of the major symptoms of narcolepsy, but little is known about how strong, positive emotions trigger these episodes of muscle paralysis. Prior research shows that amygdala neurons are active during cataplexy and cataplexy is reduced by lesions of the amygdala. We found that cataplexy is substantially increased by selective activation of GABAergic neurons in the central nucleus of the amygdala (CeA). We also demonstrate that inhibition of these neurons reduces reward-promoted cataplexy. These results build upon prior work to establish the CeA as a crucial element in the neural mechanisms of cataplexy. These results demonstrate the importance of the CeA in regulating responses to rewarding stimuli, shedding light on the broader neurobiology of emotions and motor control.
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Bonnavion P, Mickelsen LE, Fujita A, de Lecea L, Jackson AC. Hubs and spokes of the lateral hypothalamus: cell types, circuits and behaviour. J Physiol 2016; 594:6443-6462. [PMID: 27302606 DOI: 10.1113/jp271946] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 05/31/2016] [Indexed: 12/13/2022] Open
Abstract
The hypothalamus is among the most phylogenetically conserved regions in the vertebrate brain, reflecting its critical role in maintaining physiological and behavioural homeostasis. By integrating signals arising from both the brain and periphery, it governs a litany of behaviourally important functions essential for survival. In particular, the lateral hypothalamic area (LHA) is central to the orchestration of sleep-wake states, feeding, energy balance and motivated behaviour. Underlying these diverse functions is a heterogeneous assembly of cell populations typically defined by neurochemical markers, such as the well-described neuropeptides hypocretin/orexin and melanin-concentrating hormone. However, anatomical and functional evidence suggests a rich diversity of other cell populations with complex neurochemical profiles that include neuropeptides, receptors and components of fast neurotransmission. Collectively, the LHA acts as a hub for the integration of diverse central and peripheral signals and, through complex local and long-range output circuits, coordinates adaptive behavioural responses to the environment. Despite tremendous progress in our understanding of the LHA, defining the identity of functionally discrete LHA cell types, and their roles in driving complex behaviour, remain significant challenges in the field. In this review, we discuss advances in our understanding of the neurochemical and cellular heterogeneity of LHA neurons and the recent application of powerful new techniques, such as opto- and chemogenetics, in defining the role of LHA circuits in feeding, reward, arousal and stress. From pioneering work to recent developments, we review how the interrogation of LHA cells and circuits is contributing to a mechanistic understanding of how the LHA coordinates complex behaviour.
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Affiliation(s)
- Patricia Bonnavion
- Laboratory of Neurophysiology, Université Libre de Bruxelles (ULB)-UNI, 1050, Brussels, Belgium
| | - Laura E Mickelsen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Akie Fujita
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
| | - Luis de Lecea
- Department of Psychiatry and Behavioural Sciences, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, 06269, USA
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Arrigoni E, Chen MC, Fuller PM. The anatomical, cellular and synaptic basis of motor atonia during rapid eye movement sleep. J Physiol 2016; 594:5391-414. [PMID: 27060683 DOI: 10.1113/jp271324] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 03/02/2016] [Indexed: 01/14/2023] Open
Abstract
Rapid eye movement (REM) sleep is a recurring part of the sleep-wake cycle characterized by fast, desynchronized rhythms in the electroencephalogram (EEG), hippocampal theta activity, rapid eye movements, autonomic activation and loss of postural muscle tone (atonia). The brain circuitry governing REM sleep is located in the pontine and medullary brainstem and includes ascending and descending projections that regulate the EEG and motor components of REM sleep. The descending signal for postural muscle atonia during REM sleep is thought to originate from glutamatergic neurons of the sublaterodorsal nucleus (SLD), which in turn activate glycinergic pre-motor neurons in the spinal cord and/or ventromedial medulla to inhibit motor neurons. Despite work over the past two decades on many neurotransmitter systems that regulate the SLD, gaps remain in our knowledge of the synaptic basis by which SLD REM neurons are regulated and in turn produce REM sleep atonia. Elucidating the anatomical, cellular and synaptic basis of REM sleep atonia control is a critical step for treating many sleep-related disorders including obstructive sleep apnoea (apnea), REM sleep behaviour disorder (RBD) and narcolepsy with cataplexy.
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Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA.
| | - Michael C Chen
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA
| | - Patrick M Fuller
- Department of Neurology, Beth Israel Deaconess Medical Center, Division of Sleep Medicine, Harvard Medical School, Boston, MA, 02215, USA.
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Branch AF, Navidi W, Tabuchi S, Terao A, Yamanaka A, Scammell TE, Diniz Behn C. Progressive Loss of the Orexin Neurons Reveals Dual Effects on Wakefulness. Sleep 2016; 39:369-77. [PMID: 26446125 DOI: 10.5665/sleep.5446] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 09/05/2015] [Indexed: 01/12/2023] Open
Abstract
STUDY OBJECTIVES Narcolepsy is caused by loss of the orexin (also known as hypocretin) neurons. In addition to the orexin peptides, these neurons release additional neurotransmitters, which may produce complex effects on sleep/wake behavior. Currently, it remains unknown whether the orexin neurons promote the initiation as well as the maintenance of wakefulness, and whether the orexin neurons influence initiation or maintenance of sleep. To determine the effects of the orexin neurons on the dynamics of sleep/wake behavior, we analyzed sleep/wake architecture in a novel mouse model of acute orexin neuron loss. METHODS We used survival analysis and other statistical methods to analyze sleep/wake architecture in orexin-tTA ; TetO diphtheria toxin A mice at different stages of orexin neuron degeneration. RESULTS Progressive loss of the orexin neurons dramatically reduced survival of long wake bouts, but it also improved survival of brief wake bouts. In addition, with loss of the orexin neurons, mice were more likely to wake during the first 30 sec of nonrapid eye movement sleep and then less likely to return to sleep during the first 60 sec of wakefulness. CONCLUSIONS These findings help explain the sleepiness and fragmented sleep that are characteristic of narcolepsy. Orexin neuron loss impairs survival of long wake bouts resulting in poor maintenance of wakefulness, but this neuronal loss also fragments sleep by increasing the risk of awakening at the beginning of sleep and then reducing the likelihood of quickly returning to sleep.
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Affiliation(s)
- Abigail F Branch
- Department of Applied Mathematics & Statistics, Colorado School of Mines, Golden, CO
| | - William Navidi
- Department of Applied Mathematics & Statistics, Colorado School of Mines, Golden, CO
| | - Sawako Tabuchi
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Akira Terao
- Department of Biology, Tokai University, Sapporo, Japan
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA
| | - Cecilia Diniz Behn
- Department of Applied Mathematics & Statistics, Colorado School of Mines, Golden, CO.,Division of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO
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Kazaglis L, Molero H, Azeem MW, Khawaja IS. Overview and Management of Common Sleep Disorders in Children: A Review for Psychiatrists. Psychiatr Ann 2016. [DOI: 10.3928/00485713-20151209-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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