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Thorpy MJ, Siegel JM, Dauvilliers Y. REM sleep in narcolepsy. Sleep Med Rev 2024; 77:101976. [PMID: 39186901 DOI: 10.1016/j.smrv.2024.101976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 06/28/2024] [Accepted: 07/09/2024] [Indexed: 08/28/2024]
Abstract
Narcolepsy is mainly associated with excessive daytime sleepiness, but the characteristic feature is abnormal rapid eye movement (REM) sleep phenomena. REM sleep disturbances can manifest as cataplexy (in narcolepsy type 1), sleep paralysis, sleep-related hallucinations, REM sleep behavior disorder, abnormal dreams, polysomnographic evidence of REM sleep disruption with sleep-onset REM periods, and fragmented REM sleep. Characterization of REM sleep and related symptoms facilitates the differentiation of narcolepsy from other central hypersomnolence disorders and aids in distinguishing between narcolepsy types 1 and 2. A circuit comprising regions within the brainstem, forebrain, and hypothalamus is involved in generating and regulating REM sleep, which is influenced by changes in monoamines, acetylcholine, and neuropeptides. REM sleep is associated with brainstem functions, including autonomic control, and REM sleep disturbances may be associated with increased cardiovascular risk. Medications used to treat narcolepsy (and REM-related symptoms of narcolepsy) include stimulants/wake-promoting agents, pitolisant, oxybates, and antidepressants; hypocretin agonists are a potential new class of therapeutics. The role of REM sleep disturbances in narcolepsy remains an area of active research in pathophysiology, symptom management, and treatment. This review summarizes the current understanding of the role of REM sleep and its dysfunction in narcolepsy.
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Affiliation(s)
| | - Jerome M Siegel
- Department of Psychiatry and Brain Research Institute, University of California, Los Angeles, CA, USA; Department of Veterans Affairs, Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Yves Dauvilliers
- Sleep and Wake Disorders Centre, Department of Neurology, Gui de Chauliac Hospital, University Montpellier, INSERM INM, France
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Cohen JS, Radhakrishnan H, Olm CA, Das SR, Cook PA, Wolk DA, Weintraub D, Irwin DJ, McMillan CT. Microstructural changes in the inferior tuberal hypothalamus correlate with daytime sleepiness in Lewy body disease. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.08.16.24312102. [PMID: 39185524 PMCID: PMC11343243 DOI: 10.1101/2024.08.16.24312102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Background Excessive daytime sleepiness (EDS) is a disabling symptom of Lewy body disorders (LBD). The hypothalamus is a key sleep-wake regulator, but its contribution to EDS in LBD remains unclear. Objectives Use diffusion MRI to evaluate the relationship of hypothalamic microstructure to EDS symptoms in LBD. Methods We studied 102 patients with clinically-defined LBD (Parkinson's disease, n=93; Parkinson's disease dementia, n=4; and dementia with Lewy bodies, n=5) and Epworth Sleepiness Scale (ESS) within 2 years of MRI. Mean diffusivity (MD) was compared between EDS+ (ESS≥10, n=37) and EDS- (ESS<10, n=65) groups in the whole hypothalamus and three subregions, covarying for age and sex. Secondary analyses tested correlations between subregion MD and continuous ESS, global cognition, and motor scores; and between subregion volume and continuous ESS. Results MD was increased in EDS+ compared to EDS- only in the inferior tuberal subregion (Cohen's d=0.43, p=0.043, β=0.117±0.057), with trend level differences in the whole hypothalamus (Cohen's d=0.39, p=0.064, β=0.070±0.037) and superior tuberal subregion (Cohen's d=0.38, p=0.073, β=0.063±0.035). No difference was seen in the posterior subregion (Cohen's d=0.1, p=0.628, β=0.019±0.038). Significant correlations with continuous ESS were seen in MD of whole hypothalamus (r2=0.074, p=0.0057), superior tuberal (r2=0.081, p=0.0038), and inferior tuberal (r2=0.073, p=0.0059) subregions. There was no correlation of hypothalamic MD with global cognition or motor scores, and no correlation of whole/subregional hypothalamic volumes with ESS. Conclusions Daytime sleepiness associates with increased MD in the inferior tuberal hypothalamus in an LBD cohort. This suggests degeneration within this region could contribute to EDS symptoms.
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Vringer M, Zhou J, Gool JK, Bijlenga D, Lammers GJ, Fronczek R, Schinkelshoek MS. Recent insights into the pathophysiology of narcolepsy type 1. Sleep Med Rev 2024; 78:101993. [PMID: 39241492 DOI: 10.1016/j.smrv.2024.101993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 09/09/2024]
Abstract
Narcolepsy type 1 (NT1) is a sleep-wake disorder in which people typically experience excessive daytime sleepiness, cataplexy and other sleep-wake disturbances impairing daily life activities. NT1 symptoms are due to hypocretin deficiency. The cause for the observed hypocretin deficiency remains unclear, even though the most likely hypothesis is that this is due to an auto-immune process. The search for autoantibodies and autoreactive T-cells has not yet produced conclusive evidence for or against the auto-immune hypothesis. Other mechanisms, such as reduced corticotrophin-releasing hormone production in the paraventricular nucleus have recently been suggested. There is no reversive treatment, and the therapeutic approach is symptomatic. Early diagnosis and appropriate NT1 treatment is essential, especially in children to prevent impaired cognitive, emotional and social development. Hypocretin receptor agonists have been designed to replace the attenuated hypocretin signalling. Pre-clinical and clinical trials have shown encouraging initial results. A better understanding of NT1 pathophysiology may contribute to faster diagnosis or treatments, which may cure or prevent it.
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Affiliation(s)
- Marieke Vringer
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jingru Zhou
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Jari K Gool
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands; Department of Anatomy & Neurosciences, Amsterdam UMC location Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Compulsivity, Impulsivity and Attention, Amsterdam Neuroscience, Amsterdam, the Netherlands
| | - Denise Bijlenga
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Gert Jan Lammers
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Rolf Fronczek
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Mink S Schinkelshoek
- Stichting Epilepsie Instellingen Nederland (SEIN), Sleep-Wake center, Heemstede, the Netherlands; Department of Neurology, Leiden University Medical Centre, Leiden, the Netherlands.
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Juvodden HT, Alnæs D, Agartz I, Andreassen OA, Server A, Thorsby PM, Westlye LT, Knudsen-Heier S. Cortical thickness and sub-cortical volumes in post-H1N1 narcolepsy type 1: A brain-wide MRI case-control study. Sleep Med 2024; 116:81-89. [PMID: 38432031 DOI: 10.1016/j.sleep.2024.02.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/16/2024] [Accepted: 02/16/2024] [Indexed: 03/05/2024]
Abstract
OBJECTIVE There was more than a 10-fold increase in the incidence of narcolepsy type 1 (NT1) after the H1N1 mass vaccination in 2009/2010 in several countries. NT1 is associated with loss and increase of cell groups in the hypothalamus which may be associated with secondary affected sub-cortical and cortical gray matter. We performed a case-control comparison of MRI-based global and sub-cortical volume and cortical thickness in post-H1N1 NT1 patients compared with controls. METHODS We included 54 post-H1N1 NT1 patients (51 with confirmed hypocretin-deficiency; 48 H1N1-vaccinated with Pandemrix®; 39 females, mean age 21.8 ± 11.0 years) and 114 healthy controls (77 females, mean age 23.2 ± 9.0 years). 3T MRI brain scans were obtained, and the T1-weighted MRI data were processed using FreeSurfer. Group differences among three global, 10 sub-cortical volume measures and 34 cortical thickness measures for bilateral brain regions were tested using general linear models with permutation testing. RESULTS Patients had significantly thinner brain cortex bilaterally in the temporal poles (Cohen's d = 0.68, p = 0.00080), entorhinal cortex (d = 0.60, p = 0.0018) and superior temporal gyrus (d = 0.60, p = 0.0020) compared to healthy controls. The analysis revealed no significant group differences for sub-cortical volumes. CONCLUSIONS Post-H1N1(largely Pandemrix®-vaccinated) NT1 patients have significantly thinner cortex in temporal brain regions compared to controls. We speculate that this effect can be partly attributed to the hypothalamic neuronal change in NT1, including loss of function of the widely projecting hypocretin-producing neurons and secondary effects of the abnormal sleep-wake pattern in NT1 or could be specific for post-H1N1 (largely Pandemrix®-vaccinated) NT1 patients.
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Affiliation(s)
- Hilde T Juvodden
- Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias (NevSom), Department of Rare Disorders, Oslo University Hospital, Ullevål, Norway.
| | - Dag Alnæs
- NORMENT Centre, Division of Mental Health and Addiction, University of Oslo and Oslo University Hospital, Norway
| | - Ingrid Agartz
- Norwegian Centre for Mental Disorders Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway; Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway; K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Norway
| | - Ole A Andreassen
- NORMENT Centre, Division of Mental Health and Addiction, University of Oslo and Oslo University Hospital, Norway; K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Norway
| | - Andres Server
- Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Per M Thorsby
- Hormone Laboratory, Department of Medical Biochemistry, Biochemical Endocrinology and Metabolism Research Group, Oslo University Hospital, Aker, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lars T Westlye
- NORMENT Centre, Division of Mental Health and Addiction, University of Oslo and Oslo University Hospital, Norway; K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Norway; Department of Psychology, University of Oslo, Norway
| | - Stine Knudsen-Heier
- Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias (NevSom), Department of Rare Disorders, Oslo University Hospital, Ullevål, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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Wenhong C, Xiaoying M, Lingli S, Binyun T, Yining W, Mingming Z, Yian L, Lixia Q, Wenyu H, Fengjin P. Assessing resting-state brain functional connectivity in adolescents and young adults with narcolepsy using functional near-infrared spectroscopy. Front Hum Neurosci 2024; 18:1373043. [PMID: 38606200 PMCID: PMC11007108 DOI: 10.3389/fnhum.2024.1373043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/13/2024] [Indexed: 04/13/2024] Open
Abstract
This study aimed to elucidate the alterations in the prefrontal cortex's functional connectivity and network topology in narcolepsy patients using functional near-infrared spectroscopy (fNIRS). Twelve narcolepsy-diagnosed patients from Guangxi Zhuang Autonomous Region's People's Hospital Sleep Medicine Department and 11 matched healthy controls underwent resting fNIRS scans. Functional connectivity and graph theory analyses were employed to assess the prefrontal cortex network's properties and their correlation with clinical features. Results indicated increased functional connectivity in these adolescent and young adult patients with narcolepsy, with significant variations in metrics like average degree centrality and node efficiency, particularly in the left middle frontal gyrus. These alterations showed correlations with clinical symptoms, including depression and sleep efficiency. However, the significance of these findings was reduced post False Discovery Rate adjustment, suggesting a larger sample size is needed for validation. In conclusion, the study offers initial observations that alterations in the prefrontal cortex's functional connectivity may potentially act as a neurobiological indicator of narcolepsy, warranting further investigation with a larger cohort to substantiate these findings and understand the underlying mechanisms.
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Affiliation(s)
- Chen Wenhong
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Mo Xiaoying
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Shi Lingli
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Tang Binyun
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Wen Yining
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Zhao Mingming
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Lu Yian
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Qin Lixia
- Guangxi Clinical Reserch Center for Sleep Medicine, The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Hu Wenyu
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
| | - Pan Fengjin
- Department of Sleep Medicine, The People’s Hospital of Guangxi Zhuang Autonomous Region, Nanning, Guangxi, China
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Picard K, Dolhan K, Watters JJ, Tremblay MÈ. Microglia and Sleep Disorders. ADVANCES IN NEUROBIOLOGY 2024; 37:357-377. [PMID: 39207702 DOI: 10.1007/978-3-031-55529-9_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
Sleep is a physiological state that is essential for maintaining physical and mental health. Sleep disorders and sleep deprivation therefore have many adverse effects, including an increased risk of metabolic diseases and a decline in cognitive function that may be implicated in the long-term development of neurodegenerative diseases. There is increasing evidence that microglia, the resident immune cells of the central nervous system (CNS), are involved in regulating the sleep-wake cycle and the CNS response to sleep alteration and deprivation. In this chapter, we will discuss the involvement of microglia in various sleep disorders, including sleep-disordered breathing, insomnia, narcolepsy, myalgic encephalomyelitis/chronic fatigue syndrome, and idiopathic rapid-eye-movement sleep behavior disorder. We will also explore the impact of acute and chronic sleep deprivation on microglial functions. Moreover, we will look into the potential involvement of microglia in sleep disorders as a comorbidity to Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Katherine Picard
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Kira Dolhan
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
- Department of Psychology, University of Victoria, Victoria, BC, Canada
- Department of Biology, University of Victoria, Victoria, BC, Canada
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin Madison, Madison, WI, USA
| | - Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada.
- Département de Médecine Moléculaire, Université Laval, Québec, QC, Canada.
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada.
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada.
- Institute on Aging and Lifelong Health (IALH), University of Victoria, Victoria, BC, Canada.
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7
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Pintwala SK, Peever J. Brain Circuits Underlying Narcolepsy. Neuroscientist 2023; 29:751-766. [PMID: 34704497 DOI: 10.1177/10738584211052263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Narcolepsy is a sleep disorder manifesting symptoms such as excessive daytime sleepiness and often cataplexy, a sudden and involuntary loss of muscle activity during wakefulness. The underlying neuropathological basis of narcolepsy is the loss of orexin neurons from the lateral hypothalamus. To date numerous animal models of narcolepsy have been produced in the laboratory, being invaluable tools for delineating the brain circuits of narcolepsy. This review will examine the evidence regarding the function of the orexin system, and how loss of this wake-promoting system manifests in excessive daytime sleepiness. This review will also outline the brain circuits controlling cataplexy, focusing on the contribution of orexin signaling loss in narcolepsy. Although our understanding of the brain circuits of narcolepsy has made great progress in recent years, much remains to be understood.
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Affiliation(s)
| | - John Peever
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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8
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Juvodden HT, Alnæs D, Lund MJ, Agartz I, Andreassen OIA, Server A, Thorsby PM, Westlye LT, Knudsen Heier S. Larger hypothalamic volume in narcolepsy type 1. Sleep 2023; 46:zsad173. [PMID: 37463428 PMCID: PMC10636249 DOI: 10.1093/sleep/zsad173] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 05/18/2023] [Indexed: 07/20/2023] Open
Abstract
STUDY OBJECTIVES Narcolepsy type 1 (NT1) is a neurological sleep disorder. Postmortem studies have shown 75%-90% loss of the 50 000-70 000 hypocretin-producing neurons and 64%-94% increase in the 64 000-120 000 histaminergic neurons and conflicting indications of gliosis in the hypothalamus of NT1 patients. The aim of this study was to compare MRI-based volumes of the hypothalamus in patients with NT1 and controls in vivo. METHODS We used a segmentation tool based on deep learning included in Freesurfer and computed the volume of the whole hypothalamus, left/right part of the hypothalamus, and 10 hypothalamic subregions. We included 54 patients with post-H1N1 NT1 (39 females, mean age 21.8 ± 11.0 years) and 114 controls (77 females, mean age 23.2 ± 9.0 years). Group differences were tested with general linear models using permutation testing in Permutation Analysis of Linear Models and evaluated after 10 000 permutations, yielding two-tailed P-values. Furthermore, a stepwise Bonferroni correction was performed after dividing hypothalamus into smaller regions. RESULTS The analysis revealed larger volume for patients compared to controls for the whole hypothalamus (Cohen's d = 0.71, p = 0.0028) and for the left (d = 0.70, p = 0.0037) and right part of the hypothalamus (d = 0.65, p = 0.0075) and left (d = 0.72, p = 0.0036) and right tubular-inferior (d = 0.71, p = 0.0037) hypothalamic subregions. CONCLUSIONS In conclusion, patients with post-H1N1 NT1 showed significantly larger hypothalamic volume than controls, in particular in the tubular-inferior subregions which could reflect several processes as previous studies have indicated neuroinflammation, gliosis, and changes in the numbers of different cell types.
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Affiliation(s)
- Hilde T Juvodden
- Department of Rare Disorders, Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias (NevSom), Oslo University Hospital, Ullevål, Oslo, Norway
| | - Dag Alnæs
- Division of Mental Health and Addiction, NORMENT Centre, University of Oslo and Oslo University Hospital, Oslo, Norway
- Departement of Psychology, Pedagogy and Law, Kristiania University College, Oslo, Norway
| | - Martina J Lund
- Division of Mental Health and Addiction, NORMENT Centre, University of Oslo and Oslo University Hospital, Oslo, Norway
- Norwegian Centre for Mental Disorders Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Ingrid Agartz
- Norwegian Centre for Mental Disorders Research, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
- Department of Psychiatric Research, Diakonhjemmet Hospital, Oslo, Norway
- K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
| | - OIe A Andreassen
- Division of Mental Health and Addiction, NORMENT Centre, University of Oslo and Oslo University Hospital, Oslo, Norway
- K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
| | - Andres Server
- Department of Radiology and Nuclear Medicine, Oslo University Hospital, Oslo, Norway
| | - Per M Thorsby
- Hormone Laboratory, Department of Medical Biochemistry, Biochemical Endocrinology and Metabolism Research Group, Oslo University Hospital, Aker, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Lars T Westlye
- Division of Mental Health and Addiction, NORMENT Centre, University of Oslo and Oslo University Hospital, Oslo, Norway
- K.G. Jebsen Centre for Neurodevelopmental Disorders, University of Oslo, Oslo, Norway
- Department of Psychology, University of Oslo, Oslo, Norway
| | - Stine Knudsen Heier
- Department of Rare Disorders, Norwegian Centre of Expertise for Neurodevelopmental Disorders and Hypersomnias (NevSom), Oslo University Hospital, Ullevål, Oslo, Norway
- Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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9
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Shan L, Linssen S, Harteman Z, den Dekker F, Shuker L, Balesar R, Breesuwsma N, Anink J, Zhou J, Lammers GJ, Swaab DF, Fronczek R. Activated Wake Systems in Narcolepsy Type 1. Ann Neurol 2023; 94:762-771. [PMID: 37395722 DOI: 10.1002/ana.26736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/27/2023] [Accepted: 06/29/2023] [Indexed: 07/04/2023]
Abstract
OBJECTIVE Narcolepsy type 1 (NT1) is assumed to be caused solely by a lack of hypocretin (orexin) neurotransmission. Recently, however, we found an 88% reduction in corticotropin-releasing hormone (CRH)-positive neurons in the paraventricular nucleus (PVN). We assessed the remaining CRH neurons in NT1 to determine whether they co-express vasopressin (AVP) to reflect upregulation. We also systematically assessed other wake-systems, since current NT1 treatments target histamine, dopamine, and norepinephrine pathways. METHODS In postmortem tissue of people with NT1 and matched controls, we immunohistochemically stained and quantified neuronal populations expressing: CRH and AVP in the PVN, and CRH in the Barrington nucleus; the key neuronal histamine-synthesizing enzyme, histidine decarboxylase (HDC) in the hypothalamic tuberomammillary nucleus (TMN); the rate-limited-synthesizing enzyme, tyrosine hydroxylase (TH), for dopamine in the mid-brain and for norepinephrine in the locus coeruleus (LC). RESULTS In NT1, there was: a 234% increase in the percentage of CRH cells co-expressing AVP, while there was an unchanged integrated optical density of CRH staining in the Barrington nucleus; a 36% increased number of histamine neurons expressing HDC, while the number of typical human TMN neuronal profiles was unchanged; a tendency toward an increased density of TH-positive neurons in the substantia nigra compacta; while the density of TH-positive LC neurons was unchanged. INTERPRETATION Our findings suggest an upregulation of activity by histamine neurons and remaining CRH neurons in NT1. This may explain earlier reports of normal basal plasma cortisol levels but lower levels after dexamethasone suppression. Alternatively, CRH neurons co-expressing AVP neurons are less vulnerable. ANN NEUROL 2023;94:762-771.
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Affiliation(s)
- Ling Shan
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Suzan Linssen
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Zoe Harteman
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Fleur den Dekker
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Lamis Shuker
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Rawien Balesar
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Nicole Breesuwsma
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Jasper Anink
- Department of (Neuro) Pathology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Jingru Zhou
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Gert Jan Lammers
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Dick F Swaab
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Rolf Fronczek
- Leiden University Medical Centre, Department of Neurology, Leiden, The Netherlands, and Sleep Wake Centre SEIN, Heemstede, The Netherlands
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10
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Barateau L, Pizza F, Chenini S, Peter-Derex L, Dauvilliers Y. Narcolepsies, update in 2023. Rev Neurol (Paris) 2023; 179:727-740. [PMID: 37634997 DOI: 10.1016/j.neurol.2023.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 08/01/2023] [Indexed: 08/29/2023]
Abstract
Narcolepsy type 1 (NT1) and type 2 (NT2), also known as narcolepsy with and without cataplexy, are sleep disorders that benefited from major scientific advances over the last two decades. NT1 is caused by the loss of hypothalamic neurons producing orexin/hypocretin, a neurotransmitter regulating sleep and wake, which can be measured in the cerebrospinal fluid (CSF). A low CSF level of hypocretin-1/orexin-A is a highly specific and sensitive biomarker, sufficient to diagnose NT1. Orexin-deficiency is responsible for the main NT1 symptoms: sleepiness, cataplexy, disrupted nocturnal sleep, sleep-related hallucinations, and sleep paralysis. In the absence of a lumbar puncture, the diagnosis is based on neurophysiological tests (nocturnal and diurnal) and the presence of the pathognomonic symptom cataplexy. In the revised version of the International Classification of sleep Disorders, 3rd edition (ICSD-3-TR), a sleep onset rapid eye movement sleep (REM) period (SOREMP) (i.e. rapid occurrence of REM sleep) during the previous polysomnography may replace the diurnal multiple sleep latency test, when clear-cut cataplexy is present. A nocturnal SOREMP is very specific but not sensitive enough, and the diagnosis of cataplexy is usually based on clinical interview. It is thus of crucial importance to define typical versus atypical cataplectic attacks, and a list of clinical features and related degrees of certainty is proposed in this paper (expert opinion). The time frame of at least three months of evolution of sleepiness to diagnose NT1 was removed in the ICSD-3-TR, when clear-cut cataplexy or orexin-deficiency are established. However, it was kept for NT2 diagnosis, a less well-characterized disorder with unknown clinical course and absence of biolo biomarkers; sleep deprivation, shift working and substances intake being major differential diagnoses. Treatment of narcolepsy is nowadays only symptomatic, but the upcoming arrival of non-peptide orexin receptor-2 agonists should be a revolution in the management of these rare sleep diseases.
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Affiliation(s)
- L Barateau
- Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU de Montpellier, Montpellier, France; National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, and Kleine-Levin Syndrome, Montpellier, France; Institute of Neurosciences of Montpellier, University of Montpellier, Inserm, Montpellier, France.
| | - F Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy; IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy
| | - S Chenini
- Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU de Montpellier, Montpellier, France; National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, and Kleine-Levin Syndrome, Montpellier, France; Institute of Neurosciences of Montpellier, University of Montpellier, Inserm, Montpellier, France
| | - L Peter-Derex
- Center for Sleep Medicine and Respiratory Diseases, Croix-Rousse Hospital, Hospices Civils de Lyon, Lyon 1 University, Lyon, France; Lyon Neuroscience Research Center, PAM Team, Inserm U1028, CNRS UMR 5292, Lyon, France
| | - Y Dauvilliers
- Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU de Montpellier, Montpellier, France; National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, and Kleine-Levin Syndrome, Montpellier, France; Institute of Neurosciences of Montpellier, University of Montpellier, Inserm, Montpellier, France.
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11
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Wu MF, Thannickal TC, Li S, McGregor R, Lai YY, Siegel JM. Effects of sodium oxybate on hypocretin/orexin and locus coeruleus neurons. Sleep 2023; 46:zsad135. [PMID: 37155728 PMCID: PMC10848214 DOI: 10.1093/sleep/zsad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 04/22/2023] [Indexed: 05/10/2023] Open
Abstract
Long-term use of sodium oxybate (SXB), (also called gamma-hydroxybutyrate [GHB]) attenuates the cataplexy and sleepiness of human narcolepsy. We had previously found that chronic opiate usage in humans and long-term opiate administration to mice significantly increased the number of detected hypocretin/orexin (Hcrt) neurons, decreased their size, and increased Hcrt level in the hypothalamus. We also found that opiates significantly decreased cataplexy in human narcoleptics as well as in narcoleptic mice and that cessation of locus coeruleus neuronal activity preceded and was tightly linked to cataplectic attacks in narcoleptic dogs. We tested the hypothesis that SXB produces changes similar to opiates and now report that chronic SXB administration significantly increased the size of Hcrt neurons, the reverse of what we had seen with opiates in humans and mice. Levels of Hcrt in the hypothalamus were nonsignificantly lower, in contrast to the significant increase in hypothalamic Hcrt level after opiates. SXB decreased tyrosine hydroxylase levels in the locus coeruleus, the major descending projection of the hypocretin system, also the reverse of what we saw with opioids. Therefore despite some similar effects on narcoleptic symptomatology, SXB does not produce anatomical changes similar to those elicited by opiates. Analysis of changes in other links in the cataplexy pathway might further illuminate SXB's mechanism of action on narcolepsy.
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Affiliation(s)
- Ming-Fung Wu
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Neurobiology Research, VA Greater Los Angeles Healthcare System, North Hills, CA, USA
| | - Thomas C Thannickal
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Songlin Li
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ronald McGregor
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Yuan-Yang Lai
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Jerome M Siegel
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Neurobiology Research, VA Greater Los Angeles Healthcare System, North Hills, CA, USA
- Brain Research Institute, University of California, Los Angeles, CA, USA
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12
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Sulaman BA, Wang S, Tyan J, Eban-Rothschild A. Neuro-orchestration of sleep and wakefulness. Nat Neurosci 2023; 26:196-212. [PMID: 36581730 DOI: 10.1038/s41593-022-01236-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/16/2022] [Indexed: 12/31/2022]
Abstract
Although considered an inactive state for centuries, sleep entails many active processes occurring at the cellular, circuit and organismal levels. Over the last decade, several key technological advances, including calcium imaging and optogenetic and chemogenetic manipulations, have facilitated a detailed understanding of the functions of different neuronal populations and circuits in sleep-wake regulation. Here, we present recent progress and summarize our current understanding of the circuitry underlying the initiation, maintenance and coordination of wakefulness, rapid eye movement sleep (REMS) and non-REMS (NREMS). We propose a de-arousal model for sleep initiation, in which the neuromodulatory milieu necessary for sleep initiation is achieved by engaging in repetitive pre-sleep behaviors that gradually reduce vigilance to the external environment and wake-promoting neuromodulatory tone. We also discuss how brain processes related to thermoregulation, hunger and fear intersect with sleep-wake circuits to control arousal. Lastly, we discuss controversies and lingering questions in the sleep field.
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Affiliation(s)
- Bibi A Sulaman
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA
| | - Su Wang
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
| | - Jean Tyan
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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13
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Justinussen JL, Egebjerg C, Kornum BR. How hypocretin agonists may improve the quality of wake in narcolepsy. Trends Mol Med 2023; 29:61-69. [PMID: 36400667 DOI: 10.1016/j.molmed.2022.10.008] [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: 08/12/2022] [Revised: 10/18/2022] [Accepted: 10/21/2022] [Indexed: 11/17/2022]
Abstract
Excessive daytime sleepiness (EDS) is a complex symptom characterized by a strong urge to sleep during daytime accompanied by problems such as attention deficits, anxiety, and lower cognitive performance. The efficacy of treatments for EDS is determined by their ability to decrease sleepiness, and less attention has been given to the effects these compounds have on the quality of the wake itself. Hypocretin (HCRT; orexin) signalling is implicated in narcolepsy, and hypocretin receptor 2 (HCRTR2) agonists are in clinical trials for treating EDS in narcolepsy. Here, we review preclinical research to determine how HCRTR2 agonists may affect attention and anxiety compared with other EDS treatment strategies. We conclude that such compounds may improve not only the quantity but also the quality of wake, and we hope that they will create opportunities for more nuanced treatment strategies in narcolepsy.
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Affiliation(s)
| | - Christine Egebjerg
- Department of Neuroscience, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Birgitte R Kornum
- Department of Neuroscience, University of Copenhagen, 2200 Copenhagen, Denmark.
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14
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Kotagal S. Update on Central Hypersomnia Disorders in Children. CURRENT SLEEP MEDICINE REPORTS 2022. [DOI: 10.1007/s40675-022-00237-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Chavda V, Chaurasia B, Umana GE, Tomasi SO, Lu B, Montemurro N. Narcolepsy-A Neuropathological Obscure Sleep Disorder: A Narrative Review of Current Literature. Brain Sci 2022; 12:1473. [PMID: 36358399 PMCID: PMC9688775 DOI: 10.3390/brainsci12111473] [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: 09/05/2022] [Revised: 10/22/2022] [Accepted: 10/28/2022] [Indexed: 08/29/2023] Open
Abstract
Narcolepsy is a chronic, long-term neurological disorder characterized by a decreased ability to regulate sleep-wake cycles. Some clinical symptoms enter into differential diagnosis with other neurological diseases. Excessive daytime sleepiness and brief involuntary sleep episodes are the main clinical symptoms. The majority of people with narcolepsy experience cataplexy, which is a loss of muscle tone. Many people experience neurological complications such as sleep cycle disruption, hallucinations or sleep paralysis. Because of the associated neurological conditions, the exact pathophysiology of narcolepsy is unknown. The differential diagnosis is essential because relatively clinical symptoms of narcolepsy are easy to diagnose when all symptoms are present, but it becomes much more complicated when sleep attacks are isolated and cataplexy is episodic or absent. Treatment is tailored to the patient's symptoms and clinical diagnosis. To facilitate the diagnosis and treatment of sleep disorders and to better understand the neuropathological mechanisms of this sleep disorder, this review summarizes current knowledge on narcolepsy, in particular, genetic and non-genetic associations of narcolepsy, the pathophysiology up to the inflammatory response, the neuromorphological hallmarks of narcolepsy, and possible links with other diseases, such as diabetes, ischemic stroke and Alzheimer's disease. This review also reports all of the most recent updated research and therapeutic advances in narcolepsy. There have been significant advances in highlighting the pathogenesis of narcolepsy, with substantial evidence for an autoimmune response against hypocretin neurons; however, there are some gaps that need to be filled. To treat narcolepsy, more research should be focused on identifying molecular targets and novel autoantigens. In addition to therapeutic advances, standardized criteria for narcolepsy and diagnostic measures are widely accepted, but they may be reviewed and updated in the future with comprehension. Tailored treatment to the patient's symptoms and clinical diagnosis and future treatment modalities with hypocretin agonists, GABA agonists, histamine receptor antagonists and immunomodulatory drugs should be aimed at addressing the underlying cause of narcolepsy.
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Affiliation(s)
- Vishal Chavda
- Department of Pathology, Stanford of School of Medicine, Stanford University Medical Centre, Palo Alto, CA 94305, USA
| | - Bipin Chaurasia
- Department of Neurosurgery, Neurosurgery Clinic, Birgunj 44300, Nepal
| | - Giuseppe E. Umana
- Department of Neurosurgery, Associate Fellow of American College of Surgeons, Trauma and Gamma-Knife Centre, Cannizzaro Hospital Catania, 95100 Catania, Italy
| | | | - Bingwei Lu
- Department of Pathology, Stanford of School of Medicine, Stanford University Medical Centre, Palo Alto, CA 94305, USA
| | - Nicola Montemurro
- Department of Neurosurgery, Azienda Ospedaliera Universitaria Pisana (AOUP), University of Pisa, 56100 Pisa, Italy
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16
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Barateau L, Pizza F, Plazzi G, Dauvilliers Y. 50th anniversary of the ESRS in 2022-JSR special issue. J Sleep Res 2022; 31:e13631. [PMID: 35624073 DOI: 10.1111/jsr.13631] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 01/21/2023]
Abstract
This article addresses the clinical presentation, diagnosis, pathophysiology and management of narcolepsy type 1 and 2, with a focus on recent findings. A low level of hypocretin-1/orexin-A in the cerebrospinal fluid is sufficient to diagnose narcolepsy type 1, being a highly specific and sensitive biomarker, and the irreversible loss of hypocretin neurons is responsible for the main symptoms of the disease: sleepiness, cataplexy, sleep-related hallucinations and paralysis, and disrupted nocturnal sleep. The process responsible for the destruction of hypocretin neurons is highly suspected to be autoimmune, or dysimmune. Over the last two decades, remarkable progress has been made for the understanding of these mechanisms that were made possible with the development of new techniques. Conversely, narcolepsy type 2 is a less well-defined disorder, with a variable phenotype and evolution, and few reliable biomarkers discovered so far. There is a dearth of knowledge about this disorder, and its aetiology remains unclear and needs to be further explored. Treatment of narcolepsy is still nowadays only symptomatic, targeting sleepiness, cataplexy and disrupted nocturnal sleep. However, new psychostimulants have been recently developed, and the upcoming arrival of non-peptide hypocretin receptor-2 agonists should be a revolution in the management of this rare sleep disease, and maybe also for disorders beyond narcolepsy.
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Affiliation(s)
- Lucie Barateau
- Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU Montpellier, Montpellier, France.,National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, and Kleine-Levin Syndrome, Montpellier, France.,Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
| | - Fabio Pizza
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Giuseppe Plazzi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.,Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Yves Dauvilliers
- Sleep-Wake Disorders Unit, Department of Neurology, Gui-de-Chauliac Hospital, CHU Montpellier, Montpellier, France.,National Reference Centre for Orphan Diseases, Narcolepsy, Idiopathic Hypersomnia, and Kleine-Levin Syndrome, Montpellier, France.,Institute for Neurosciences of Montpellier, University of Montpellier, INSERM, Montpellier, France
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17
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Kaplan GB, Lakis GA, Zhoba H. Sleep-Wake and Arousal Dysfunctions in Post-Traumatic Stress Disorder:Role of Orexin Systems. Brain Res Bull 2022; 186:106-122. [PMID: 35618150 DOI: 10.1016/j.brainresbull.2022.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 04/20/2022] [Accepted: 05/10/2022] [Indexed: 12/15/2022]
Abstract
Post-traumatic stress disorder (PTSD) is a trauma-related condition that produces distressing fear memory intrusions, avoidance behaviors, hyperarousal/startle, stress responses and insomnia. This review focuses on the importance of the orexin neural system as a novel mechanism related to the pathophysiology of PTSD. Orexinergic neurons originate in the lateral hypothalamus and project widely to key neurotransmitter system neurons, autonomic neurons, the hypothalamic-pituitaryadrenal (HPA) axis, and fear-related neural circuits. After trauma or stress, the basolateral amygdala (BLA) transmits sensory information to the central nucleus of the amygdala (CeA) and in turn to the hypothalamus and other subcortical and brainstem regions to promote fear and threat. Orexin receptors have a prominent role in this circuit as fear conditioned orexin receptor knockout mice show decreased fear expression while dual orexin receptor antagonists (DORAs) inhibit fear acquisition and expression. Orexin activation of an infralimbic-amygdala circuit impedes fear extinction while DORA treatments enhance it. Increased orexin signaling to the amygdalocortical- hippocampal circuit promotes avoidance behaviors. Orexin has an important role in activating sympathetic nervous system (SNS) activity and the HPA axis stress responses. Blockade of orexin receptors reduces fear-conditioned startle responses. In PTSD models, individuals demonstrate sleep disturbances such as increased sleep latency and more transitions to wakefulness. Increased orexin activity impairs sleep by promoting wakefulness and reducing total sleep time while DORA treatments enhance sleep onset and maintenance. The orexinergic neural system provides important mechanisms for understanding multiple PTSD behaviors and provides new medication targets to treat this often persistent and debilitating illness.
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Affiliation(s)
- Gary B Kaplan
- Mental Health Service, VA Boston Healthcare System, West Roxbury, MA, 02132 USA; Department of Psychiatry, Boston University School of Medicine, Boston, MA, 02118 USA; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA, 02118 USA.
| | - Gabrielle A Lakis
- Research Service, VA Boston Healthcare System, West Roxbury, MA, 02132 USA; Undergraduate Program in Neuroscience, Boston University, Boston, MA, 02215 USA
| | - Hryhoriy Zhoba
- Research Service, VA Boston Healthcare System, West Roxbury, MA, 02132 USA
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18
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Latorre D, Federica S, Bassetti CLA, Kallweit U. Narcolepsy: a model interaction between immune system, nervous system, and sleep-wake regulation. Semin Immunopathol 2022; 44:611-623. [PMID: 35445831 PMCID: PMC9519713 DOI: 10.1007/s00281-022-00933-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/22/2022] [Indexed: 12/21/2022]
Abstract
Narcolepsy is a rare chronic neurological disorder characterized by an irresistible excessive daytime sleepiness and cataplexy. The disease is considered to be the result of the selective disruption of neuronal cells in the lateral hypothalamus expressing the neuropeptide hypocretin, which controls the sleep-wake cycle. Diagnosis and management of narcolepsy represent still a substantial medical challenge due to the large heterogeneity in the clinical manifestation of the disease as well as to the lack of understanding of the underlying pathophysiological mechanisms. However, significant advances have been made in the last years, thus opening new perspective in the field. This review describes the current knowledge of clinical presentation and pathology of narcolepsy as well as the existing diagnostic criteria and therapeutic intervention for the disease management. Recent evidence on the potential immune-mediated mechanisms that may underpin the disease establishment and progression are also highlighted.
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Affiliation(s)
| | - Sallusto Federica
- Institute of Microbiology, ETH Zurich, Zurich, Switzerland.,Center of Medical Immunology, Institute for Research in Biomedicine, Università della Svizzera italiana, Bellinzona, Switzerland
| | | | - Ulf Kallweit
- Clinical Sleep and Neuroimmunology, Institute of Immunology, University Witten/Herdecke, Witten, Germany.,Center for Biomedical Education and Research (ZBAF), University Witten/Herdecke, Witten, Germany
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19
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Abstract
How does dopamine, the brain's pleasure signal, regulate the dream stage of sleep?
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Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Patrick M Fuller
- Department of Neurological Surgery, University of California, Davis School of Medicine, Davis, CA, USA
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20
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Inoue Y, Uchiyama M, Umeuchi H, Onishi K, Ogo H, Kitajima I, Matsushita I, Nishino I, Uchimura N. Optimal dose determination of enerisant (TS-091) for patients with narcolepsy: two randomized, double-blind, placebo-controlled trials. BMC Psychiatry 2022; 22:141. [PMID: 35193545 PMCID: PMC8862520 DOI: 10.1186/s12888-022-03785-7] [Citation(s) in RCA: 2] [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] [Received: 07/16/2021] [Accepted: 02/09/2022] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The histamine H3 receptor has emerged as one of the most promising targets of novel pharmacotherapy for narcolepsy. Studies now aim to investigate the optimal dose of enerisant, a novel H3 antagonist/inverse agonist, for the treatment of excessive daytime sleepiness in patients with narcolepsy. METHODS We conducted two phase 2, fixed-dose, double-blind, randomized, placebo-controlled trials in patients with narcolepsy. The first phase 2 study (Study 1) was conducted to investigate the efficacy and safety of enerisant at dosages of 25, 50, and 100 mg/day administered for 3 weeks based on the results of a phase 1 study conducted on healthy volunteers. The primary endpoint was mean sleep latency in maintenance of wakefulness test (MWT), and the secondary endpoint was the total score on the Epworth Sleepiness Scale (ESS). The dosages of enerisant in the second phase 2 study (Study 2) were set at 5 and 10 mg/day based on the simulation of receptor occupancy results from positron emission tomography study. RESULTS Forty-six and fifty-three patients were randomized in Study 1 and Study 2, respectively. The efficacy of enerisant was partially confirmed in Study 1 with ESS; however, the doses were not tolerated, and there were many withdrawals due to adverse events (mainly insomnia, headache, and nausea). The doses in Study 2 were well tolerated, with a lower incidence of adverse events in Study 2 than in Study 1, although the efficacy could not be confirmed with MWT and ESS in Study 2. CONCLUSIONS The optimal dose of enerisant could not be determined in these two studies. Although enerisant has a favorable pharmacokinetic profile, it is thought to have large interindividual variabilities in terms of efficacy and safety, suggesting the necessity of tailored dosage adjustments. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT03267303 ; Registered 30 August 2017 (Study 2). Japic identifier: JapicCTI-142529 ; Registered 7 May 2014 (Study 1) and JapicCTI-173689 ; Registered 30 August 2017, https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?clinicalTrialId=29277 (Study 2).
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Affiliation(s)
- Yuichi Inoue
- Japan Somnology Center, Institute of Neuropsychiatry, 5-10-10 Yoyogi, Shibuya-ku, Tokyo, 151-0053, Japan.
- Department of Somnology, Tokyo Medical University, 6-7-1 Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
| | - Makoto Uchiyama
- Department of Psychiatry, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi, , Tokyo, 173-8610, Japan
- Tokyoadachi Hospital, 5-23-20 Hokima, Adachi, Tokyo, 121-0064, Japan
| | - Hideo Umeuchi
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Koichi Onishi
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Hiroki Ogo
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Iwao Kitajima
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Isao Matsushita
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Izumi Nishino
- Development Headquarters, Taisho Pharmaceutical Co., Ltd., 3-24-1 Takada, Toshima-Ku, Tokyo, 170-8633, Japan
| | - Naohisa Uchimura
- Department of Neuropsychiatry, Kurume University School of Medicine, 67 Asahi-machi, Kurume, Fukuoka, 830-0011, Japan
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21
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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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22
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Abstract
Sleep homeostasis is a complex neurobiologic phenomenon involving a number of molecular pathways, neurotransmitter release, synaptic activity, and factors modulating neural networks. Sleep plasticity allows for homeostatic optimization of neural networks and the replay-based consolidation of specific circuits, especially important for cognition, behavior, and information processing. Furthermore, research is currently moving from an essentially brain-focused to a more comprehensive view involving other systems, such as the immune system, hormonal status, and metabolic pathways. When dysfunctional, these systems contribute to sleep loss and fragmentation as well as to sleep need. In this chapter, the implications of neural plasticity and sleep homeostasis for the diagnosis and treatment of some major sleep disorders, such as insomnia and sleep deprivation, obstructive sleep apnea syndrome, restless legs syndrome, REM sleep behavior disorder, and narcolepsy are discussed in detail with their therapeutical implications. This chapter highlights that sleep is necessary for the maintenance of an optimal brain function and is sensitive to both genetic background and environmental enrichment. Even in pathologic conditions, sleep acts as a resilient plastic state that consolidates prior information and prioritizes network activity for efficient brain functioning.
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23
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Kim HC, Lee DA, Lee HJ, Shin KJ, Park KM. Alterations in the structural covariance network of the hypothalamus in patients with narcolepsy. Neuroradiology 2022; 64:1351-1357. [PMID: 35013760 DOI: 10.1007/s00234-021-02878-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 12/06/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE The hypothalamus plays a pivotal role in the pathogenesis of narcolepsy. This study aimed to evaluate the differences in the structural covariance network of thehypothalamus based on volume differences between patients with narcolepsy and healthy controls. METHODS We retrospectively enrolled 15 patients with narcolepsy and 19 healthy controls.All subjects underwent three-dimensional T1-weighted imaging using a 3-T magnetic resonance imaging scanner. Hypothalamic subunits were segmented, and the volumes of individual hypothalamic subunits were obtained using the FreeSurfer program. Subsequently, we conducted a structural covariance network analysis of the subunit volumes with graph theory using the BRAPH program in patients with narcolepsy and in healthy controls. RESULTS There were no significant differences in the volumes of the entire right and left hypothalamus nor in the hypothalamic subunit between patients with narcolepsy and healthy controls. However, we found significant differences in the structural covariance network in the hypothalamus between these groups. The characteristic path length was significantly lower in patients with narcolepsy than in healthy controls (1.698 vs. 2.831, p = 0.001). However, other network measures did not differ between patients with narcolepsy and healthy controls. CONCLUSION We found that the structural covariance network of the hypothalamus, as assessed from the subunit volumes of hypothalamic regions using a graph theoretical analysis, is different in patients with narcolepsy compared to healthy controls. These findings may contribute to the understanding of the pathogenesis of narcolepsy.
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Affiliation(s)
- Hyung Chan Kim
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, South Korea
| | - Dong Ah Lee
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, South Korea
| | - Ho-Joon Lee
- Department of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan, South Korea
| | - Kyong Jin Shin
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, South Korea
| | - Kang Min Park
- Department of Neurology, Haeundae Paik Hospital, Inje University College of Medicine, Haeundae-ro 875, Haeundae-gu, Busan, 48108, South Korea.
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Arrigoni E, Fuller PM. The Role of the Central Histaminergic System in Behavioral State Control. Curr Top Behav Neurosci 2022; 59:447-468. [PMID: 34595740 DOI: 10.1007/7854_2021_263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Histamine is a small monoamine signaling molecule that plays a role in many peripheral and central physiological processes, including the regulation of wakefulness. The tuberomammillary nucleus is the sole neuronal source of histamine in the brain, and histamine neurons are thought to promote wakefulness and vigilance maintenance - under certain environmental and/or behavioral contexts - through their diffuse innervation of the cortex and other wake-promoting brain circuits. Histamine neurons also contain a number of other putative neurotransmitters, although the functional role of these co-transmitters remains incompletely understood. Within the brain histamine operates through three receptor subtypes that are located on pre- and post-synaptic membranes. Some histamine receptors exhibit constitutive activity, and hence exist in an activated state even in the absence of histamine. Newer medications used to reduce sleepiness in narcolepsy patients in fact enhance histamine signaling by blunting the constitutive activity of these histamine receptors. In this chapter, we provide an overview of the central histamine system with an emphasis on its role in behavioral state regulation and how drugs targeting histamine receptors are used clinically to treat a wide range of sleep-wake disorders.
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Affiliation(s)
- Elda Arrigoni
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
| | - Patrick M Fuller
- Department of Neurological Surgery, University of California Davis School of Medicine, Davis, CA, USA
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25
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Grady FS, Boes AD, Geerling JC. A Century Searching for the Neurons Necessary for Wakefulness. Front Neurosci 2022; 16:930514. [PMID: 35928009 PMCID: PMC9344068 DOI: 10.3389/fnins.2022.930514] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/15/2022] [Indexed: 11/25/2022] Open
Abstract
Wakefulness is necessary for consciousness, and impaired wakefulness is a symptom of many diseases. The neural circuits that maintain wakefulness remain incompletely understood, as do the mechanisms of impaired consciousness in many patients. In contrast to the influential concept of a diffuse "reticular activating system," the past century of neuroscience research has identified a focal region of the upper brainstem that, when damaged, causes coma. This region contains diverse neuronal populations with different axonal projections, neurotransmitters, and genetic identities. Activating some of these populations promotes wakefulness, but it remains unclear which specific neurons are necessary for sustaining consciousness. In parallel, pharmacological evidence has indicated a role for special neurotransmitters, including hypocretin/orexin, histamine, norepinephrine, serotonin, dopamine, adenosine and acetylcholine. However, genetically targeted experiments have indicated that none of these neurotransmitters or the neurons producing them are individually necessary for maintaining wakefulness. In this review, we emphasize the need to determine the specific subset of brainstem neurons necessary for maintaining arousal. Accomplishing this will enable more precise mapping of wakefulness circuitry, which will be useful in developing therapies for patients with coma and other disorders of arousal.
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Affiliation(s)
- Fillan S Grady
- Geerling Laboratory, Department of Neurology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, United States
| | - Aaron D Boes
- Boes Laboratory, Departments of Pediatrics, Neurology, and Psychiatry, The University of Iowa, Iowa City, IA, United States
| | - Joel C Geerling
- Geerling Laboratory, Department of Neurology, Iowa Neuroscience Institute, The University of Iowa, Iowa City, IA, United States
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Maski K, Mignot E, Plazzi G, Dauvilliers Y. Disrupted nighttime sleep and sleep instability in narcolepsy. J Clin Sleep Med 2022; 18:289-304. [PMID: 34463249 PMCID: PMC8807887 DOI: 10.5664/jcsm.9638] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
STUDY OBJECTIVES This review aimed to summarize current knowledge about disrupted nighttime sleep (DNS) and sleep instability in narcolepsy, including self-reported and objective assessments, potential causes of sleep instability, health consequences and functional burden, and management. METHODS One hundred two peer-reviewed publications from a PubMed search were included. RESULTS DNS is a key symptom of narcolepsy but has received less attention than excessive daytime sleepiness and cataplexy. There has been a lack of clarity regarding the definition of DNS, as many sleep-related symptoms and conditions disrupt sleep quality in narcolepsy (eg, hallucinations, sleep paralysis, rapid eye movement sleep behavior disorder, nightmares, restless legs syndrome/periodic leg movements, nocturnal eating, sleep apnea, depression, anxiety). In addition, the intrinsic sleep instability of narcolepsy results in frequent spontaneous wakings and sleep stage transitions, contributing to DNS. Sleep instability likely emerges in the setting of orexin insufficiency/deficiency, but its exact pathophysiology remains unknown. DNS impairs quality of life among people with narcolepsy, and more research is needed to determine its contributions to cardiovascular risk. Multimodal treatment is appropriate for DNS management, including behavioral therapies, counseling on sleep hygiene, and/or medication. There is strong evidence showing improvement in self-reported sleep quality and objective sleep stability measures with sodium oxybate, but rigorous clinical trials with other pharmacotherapies are needed. Treatment may be complicated by comorbidities, concomitant medications, and mood disorders. CONCLUSIONS DNS is a common symptom of narcolepsy deserving consideration in clinical care and future research. CITATION Maski K, Mignot E, Plazzi G, Dauvilliers Y. Disrupted nighttime sleep and sleep instability in narcolepsy. J Clin Sleep Med. 2022;18(1):289-304.
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Affiliation(s)
- Kiran Maski
- Department of Neurology, Boston Children’s Hospital, Boston, Massachusetts,Address correspondence to: Kiran Maski, MD, MPH, Department of Neurology, Boston Children’s Hospital, 300 Longwood Avenue, Boston, MA 02130; Phone: +01 857-218-5536; Fax: +01 617-730-0282;
| | - Emmanuel Mignot
- Stanford Center for Sleep Sciences and Medicine, Redwood City, California
| | - Giuseppe Plazzi
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio-Emilia, Modena, Italy,IRCCS, Istituto delle Scienze Neurologiche, Bologna, Italy
| | - Yves Dauvilliers
- National Reference Network for Narcolepsy, Sleep and Wake Disorders Centre, Department of Neurology, Gui de Chauliac Hospital, Montpellier, France,University of Montpellier, INSERM Institute for Neurosciences Montpellier, Montpellier, France
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27
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The Histamine System in Zebrafish Brain: Organization, Receptors, and Behavioral Roles. Curr Top Behav Neurosci 2021; 59:291-302. [PMID: 34761361 DOI: 10.1007/7854_2021_259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Three of the four histamine receptors have been identified in zebrafish. Whereas only one histamine receptor 1 gene (hrh1) is known, two copies of histamine receptor 2 (hrh2a and hrh2b) have been identified. Although initially only one gene encoding for histamine receptor 3 (hrh3) was recognized in zebrafish, the genome database contains information for two more hrh3-like genes, whereas no genes corresponding for histamine receptor 4 with expression mainly in the immune system have been identified. Hrh1 and hrh3 show prominent uneven expression in the zebrafish brain, with the strongest expression in the dorsal telencephalon. Quantitatively significant expression of hrh1, hrh2, and hrh3 can also be found in several peripheral organs. Whereas antagonists of hrh1, hrh2, and hrh3 all affect the locomotor activity of zebrafish larvae, interpretation of the data is hampered by a lack of information on receptor binding and signaling characteristics. Zebrafish mutants lacking any of the three histamine receptors have shown modest behavioral phenotypes, possibly due to genetic compensation. None of the receptor mutant fish have shown significant sleep phenotypes. Adult zebrafish lacking hrh3 display decreased locomotor activity. The zebrafish histamine system shows significant life-long plasticity: presenilin 1 mutant zebrafish develop an abnormally large number of histamine neurons and increased thigmotaxis and anxiety-related phenotype. Overexpression of histidine decarboxylase (hdc) in larval zebrafish is associated with an increased number of hypocretin neurons, whereas translation inhibition of hdc or exposure to α-fluoromethylhistidine leads to decreased numbers of hypocretin neurons. Current pharmacological evidence suggests that this may be mediated by hrh1. Further studies using acute, e.g., pharmacogenetic or optogenetic manipulation of selected components of brain circuits, are required to understand the full range of physiological functions of zebrafish histamine receptors.
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28
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Melzi S, Morel AL, Scoté-Blachon C, Liblau R, Dauvilliers Y, Peyron C. Histamine in murine narcolepsy: What do genetic and immune models tell us? Brain Pathol 2021; 32:e13027. [PMID: 34672414 PMCID: PMC8877734 DOI: 10.1111/bpa.13027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/14/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022] Open
Abstract
An increased number of histaminergic neurons, identified by labeling histidine‐decarboxylase (HDC) its synthesis enzyme, was unexpectedly found in patients with narcolepsy type 1 (NT1). In quest for enlightenment, we evaluate whether an increase in HDC cell number and expression level would be detected in mouse models of the disease, in order to provide proof of concepts reveling possible mechanisms of compensation for the loss of orexin neurons, and/or of induced expression as a consequence of local neuroinflammation, a state that likely accompanies NT1. To further explore the compensatory hypothesis, we also study the noradrenergic wake‐promoting system. Immunohistochemistry for HDC, orexin, and melanin‐concentrating hormone (MCH) was used to count neurons. Quantitative‐PCR of HDC, orexin, MCH, and tyrosine‐hydroxylase was performed to evaluate levels of mRNA expression in the hypothalamus or the dorsal pons. Both quantifications were achieved in genetic and neuroinflammatory models of narcolepsy with major orexin impairment, namely the orexin‐deficient (Orex‐KO) and orexin‐hemagglutinin (Orex‐HA) mice respectively. The number of HDC neurons and mRNA expression level were unchanged in Orex‐KO mice compared to controls. Similarly, we found no change in tyrosine‐hydroxylase mRNA expression in the dorsal pons between groups. Further, despite the presence of protracted local neuroinflammation as witnessed by the presence of reactive microglia, we found no change in the number of neurons nor the expression of HDC in Orex‐HA mice compared to controls. Importantly, no correlation was found in all conditions between HDC and orexin. Our findings indicate that, in mice, the expression of histamine and noradrenalin, two wake‐promoting systems, are not modulated by orexin level whether the lack of orexin is constitutive or induced at adult age, showing thus no compensation. They also show no recruitment of histamine by local neuroinflammation. Further studies will be needed to further define the role of histamine in the pathophysiology of NT1.
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Affiliation(s)
- Silvia Melzi
- Sleep Team, Center for Research in Neuroscience of LYON, CNRS UMR5292, INSERM U1028, University of Lyon1, Bron, France
| | - Anne-Laure Morel
- Sleep Team, Center for Research in Neuroscience of LYON, CNRS UMR5292, INSERM U1028, University of Lyon1, Bron, France
| | - Céline Scoté-Blachon
- Functional Neurogenetics platform, Center for Research in Neuroscience of LYON, CNRS UMR5292, INSERM U1028, University of Lyon1, Bron, France
| | - Roland Liblau
- Toulouse Institute for Infectious and Inflammatory diseases, Centre National de la Recherche Scientifique, Institut National de la Santé et de la Recherche Médicale, UPS, University of Toulouse, Toulouse, France
| | - Yves Dauvilliers
- National Reference Centre for Orphan Diseases, Narcolepsy - Rare hypersomnia, Sleep Unit, Department of Neurology, CHU Montpellier, Institute for Neuroscience of Montpellier INM, INSERM U1298, University of Montpellier, Montpellier, France
| | - Christelle Peyron
- Sleep Team, Center for Research in Neuroscience of LYON, CNRS UMR5292, INSERM U1028, University of Lyon1, Bron, France
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29
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Seifinejad A, Vassalli A, Tafti M. Neurobiology of cataplexy. Sleep Med Rev 2021; 60:101546. [PMID: 34607185 DOI: 10.1016/j.smrv.2021.101546] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/29/2021] [Accepted: 09/06/2021] [Indexed: 11/17/2022]
Abstract
Cataplexy is the pathognomonic and the most striking symptom of narcolepsy. It has originally been, and still is now, widely considered as an abnormal manifestation of rapid eye movement (REM) sleep during wakefulness due to the typical muscle atonia. The neurocircuits of cataplexy, originally confined to the brainstem as those of REM sleep atonia, now include the hypothalamus, dorsal raphe (DR), amygdala and frontal cortex, and its neurochemistry originally focused on catecholamines and acetylcholine now extend to hypocretin (HCRT) and other neuromodulators. Here, we review the neuroanatomy and neurochemistry of cataplexy and propose that cataplexy is a distinct brain state that, despite similarities with REM sleep, involves cataplexy-specific features.
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Affiliation(s)
- Ali Seifinejad
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland
| | - Anne Vassalli
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland
| | - Mehdi Tafti
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, 1005 Lausanne, Switzerland.
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30
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The Histaminergic System in Neuropsychiatric Disorders. Biomolecules 2021; 11:biom11091345. [PMID: 34572558 PMCID: PMC8467868 DOI: 10.3390/biom11091345] [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: 07/14/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 12/18/2022] Open
Abstract
Histamine does not only modulate the immune response and inflammation, but also acts as a neurotransmitter in the mammalian brain. The histaminergic system plays a significant role in the maintenance of wakefulness, appetite regulation, cognition and arousal, which are severely affected in neuropsychiatric disorders. In this review, we first briefly describe the distribution of histaminergic neurons, histamine receptors and their intracellular pathways. Next, we comprehensively summarize recent experimental and clinical findings on the precise role of histaminergic system in neuropsychiatric disorders, including cell-type role and its circuit bases in narcolepsy, schizophrenia, Alzheimer's disease, Tourette's syndrome and Parkinson's disease. Finally, we provide some perspectives on future research to illustrate the curative role of the histaminergic system in neuropsychiatric disorders.
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31
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Shan L, Swaab DF. Changes in histaminergic system in neuropsychiatric disorders and the potential treatment consequences. Curr Neuropharmacol 2021; 20:403-411. [PMID: 34521328 PMCID: PMC9413789 DOI: 10.2174/1570159x19666210909144930] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/05/2021] [Accepted: 08/26/2021] [Indexed: 11/22/2022] Open
Abstract
In contrast to that of other monoamine neurotransmitters, the association of the histaminergic system with neuropsychiatric disorders is not well documented. In the last two decades, several clinical studies involved in the development of drugs targeting the histaminergic system have been reported. These include the H3R-antagonist/inverse agonist, pitolisant, used for the treatment of excessive sleepiness in narcolepsy, and the H1R antagonist, doxepin, used to alleviate symptoms of insomnia. The current review summarizes reports from animal models, including genetic and neuroimaging studies, as well as human brain samples and cerebrospinal fluid measurements from clinical trials, on the possible role of the histaminergic system in neuropsychiatric disorders. These studies will potentially pave the way for novel histamine-related therapeutic strategies.
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Affiliation(s)
- Ling Shan
- Department of Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam. Netherlands
| | - Dick F Swaab
- Department of Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam. Netherlands
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32
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Different Peas in the Same Pod: The Histaminergic Neuronal Heterogeneity. Curr Top Behav Neurosci 2021; 59:303-327. [PMID: 34455575 DOI: 10.1007/7854_2021_241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The histaminergic neuronal system is recently receiving increasing attention, as much has been learned over the past 25 years about histamine role as a neurotransmitter. Indeed, this amine is crucial in maintaining arousal and provides important contributions to regulate circadian rhythms, energy, endocrine homeostasis, motor behavior, and cognition. The extent to which these distinct physiological functions are operated by independent histamine neuronal subpopulation is unclear. In the rat brain histamine neuronal cell bodies are grouped within the tuberomamillary nucleus of the posterior hypothalamus in five clusters, E1-E5, each sending overlapping axons throughout the entire central nervous system with no strict topographical pattern. These features lead to the concept that histamine regulation of a wide range of functions in the central nervous system is achieved by the histaminergic neuronal system as a whole. However, increasing experimental evidence suggesting that the histaminergic system is organized into distinct pathways modulated by selective mechanisms challenges this view. In this review, we summarized experimental evidence supporting the heterogeneity of histamine neurons, and their organization in functionally distinct circuits impinging on separate brain regions and displaying selective control mechanisms. This implies independent functions of subsets of histaminergic neurons according to their respective origin and terminal projections with relevant consequences for the development of specific compounds that affect only subsets of histamine neurons, thus increasing the target specificity.
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33
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Mochizuki T. Histamine as an Alert Signal in the Brain. Curr Top Behav Neurosci 2021; 59:413-425. [PMID: 34448132 DOI: 10.1007/7854_2021_249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Sleep-wake behavior is a well-studied physiology in central histamine studies. Classical histamine H1 receptor antagonists, such as diphenhydramine and chlorpheniramine, promote sleep in animals and humans. Further, neuronal histamine release shows a clear circadian rhythm in parallel with wake behavior. However, the early stages of histamine-associated knockout mouse studies showed relatively small defects in normal sleep-wake control. To reassess the role of histamine in behavioral state control, this review summarizes the progress in sleep-wake studies of histamine-associated genetic mouse models and discusses the significance of histamine for characteristic aspects of wake behavior. Based on analysis of recent mouse models, we propose that neuronal histamine may serve as an alert signal in the brain, when high attention or a strong wake-drive is needed, such as during exploration, self-defense, learning, or to counteract hypersomnolent diseases. Enhanced histaminergic neurotransmission may help performance or sense of signals concerning internal or environmental dangers, like peripheral histamine from mast cells in response to allergic stimuli and inflammatory signals.
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Affiliation(s)
- Takatoshi Mochizuki
- Department of Biology, Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.
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34
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Fiscon G, Conte F, Amadio S, Volonté C, Paci P. Drug Repurposing: A Network-based Approach to Amyotrophic Lateral Sclerosis. Neurotherapeutics 2021; 18:1678-1691. [PMID: 33987813 PMCID: PMC8609089 DOI: 10.1007/s13311-021-01064-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2021] [Indexed: 02/07/2023] Open
Abstract
The continuous adherence to the conventional "one target, one drug" paradigm has failed so far to provide effective therapeutic solutions for heterogeneous and multifactorial diseases as amyotrophic lateral sclerosis (ALS), a rare progressive and chronic, debilitating neurological disease for which no cure is available. The present study is aimed at finding innovative solutions and paradigms for therapy in ALS pathogenesis, by exploiting new insights from Network Medicine and drug repurposing strategies. To identify new drug-ALS disease associations, we exploited SAveRUNNER, a recently developed network-based algorithm for drug repurposing, which quantifies the proximity of disease-associated genes to drug targets in the human interactome. We prioritized 403 SAveRUNNER-predicted drugs according to decreasing values of network similarity with ALS. Among catecholamine, dopamine, serotonin, histamine, and GABA receptor modulators, as well as angiotensin-converting enzymes, cyclooxygenase isozymes, and serotonin transporter inhibitors, we found some interesting no customary ALS drugs, including amoxapine, clomipramine, mianserin, and modafinil. Furthermore, we strengthened the SAveRUNNER predictions by a gene set enrichment analysis that confirmed modafinil as a drug with the highest score among the 121 identified drugs with a score > 0. Our results contribute to gathering further proofs of innovative solutions for therapy in ALS pathogenesis.
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Affiliation(s)
- Giulia Fiscon
- Institute for Systems Analysis and Computer Science “A. Ruberti”, National Research Council (IASI–CNR), Via Dei Taurini 19, 00185 Rome, Italy
- Fondazione per la Medicina Personalizzata, Via Goffredo Mameli, Genova, Italy
| | - Federica Conte
- Institute for Systems Analysis and Computer Science “A. Ruberti”, National Research Council (IASI–CNR), Via Dei Taurini 19, 00185 Rome, Italy
| | - Susanna Amadio
- IRCCS Santa Lucia Foundation, Preclinical Neuroscience, Via Del Fosso di Fiorano 65, 00143 Rome, Italy
| | - Cinzia Volonté
- Institute for Systems Analysis and Computer Science “A. Ruberti”, National Research Council (IASI–CNR), Via Dei Taurini 19, 00185 Rome, Italy
- IRCCS Santa Lucia Foundation, Preclinical Neuroscience, Via Del Fosso di Fiorano 65, 00143 Rome, Italy
| | - Paola Paci
- Institute for Systems Analysis and Computer Science “A. Ruberti”, National Research Council (IASI–CNR), Via Dei Taurini 19, 00185 Rome, Italy
- Department of Computer, Control, and Management Engineering Antonio Ruberti (DIAG), Sapienza University, Rome, Italy
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35
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Brink-Kjaer A, Christensen JAE, Cesari M, Mignot E, Sorensen HBD, Jennum P. Cortical arousal frequency is increased in narcolepsy type 1. Sleep 2021; 44:6009075. [PMID: 33249455 DOI: 10.1093/sleep/zsaa255] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 11/04/2020] [Indexed: 11/14/2022] Open
Abstract
STUDY OBJECTIVES Hypocretin deficient narcolepsy (type 1, NT1) presents with multiple sleep abnormalities including sleep-onset rapid eye movement (REM) periods (SOREMPs) and sleep fragmentation. We hypothesized that cortical arousals, as scored by an automatic detector, are elevated in NT1 and narcolepsy type 2 (NT2) patients as compared to control subjects. METHODS We analyzed nocturnal polysomnography (PSG) recordings from 25 NT1 patients, 20 NT2 patients, 18 clinical control subjects (CC, suspected central hypersomnia but with normal cerebrospinal (CSF) fluid hypocretin-1 (hcrt-1) levels and normal results on the multiple sleep latency test), and 37 healthy control (HC) subjects. Arousals were automatically scored using Multimodal Arousal Detector (MAD), a previously validated automatic wakefulness and arousal detector. Multiple linear regressions were used to compare arousal index (ArI) distributions across groups. Comparisons were corrected for age, sex, body-mass index, medication, apnea-hypopnea index, periodic leg movement index, and comorbid rapid eye movement sleep behavior disorder. RESULTS NT1 was associated with an average increase in ArI of 4.02 events/h (p = 0.0246) compared to HC and CC, while no difference was found between NT2 and control groups. Additionally, a low CSF hcrt-1 level was predictive of increased ArI in all the CC, NT2, and NT1 groups. CONCLUSIONS The results further support the hypothesis that a loss of hypocretin neurons causes fragmented sleep, which can be measured as an increased ArI as scored by the MAD.
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Affiliation(s)
- Andreas Brink-Kjaer
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark.,Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Denmark.,Stanford Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
| | - Julie A E Christensen
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark.,Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, Denmark
| | - Matteo Cesari
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Emmanuel Mignot
- Stanford Center for Sleep Sciences and Medicine, Stanford University, Palo Alto, CA
| | - Helge B D Sorensen
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Poul Jennum
- Department of Health Technology, Technical University of Denmark, Kongens Lyngby, Denmark
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36
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Berteotti C, Lo Martire V, Alvente S, Bastianini S, Bombardi C, Matteoli G, Ohtsu H, Lin JS, Silvani A, Zoccoli G. Orexin/Hypocretin and Histamine Cross-Talk on Hypothalamic Neuron Counts in Mice. Front Neurosci 2021; 15:660518. [PMID: 34093114 PMCID: PMC8173058 DOI: 10.3389/fnins.2021.660518] [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: 01/29/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022] Open
Abstract
The loss of hypothalamic neurons that produce wake-promoting orexin (hypocretin) neuropeptides is responsible for narcolepsy type 1 (NT1). While the number of histamine neurons is increased in patients with NT1, results on orexin-deficient mouse models of NT1 are inconsistent. On the other hand, the effect of histamine deficiency on orexin neuron number has never been tested on mammals, even though histamine has been reported to be essential for the development of a functional orexin system in zebrafish. The aim of this study was to test whether histamine neurons are increased in number in orexin-deficient mice and whether orexin neurons are decreased in number in histamine-deficient mice. The hypothalamic neurons expressing L-histidine decarboxylase (HDC), the histamine synthesis enzyme, and those expressing orexin A were counted in four orexin knock-out mice, four histamine-deficient HDC knock-out mice, and four wild-type C57BL/6J mice. The number of HDC-positive neurons was significantly higher in orexin knock-out than in wild-type mice (2,502 ± 77 vs. 1,800 ± 213, respectively, one-tailed t-test, P = 0.011). Conversely, the number of orexin neurons was not significantly lower in HDC knock-out than in wild-type mice (2,306 ± 56 vs. 2,320 ± 120, respectively, one-tailed t-test, P = 0.459). These data support the view that orexin peptide deficiency is sufficient to increase histamine neuron number, supporting the involvement of the histamine waking system in the pathophysiology of NT1. Conversely, these data do not support a significant role of histamine in orexin neuron development in mammals.
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Affiliation(s)
- Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Viviana Lo Martire
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Sara Alvente
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Cristiano Bombardi
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
| | - Gabriele Matteoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | | | - Jian-Sheng Lin
- Physiologie Intégrée du Système d'éveil, Centre de Recherche en Neurosciences de Lyon, INSERM U1028-CNRS UMR, Bron, France
| | - Alessandro Silvani
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Giovanna Zoccoli
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Center for Applied Biomedical Research, S. Orsola University Hospital, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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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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38
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Shimada M, Miyagawa T, Kodama T, Toyoda H, Tokunaga K, Honda M. Metabolome analysis using cerebrospinal fluid from narcolepsy type 1 patients. Sleep 2021; 43:5837570. [PMID: 32412602 DOI: 10.1093/sleep/zsaa095] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/25/2020] [Indexed: 12/14/2022] Open
Abstract
Narcolepsy type 1 (NT1) is a hypersomnia characterized by excessive daytime sleepiness and cataplexy. Inappropriate regulation of fatty acid metabolism has been suggested to be involved in the pathophysiology of NT1, but the detailed mechanisms remain uncertain. Here we performed a metabolomic analysis of cerebrospinal fluid samples from 14 NT1 and 17 control subjects using a novel capillary electrophoresis coupled with Fourier transform mass spectrometry. A total of 268 metabolites were identified and the amount of histidine was the most significantly increased in NT1 patients (p = 4.0 × 10-4). Validation analysis using high-performance liquid chromatography (HPLC) including independent replication samples also identified the association of histidine (p = 2.02 × 10-3). Further, levels of histamine, which is synthesized from histidine, were also examined using HPLC and were found to be significantly decreased in NT1 patients (p = 6.12 × 10-4). Pathway analysis with nominally significant metabolites identified several pathways related to the metabolism of glycogenic amino acids, suggesting that glycogenesis is enhanced in NT1 as a compensatory mechanism for fatty acid metabolism. We performed further exploratory analysis, searching for metabolites associated with sleep variables from polysomnography and the multiple sleep latency test. As a result, 5'-deoxy-5'-methylthioadenosine showed a significant association with apnea-hypopnea index (p = 2.66 ×10-6). Moreover, gamma aminobutyric acid displayed a negative correlation with rapid eye movement sleep latency (REML), and thus might represent an intriguing target for future studies to elucidate how the controlling circuit of REM sleep is associated with abnormally short REML in NT1.
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Affiliation(s)
- Mihoko Shimada
- Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Taku Miyagawa
- Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Tohru Kodama
- Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hiromi Toyoda
- Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Katsushi Tokunaga
- Department of Human Genetics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.,Genome Medical Science Project (Toyama), National Center for Global Health and Medicine (NCGM), Tokyo, Japan
| | - Makoto Honda
- Department of Psychiatry and Behavioral Sciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Seiwa Hospital, Institute of Neuropsychiatry, Tokyo, Japan
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Kaushik MK, Aritake K, Cherasse Y, Imanishi A, Kanbayashi T, Urade Y, Yanagisawa M. Induction of narcolepsy-like symptoms by orexin receptor antagonists in mice. Sleep 2021; 44:6145803. [PMID: 33609365 DOI: 10.1093/sleep/zsab043] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Orexins/hypocretins are hypothalamic neuropeptides that promote and stabilize wakefulness by binding to the orexin receptor type-1 (OX1R) and type-2 (OX2R). Disruption of orexinergic signaling results in the sleep disorder narcolepsy in mice, rats, dogs, and humans. The orexin receptor antagonist suvorexant promotes sleep by blocking both OX1R and OX2R. Whereas suvorexant has been clinically approved for the treatment of insomnia because it is well tolerated in experimental animals as well as in human patients, a logical question remains as to why orexin receptor antagonists do not induce overt narcolepsy-like symptoms. Here we show that acute and chronic suvorexant promotes both rapid eye movement (REM) and non-REM (NREM) sleep without inducing cataplexy in mice. Interestingly, chronic suvorexant increases OX2R mRNA and decreases orexin mRNA and peptide levels, which remain low long after termination of suvorexant administration. When mice are chronically treated with suvorexant and then re-challenged with the antagonist after a 1-week washout, however, cataplexy and sleep-onset REM (SOREM) are observed, which are exacerbated by chocolate administration. Heterozygous orexin knockout mice, with lower brain orexin levels, show cataplexy and SOREM after acute suvorexant administration. Furthermore, we find that acute suvorexant can induce cataplexy and SOREM in wild-type mice when co-administered with chocolate under stress-free (temporally anesthetized) conditions. Taken together, these results suggest that suvorexant can inhibit orexin synthesis resulting in susceptibility to narcolepsy-like symptoms in mice under certain conditions.
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Affiliation(s)
- Mahesh K Kaushik
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Kosuke Aritake
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Yoan Cherasse
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Aya Imanishi
- Department of Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan
| | - Takashi Kanbayashi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
| | - Yoshihiro Urade
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
- Isotope Science Center, The University of Tokyo, Tokyo, Japan
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Japan
- Department of Molecular Genetics, University of Texas Southwestern Medical Center at Dallas, Dallas, TX
- Life Science Center, Tsukuba Advanced Research Alliance, University of Tsukuba, Tsukuba, Japan
- R&D Center for Frontiers of MIRAI in Policy and Technology, University of Tsukuba, Tsukuba, Japan
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40
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Shan L, Fronczek R, Lammers GJ, Swaab DF. The tuberomamillary nucleus in neuropsychiatric disorders. HANDBOOK OF CLINICAL NEUROLOGY 2021; 180:389-400. [PMID: 34225943 DOI: 10.1016/b978-0-12-820107-7.00024-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The tuberomamillary nucleus (TMN) is located within the posterior part of the hypothalamus. The histamine neurons in it synthesize histamine by means of the key enzyme histidine decarboxylase (HDC) and from the TMN, innervate a large number of brain areas, such as the cerebral cortex, hippocampus, amygdala as well as the thalamus, hypothalamus, and basal ganglia. Brain histamine is reduced to an inactivated form, tele-methylhistamine (t-MeHA), by histamine N-methyltransferase (HMT). In total, there are four types of histamine receptors (H1-4Rs) in the brain, all of which are G-protein coupled. The histaminergic system controls several basal physiological functions, including the sleep-wake cycle, energy and endocrine homeostasis, sensory and motor functions, and cognitive functions such as attention, learning, and memory. Histaminergic dysfunction may contribute to clinical disorders such as Parkinson's disease, Alzheimer's disease, Huntington's disease, narcolepsy type 1, schizophrenia, Tourette syndrome, and autism spectrum disorder. In the current chapter, we focus on the role of the histaminergic system in these neurological/neuropsychiatric disorders. For each disorder, we first discuss human data, including genetic, postmortem brain, and cerebrospinal fluid studies. Then, we try to interpret the human changes by reviewing related animal studies and end by discussing, if present, recent progress in clinical studies on novel histamine-related therapeutic strategies.
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Affiliation(s)
- Ling Shan
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands; Sleep Wake Centre SEIN, Heemstede, The Netherlands; Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands.
| | - Rolf Fronczek
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands; Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Gert Jan Lammers
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands; Sleep Wake Centre SEIN, Heemstede, The Netherlands
| | - Dick F Swaab
- Department Neuropsychiatric Disorders, Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands
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41
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Cheng J, Wu F, Zhang M, Ding D, Fan S, Chen G, Zhang J, Wang L. The Interaction Between the Ventrolateral Preoptic Nucleus and the Tuberomammillary Nucleus in Regulating the Sleep-Wakefulness Cycle. Front Neurosci 2021; 14:615854. [PMID: 33381012 PMCID: PMC7767984 DOI: 10.3389/fnins.2020.615854] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 11/20/2020] [Indexed: 11/20/2022] Open
Abstract
The ventrolateral preoptic nucleus (VLPO) in the anterior hypothalamus and the tuberomammillary nucleus (TMN) in the posterior hypothalamus are critical regions which involve the regulation of sleep-wakefulness flip-flop in the central nervous system. Most of the VLPO neurons are sleep-promoting neurons, which co-express γ-aminobutyric acid (GABA) and galanin, while TMN neurons express histamine (HA), a key wake-promoting neurotransmitter. Previous studies have shown that the two regions are innervated between each other, but how to regulate the sleep-wake cycle are not yet clear. Here, bicuculline (Bic), a GABAA-receptor antagonist, L-glutamate (L-Glu), an excitatory neurotransmitter, and triprolidine (Trip), a HA1 receptor (HRH1) inhibitor, were bilaterally microinjected into TMN or VLPO after surgically implanting the electroencephalogram (EEG) and electromyography (EMG) electrode recording system. Microinjecting L-Glu into VLPO during the night significantly increased the NREM sleep time, and this phenomenon was weakened after selectively blocking GABAA receptors with Bic microinjected into TMN. Those results reveal that VLPO neurons activated, which may inhibit TMN neurons inducing sleep via GABAA receptors. On the contrary, exciting TMN neurons by L-Glu during the day, the wakefulness time was significantly increased. These phenomena were reversed by blocking HRH1 with Trip microinjected into VLPO. Those results reveal that TMN neuron activating may manipulate VLPO neurons via HRH1, and induce wakefulness. In conclusion, VLPO GABAergic neurons and TMN histaminergic neurons may interact with each other in regulating the sleep-wake cycle.
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Affiliation(s)
- Juan Cheng
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Fang Wu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.,Teaching and Research Office of Physiology, School of Basic Medical Sciences, Anhui Medical College, Hefei, China
| | - Mingrui Zhang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Ding Ding
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.,Teaching and Research Office of Physiology, School of Basic Medical Sciences, Anhui Medical College, Hefei, China
| | - Sumei Fan
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Guihai Chen
- The Affiliated Chaohu Hospital, Anhui Medical University, Hefei, China
| | - Jin Zhang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China.,Department of Neurology, Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Liecheng Wang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
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42
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Berteotti C, Liguori C, Pace M. Dysregulation of the orexin/hypocretin system is not limited to narcolepsy but has far-reaching implications for neurological disorders. Eur J Neurosci 2020; 53:1136-1154. [PMID: 33290595 DOI: 10.1111/ejn.15077] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 10/05/2020] [Accepted: 10/05/2020] [Indexed: 12/23/2022]
Abstract
Neuropeptides orexin A and B (OX-A/B, also called hypocretin 1 and 2) are released selectively by a population of neurons which projects widely into the entire central nervous system but is localized in a restricted area of the tuberal region of the hypothalamus, caudal to the paraventricular nucleus. The OX system prominently targets brain structures involved in the regulation of wake-sleep state switching, and also orchestrates multiple physiological functions. The degeneration and dysregulation of the OX system promotes narcoleptic phenotypes both in humans and animals. Hence, this review begins with the already proven involvement of OX in narcolepsy, but it mainly discusses the new pre-clinical and clinical insights of the role of OX in three major neurological disorders characterized by sleep impairment which have been recently associated with OX dysfunction, such as Alzheimer's disease, stroke and Prader Willi syndrome, and have been emerged over the past 10 years to be strongly associated with the OX dysfunction and should be more considered in the future. In the light of the impairment of the OX system in these neurological disorders, it is conceivable to speculate that the integrity of the OX system is necessary for a healthy functioning body.
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Affiliation(s)
- Chiara Berteotti
- PRISM Lab, Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Claudio Liguori
- Sleep Medicine Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy.,Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy
| | - Marta Pace
- Genetics and Epigenetics of Behaviour Laboratory, Istituto Italiano di Tecnologia, Genova, Italy
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43
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de Biase S, Pellitteri G, Gigli GL, Valente M. Evaluating pitolisant as a narcolepsy treatment option. Expert Opin Pharmacother 2020; 22:155-162. [PMID: 32941089 DOI: 10.1080/14656566.2020.1817387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION Narcolepsy is a chronic sleep disorder characterized by a pentad of excessive daytime sleepiness (EDS), cataplexy, sleep paralysis, hypnagogic/hypnopompic hallucinations, and disturbed nocturnal sleep. Treatment of narcolepsy remains challenging and current therapy is strictly symptomatically based. AREAS COVERED The present manuscript is based on an extensive Internet and PubMed search from 1990 to 2020. It is focused on the clinical and pharmacological properties of pitolisant in the treatment of narcolepsy. EXPERT OPINION Currently there is no cure for narcolepsy. Although efforts have been made, current treatments do not always allow to obtain an optimal control of symptoms. Pitolisant is an antagonist/inverse agonist of the histamine H3 autoreceptor. Its mechanism of action is novel and distinctive compared to the other available therapies for narcolepsy. Clinical trials suggest that pitolisant administered at a dose of ≤36 mg/day is an effective treatment option for narcolepsy, reducing EDS and cataplexy. Pitolisant is available as oral tablets and offers a convenient once-daily regimen. Pitolisant is generally well tolerated and showed minimal abuse potential in animals and humans. Long-term studies comparing the effectiveness and tolerability of pitolisant with active drugs (e.g. modafinil, sodium oxybate) are needed.
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Affiliation(s)
| | - Gaia Pellitteri
- Neurology Unit, Department of Neurosciences, University Hospital of Udine , Udine, Italy
| | - Gian Luigi Gigli
- Neurology Unit, Department of Neurosciences, University Hospital of Udine , Udine, Italy.,Department of Mathematics, Informatics and Physics (DMIF), University of Udine , Udine, Italy
| | - Mariarosaria Valente
- Neurology Unit, Department of Neurosciences, University Hospital of Udine , Udine, Italy.,Department of Medical Area (DAME), University of Udine , Udine, Italy
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44
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Mahoney CE, Mochizuki T, Scammell TE. Dual orexin receptor antagonists increase sleep and cataplexy in wild type mice. Sleep 2020; 43:zsz302. [PMID: 31830270 PMCID: PMC7294412 DOI: 10.1093/sleep/zsz302] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 11/26/2019] [Indexed: 11/13/2022] Open
Abstract
Orexin receptor antagonists are clinically useful for treating insomnia, but thorough blockade of orexin signaling could cause narcolepsy-like symptoms. Specifically, while sleepiness is a desirable effect, an orexin antagonist could also produce cataplexy, sudden episodes of muscle weakness often triggered by strong, positive emotions. In this study, we examined the effects of dual orexin receptor antagonists (DORAs), lemborexant (E2006) and almorexant, on sleep-wake behavior and cataplexy during the dark period in wild-type (WT) mice and prepro-orexin knockout (OXKO) mice. In WT mice, lemborexant at 10 and 30 mg/kg quickly induced NREM sleep in a dose-dependent fashion. In contrast, lemborexant did not alter sleep-wake behavior in OXKO mice. Under the baseline condition, cataplexy was rare in lemborexant-treated WT mice, but when mice were given chocolate as a rewarding stimulus, lemborexant dose-dependently increased cataplexy. Almorexant produced similar results. Collectively, these results demonstrate that DORAs potently increase NREM and REM sleep in mice via blockade of orexin signaling, and higher doses can cause cataplexy when co-administered with a likely rewarding stimulus.
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Affiliation(s)
- Carrie E Mahoney
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Takatoshi Mochizuki
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Japan
| | - Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
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45
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Sanchez-Alavez M, Benedict J, Wills DN, Ehlers CL. Effect of suvorexant on event-related oscillations and EEG sleep in rats exposed to chronic intermittent ethanol vapor and protracted withdrawal. Sleep 2020; 42:5304584. [PMID: 30715515 DOI: 10.1093/sleep/zsz020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/07/2018] [Indexed: 01/27/2023] Open
Abstract
STUDY OBJECTIVES Insomnia is a prominent complaint in patients with alcohol use disorders (AUD). However, despite the importance of sleep in the maintenance of sobriety, treatment options for sleep disturbance associated with a history of AUD are currently limited. Recent clinical trials have demonstrated that suvorexant, a dual Hct/OX receptor antagonist, normalizes sleep in patients with primary insomnia; yet, its potential for the treatment of sleep pathology associated with AUD has not been investigated in either preclinical or clinical studies. METHODS This study employed a model whereby ethanol vapor exposure or control conditions were administered for 8 weeks to adult rats. Waking event-related oscillations (EROs) and EEG sleep were evaluated at baseline before exposure and again following 24 hr of withdrawal from the exposure. Subsequently, the ability of vehicle (VEH) and two doses (10, 30 mg/kg IP) of suvorexant to modify EROs, sleep, and the sleep EEG was investigated. RESULTS After 24 hr following EtOH withdrawal, the ethanol-treated group had increases in waking ERO θ and β activity, more fragmented sleep (shorter duration and increased frequency of slow wave (SW) and rapid eye movement [REM] sleep episodes), and increased θ and β power in REM and SW sleep. Suvorexant induced a dose-dependent decrease in the latency to REM and SW sleep onsets but also produced REM and SW sleep fragmentation and increased β energy in waking EROs when compared with VEH. CONCLUSIONS Taken together, these studies suggest that suvorexant has overall sleep-promoting effects, but it may exacerbate some aspects of sleep and EEG pathology.
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Affiliation(s)
| | - Jessica Benedict
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
| | - Derek N Wills
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
| | - Cindy L Ehlers
- Department of Neurosciences, The Scripps Research Institute, La Jolla, CA
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46
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Kornum BR. Narcolepsy type 1: what have we learned from immunology? Sleep 2020; 43:5813740. [DOI: 10.1093/sleep/zsaa055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/19/2020] [Indexed: 12/31/2022] Open
Abstract
Abstract
Narcolepsy type 1 is hypothesized to be an autoimmune disease targeting the hypocretin/orexin neurons in the hypothalamus. Ample genetic and epidemiological evidence points in the direction of a pathogenesis involving the immune system, but this is not considered proof of autoimmunity. In fact, it remains a matter of debate how to prove that a given disease is indeed an autoimmune disease. In this review, a set of commonly used criteria for autoimmunity is described and applied to narcolepsy type 1. In favor of the autoimmune hypothesis are data showing that in narcolepsy type 1 a specific adaptive immune response is directed to hypocretin/orexin neurons. Autoreactive T cells and autoantibodies have been detected in blood samples from patients, but it remains to be seen if these T cells or antibodies are in fact present in the hypothalamus. It is also unclear if the autoreactive T cells and/or autoantibodies can transfer the disease to healthy individuals or animals or if immunization with the proposed autoantigens can induce the disease in animal models. Most importantly, it is still controversial whether suppression of the autoimmune response can prevent disease progression. In conclusion, narcolepsy type 1 does still not fully meet the criteria for being classified as a genuine autoimmune disease, but more and more results are pointing in that direction.
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Affiliation(s)
- Birgitte R Kornum
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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47
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Scammell TE, Jackson AC, Franks NP, Wisden W, Dauvilliers Y. Histamine: neural circuits and new medications. Sleep 2019; 42:5099478. [PMID: 30239935 PMCID: PMC6335869 DOI: 10.1093/sleep/zsy183] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Indexed: 12/12/2022] Open
Abstract
Histamine was first identified in the brain about 50 years ago, but only in the last few years have researchers gained an understanding of how it regulates sleep/wake behavior. We provide a translational overview of the histamine system, from basic research to new clinical trials demonstrating the usefulness of drugs that enhance histamine signaling. The tuberomammillary nucleus is the sole neuronal source of histamine in the brain, and like many of the arousal systems, histamine neurons diffusely innervate the cortex, thalamus, and other wake-promoting brain regions. Histamine has generally excitatory effects on target neurons, but paradoxically, histamine neurons may also release the inhibitory neurotransmitter GABA. New research demonstrates that activity in histamine neurons is essential for normal wakefulness, especially at specific circadian phases, and reducing activity in these neurons can produce sedation. The number of histamine neurons is increased in narcolepsy, but whether this affects brain levels of histamine is controversial. Of clinical importance, new compounds are becoming available that enhance histamine signaling, and clinical trials show that these medications reduce sleepiness and cataplexy in narcolepsy.
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Affiliation(s)
- Thomas E Scammell
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA
| | - Alexander C Jackson
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT
| | - Nicholas P Franks
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, UK
| | - William Wisden
- Department of Life Sciences and UK Dementia Research Institute, Imperial College London, UK
| | - Yves Dauvilliers
- Centre National de Référence Narcolepsie Hypersomnies, Unité des Troubles du Sommeil, Service de Neurologie, Hôpital Gui-de-Chauliac, Université Montpellier, INSERM, Montpellier, France
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48
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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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49
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Pittenger C. The histidine decarboxylase model of tic pathophysiology: a new focus on the histamine H 3 receptor. Br J Pharmacol 2019; 177:570-579. [PMID: 30714121 DOI: 10.1111/bph.14606] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/12/2018] [Accepted: 01/07/2019] [Indexed: 12/16/2022] Open
Abstract
Histamine dysregulation was implicated as a rare cause of Tourette syndrome and other tic disorders a decade ago by a landmark genetic study in a high density family pedigree, which implicated a hypomorphic mutation in the histidine decarboxylase (Hdc) gene as a rare but high penetrance genetic cause. Studies in Hdc knockout (KO) mice have confirmed that this mutation causes tic-relevant behavioural and neurochemical abnormalities that parallel what is seen in patients and thus validate the KO as a potentially informative model of tic pathophysiology. Recent studies have focused on the potential role of the histamine H3 receptor in this model, and by association in tic disorders and related neuropsychiatric conditions. The H3 receptor is up-regulated in the striatum in Hdc KO mice. As the H3 receptor has constitutive activity in the absence of ligand, this receptor up-regulation may have significant cellular effects despite the absence of neurotransmitter histamine in these mice. Activation in vivo of H3 receptors in wild type mice regulates signalling in striatal medium spiny neurons (MSNs) that interacts non-linearly with dopamine receptor signalling. Baseline signalling alterations in MSNs in Hdc KO mice resemble those seen after H3 receptor agonist treatment in wild type animals. H3 receptor agonist treatment in the KOs further accentuates most of these signalling abnormalities and produces behavioural stereotypy. Together, these data suggest the intriguing hypothesis that constitutive signalling by up-regulated H3 receptors explains many of the molecular and behavioural abnormalities seen in these animals. LINKED ARTICLES: This article is part of a themed section on New Uses for 21st Century. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.3/issuetoc.
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Mori I. The olfactory bulb: A link between environmental agents and narcolepsy. Med Hypotheses 2019; 126:66-68. [PMID: 31010502 DOI: 10.1016/j.mehy.2019.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/18/2019] [Accepted: 03/21/2019] [Indexed: 12/18/2022]
Abstract
Narcolepsy with cataplexy is a lifelong sleep disorder associated with orexin/hypocretin deficiency in the central nervous system. In addition to a genetic predisposition, a variety of environmental factors, such as influenza viruses, have been implicated in the pathogenesis of the disease. In this article, a hypothesis is proposed that environmental agents access the olfactory bulb and trigger neuroinflammation, which in turn induces neurodegeneration of orexinergic neurons in the lateral hypothalamus and other neuronal subpopulations regulating the sleep-wake cycle, which triggers the development of narcolepsy.
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Affiliation(s)
- Isamu Mori
- Faculty of Health and Nutrition, Shubun University, Ichinomiya, Aichi 491-0938, Japan.
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