suvorexant and Sleep-Disorders--Circadian-Rhythm

INTRODUCTION. Recent research has reported the existence of a new class of neuropeptides, called orexins or hypocretins, which are produced by a small group of neurons in the hypothalamus and whose actions are mediated by two types of receptors: OX1R and OX2R. More specifically, the orexinergic neurons have been located exclusively in cells in the lateral, dorsomedial and perifornical areas of the hypothalamus. Despite this highly specific anatomical origin, the orexinergic neurons are projected widely into a number of brainstem, cortical and limbic regions. DEVELOPMENT. This fuzzy pattern of distribution of the orexinergic fibres would be indicating the involvement of this peptidic system in a wide range of functions; indeed, it has been related with the mechanisms that enable regulation of the sleep-wake cycle, the ingestion of food and drink, and some particular types of learning, such as learning certain preferences regarding tastes. It has also been suggested that upsets in the functioning of the orexinergic system would explain the appearance of certain clinical disorders like narcolepsy, obesity or addiction to drug of abuse. CONCLUSIONS. Further research will help to determine the functioning of orexinergic neurons and the interaction between the systems that regulate emotion, energetic homeostasis and the reward mechanisms, on the one hand, and the systems that regulate the sleep-wake cycle on the other. That knowledge would almost certainly make it possible to develop new drugs that, by acting upon the orexinergic system, would be effective in the treatment of sleep disorders such as insomnia or narcolepsy, eating disorders or drug addiction.. Orexina: implicaciones clinicas y terapeuticas.. Introduccion. Se ha descrito recientemente una nueva clase de neuropeptidos, las orexinas, tambien llamadas hipocretinas, producidos por un reducido grupo de neuronas hipotalamicas y cuyas acciones son mediadas por dos tipos de receptores, OX1R y OX2R. En concreto, las neuronas orexinergicas se han localizado en exclusiva en celulas de areas del hipotalamo lateral, dorsomedial y perifornical. A pesar de este origen anatomico tan localizado, las neuronas orexinergicas se proyectan ampliamente a numerosas regiones troncoencefalicas, corticales y limbicas. Desarrollo. Este patron difuso de distribucion de las fibras orexinergicas estaria indicando la intervencion de este sistema peptidico en una amplia variedad de funciones y, de hecho, se ha relacionado con los mecanismos que permiten la regulacion del ciclo sueño-vigilia, la ingesta de comida y de bebida y determinados aprendizajes como el aprendizaje de preferencias gustativas. Se ha sugerido tambien que la alteracion en el funcionamiento del sistema orexinergico explicaria la aparicion de determinados trastornos clinicos como la narcolepsia, la obesidad o la adiccion a drogas de abuso. Conclusiones. Nuevas investigaciones ayudaran a conocer el funcionamiento de las neuronas orexinergicas y la interaccion entre los sistemas que regulan la emocion, la homeostasis energetica y los mecanismos de recompensa con los sistemas que regulan el ciclo de sueño-vigilia. Se confia en que ese conocimiento permita desarrollar nuevos farmacos que, actuando sobre el sistema orexinergico, sean eficaces en el tratamiento de las alteraciones del sueño como el insomnio o la narcolepsia, de los trastornos de la alimentacion o de la drogadiccion.

Topics: Animals; Arousal; Azepines; Benzoxazoles; Disease Models, Animal; Drug Evaluation, Preclinical; Feeding and Eating Disorders; Feeding Behavior; Humans; Intracellular Signaling Peptides and Proteins; Mice; Mice, Knockout; Mice, Transgenic; Motor Activity; Naphthyridines; Narcolepsy; Neuropeptides; Obesity; Orexin Receptor Antagonists; Orexin Receptors; Orexins; Sleep Disorders, Circadian Rhythm; Sleep Disorders, Intrinsic; Substance-Related Disorders; Triazoles; Urea

Many shift workers have difficulty sleeping during the daytime owing to an inappropriately timed circadian drive for wakefulness.. To determine whether a dual hypocretin receptor antagonist would enable shift workers to have more daytime sleep.. This double-blind, placebo-controlled randomized clinical trial included 2 weeks of baseline data and 3 weeks of intervention data, from March 2016 to December 2018. Individuals were recruited through poster advertisements in the broader San Francisco Bay area in California. From an initial voluntary recruitment cohort of 38 shift workers, 19 individuals with self-reported difficulty sleeping during the daytime following night work shift were included. Data were analyzed from Janaury to March 2019.. 1 week of 10 mg suvorexant or placebo, titrated upward to 20 mg suvorexant or placebo for 2 additional weeks.. Objective (ie, actigraphy) and subjective (ie, sleep logs) measures of sleep.. Among 19 participants who completed the study (mean [SD] age, 37.7 [11.1] years; 13 [68%] men), 8 participants (42%) were assigned to the suvorexant group and 11 participants (58%) were assigned to the placebo group. Compared with individuals in the placebo group, individuals in the suvorexant group increased their objective total sleep time by a mean (SE) of 1.04 (0.53) hours (P = .05) at the end of 1 week of 10-mg doses and by 2.16 (0.75) hours (P = .004) by the end of the 2 weeks of 20-mg doses. Subjective sleep was similarly improved as, compared with the placebo group, individuals in the suvorexant group increased their subjective total sleep time by a mean (SE) of 2.08 (0.47) hours (P < .001) at the end of 1 week of 10-mg doses and by 2.97 (0.56) hours (P < .001) by the end of the 2 weeks of 20-mg doses. Physician ratings of daytime sleep aligned with these measures, as there was no change in the placebo group and a much improved change in the suvorexant group. No adverse events were reported in the suvorexant group.. This pilot study found that the use of a dual hypocretin receptor antagonist in shift workers under real-world conditions resulted in more than 2 extra hours of daytime sleep per episode. Future research should confirm this pilot finding in a larger sample size and examine whether, over the long term, use of this medication has a concomitant improvement in medical and psychiatric health as well as workplace performance and safety.. ClinicalTrials.gov Identifier: NCT02491788.

Topics: Actigraphy; Adult; Azepines; California; Case-Control Studies; Circadian Rhythm; Double-Blind Method; Female; Humans; Male; Middle Aged; Orexin Receptor Antagonists; Placebos; Sleep; Sleep Disorders, Circadian Rhythm; Sleep Initiation and Maintenance Disorders; Triazoles

Non-24-hour sleep-wake disorder (N24SWD) is often observed in the visually impaired and those who isolate indoors. Melatonin receptor agonists may be used for treatment, but there is currently no evidence that they are effective in patients without visual impairment.. We report a case of a 23-year-old woman who withdrew from her social life owing to autism spectrum disorder and experienced an unusual sleep rhythm. She presented with N24SWD. The N24SWD cycle averaged 25.6 days but was extended to 42 days using ramelteon. However, this was not enough. We prescribed the addition of suvorexant and the sleep cycle returned to normal.. N24SWD is a disease that seriously impairs social life and productivity. We propose a possible treatment strategy for N24SWD using ramelteon and suvorexant.

Topics: Autism Spectrum Disorder; Azepines; Drug Therapy, Combination; Female; Humans; Indenes; Sleep Aids, Pharmaceutical; Sleep Disorders, Circadian Rhythm; Treatment Outcome; Triazoles; Young Adult

Huntington's disease (HD) is associated with sleep and circadian disturbances in addition to hallmark motor and cognitive impairments. Electrophysiological studies on HD mouse models have revealed an aberrant oscillatory activity at the beta frequency, during sleep, that is associated with HD pathology. Moreover, HD animal models display an abnormal sleep-wake cycle and sleep fragmentation. In this study, we investigated a potential involvement of the orexinergic system dysfunctioning in sleep-wake and circadian disturbances and abnormal network (i.e., beta) activity in the R6/1 mouse model. We found that the age at which orexin activity starts to deviate from normal activity pattern coincides with that of sleep disturbances as well as the beta activity. We also found that acute administration of Suvorexant, an orexin 1 and orexin 2 receptor antagonist, was sufficient to decrease the beta power significantly and to improve sleep in R6/1 mice. In addition, a 5-day treatment paradigm alleviated cognitive deficits and induced a gain of body weight in female HD mice. These results suggest that restoring normal activity of the orexinergic system could be an efficient therapeutic solution for sleep and behavioral disturbances in HD.

Topics: Animals; Azepines; Cognitive Dysfunction; Disease Models, Animal; Female; Huntington Disease; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Orexin Receptor Antagonists; Orexins; Sleep Disorders, Circadian Rhythm; Triazoles