The hypocretin/orexin system in sleep disorders: preclinical insights and clinical progress

Matthew Chow1, Michelle Cao1

  • 1Department of Psychiatry and Behavioral Sciences, Division of Sleep Medicine, Stanford University School of Medicine, Stanford, CA, USA.

Insights

The hypocretin/orexin (HCRT/OX) system is crucial for stable sleep-wake cycles. Disruptions lead to disorders like narcolepsy, prompting new HCRT/OX-targeting treatments.

Area of Science:

  • Neuroscience
  • Sleep Medicine
  • Pharmacology

Background:

  • The hypocretin/orexin (HCRT/OX) system, involving neuropeptides HCRT-1 and -2/OX-A and -B, is vital for regulating wakefulness.
  • This system interacts with monoaminergic, cholinergic, and GABAergic neurons to maintain sleep-wake stability.
  • Deficiency in the HCRT/OX system causes unstable sleep-wake transitions, leading to narcolepsy symptoms like excessive daytime sleepiness and cataplexy.

Purpose of the Study:

  • To review the origin and mechanisms of HCRT/OX receptors.
  • To discuss the clinical progress and therapeutic applications of targeting the HCRT/OX system for sleep disorders.
  • To highlight recent advancements in HCRT/OX agonist and antagonist development.

Main Methods:

  • Literature review of studies on the HCRT/OX system in sleep-wake regulation.
  • Analysis of research on narcolepsy-cataplexy and its link to HCRT/OX deficiency.
  • Examination of preclinical and clinical data for HCRT/OX receptor modulators.

Main Results:

  • The HCRT/OX system plays a fundamental role in maintaining consolidated wakefulness and preventing sleep intrusions.
  • Pharmacological targeting of HCRT/OX receptors has shown promise, with approved medications for insomnia.
  • Research continues to explore agonists and antagonists for various sleep-wake disorders.

Conclusions:

  • The HCRT/OX system is a key regulator of sleep-wake states, and its dysfunction underlies significant neurological disorders.
  • Targeting HCRT/OX receptors offers a promising therapeutic avenue for managing sleep disorders.
  • Continued research into HCRT/OX pharmacology is essential for developing novel treatments.

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