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The hypocretin/orexin ligand-receptor system: implications for sleep and sleep disorders

T S Kilduff1, C Peyron

  • 1Molecular Neurobiology Laboratory, SRI International, Menlo Park, CA 94025, USA.

Trends in Neurosciences
|July 25, 2000
PubMed

Insights

Hypocretins, also known as orexins, are neurotransmitters initially linked to appetite control. New research suggests their crucial role in narcolepsy and normal sleep regulation, potentially influencing arousal states.

Area of Science:

  • Neuroscience
  • Sleep Medicine
  • Endocrinology

Background:

  • The hypocretin/orexin system was first identified for its role in regulating food intake.
  • Emerging evidence links this system to the pathophysiology of narcolepsy, a sleep disorder.
  • The precise functions of hypocretins/orexins in normal physiological processes are still under investigation.

Purpose of the Study:

  • To review the research history of hypocretins/orexins, from discovery to current understanding.
  • To explore the involvement of the hypocretin/orexin system in narcolepsy and normal sleep.
  • To propose a model for the role of hypocretin/orexin-producing cells in arousal state control.

Main Methods:

  • Literature review of studies on hypocretin/orexin peptides and their receptors.
  • Analysis of research implicating the system in food intake, narcolepsy, and sleep.
  • Synthesis of findings to propose a functional model.

Main Results:

  • The hypocretin/orexin system, initially studied for appetite, is now strongly implicated in narcolepsy.
  • These peptides and their receptors play a significant role in regulating sleep-wake cycles.
  • Evidence suggests a potential involvement in the control of arousal states.

Conclusions:

  • The hypocretin/orexin system is critical for maintaining wakefulness and is a key factor in narcolepsy.
  • Further research is needed to fully elucidate the complex roles of these peptides in sleep and arousal.
  • A proposed model highlights the potential involvement of hypocretin/orexin neurons in arousal state regulation.

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