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Isolation of Targeted Hypothalamic Neurons for Studies of Hormonal, Metabolic, and Electrical Regulation
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Isolation of Targeted Hypothalamic Neurons for Studies of Hormonal, Metabolic, and Electrical Regulation

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Functions of the orexinergic/hypocretinergic system

Jyrki P Kukkonen1, Tomas Holmqvist, Sylwia Ammoun

  • 1Laboratory of Cell Physiology, Department of Neuroscience, Division of Physiology, Uppsala University, Biomedical Center, SE-75123 Uppsala, Sweden. jkukkone@fysiologi.uu.se

American Journal of Physiology. Cell Physiology
|November 7, 2002
PubMed

Insights

Orexins, peptides from the hypothalamus, regulate feeding, sleep, and autonomic functions through OX1 and OX2 receptors. These peptides and their receptors are also present in peripheral organs involved in metabolism.

Area of Science:

  • Neuroendocrinology
  • Physiology
  • Molecular Biology

Background:

  • Orexin A and orexin B are hypothalamic peptides crucial for regulating vital physiological functions.
  • These peptides exert their effects through two G protein-coupled receptors: OX1 and OX2 receptors.
  • Orexinergic neurons are localized in the lateral hypothalamus, projecting to key brain regions.

Purpose of the Study:

  • To review the physiological properties of cells that secrete or respond to orexins.
  • To explore the role of orexins and their receptors in both the central and peripheral nervous systems.
  • To understand the regulation of orexinergic cell activity by feeding and sleep signals.

Main Methods:

  • Review of existing literature on orexin physiology.
  • Analysis of studies on orexin A and orexin B actions.
  • Examination of orexin receptor distribution and function.

Main Results:

  • Orexins enhance synaptic activity in feeding, sleep, and autonomic control regions.
  • Orexin signaling involves Ca2+ elevation, primarily dependent on calcium influx.
  • Orexin and orexin receptors are found in peripheral organs like the gastrointestinal tract, pancreas, and adrenal gland.

Conclusions:

  • Orexins play a significant role in central nervous system functions related to feeding, sleep, and autonomic control.
  • The presence of orexins and their receptors in peripheral metabolic organs suggests broader physiological roles.
  • Further research into orexinergic cell physiology is warranted to fully elucidate their functions.

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