title: Physiology of the orexinergic/hypocretinergic system: a revisit in 2012.
abstract: The neuropeptides orexins and their G protein-coupled receptors, OX(1) and OX(2), were discovered in 1998, and since then, their role has been investigated in many functions mediated by the central nervous system, including sleep and wakefulness, appetite/metabolism, stress response, reward/addiction, and analgesia. Orexins also have peripheral actions of less clear physiological significance still. Cellular responses to the orexin receptor activity are highly diverse. The receptors couple to at least three families of heterotrimeric G proteins and other proteins that ultimately regulate entities such as phospholipases and kinases, which impact on neuronal excitation, synaptic plasticity, and cell death. This article is a 10-year update of my previous review on the physiology of the orexinergic/hypocretinergic system. I seek to provide a comprehensive update of orexin physiology that spans from the molecular players in orexin receptor signaling to the systemic responses yet emphasizing the cellular physiological aspects of this system.
authors.affiliation: Dept. of Veterinary Biosciences, University of Helsinki, Finland. jyrki.kukkonen@helsinki.fi
authors.forename: Jyrki P
authors.initials: JP
authors.lastname: Kukkonen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002490:Central Nervous System / Q000737:chemistry / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D064446:Orexin Receptors; D000068797:Orexins; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D018013:Receptors, Neuropeptide / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D064446:Orexin Receptors; D000068797:Orexins; D043562:Receptors, G-Protein-Coupled; D018013:Receptors, Neuropeptide