title: Hypocretin release in normal and narcoleptic dogs after food and sleep deprivation, eating, and movement.
abstract: Hypocretins (orexins) are recently discovered hypothalamic neuropeptides that have been implicated in the etiology of narcolepsy. The normal behavioral functions of these peptides are unclear, although a role in feeding has been suggested. We measured hypocretin-1 (Hcrt-1) in the cerebrospinal fluid of dogs during a variety of behaviors. We found that 48 h without food (24 h beyond normal 24-h fasting period) produced no significant change in Hcrt-1 levels nor did feeding after the deprivation. In contrast, 24 h of sleep deprivation produced on average a 70% increase in Hcrt-1 level compared with baseline levels. The amount of increase was correlated with the level of motor activity during the sleep-deprivation procedure. A 2-h period of exercise in the same dogs produced a 57% increase in Hcrt-1 levels relative to quiet waking levels, with the magnitude of the increase being highly correlated with the level of motor activity. The strong correlation between motor activity and Hcrt-1 release may explain some of the previously reported behavioral, physiological, and pathological phenomena ascribed to the Hcrt system.
authors.affiliation: Neurobiology Research (151A3), Veterans Affairs Greater Los Angeles Healthcare System-Sepulveda, North Hills, California 91343, USA. mfwu@ucla.edu
authors.forename: M-F
authors.initials: MF
authors.lastname: Wu
authors.forename: J
authors.initials: J
authors.lastname: John
authors.forename: N
authors.initials: N
authors.lastname: Maidment
authors.forename: H A
authors.initials: HA
authors.lastname: Lam
authors.forename: J M
authors.initials: JM
authors.lastname: Siegel
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002352:Carrier Proteins / Q000134:cerebrospinal fluid*; D004285:Dogs; D004435:Eating / Q000502:physiology*; D005260:Female; D005508:Food Deprivation / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D009290:Narcolepsy / Q000134:cerebrospinal fluid* / Q000235:genetics; D009479:Neuropeptides / Q000134:cerebrospinal fluid*; D000068797:Orexins; D012892:Sleep Deprivation
chemical_list: D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins