Hypocretin release in normal and narcoleptic dogs after food and sleep deprivation, eating, and movement.
|Title||Hypocretin release in normal and narcoleptic dogs after food and sleep deprivation, eating, and movement.|
|Publication Type||Journal Article|
|Year of Publication||2002|
|Authors||Wu, M-F, John J, Maidment N, Lam HA, Siegel JM|
|Journal||American journal of physiology. Regulatory, integrative and comparative physiology|
|Date Published||2002 Nov|
|Keywords||Aging, Animals, Body Weight, Carrier Proteins, Dogs, Eating, Female, Food Deprivation, Intracellular Signaling Peptides and Proteins, Male, Motor Activity, narcolepsy, Neuropeptides, sleep deprivation|
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.
|Alternate Journal||Am. J. Physiol. Regul. Integr. Comp. Physiol.|