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Acute effects of melatonin on spontaneous and picrotoxin‐evoked sleep–wake behaviour in the rat
Author(s) -
Langebartels Anke,
Mathias Stefan,
Lancel Marike
Publication year - 2001
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1046/j.1365-2869.2001.00257.x
Subject(s) - melatonin , picrotoxin , wakefulness , circadian rhythm , medicine , endocrinology , gabaa receptor , melatonin receptor , sleep (system call) , psychology , electroencephalography , receptor , neuroscience , computer science , operating system
Various studies indicate that exogenous melatonin has hypnotic properties in humans, which may be mediated by its influence on the circadian timing system or direct sleep‐promoting actions, e.g. through a modulation of GABAergic transmission. The aim of the present placebo‐controlled study was to examine the effects of melatonin on sleep in rats and the contribution of γ‐aminobutyric acid (GABA) A receptors. Sleep–wake behaviour was assessed in nine rats after intraperitoneal (i.p.) administration of pharmacological doses of melatonin (5 and 10 mg kg –1 ) and after combined administration of the GABA A receptor antagonist picrotoxin (1.5 mg kg –1 ) and melatonin (10 mg kg –1 ). To prevent chronobiotic effects, melatonin was delivered in the middle of the light period. Neither doses of melatonin exerted significant effects on brain temperature, sleep architecture or sleep electroencephalogram (EEG). Moreover, melatonin failed to attenuate the picrotoxin‐induced promotion of wakefulness. These observations indicate that melatonin hardly influences sleep–wake behaviour in rats.