Kivonat:
The effects of the widely used selective serotonin reuptake
inhibitor (SSRI) antidepressants on sleep have been intensively
investigated. However, only a few animal studies examined the
effect of escitalopram, the more potent S-enantiomer of
citalopram, and conclusions of these studies on sleep
architecture are limited due to the experimental design. Here,
we investigate the acute (2 and 10 mg/kg, i.p. injected at the
beginning of the passive phase) or chronic (10 mg/kg/day for 21
days, by osmotic minipumps) effects of escitalopram on the sleep
and quantitative electroencephalogram (EEG) of Wistar rats. The
first 3 h of EEG recording was analyzed at the beginning of
passive phase, immediately after injections. The acutely
injected 2 and 10 mg/kg and the chronically administered 10
mg/kg/day escitalopram caused an approximately three, six and
twofold increases in rapid eye movement sleep (REMS) latency,
respectively. Acute 2-mg/kg escitalopram reduced REMS, but
increased intermediate stage of sleep (IS) while the 10 mg/kg
reduced both. We also observed some increase in light slow wave
sleep and passive wake parallel with a decrease in deep slow
wave sleep and theta power in both active wake and REMS after
acute dosing. Following chronic treatment, only the increase in
REMS latency remained significant compared to control animals.
In conclusion, adaptive changes in the effects of escitalopram,
which occur after 3 weeks of treatment, suggest desensitization
in the function of 5-HT(1A) and 5-HT(1B) receptors.
