Effects of acute and chronic treatment with amitryptyline on the sleep-wake activity of rats.
Amitriptyline (1, 5 or 15 mg/kg intraperitoneally, twice a day) was administered to rats and the sleep-wake activity was recorded for either 24 hr (1 mg/kg) or 12 hr (5 or 15 mg/kg) on the day before treatment with amitriptyline, on days 1 and 5 of the treatment and on day 6, when the drug was withdrawn. In the first 3 hr amitriptyline increased non-REM sleep (NREMS), and decreased REM sleep (REMS) and wakefulness; the effects were dose-dependent. The changes in non-REM sleep and wakefulness (W) were followed by a compensatory reaction 6-12 hr after the treatment. The effects of chronic injection of amitriptyline on non-REM sleep revealed a definite decrease only in the case of the 15 mg/kg dose. Rebound of REM sleep appeared after withdrawal of the 5 and 15 mg/kg doses. Amitriptyline at 1 mg/kg had no effect on the sleep-wake activity during the dark period. The results show that the increase in non-REM sleep is as characteristic of amitriptyline as the reduction of REM sleep, and that these effects are resistant to chronic treatment when the dose is small.
D000639:Amitriptyline / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography; D008297:Male; D051381:Rats; D012890:Sleep / Q000187:drug effects*; D012895:Sleep, REM / Q000187:drug effects; D013997:Time Factors; D014851:Wakefulness / Q000187:drug effects*
D000639:Amitriptyline