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mg kg) on the day before treatment with amitriptyline, on days 1 and 5 of the treatment and on day 6, when the drug was withdrawn.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.
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience