Sleep-wake effects of meta-chlorophenyl piperazine and mianserin in the behaviorally depressed rat.

The present study examined the effects of meta-chlorophenyl piperazine (mCPP) and mianserin on the sleep-wake cycle of the clomipramine-induced behaviorally screened depressed rats. Six-hour polygraphic recordings were made between 06:00 and 12:00 h, after a single injection of either saline or mianserin or mCPP into the lateral cerebral ventricle (i.c.v.) of both the depressed (n=12) and control rats (n=12). The injection of mCPP in the depressed rats caused a significant reduction in the total duration and number of rapid eye movement (REM) sleep episodes while it increased the REM sleep onset latency compared to the control saline injections. The injection of mianserin in the depressed rats also caused a significant reduction in the total duration and number of REM sleep episodes without changing the REM sleep latency. These results demonstrate for the first time that the central administration of mCPP and mianserin could act as an antidepressant in the clomipramine-induced rat model of depression.