Quipazine has a biphasic effect on slow wave sleep and reduces REM sleep rebound in REM sleep deprived rats.

Rats implanted with electrodes for polygraphic recording were deprived of REM sleep for 24 hr. Following REM sleep deprivation animals were injected with quipazine maleate (7.5 mg/kg IP) and were polygraphically recorded for 48 hr. The results show that quipazine reduces REM sleep rebound and that it has a biphasic effect on slow-wave sleep: initial 6 hr suppression is followed by a delayed increase in the second 24 hr recording period. The initial suppression of slow-wave sleep we attribute to the stimulation of central serotonergic receptors while the effect on REM sleep rebound may result from quipazine's action on central catecholamines.