Superfusion of clomipramine within the ventromedial hypothalamus selectively suppresses paradoxical sleep in freely moving rats.

Sleep patterns were continuously recorded in rats which received during 2 hours and a half a push-pull superfusion of clomipramine at 10(-6) mol/l or 10(-8) mol/l concentrations, within the ventromedial hypothalamus. The superfusion of 10(-6) mol/l clomipramine resulted in a suppression of paradoxical sleep (PS) and a reduction of slow wave sleep (SWS), whereas lower concentrations of this drug (10(-8) mol/l) suppressed PS but did not affect SWS. In both cases, a secondary rebound of PS was observed. These findings are discussed with regard to the present knowledge of the role of the hypothalamus in sleep.