EFFECTS OF SELECTIVE ACTIVATION OF THE 5-HT1B RECEPTOR WITH CP-94,253ON SLEEP AND WAKEFULNESS IN THE RAT

The effects of the 5-HT1B receptor agonist CP-94,253 were compared wit h those of the mixed beta-adrenoceptor and 5-HT1A/B receptor antagonis t(+/-)pindolol in rats implanted for chronic sleep recordings. CP-94,2 53 (5.0-10.0 mg/kg) significantly increased waking and reduced slow wa ve sleep (SWS) and REM sleep (REMS). At 2.0-4.0 mg/kg (+/-)pindolol re duced REMS. Pretreatment with (+/-)pindolol (2.0-4.0 mg/kg) reversed t he effect of CP-94,253 on waking and SWS, while REMS remained suppress ed. It is suggested that the 5-HT1B receptor together with other 5-HT receptor subtypes may have a direct regulatory action on sleep and wak ing in the rat.