AROUSAL-ENHANCING PROPERTIES OF THE CB1 CANNABINOID RECEPTOR ANTAGONIST SR 141716A IN RATS AS ASSESSED BY ELECTROENCEPHALOGRAPHIC SPECTRAL AND SLEEP-WAKING CYCLE ANALYSIS

The effects of the central (CB1) cannabinoid receptor antagonist SR 14 1716A on the sleep-waking cycle were investigated in freely-moving rat s using time scoring and power spectral analysis of the electroencepha logram (EEG). Over a 4-hour recording period, SR 141716A (0.1, 0.3, 1, 3, and 10 mg/kg I.P.) dose-dependently increased the time spent in wa kefulness at the expense of slow-wave sleep (SWS) and rapid eye moveme nt sleep (REMS), delayed the occurrence of REMS but did not change the mean duration of REMS episodes. Moreover, the compound induced no cha nge in motor behavior. At the efficient dose of 3 mg/kg I.P., SR 14171 6A reduced the spectral power of the EEG signals typical of SWS but di d not affect those of wakefulness. Taken together, these results demon strate that the EEG effects of SR 141716A reflect arousal-enhancing pr operties. In addition, the present study suggests that an endogenous c annabinoid-like system is involved in the control of the sleep-waking cycle.