Intrinsic effects of the benzodiazepine receptor antagonist RO 15-1788 in sleepy and alert subjects.

The present paper investigated the differential effects of 5 mg, 60 mg and 120 mg of the benzodiazepine receptor antagonist RO 15-1788 on the ability to resist sleep of sleepy and alert subjects. Repeated administrations of 5 mg potentiated the hypnotic effects of sleep-deprivation in alert subjects and decreased the hypnotic effects in sleepy subjects. Similar differential effects were found with respect to two factors of subjective mood. The two higher levels of the drug decreased sleepiness more in sleepy than in alert subjects. These results are interpreted to support the hypothesis that the effects of RO 15-1788 may be dependent on the level of an endogenous benzodiazepine-like sleep factor.