The intrinsic effects of sarmazenil on sleep propensity and performance level of sleep-deprived subjects.

The effect of two dosages of sarmazenil (RO 15-3505) on sleep propensity and performance was investigated in a double-blind, placebo-controlled paradigm. The design included three 24-h testing periods, separated by at least one 7-day rest period, commencing after 24-h of sleep deprivation. Twelve normal, healthy, adult males (mean age 27 +/- 2.8 years) were paid to participate. During the experimental periods, they came to the sleep laboratory at 2100 hours and spent the night awake under close supervision. At 0700 hours, a schedule of 7 min "attempting" sleep in bed, 13 min awake outside the bedroom, began. This schedule was maintained for 24 h. Repeated administrations of 1 mg and 2 mg sarmazenil significantly reduced the 24-h levels of total sleep. This was particularly evident during the period 0700-2300 hours. Sarmazenil also significantly improved reaction time and tended to increase the number of correct responses in the "categories search" task. Sarmazenil tended to improve reaction time in the "Stroop" test but this was significant only for the "easy" version of the test during the night.