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 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