Fig. 3.

Discriminative stimulus effects of a combination of midazolam and flunitrazepam after administration of vehicle (○) or various doses of flumazenil in four monkeys (subjects RO, SA, LI, and NI). Abscissa, dose in milligrams per kilogram body weight with the top label on the abscissa indicating the dose of midazolam and the bottom label indicating the dose of flunitrazepam; data above V represent the effects of vehicle. Doses of midazolam and flunitrazepam were multiples of ED₅₀ values obtained when that drug was studied alone; those values were 0.097 mg/kg for midazolam and 0.12 mg/kg for flunitrazepam. Ordinate, mean (±1 S.E.M.) percentage of total responding that occurred on the midazolam lever.