Effects of orally-administered ethanol and tertiary-butanol on fixed-ratio responding of rats.

Bar-press responding of rats was maintained under a 30-response fixed-ratio schedule of food presentation. Responding was characterized by an initial pause followed by a high rate of responding which prevailed until food delivery. Oral administration (15 minutes pre-session) of ethanol (0.25-6.0 g/kg) or tertiary-butanol (0.25-3.0 g/kg) produced dose-related decreases in responding at the higher doses; tertiary-butanol was 1.6 times as potent as ethanol. The 3.0 g/kg dose of ethanol or the 1.0 g/kg dose of tertiary-butanol decreased responding by about twenty percent when given either 15, 30, or 60 minutes prior to the experimental session. Overall response rate and response rate exclusive of the initial pause were decreased similarly.