TY - JOUR T1 - Chronic chlordiazepoxide and pentobarbital interactions on punished and unpunished behavior. JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 515 LP - 520 VL - 207 IS - 2 AU - D E McMillan AU - J D Leander Y1 - 1978/11/01 UR - http://jpet.aspetjournals.org/content/207/2/515.abstract N2 - Dose-effect curves were determined in rats for the effects of drugs on punished and unpunished responding maintained by fixed-interval schedules of food presentation before, during and after the drinking of large daily doses of chlordiazepoxide and pentobarbital. An average intake of 50 mg/kg/day of chlordiazepoxide produced tolerance to the rate-decreasing effects of chlordiazepoxide on unpunished responding and cross-tolerance to the rate-decreasing effects of pentobarbital. During chlordiazepoxide drinking, rate-increasing effects of both chlordiazepoxide and pentobarbital on punished responding became apparent. There was no evidence for cross-tolerance between chlordiazepoxide and chlorpromazine. An average intake of 100 mg/kg/day of pentobarbital produced similar evidence of tolerance to the rate-decreasing effects of pentobarbital on unpunished responding and cross-tolerance to the rate-decreasing effects of chlordiazepoxide. Removal of chlordiazepoxide from the drinking water temporarily increased unpunished responding; however, 6 weeks after withdrawal of chlordiazepoxide or pentobarbital from the drinking water, the dose-effect curves for injections of these drugs appeared to be returning to their original positions. ER -