Abstract

The effects of buprenorphine and diprenorphine were examined in squirrel monkeys responding under a multiple fixed-ratio, fixed-interval schedule of food presentation. Buprenorphine (0.003-1.0 mg/kg) produced dose-dependent decreases in rates of responding under both components of the multiple schedule. These effects of buprenorphine (greater than 0.03 mg/kg) were still apparent 1 and 2 days after administration. Diprenorphine decreased rates of responding in a manner similar to that of buprenorphine; however, diprenorphine was less potent than buprenorphine and its duration of action was shorter. Buprenorphine-induced decreases in rates of responding under both components of the multiple schedule were antagonized by naloxone (0.1-1.0 mg/kg), whereas those of diprenorphine were not. At 0.3 mg/kg of naloxone the buprenorphine dose-effect curve was shifted approximately 1 log U to the right. Buprenorphine did not antagonize morphine-induced decreases in rates of responding under the multiple schedule; however, effects of morphine were antagonized by both naloxone and diprenorphine. Finally, the effects of buprenorphine were not attenuated when buprenorphine was administered once daily for 17 days.