TASTE CONDITIONING EFFECTS OF BUPRENORPHINE IN MORPHINE-NAIVE AND MORPHINE-EXPERIENCED RATS

Male Sprague-Dawley rats were injected daily with saline (morphine-nai ve rats) or 20 mg kg(-1) morphine (morphine-experienced rats), startin g 15 days before the experiment. Subsequent taste conditioning indicat ed that 0.1 mg kg(-1) buprenorphine significantly decreased 0.025% sac charin consumption in morphine-naive, but not in morphine-experienced rats. A 10 mg kg(-1) dose of morphine gave similar results, while d-am phetamine (0.75 mg kg(-1)) was consistently aversive. It was concluded that morphine experience selectively blocks the aversive effects of b uprenorphine in rats; thus it possibly increases the potential for bup renorphine abuse. (C) 1998 The Italian Pharmacological Society.