Stress or drug priming induces reinstatement of extinguished conditioned place preference

To construct a model for the relapse of drug use, we investigated the reins tatement of morphine-induced conditioned place preference (CPP) in rats. Af ter the morphine CPP paradigm was established, rats were left extinguishing for 9 days, then exposed to 15 min of random foot shock or s.c. drug primi ng with different doses of morphine or amphetamine, respectively. Foot shoc k or a higher dose (0.25 mg/kg) of both drugs could reinstate the CPP induc ed by 4 mg/kg of morphine after a 9-day extinction, while a lower dose (0.1 25 mg/kg) of both drugs had no effect. It is concluded that the CPP extinct ion-reinstatement paradigm might be used as a model to investigate the mech anism of relapse in addicts. Neuroreport 11:2781-2784 (C) Lippincott Willia ms & Wilkins.