Extinction of conditioned opiate withdrawal in rats is blocked by intracerebroventricular infusion of an NMDA receptor antagonist

► The neurobiology of extinction of cue-induced drug withdrawal is poorly understood. ► We studied morphine withdrawal-induced conditioned place aversion in rats. ► We found that extinction in this paradigm is dependent upon brain NMDA receptors. ► The specific locus of the critical NMDA receptors is not yet known.