The NMDA receptor antagonist MK-801 blocks acquisition and extinction of conditioned hypoalgesic responses in the rat.


The role of the N-methyl-D-aspartate (NMDA) receptor in Pavlovian conditioning of hypoalgesic responses in the hotplate apparatus was examined using the non-competitive NMDA antagonist MK-801. Either MK-801 or saline were administered before the training phase, test phase, or both, and MK-801 disrupted the acquisition and extinction but not the expression… (More)