THE NMDA RECEPTOR ANTAGONIST CPP IMPAIRS CONDITIONED TASTE-AVERSION AND INSULAR CORTEX LONG-TERM POTENTIATION IN-VIVO

It has been proposed that long-term potentiation (LTP) a form of activ ity-dependent modification of synaptic efficacy, may be a synaptic mec hanism for certain types of learning. Recent studies on the insular co rtex (IC) a region of the temporal cortex implicated in the acquisitio n and storage of conditioned taste aversion (CTA), have demonstrated t hat tetanic stimulation of the basolateral nucleus of the amygdala (Bl a) induce an N-methyl-D-aspartate (NMDA) dependent LTP in the IC of ad ult rats in vivo. Here we present experimental data showing that intra cortical administration of the NMDA receptor competitive antagonist CP P (-3(-2 carboxipiperazin-4-yl)-propyl-1-phosphonic acid) disrupts the acquisition of conditioned taste aversion, as well as, the IC-LTP ind uction in vivo. These findings are of particular interest since they p rovide support for the view that the neural mechanisms underlying NMDA dependent neocortical LTP, constitute a possible mechanism for the le arning related functions performed by the IC. (C) 1998 Elsevier Scienc e B.V. All rights reserved.