CNQX INFUSED INTO RAT HIPPOCAMPUS OR AMYGDALA DISRUPTS THE EXPRESSION OF MEMORY OF 2 DIFFERENT TASKS

The bilateral infusion of CNQX (0.5 or 1.25 μg) into the amygdala or dorsal hippocampus 10 min prior to a retention test partially blocked the expression of step-down inhibitory avoidance in rats 24 h after training. When infused into both the amygdala and the hippocampus at a dose of 0.5 μg. CNQX caused a complete blockade of the expression of that task. Retention test performance recovered 2 h after the infusions. In rats trained for habituation to a novel environment and tested 24 h later, pretest intrahippocampal CNQX (0.5 μg) blocked the expression of retention at a dose of 0.5 μg, and intra-amygdala CNQX (0.5 or 1.25 μg) had no effect. The data suggest that, up to at least 1 day after training, memory of the avoidance task depends on glutamate acting on non-NMDA receptors in both the hippocampus and the amygdala, whereas memory of the habituation task depends on non-NMDA receptor activity in the hippocampus but not the amygdala. © 1978 Academic Press, Inc.