Attenuation of hippocampal inhibition by a NMDA (N-methyl-D-aspartate) receptor antagonist.

The effects of the competitive NMDA (N-methyl-D-aspartate) receptor antagonist, APV (2-amino-5-phosphonopentanoate; AP5), were examined in the hippocampal slice preparation. APV (50-100 microM) attenuated inhibition of the orthodromically evoked population spikes in the CA1 region produced by a conditioning stimulus to the alveus or to the stratum radiatum. This suggests that NMDA receptors contribute to synaptic activation of the inhibitory interneurons by a single afferent volley.