A possible correlate of the postsynaptic condition for long-lasting potentiation in the guinea pig hippocampus in vitro.

Picrotoxin and 2-amino-5-phosphonovalerate (APV) have previously been reported to influence the production of long-lasting potentiation in the hippocampus (facilitation and depression, respectively). We have examined how these drugs modify the postsynaptic responses to tetanic afferent activation used to elicit long-lasting potentiation. The experiments were performed in the CA1 area of transverse hippocampal slices maintained in vitro. A slow extracellular dendritic negativity-interpreted as a sign of a dendritic depolarizing process-was enhanced by picrotoxin and depressed by APV. This dendritic potential may represent a postsynaptic event involved in the production of long-lasting potentiation.