Long-lasting physiological effects of bath applied N-methyl-d-aspartate

The present experiments describe a long-lasting form of potentiation induced in field CA1 of rat hippocampal slices by bath application of N-methyl-d-aspartate (NMDA), in association with low magnesium concentrations, glycine and spermine. The potentiation effect consisted of a 50% increase in slope of field potentials and was stable for at least 80 min post treatment. It was not accompanied by detectable changes in antidromic responses and was completely blocked by an antagonist of NMDA receptor. The possible relationship of pharmacologically induced potentiation to long-term potentiation (LTP) is discussed.