INDUCTION OF LONG-LASTING POTENTIATION BY SEQUENCED APPLICATIONS OF ISOPROTERENOL

NOREPINEPHRINE is associated with long-lasting modifications of neuron al activation in hippocampal slices. Long-lasting potentiation is prod uced by a single application of 1.0 mu M isoproterenol (a beta-adrener gic antagonist) to the dentate gyrus. The results of the present work indicate that a much lower 75 nM concentration of isoproterenol produc es long-lasting potentiation in the dentate gyrus if it is perfused in two applications separated by a 30 min wash. The potentiation so prod uced is prevented by beta-adrenergic receptor antagonists, but not pre vented by the NMDA receptor antagonist aphosphonopentanoic acid. The i mplication of these results is that long-lasting potentiation in the d entate gyrus can be produced by more than one beta-adrenergic-activate d mechanism.