INTERACTIVE AND DISCONTINUOUS LONG-LASTING POTENTIATION IN THE DENTATE GYRUS

NON-overlapping applications of l-isoproterenol, a beta-adrenergic ago nist, and the neuropeptide cholecystokinin 8-S produce long-lasting po tentiation of evoked action potentials in the dentate gyrus. There is no corresponding modification of excitatory post-synaptic potentials. This effect, referred to as interactive long-lasting potentiation, is pharmacologically similar to the long-lasting potentiation produced by discontinuous or non-overlapping applications of l-isoproterenol. Met oprolol or propranolol, both beta-adrenergic antagonists, prevent inte ractive long-lasting potentiation, but D-amino-5-phosphono-pentanoic a cid, an N-methyl-D-aspartate receptor antagonist, does not. Cholecysto kinin 8-S and beta-adrenergic receptors may activate a common intermed iate in the interactive paradigm.