LTP IN THE LATERAL PERFORANT PATH IS BETA-ADRENERGIC RECEPTOR-DEPENDENT

NOREPINEPHRINE induces an activity-independent long-lasting depression of synaptic transmission in the lateral perforant path input to denta te granule cells, whereas high frequency stimulation induces activity- dependent long-term potentiation (LTP). We investigated the role of en dogenous activation of beta-adrenergic receptors in LTP of the lateral and medial perforant paths under conditions affording selective stimu lation of these pathways in the rat hippo-campal slice. Propranolol (1 mu M), a beta-receptor antagonist, blocked LTP induction of both late ral and medial perforant path-evoked field excitatory postsynaptic pot entials. The results indicate a broad requirement for norepinephrine i n different types oi synaptic plasticity, including activity-independe nt depression an activity-dependent LTP in the lateral perforant path.