PHARMACOLOGICAL DIFFERENTIATION OF THE EFFECTS OF COACTIVATION OF BETA-ADRENERGIC AND METABOTROPIC GLUTAMATE RECEPTORS IN RAT HIPPOCAMPUS

Activation of metabotropic glutamate receptors (mGluRs) can potentiate the cAMP response elicited by activation of B-adrenergic receptors (b eta ARs) in the hippocampus. We have shown that co-activation of mGluR s and beta ARs induces both an acute depression of excitatory synaptic transmission and a long-lasting excitation of CA1 pyramidal cells. Ho wever, these studies were performed using a non-selective mGluR agonis t. We have now used subtype selective mGluR agonists, and report that while the acute depression of transmission exhibits a pharmacology con sistent with mediation by this mGluR subtype, the lasting excitation o f CA1 pyramidal cells may be mediated by an interaction between beta A Rs and mGluRs that are coupled to phosphoinositide hydrolysis.