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The present study investigated the modulation by beta-adrenoceptors (beta-AR s) of excitatory synaptic transmission in layer Ⅴ/Ⅵ pyramidal neurons of the rat medial prefrontal cortex (mPFC),using whole-cell patch clamp recording.Isoproterenol (ISO),a selective beta-AR agonist,induced a significant increase in the frequency of spontaneous excitatory post-synaptic currents (sEPSCs) and miniature excitatory post-synaptic currents (mEPSC s),which could be blocked by the beta-AR antagonist propranolol.The ISO facilitation of the frequency of mEPSCs no longer appeared when the voltage-gated Ca2+ channel blocker cadmium was pre-administered.ISO significantly enhanced the evoked excitatory post-synaptic currents (eEPSCs) mediated by non-NMDA receptors and NMDA receptor.It also enhanced the currents induced by pressure-or bath-applied NMDA.The ISO facilitation of NMDA-R mediated eEPSC and NMDA-induced current was partly or completely blocked in the presence of Rp-cAMPS,a protein kinase A (PKA) inhibitor.ISO induced a marked decrease in the paired-pulse facilitation of the non-NMDA-R and NMDA-R mediated eEPSCs.The present study provides the first electrophysiological demonstration that activation of beta-AR s facilitates excitatory synaptic transmission in the mPFC through both pre-and post-synaptic mechanisms.