Beta-receptor agonist increases voltage-gated Naplus currents in medial prefrontal cortex pyramidal neurons

Voltage-gated Na+ currents were recorded in cell-attached configuration from mPFC pyramidal neurons in slices obtained from 3-weeks-old rats. Isoproterenol (2 µM) did not influence maximal amplitude of Na+ currents (43.7±8.6 pA in control and 41.6±8.1 pA in the presence of the drug, P>0.05, n=9). The β-receptor agonist however increased submaximal Na+ currents (145±6.0% after β-receptor stimulation vs. 100% in control, P<0.001, n=10). This effect was abolished by β-receptor antagonist propranolol (30–60 µM). Isoproterenol (2 µM) depolarized the membrane potential recorded in perforated-patch configuration (−71.7±3.5 mV in control and −69.5±3.9 mV in the presence of the drug P<0.05, n=3). This depolarization was absent when cesium ions (3 mM) were added to the bath. It is concluded that isoproterenol increses submaximal voltage-gated Na+ currents in mPFC pyramidal neurons.