Electroacupuncture of Neiguan (PC 6) inhibits enhanced voltage-gated sodium currents in ischemic ventricular myocytes

AbstractObjectiveTo examine the effect of electroacupuncture (EA) at bilateral Neiguan (PC 6) on voltage-gated Na+ currents (INa) and channels (Nav) in ischemic ventricular myocytes.MethodsEA serum was prepared from six male adult Sprague-Dawley rats that had received EA at bilateral Neiguan (PC 6). Eighteen ventricular myocytes were prepared from six SD rats using an enzy-molysis approach. Myocardial ischemia was mimicked by perfusion of ischemic solution. Whole-cell patch-clamping was used to record three currents evoked from isolated cells. The first current was the control, and recorded in absence of ischemic solution current. The second was the ischemic current, and recorded after perfusion of ischemic solution for 5 min, while the EA current was last, and recorded after perfusion of EA serum for 5 min. Nav kinetic curves were fitted using related formulas.ResultsCompared with those in controls, in the presence of ischemic solution, peak amplitudes of INa significantly increased from – 40 mV to +30 mV, and half-maximal inactivation potentials of Nav increased significantly, while half-maximal activation potentials, slope factors and the recovery time from inactivation to activation of Nav were unchanged. Compared with those in the ischemic solution, in the presence of EA serum, peak ischemic current amplitudes significantly reduced from −40 mV to +40 mV, and half-maximal inactivation potentials were restored, while half-maximal activation potentials, slope factors and the recovery time from inactivation to activation of Nav were unchanged.ConclusionEA at bilateral Neiguan (PC 6) can reduce enhanced INa via restoration of delayed Nav inactivation in ischemic ventricular myocytes