Effect Of Breviscapin On I_Na Channel Current In Isolated Ventricular Myocytes Of Rats

Objective:The effects of breviscapine on I_Na channel in isolated ventricular myocytes of rats were determined. The mechanism of breviscapine at the ionic channel level was explored. Methods:Single ventricular myocytes of rats were isolated by enzymatic dissociation. The whole-cell patch-clamp recording technique was used to record the change of I_Na channel current influenced by breviscapine. Results:(1) Breviscapine decreased the I_Na channel current in a dose-dependent andvoltage-dependent manner in ventricular myocytes of rats.(2) The current-voltage curve was significantly decreased. Breviscapin at concentrations of 1, 3, 30, 100 mg·L^-1 respectively decreased I_Na current density (7.98±0.6) %, (37.73±2.31) %, (65.58%±2.9) % and (88.09±5.6) %. I_Na was inhibited in a voltage-dependent manner, showing a significant attenuating effect at test potentials from -30 mV to 0.(3) The I_Na inactivation curve was shifted to left and the activation curve was shifted to right.(4) Breviscapine could make the recovery curve slower.Conclusions:Breviscapine concentration-dependently decreased I_Na channel current in rat ventricular myocytes.