Effects Of Cyclovirobuxine D On The Action Potential Of Ventricular Myocytes In Guinea Pig

Objective:To investigate the effect of Cyclovirobuxine D(CVB-D) on action potentials in isolated guinea pig ventricular myocytes.Methods:The single myocytes were enzymatically obtained from the guinea pig hearts and the action potentials were examined by whole-cell patch-clamp technique.Results:4×10-4g/L CVB-D decreased action potential amptitude(APA) from 119.0±2.5mV to 117.8±2.7 mV(n=6,P<0.01),prolonged action potential duration of repolari- zation 50%(APD50) from 593.5±73.7ms to 642.6±45.2ms (n=6,P<0.05).prolonged action potential duration of repolarization 90%(APD90)from 622.0±64.4ms to 663.2±44.6ms (n=6,P<0.05),prolonged action potential duration of repolarization 50% to repolarization 90%(APD50-90) from 22.2±7.2ms to 27.8±7.3ms(n=6,P<0.05),and decreased decay slope of phase 3(V3)from -2.2±0.6V/s to -1.8±0.5V/s(n=6,P<0.05).Compare with the former, 4×10-3g/L CVB-D makes the APD50-90 pass to increase trend gradually,but the variety trend of the V3 decrease gradually,other index sign varieties are consistent.Conclusions:CVB-D decreased APA and V3,and prolonged APD50,APD90,APD50-90, which may be its mechanism of Anti -arrhythmic effect.