Effect of exogenous phosphocreatine on natrium current in ischemic ventricular myocytes of guinea pig

Objective: The aim of this study is to determine the effect of exogenous phosphocreatine(PCr) with different concentration on natrium ( I_Na ) current in guinea pig ischemic ventricular myocytes and to explore the antiarrhythmia mechanism in the treatment of ischemic heart disease. Methods: Ventricular myocytes were isolated enzymatically from left ventricular of guinea pig. Peak I_Nacurrent was recorded using patch clamp techniques in the whole-cell configuration when myocytes had been superfused with normal Tyrode solution, simple ischemic solution, ischemic solution containing PCr with different concentration of 5, 10, 20, 30 mmol/L for 10 minutes respectively. Results: Peak I_Na current density of myocytes superfused with simple simulated ischemic solution was significantly reduced by 80.1?2.5%(p<0.05)compared with myocytes superfused with normal Tyrode solution. Ischemic solution containing PCr of 5, 10, 20, 30mmol/L reduced peak I_Na current density by 56.2?4.6%(p<0.05)；30.3?5.3%(p<0.05)；39.0?5.5%(p<0.05)；42.6?4.8%(p<0.05)respectively. There was Statistical significance among ischemic solution containing PCr of 10 and 5, 20, 30 mmol/L(p<0.05)。Conclusion: PCr could reverse the inhibition of I_Nacurrent under ischemic condition, which could be the mechanism responsible for arrhythmia prevention in ischemia heart disease. 0~10mmol/L PCr exerted significant dose-effect relationship and concentration more than 10mmol/L could slightly decrease I_Na current density.