Puerarin blocks Na(+) current in rat ventricular myocytes

AIM: To study the effect of puerarin (Pue) on Na(+) channel in rat ventricular myocytes. METHODS: Whole-cell patch-clamp technique was applied on isolated cardiomyocytes from rats. RESULTS: Pue inhibited cardiac I(Na) in a positive rate-dependent and dose-dependent manner, with an IC(50) of 349 mumol/L. The kinetics of blockage of cardiac sodium channel by Pue resembled the ClassIa/Ic of antiarrhythmic agents. Pue 300 mumol/L did not alter the shape of the I-V curve of I(Na), but markedly shifted the steady-state inactivation curve of I(Na) towards more negative potential by 15.9 mV, and postponed the recovery of I(Na) inactivation state from (21.9 +/- 1.6) ins to (54.4 +/- 3.4) Ins (P<0.01). It demonstrated that the steady state of inactivation was affected by Pue significantly. CONCLUSION: Pue protected ventricular myocytes against cardiac damage and arrhythmias by inhibiting recovery from inactivation of cardiac Na(+) channels.Chemistry, MultidisciplinaryPharmacology & PharmacySCI(E)中国科学引文数据库(CSCD)0ARTICLE121212-12162