Puerarin blocks Na+ current in rat ventricular myocytes.
OBJECTIVE
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 INa in a positive rate-dependent and dose-dependent manner, with an IC(50) of 349 micromol/L. The kinetics of blockage of cardiac sodium channel by Pue resembled the ClassIa/Ic of antiarrhythmic agents. Pue 300 micromol/L did not alter the shape of the I-V curve of INa, but markedly shifted the steady-state inactivation curve of INa towards more negative potential by 15.9 mV, and postponed the recovery of INa inactivation state from (21.9+/-1.6) ms to (54.4+/-3.4) ms (P<0.01). It demonstrated that the steady state of inactivation was affected by Pue significantly.


CONCLUSIONS
Pue protected ventricular myocytes against cardiac damage and arrhythmias by inhibiting recovery from inactivation of cardiac Na+ channels.
Zhang
Guang-Qin
GQ
Research Division of Pharmacology, China Pharmaceutical University, Nanjing 210009, China.
Hao
Xue-Mei
XM
Dai
De-Zai
DZ
Fu
Yu
Y
Zhou
Pei-Ai
PA
Wu
Cai-Hong
CH
D000818:Animals; D002469:Cell Separation; D005260:Female; D006352:Heart Ventricles / Q000166:cytology; D007529:Isoflavones / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000166:cytology; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D026941:Sodium Channel Blockers / Q000494:pharmacology*; D015222:Sodium Channels / Q000187:drug effects*
D007529:Isoflavones; D026941:Sodium Channel Blockers; D015222:Sodium Channels; C033607:puerarin