Effects Of Hypaconitine Combined With Liquiritin On The MRNA Expression Of Ion Channel Genes Related With Cardiac Muscle Excitation-contraction Coupling

Fuzi has the pharmacological effects of cardiac, anti-inflammatory, anti-tumor, immunoregulative activity etc. Aconitine, mesaconitine and hypaconitine are the main effective components of Fuzi, and also its toxic ingredient, which hypaconitine is the safest. So Licorice is commonly used to combine with Fuzi to reduce the toxicity of Fuzi clinically. Some reserches have found that flavonoids of the active ingredient in licorice could reduce the cardiac toxicity of Fuzi. Currently, most of the research focus on the the material composition after drug combination and the electrical physiology about the compatibility of Fuzi and licorice stuck. It was reported that Ca2+handling proteins are closely related with the cardiac excitation-contraction coupling. So our aim is to further investigate the mechanism of molecular pharmacology of the compatibility of hypaconitine and liquiritin through detecting the gene mRNA and protein expression related with the cardiac excitation-contraction coupling, as well provide some pharmacological evidence for the compatibility of Fuzi clinically.To investigate the effect on the expression of of ion channel genes related with cardiac excitation-contraction coupling by hypaconitine combined with liquiritin in vitro and in vivo, the neonatal rat cardiomyocytes were cultured stability and the spontaneous beating rate in hypaconitine-treated cardiomyocytes were observed, and the toxicity of hypaconitine and liquiritin were detected by MTT assay. Furthermore, the mRNA expression level of Cav1.2, NCX, SCN5A and RyR2 in primary cultured neonatal rat cardiomyocytes and myocardial tissues of adult Wistar rat were determined by real-time fluorescent quantitive PCR(FQ-PCR) after drug treatment of different concerntraton of hypaconitine, liquiritin and the co-administration of hypaconitine and liquiritin. In the current study, hypaconitine increased the spontaneous beating rate significantly and cardiomyocytes stopped beating when the dose of hypaconitine was over 32,μmol/L. Moreover, the survival rate of cardiomyocytes didn't decrease significantly after co-incubation with different concentration of hypaconitine and liquiritin. The in vivo study indicated that hypaconitine significantly down-regulated NCX mRNA expression and up-regulated RyR? mRNA expression, liquiritin displayed a significant down-regulation only for NCX mRNA expression. Intriguingly, the co-administration of liquiritin and high dose of hypaconitine not only siginificantly decreased SCN5A mRNA expression and increased RyR2 mRNA expression, but also showed a siginificant antagonistic action against hypaconitine-induced inhibitory action for NCX mRNA expression. Taken together, the present study suggested that liquiritin could enhanced cardiotonic function of hypaconitine by co-inducing RyR2 mRNA expression, and ameliorated hypaconitine-reduced cardiac arrhythmia by inhibiting SCN5A mRNA expression and antagonizing NCX mRNA abnormal expression induced by hypaconitine.