Therapeutic Effects of Dauricine on Early Afterdepolariztions Induced by Dofetilide

Objective To investigate the effects and possible mechanisms of dauricine(Dau) on early afterdepolarizations induced by dofetilide. Methods Cardiac hypertrophy was induced in rabbits by aortic banding;using conventional microelectrode techniques,the effects of dofetilide at the concentration of 1 μmol·L-1 on action potential duration(APD) and incidence of early afterdepolarizations(EADs) were studied and compared in rabbit papillary muscles between control and different pathological conditions,including hypokalemia and hypertrophy;the effects of Dau in concentrations of 30 μmol·L-1on APD and EADs were observed after EADs were induced by the pathologic conditions mentioned above. Results Compared with control,dofetilide significantly prolonged the APD of rabbit papillary muscle;the same phenomena were also found in hypokalemia and hypertrophy;dofetilide significantly advanced the incidence of EADs in hypokalemia concomitant with hypertrophy;Dau inhibited the prolongation of APD and significantly suppressed the incidence of EADs induced by dofetilide. Conclusion Dau exerts good therapeutic effects on early afterdepolarizations induced by dofetilide and these effects may be associated with inhibition of Dau on several ion channels.