Antiarrhythmic effect of crotonoside by regulating sodium and calcium channels in rabbit ventricular myocytes

Publication date: Available online 18 January 2020Source: Life SciencesAuthor(s): Zhipei Liu, Yuzhong Jia, Lv Song, Youjia Tian, Peipei Zhang, Peihua Zhang, Zhenzhen Cao, Jihua MaAbstractAimsDetect the antiarrhythmic effect of crotonoside (Cro).Main methodsWe used whole-cell patch-clamp techniques to detect the effects of Cro on action potentials (APs) and transmembrane ion currents in isolated rabbit left ventricular myocytes. We also verified the effect of Cro on ventricular arrhythmias caused by aconitine in vivo.Key findingsCro reduced the maximum depolarization velocity (Vmax) of APs and shortened the action potential duration (APD) in a concentration-dependent manner, but it had no significant effect on the resting membrane potential (RMP) or action potential amplitude (APA). It also inhibited the peak sodium current (INa) and L-type calcium current (ICaL) in a concentration-dependent manner with half-maximal inhibitory concentrations (IC50) of 192 μmol/L and 159 μmol/L, respectively. However, Cro had no significant effects on the inward rectifier potassium current (IK1) or rapidly activating delayed rectifier potassium current (IKr). Sea anemone toxin II (ATX II) increased the late sodium current (INaL), but Cro abolished this effect. Moreover, Cro significantly abolished ATX II-induced early afterdepolarizations (EADs) and high extracellular Ca2+ concentration (3.6 mmol/L)-induced delayed afterdepolarizations (DADs). We also verified that Cro effectively delay...

Source: Life Sciences - January 18, 2020 Category: Biology Source Type: research