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Selective inhibition of physiological late Na+ current stabilizes ventricular repolarization

机译:选择性抑制生理晚期Na +电流稳定心室复极化

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The physiological role of cardiac late Na+ current (I_(Na)) has not been well described. In this study, we tested the hypothesis that selective inhibition of physiological late I_(Na) abbreviates the normal action potential (AP) duration (APD) and counteracts the prolongation of APD and arrhythmic activities caused by inhibition of the delayed rectifier K+ current (I_(kt)). The effects of GS-458967 (GS967) on the physiological late I_(nu) and APs in rabbit isolated ventricular myocytes and on the monophasic APs and arrhythmias in rabbit isolated perfused hearts were determined. In ventricular myocytes, GS967 and, for comparison, tetrodotoxin concentration dependency decreased the physiological late I_(Na) with IC_(50) values of 0.5 and 1.9μM, respectively, and significantly shortened the APD measured at 90% repolarization (APD_(90)). A strong correlation between inhibition of the physiological late I_(Na) and shortening of APD by GS967 or tetrodotoxin (R~2 of 0.96 and 0.97, respectively) was observed. Pre-treatment of isolated myocytes or hearts with GS967 (1 pM) significantly shortened APDgo and monophasic APD90 and prevented the prolongation and associated arrhythmias caused by the I_(kr) inhibitor E4031 (1 μM). In conclusion, selective inhibition of physiological late I_(Na) shortens the APD, stabilizes ventricular repolarization, and decreases the proarrhythmic potential of pharmacological agents that slow ventricular repolarization. Thus, selective inhibition of late I_(Na) may constitute a generalizable approach to stabilize ventricular repolarization and suppress arrhythmogenicity associated with conditions whereby AP or QT intervals are prolonged.
机译:心脏晚期Na +电流(I_(NA))的生理作用尚未得到很好的描述。在这项研究中,我们测试了选择性抑制生理晚期I_(NA)的假设缩写了正常动作电位(AP)持续时间(APD)并抵消了通过抑制延迟整流k +电流引起的APD和心律失常活动的延长(I_ (kt))。确定GS-458967(GS967)对兔子中兔壳体中的生理晚期I_(NU)和AP的影响和分离灌注的心脏中的单选式APS和心律失常的影响。在室心肌细胞,GS967和例如,四曲毒素浓度依赖性分别降低了0.5和1.9μm的IC_(50)值的生理晚期I_(NA),并显着缩短了90%的复极化(APD_(90)中测量的APD )。观察到抑制生理晚期I_(NA)和GS967或四抗毒素(分别为0.96和0.97的R〜2)缩短APD之间的强相关性。与GS967(1PM)的分离的肌细胞或心脏预处理显着缩短APDGO和单张APD90,并预防由I_(KR)抑制剂E4031(1μM)引起的延长和相关的心律失常。总之,选择性抑制生理晚期I_(NA)缩短了APD,稳定心室复极化,并降低了心室再溶解的药理剂的预训练潜力。因此,晚期I_(NA)的选择性抑制可以构成可推广的方法,以稳定心室重新渗透和抑制与延长AP或QT间隔的条件相关的心律源。

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