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目的:研究蝙蝠葛碱对豚鼠心室肌细胞快激活(I_(Kr))和慢激活(I_(Ks))延迟整流钾电流及内向整流钾电流(I_(K1))的作用。方法:酶解法制备单个心室肌细胞。电压箝制方式下全细胞记录豚鼠单个心室肌细胞钾通道电流。结果:蝙蝠葛碱1-100μmol·L~(-1)浓度依赖性阻断I_(Ks),I_(Ks-tail)[IC_(50)=33(95 ％可信限:24-46)μmol·L~(-1)]及I_(Kr),I_(Kr-tail)[IC_(50))=16 (95％可信限:13-22)μmol·L~(-1)]。对I_(Ks-tail),I_(Kr-tail)的去激活过程无明显影响,给药前的时间常数分别为(92±18)ms和(140±38)ms,给药后分别为(84±16)ms和(130±26)ms(P>0.05)。蝙蝠葛碱对I_(Ks)的抑制作用具有电压依赖性。 蝙蝠葛碱20μmol·L~(-1)对I_(K1)的内向部分具有阻断作用。结论:蝙蝠葛碱对I_(Kr)和I_(Ks)具有阻断作用,但不影响此两种成分的去激活过程. 蝙蝠葛碱同时具有阻断I_(K1)的作用。
OBJECTIVE: To study the effects of dauricine on delayed rectifier potassium current and inward rectifier potassium current (I_(K1)) in ventricular myocytes of guinea pig ventricular myocytes (I_(Kr)) and slow activation (I_(Ks)). Methods: Single ventricular myocytes were prepared by enzymatic hydrolysis. Whole-cell recording of potassium channel currents in guinea pig ventricular myocytes under voltage-clamping. RESULTS: The concentration of dauricine 1-100 μmol·L -1 dose-dependently blocked I_ (Ks), I_ (Ks-tail) [IC_ (50) = 33 (95% confidence limit: 24-46) μmol · L~(-1)] and I_(Kr), I_(Kr-tail)[IC_(50))=16 (95% Confidence Limit: 13-22) μmol·L~(-1)]. There was no significant effect on the deactivation process of I_ (Ks-tail) and I_ (Kr-tail). The time constants before administration were (92±18) ms and (140±38) ms, respectively. 84±16) ms and (130±26) ms (P>0.05). The inhibitory effect of dauricine on I_ (Ks) was voltage-dependent. Dauricine 20μmol·L -1 could block the inward part of I_ (K1). Conclusion: Dauricine has a blocking effect on I_(Kr) and I_(Ks), but does not affect the deactivation of the two components. Dauricine also has the effect of blocking I_(K1).