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目的探讨普罗帕酮对兔心室肌细胞瞬时钠电流(Ⅰ_(Na-T))的张力性阻滞和使用依赖性阻滞作用。方法采用全细胞膜片钳技术检测兔心室肌细胞Ⅰ_(Na-T)的Ⅰ-Ⅴ曲线及不同频率下的峰值电流,并用10μmol/L普罗帕酮溶液灌流干预。结果普罗帕酮灌流后Ⅰ_(Na-T)的Ⅰ-Ⅴ曲线明显上移,峰值电流显著下降〔(3001±383)pA vs.(4193±378)p A,P<0.05〕。以0.06 Hz和1Hz频率刺激时,普罗帕酮未显示使用依赖性阻滞作用。当以2 Hz、5 Hz和10 Hz频率刺激时,阻滞率分别为(22±11)%、(38±14)%和(52±17)%,3组间两两比较以及与对照组和普罗帕酮在0.06 Hz和1 Hz时的阻滞率的差异有显著统计学意义(P<0.05)。结论普罗帕酮对Ⅰ_(Na-T)不但有张力性阻滞作用,也有显著的使用依赖性阻滞作用。
Objective To investigate the effect of propafenone on the tension blockade and the use-dependent block of transient sodium current (Ⅰ-Na-T) in rabbit ventricular myocytes. Methods Whole cell patch clamp technique was used to detect the Ⅰ-Ⅴ curve of Ⅰ-Ⅴ in rabbit ventricular myocytes and the peak currents at different frequencies. The perfusion was performed with 10 μmol / L propafenone. Results The Ⅰ-Ⅴ curve of Ⅰ-Na-T significantly increased after propafenone perfusion, and the peak current decreased significantly [(3001 ± 383) pA vs. (4193 ± 378) pA, P <0.05). Propafenone did not show a use-dependent block when stimulated at 0.06 Hz and 1 Hz. The block rates were (22 ± 11)%, (38 ± 14)% and (52 ± 17)% when stimulated at 2 Hz, 5 Hz and 10 Hz, respectively, compared with the control group And propafenone at 0.06 Hz and 1 Hz, the difference was statistically significant (P <0.05). Conclusions Propafenone not only has the effect of tension block on Ⅰ-Na-T, but also has significant dependence-dependent block.