用单心室肌细胞动作电位Vmax研究胺碘酮阻断心脏钠通道的作用。

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本条H, Kodama I，神谷K，富山J

用单心室肌细胞动作电位Vmax研究胺碘酮阻断心脏钠通道的作用。

中华药物学杂志。1991 3;102(3):651-6。doi: 10.1111 / j.1476-5381.1991.tb12228.x。

PubMed ID

1364834 (PubMed视图

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摘要

1.在豚鼠心脏分离的心室肌细胞中研究胺碘酮对心脏钠通道的急性影响，并与木素卡因进行比较。2.用全细胞电流钳和电压钳分别通过吸液管电极记录和控制跨膜电位。以动作电位的最大上冲程速度(Vmax)作为钠通道有效性的定性指标。3.在胺碘酮(1微米)或木素卡因(40微米)处理的肌细胞中，0.03 Hz诱导的参考动作电位的Vmax降低了6-11%，表明钠通道的tonic阻塞最小。4.对这些肌细胞应用单一条件去极化导致后续测试动作电位的Vmax显著降低。随着钳位脉冲持续时间的延长，Vmax降低呈单指数函数增强。 Time constants at 0 mV clamp were 25 ms for amiodarone and 122 ms for lignocaine. 5. Vmax recovery of test action potential following a 1000 ms 0 mV clamp was approximated by a dual exponential function. Time constants for the late slow component (tau R) at the resting potential level were 418 ms for amiodarone and 178 ms for lignocaine. tau R values were shortened in a voltage-dependent manner by hyperpolarization during the coupling interval. 6. These findings suggested that amiodarone, like lignocaine, blocks the sodium channel primarily when it is in the inactivated state. Both onset and offset kinetics of the block are very rapid. Such sodium channel blocking characteristics may contribute to its potent antiarrhythmic activity.

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胺碘酮