河豚毒素、利多卡因和胺碘酮对豚鼠心脏浦肯野纤维和乳头肌纤维Vmax的比较作用。

Comparative effects of tetrodotoxin, lidocaine, and amiodarone on Vmax in guinea pig cardiac Purkinje and papillary muscle fibers.

Aomine M

Department of Medicine, Division of Cardiology, Reingold ECG Center, Northwestern University Medical School, Chicago, IL 60611.

Gen Pharmacol. 1989;20(5):575-9. doi: 10.1016/0306-3623(89)90088-8.

Abstract

Electrophysiological effects of three drugs (tetrodotoxin, lidocaine, and amiodarone), which are known to depress Na channels in cardiac tissues, were studied on isolated guinea pig Purkinje fibers, by means of microelectrode techniques, and compared the findings with their effects on the ventricular papillary muscle. 2. Special attention was paid with regard to their effects on the maximum upstroke velocity (Vmax) of action potentials. 3. In Purkinje fibers, tetrodotoxin was the most inhibitory for Vmax, then in descending order, amiodarone, and lidocaine. 4. That is, half maximal inhibition (IC50) of Vmax by tetrodotoxin, lidocaine and amiodarone was approximately 1.7 x 10(-5) M, 1.5 x 10(-4) M and 2.8 x 10(-4) M, respectively. 5. As for papillary muscle, higher concentrations of the three drugs were needed to get similar potency. 6. The relationships between the depression in the Vmax and action potential duration are discussed in conjunction with their antiarrhythmic activities.

摘要

利用微电极技术，研究了已知可抑制心脏组织中钠通道的三种药物（河豚毒素、利多卡因和胺碘酮）对离体豚鼠浦肯野纤维的电生理效应，并将结果与其对心室乳头肌的效应进行比较。2. 特别关注了它们对动作电位最大上升速度（Vmax）的影响。3. 在浦肯野纤维中，河豚毒素对Vmax的抑制作用最强，其次是胺碘酮，利多卡因的抑制作用最弱。4. 也就是说，河豚毒素、利多卡因和胺碘酮对Vmax的半数最大抑制浓度（IC50）分别约为1.7×10⁻⁵ M、1.5×10⁻⁴ M和2.8×10⁻⁴ M。5. 对于乳头肌，需要更高浓度的这三种药物才能达到相似的效力。6. 结合它们的抗心律失常活性，讨论了Vmax降低与动作电位持续时间之间的关系。