碘杂环化合物IHC－72对心肌部分除极和触发活动的影响

Effects of 3,6-Dimethylamino-Dibenzopyriodonium Edetate on Partial Depolarization and Triggered Activity

用常规玻璃微电极技术，观察３，６－（二甲氨基）－二苯骈碘杂环依地酸盐（ＩＨＣ－７２）对豚鼠右０００室乳头肌细胞膜部分除极引发的慢反应动作电位（ＳＡＰ）、哇巴因引发的延迟后除极（ＤＡＤ）及触发活动（ＴＡ）的影响。２．５４μＭＩＨＣ－７２对ＳＡＰ各参数均无影响；２５．４，１０１．６μＭＩＨＣ－７２分别使动作电位幅值（ＡＰＡ）减少７．４％和１９．３％，０相最大上升速率（Ｖ＿（ｍａｘ））减少２．５％和３９．１％，复极１００％的动作电位时程（ＡＰＤ＿（１００））缩短７．１％和４１％。有效不应期（ＥＲＰ）相对延长４．９％和９ｌ．３％，静息膜电位（ＲＭＰ）不受影响。浓度为２５．４μＭＩＨＣ－７２对复极５０％的动作电位时程（ＡＰＤ＿（５０））无影响，而浓度为１０１．６μＭ时能使ＡＰＤ＿（５０）缩短４２．９％，且能抑制由哇巴因诱发的ＤＡＤ及ＴＡ。结果表明：ＩＨＣ－７２对慢钙内流有直接抑制作用；其抑制触发性心律失常的机理与钙拮抗有关。

Standard microelectrode technique was used to study the effects of 3,6-dimethylamino-dibenzopyriodonium edetate(IHC-72)on the slow response action potential(SAP)by partial depolarization,ouabain-induced delayed afterde polarization(DAD)and triggered activity(TA)of isolated guinea pig right ventricular papillary muscles.2.54μMIHC 72 did not affect the parameters of SAP.25.4,101.6μM IHC-72 decreased action potential amplitude(APA)by 7.4% and 19.3%,maximum upstroke velocity(Vmax) by 2.5%and 39.1%,action potential duration at 100%repolarization(APD100) by 7.1%and 41%,The effective refractory period (ERP) was relatively prolonged by 4.9%and 91.3%,and the resting membrane potential(RMP)was not influenced. 25.4 μM IHC-72 did not affect action potential duration at 50%repolarization(APD50),but l01. 6 μMIHC-72 shortened APD50 by 42.9%and inhibited ouabain-induced DAD and TA. It indicates that IHC-72 has a direct inhibitory effect on slow calcium inward current and can inhibit triggered arrhythmia.