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应用膜片钳全细胞记录技术，观察了具有正性肌力作用的苄基异喹啉衍化物ＩＱ２３，即１－〔对甲氧苄基－２－（Ｎ－苄基，Ｎ－甲基）〕－６，７－二甲氧基异喹啉盐酸盐，对豚鼠心室肌分离细胞的Ｃａ２＋通道，以及ＣＨＯＨ１０细胞表达的Ｃａ２＋通道α１亚单位的作用．结果显示，当豚鼠心室肌细胞从保持电位（Ｖｈ）－５０ｍＶ除极至测试电位（Ｖｔ）０ｍＶ时，ＩＱ２３３，１０μｍｏｌ·Ｌ－１分别使Ｃａ２＋电流（ＩＣａ）由对照的（０．４７±０．２３）ｎＡ增至（０．５７±０．２３）和（０．７９±０．３１）ｎＡ（Ｐ＜０．０５）．在ＣＨＯＨ１０细胞Ｖｔ为２０ｍＶ时，ＩＱ２３１０μｍｏｌ·Ｌ－１电压依赖性的增强Ｂａ２＋电流（ＩＢａ），ＩＢａ从（０．４５±０．１０）ｎＡ增至（０．６７±０．２０）ｎＡ（Ｖｈ＝－８０ｍＶ），或从（０．４３±０．０８）ｎＡ增至（０．６０±０．１４）ｎＡ（Ｖｈ＝－４０ｍＶ）．ＩＱ２３１０和３０μｍｏｌ·Ｌ－１还分别使电流－电压曲线的峰值和失活曲线的半失活电位向负膜电位方向移动．实验结果表明，ＩＱ２３通过作用于通道的α１亚单位，对心肌Ｌ型Ｃａ２＋通道产生电压依赖性激动作用，此作用为其正性肌力效应提供了部分解释．
Patch clamp whole cell recording technique was used to observe the positive inotropic effect of benzylisoquinoline derivative IQ23, namely 1- [p-methoxybenzyl-2- (N-benzyl, N-methyl) ] -6,7-dimethoxyisoquinoline hydrochloride on the Ca2 + channel of guinea pig ventricular myocytes and the Ca2 + channel α1 subunit of CHOH10 cells. The results showed that when the guinea pig ventricular myocytes were depolarized from the holding potential (Vh) -50mV to the test potential (Vt) at 0mV, IQ233,10μmol·L-1 decreased the Ca2 + current (ICa) from 0.47 ± 0 .23) nA increased to (0.57 ± 0.23) and (0.79 ± 0.31) nA (P <0.05). When the Vt of CHOH10 cells was 20mV, IQ2310μmol·L-1 increased voltage-dependently the Ba2 + current (IBa) and IBa increased from (0.45 ± 0.10) nA to (0.67 ± 0.20) nA = -80 mV) or from (0.43 ± 0.08) nA to (0.60 ± 0.14) nA (Vh = -40 mV). IQ2310 and 30 μmol·L-1 also shifted the peak of the current-voltage curve and the inactivation potential of the inactivation curve to the negative membrane potential, respectively. The experimental results show that IQ23 exerts a voltage-dependent agonistic effect on the L-type Ca2 + channel of myocardium by acting on the α1 subunit of the channel, and this effect provides a partial explanation for its positive inotropic effect.