碘杂环化合物IHC-72对心肌细胞慢钙通道的电压和频率依赖性阻滞效应

采用双微电极电压钳制术研究３，６－（二甲氨基）－二苯骈碘杂环依地酸盐（ＩＨＣ－７２）对家兔心室浦肯野纤维慢内向电流（Ｉｓｉ）的电压和频率依赖性阻滞效应。将控制电位（Ｅｃ）置于－５ｍＶ，维持电位（Ｅｈ）分别置于－３５，－３０，－２０ｍＶ时，１０１．６μｍｏｌ／ＬＩＨＣ－７２灌流２０ｍｉｎ前后的峰值Ｉｓｉ分别从７８．７５±１４．３３，４０．６３±５．６３，１８．８±３．５４ｎＡ降至４９．３８±１０．８４，１９．３８±５．６３，２．５±２．６７ｎＡ，抑制率分别为３７．３％，５２．３％，８６．７％（Ｐ均＜０．０１）。用０．１２５，０．２，０．５Ｈｚ频率分别刺激１０１．６μｍｏｌ／ＬΙΗＣ－７２灌流２０ｍｉｎ前后的标本，峰值Ｉｓｉ从灌流前的７５．３８±１４．０２，７５．６４±１３．８６，７４．９８±１３．１２ｎＡ降至５８．７５±９．５４，３４．３８±１０．１６，２１．２５±１１．２６ｎＡ，抑制率分别为２２．１％，５４．５％，７１．７％，Ｐ均＜０．０１。结果提示：ＩＨＣ－７２对心肌细胞慢钙通道具有电压和频率依赖性阻滞效应。

Voltage and Frequency dependent Effects of 3,6 Dimethelamino Dibenzopyriodonium Edetate on Slow Calcium Current in Cardiac Cell

Abstract The two microelectrode voltage clamp technique was used to study the voltage and frequency dependent effects of 3,6 dimethelamino dibenzo pyriodonium edetate (IHC 72) on slow calcium current (Isi) of isolated rabbit purkinje fibres. As the command potential (Ec) was changed to -5 mV and the holding potential (Eh) changed to -35, -30, -20 mV, 101.6 μmol/L IHC 72 reduced the peak Isi from 78.75±14.33, 40.63±5.63 and 18.80±3.54 nA to 49.38±10.84, 19.38±5.03, and 2.50±2.67 nA, reduced by 37.3%, 52.3% and 86.7% respectively in 20 min (P all<0.01). As the stimulation rates were 0.125,0.2, 0.5 Hz, 101.6 μmol/L IHC 72 inhibited the peak Isi from 75.38±14.02,75.64±13.86,74.98±13.12 nA to 58.75±9.54, 34.38±10.16, 21.25±11.26 nA, inhibited by 22.1%, 54.4%, 71.7% in 20 min (P all<0.01). The results indicated that IHC 72 inhibited Isi in voltage and frequency dependent manners.