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目的 观察咪唑安定复合异丙酚对大鼠心室肌细胞电生理活动的影响。方法 急性分离的大鼠单个心室肌细胞，采用膜片钳技术，观察咪唑安定、异丙酚及其复合应用时对Ｌ－型钙通道电流（Ｉｃａ）及动作电位的影响。结果 咪唑安定３μｍ ｏｌ·Ｌ－ １ 或１５μｍ ｏｌ·Ｌ－ １、异丙酚５０μｍ ｏｌ·Ｌ－ １ 或２５０μｍ ｏｌ·Ｌ－ １分别使Ｉｃａ 较用药前下降１８．８％ 和４２．０％ 、２９．２％ 和５２．５％ （Ｐ均＜ ０．０５，ｎ＝ ５）。两药复合应用时则使Ｉｃａ 较用药前下降２１．２％ 和４３．８％ （Ｐ均＜ ０．０５，ｎ＝ ５）。咪唑安定、异丙酚及其复合应用时对心肌细胞静息膜电位均未见明显影响，动作电位幅度也未见显著改变。但２５０μｍ ｏｌ·Ｌ－ １异丙酚使动作电位时程缩短（Ｐ＜ ０．０５）。结论 异丙酚、咪唑安定及两药复合应用时对产生心肌负性肌力作用与其抑制心肌细胞Ｌ－钙通道电流有关。
Objective To observe the effect of midazolam combined with propofol on electrophysiological activity of ventricular myocytes in rats. Methods Acute isolated rat ventricular myocytes were treated with patch clamp technique to observe the effect of midazolam and propofol on the L-type calcium channel current (Ica) and action potential. Results Imidazepam 3μmol·L-1 or 15μmol·L-1, propofol 50μmol·L-1 or 250μmol·L-1 decreased Ica by 18.8% and 42.0%, respectively, 29.2% and 52.5% respectively (all P <0.05, n = 5). The combination of the two drugs decreased the Ica by 21.2% and 43.8% compared with that before treatment (P <0.05, n = 5). Midazolam, propofol and its composite application of myocardial cell resting membrane potential had no significant effect, the action potential amplitude has not changed significantly. However, 250μmol·L-1 propofol shortened the duration of action potential (P <0.05). Conclusion Propofol, midazolam and the combination of the two drugs have a negative effect on the production of myocardial negatively on the inhibition of L-type calcium currents in cardiomyocytes.