异丙酚抑制大鼠心室肌细胞短暂外向钾电流

INHIBITION OF TRANSIENT OUTWARD POTASSIUM CURRENT IN RAT VENTRICULAR MYOCYTES BY PROPOFOL

利用全细胞膜片箝技术研究了异丙酚25，50μmol／L对离体大鼠心室肌细胞短暂外向钾通道电流（Ito）的影响。观察到用药后Ito的幅度明显减小，而用不含药物的灌流液冲洗细胞，可使受抑电流部分恢复。当膜电位大于0mV时，异丙酚对Ito的抑制达显著水平，但不改变其电压依赖性和I－V关系中的外向整流特性。上述结果表明，药物对钾电流的作用至少可部分介导其对心脏的保护及抑制某些心律失常的发生，预示其在心脏手术的病人麻醉中可能有良好的应用前景。

Whole-cell Patch-clamp technique was applied to investigate the effect of propofol(25, 50 μmol/L) on transient outward potassium current (Ito) in rat ventricular myocytes. It was shown that the amplitude of Ito was decreased significantly after exposureto propofol. The effect is Partially reversible after washing. At applied potential≥0mV, statistical significant differences reached between propofol (25 and 50μmol/L)group and the control group could be found. The voltuge-dependent manner and the outwbo rectifier character were not affected by the drug at the two concentrations. Itseems possible that the inhibition of potussium channels by propofol could underlie, atleast in port, its beneficial effects in various cardiovascular diseases, including certaintyPes of cardiac arrhythmia.