中文摘要：

本研究应用全细胞膜片钳技术观察氯胺酮对人心房肌细胞瞬时外向钾电流（transient outward potassium current,Ito）的影响,以了解其作用的部分机制。标本取自心脏瓣膜置换病人的右心耳,采用急性酶解法消化分离人心房肌细胞,室温下以全细胞膜片钳技术记录Ito,分别观察30、100、300和1000μmol·L-1的氯胺酮对Ito的作用。实验过程由pCLAMP9.0软件程序发放刺激和采集信号并存储于计算机中。结果表明,氯胺酮对Ito电流-电压曲线呈浓度依赖性抑制作用,在＋50mV时,30、100、300和1000μmol·L-1的氯胺酮分别阻断Ito峰电流（13.62±0.04）%、（38.92±0.05）%、（72.24±0.10）%和（83.84±0.05）%,其半数有效浓度（IC50）为121μmol·L-1。但是100μmol·L-1氯胺酮对Ito的激活和失活曲线以及复活曲线均无明显影响。由此得知,氯胺酮呈浓度依赖性抑制人心房肌细胞瞬时外向钾电流。

英文摘要：

The effects of ketamine on transient outward potassium current（Ito） of isolated human atrial myocytes were investigated to understand the mechanism of part of its effects by whole-cell patch-clamp.Atrial myocytes were enzymatically isolated from specimens of human atrial appendage obtained from patients under going cardiac valve displacing.Ito is recorded in voltage-clamp modes using the patch-clamp technique at room temperature.Currents signals were recorded by an Axopatch 200B amplifier with the Digidata 1322A-pClamp 9.0 data acquisition system.Ketamine decreased Ito of human atrial myocytes in a dose-dependent manner.The current-voltage curve was significantly lowered,30,100,300,and 1000 μmol·L-1 ketamine decreased respectively Ito current density about（13.62 ± 0.04）%,（38.92 ± 0.05）%,（72.24 ± 0.10）% and（83.84 ± 0.05）% at the potential of 50 mV,with an IC50 of 121 μmol·L-1.The Ito activation curve,inactivation curve and the recovery curve were not altered by ketamine.So,ketamine concentration-dependently decreased Ito of human atrial myocytes.