摘要
目的:研究利多卡因对大鼠心室肌瞬时外向钾电流的影响,探讨利多卡因抗心律失常是否与影响瞬时外向钾电流有关。方法:酶消化法急性分离大鼠心室肌细胞,采用全细胞膜片钳技术,记录不同浓度利多卡因对大鼠心室肌细胞瞬时外向钾电流的影响并做出量效曲线,求得其半数抑制浓度。结果:钳制电压-80mV,刺激电压+70mV条件下,临床相关浓度的利多卡因10μmol/L使瞬时外向钾电流的电流幅值降低(17.9±6.4)%(t=7.986,P<0.01),冲洗后,瞬时外向钾电流能够完全恢复。10,50,100,500,1000,5000μmol/L的利多卡因抑制瞬时外向钾电流呈浓度依赖性,电流抑制率分别为(17.9±6.4)%,(25.2±4.4)%,(30.6±8.6)%,(53.2±4.5)%,(71.8±8.9)%,(94.1±2.2)%,其半数抑制浓度为672μmol/L。结论:利多卡因可以明显阻滞大鼠心室肌的瞬时外向钾电流。
AIM:To study the influence of lidocaine on transient outward potassium currents in ventricular myocardium of rats, in order to investigate whether the antiarrhythmic action of lidocaine is related to transient outward potassium currents. METHODS:The ventricular myocardium of rats was quickly separated with the method of enzyme digestion,and the whole-cell patch clamp technique was used to record the influence of lidocaine on transient outward potassium currents of rats' ventricular myocardium,and then the dose-response curve was made,and the inhibitory concentration 50%(IC50) was also calculated. RESULTS:Lidocaine dose-dependently blocked the transient outward potassium currents evoked by a voltage step from a holding potential of -80 mV to +70 mV.Transient outward potassium peak currents was reduced by(17.9±6.4)%by clinically relevant concentration of lidocaine(10 μmol/L) (t=7.986,P< 0.01),and when lidocaine was washed out,transient outward potassium could recover completely.Transient outward potassium currents were dose-dependently inhibited by lidocaine of 50,100,500,1 000,5 000 μmol/L.The inhibitive rates of current were(17.9±6.4)%,(25.2±4.4)%,(30.6±8.6)%,(53.2±4.5)%,(71.8±8.9)%,(94.1±2.2)%respectively,and the mean IC50 value was 672 μmol/L. CONCLUSION:Lidocaine can significantly inhibit the transient outward potassium currents in the ventricular myocardium of rats.
出处
《中国临床康复》
CSCD
北大核心
2005年第15期66-68,共3页
Chinese Journal of Clinical Rehabilitation
