中文摘要：

目的用非洲爪蟾卵母细胞表达之Kv4．2和Kv1．2编码的快和慢钾通道，检验双（7）-他克林对此两种通道是否有抑制作用。方法应用爪蟾卵母细胞注射mRNA进行表达，电压钳记录Kv4．2和Kv1．2钾电流（ⅠK）。结果双（7）-他克林抑制ⅠK（Kv4.2和ⅠK（Kv1.2）的IC50值分别为（0．23±0．05）μmol／L和（0．24±0．06）μmol／L。结论此种抑制效应可能与在双（7）-他克林作用下表达的Kv4．2和Kv1．2钾通道激活曲线向超极化电压方向偏移有关。

英文摘要：

Objective To examine whether bis（7） tacrine exerts a similar inhibitory effects on encoding K^＋ channels expressed in oocytes of Xenopus laevis as reported previously on rat DRG neurons. Methods Transient and sustained potassium currents were recorded using voltage-clamp techniques on oocytes Xenopus expressing Kv4.2 and Kv1. 2 mRNA. Results It has been identified that bis（7）-tacrine inhibited IK（Kv4.2） and ⅠK（Kv1.2） markedly with IC50 values of （0.23±0.05） μmol/L and （0.24±0.06） μmol/L, respectively. Conclusion The inhibition of bis（7）-tacrine on transient and sustained potassium channels was deduced to be caused by shift of activation curves for these two K^＋ channels to the hyperpolarizing direction. These results coincide very well with the phenomenon observed in native KA and KDR channels recorded in rat DRG neurons.