海葵素对大鼠和豚鼠心室肌细胞钾电流的影响

Effects of Sea Anemone Toxin Anthopleurin-Q on Potassium Currents in Rats and Guinea Pig Ventricular Myocytes

目的研究海葵素-Q（AP-Q）对心室肌细胞钾电流的作用。方法采用酶解法制备豚鼠和大鼠单个心室肌单细胞,应用全细胞膜片钳记录方法记录心室肌细胞钾电流（Ito,IK和IK1）。结果AP-Q3~100nmolL-1浓度依赖性地阻滞Ito,EC50分别为10.5nmolL-1,去极化至＋50mV时,AP-Q10nmolL-1使Ito从给药前的（13.3±3.4）pApF-1升至（19.46±4.3）pApF-1。AP-Q0.1~100nmolL-1浓度依赖性地增大IK和尾电流（IKtail）,EC50分别为4.7和5.0nmolL-1。AP-Q1pmolL-1~100nmolL-1浓度依赖性地增大IK1,EC50值为0.2nmolL-1。结论AP-Q增大IK,Ito和IK1的作用可能是其缩短APD,增大RP的原因。

OBJECTIVE To study the effects of Sea Anemone Toxin Anthopleurin-Q （AP-Q） on potassium currents of rats and guinea pig ventrieular myocytes. METHODS The ventricular cells of guinea pigs and SD rats were obtained by enzymatic dissociation method. Whole cell patch clamp technique was used to record potassium currents, including transient outward potassium currents（Ito）, delayed rectifier potassium current （IK） and inward rectifier potassium current （IKI）. RESULTS AP-Q 3-100 umol·L^-1 increased Ito in rat ventrieular myocytes in a concentration dependent, with ECs0 values of 12.7 nmol·L^-1. At ＋50 mV of test potential, it was increased from （ 13.3 ± 3.4） pA.pF^-1 to （ 19.46±4.3 ） pA-pF^-1 by AP-Q 10 umol·L^-1. AP-Q 0.1-100 umol·L^-1 increased IK and the tail current（ IK tail ） concentration-dependent. The EC50 values were 4.7 and 5.0 nmol·L^-1, respectively. AP-Q 1 pmol·L^-1-100 nmol·L^-1 increased IK1 concentration-dependently, with an EC50 of 0.2 umol·L^-1. CONCLUSION Augmented effect of AP-Q on Ito, IK and IK1 maybe explain partly its effects on shorting APD and increasing absolute value of RP.