粉防己碱对豚鼠心室肌细胞延迟整流钾通道的影响

Effects of Tetradrine on Delayed Rectifier Potassium Channel Currents in Isolated Ventricular Myocytes of Guinea Pig

应用膜片钳全细胞记录技术研究了粉防己碱（ｔｅｔｒａｄｒｉｎｅ，Ｔｅｔ）对豚鼠心室肌细胞延迟整流钾电流（Ｉｋ）的影响。结果发现：（１）Ｔｅｔ１０－６ｍｏｌ／Ｌ对心室肌细胞Ｉｋ的外向部分有显著的激活作用。（２）Ｔｅｔ对Ｉｋ外向部分的激活作用呈剂量依赖性。阈浓度为３×１０－８ｍｏｌ／Ｌ，最大有效浓度为３×１０－５ｍｏｌ／Ｌ。（３）Ｔｅｔ使心室肌细胞Ｉｋ的外向部分呈时间依赖性增加。结果提示：Ｔｅｔ对Ｉｋ的外向部分有激活作用，这种激活作用可能是其降低心肌收缩力、抗高血压和抗心律失常的作用机制之一。

The effects of tetradrine (Tet) on delayed rectifier potassium channel currents (I k) in a single cell of ventricular myocytes in guinea pig were studied using the whole cell recording patch clamp technique. The results demonstrated that: (1) The out part of I k was significantly activated by Tet (10 -6 mol/L). (2) Tet caused a dose dependent increase in I k of the ventricular myocytes. The threshold concentration of Tet for I k was 3×10 -8 mol/L. And the maximum effective concentration of Tet for I k was 3×10 -5 mol/L. (3) Tet caused a time dependent increase in I k of the ventricular myocytes. The results suggested that Tet has an activitating effect on I k, Which might be one of the molecular mechanisms of the actions of antihypertension, reducing contractility and antiarrhythmic.