牛磺酸对低氧条件下豚鼠心室肌细胞动作电位和ATP敏感性钾电流的影响

目的：研究牛磺酸对低氧条件下单个豚鼠心室肌细胞膜上ATP敏感性钾电流（IK-ATP）的影响。方法： 应用100%纯氮饱和灌流液建立低氧模型和膜片钳全细胞记录技术。结果： 与对照组比较，低氧组心肌动作电位时程（APD）明显缩短，同时诱导出IK-ATP；给予牛磺酸后，使低氧时缩短的APD恢复至正常，并能剂量依赖性地抑制IK-ATP。结论： 牛磺酸具有抑制豚鼠心室肌细胞膜上ATP敏感钾通道（KATP）开放的作用。

Effect of taurine on action potentials and ATP-sensitive posstiaum channel activity during hypoxia in ventricular muscle of guinea pig

AIM: To study the effects of taurine on ATP sensitive potassium channel (IK_~-ATP ) during hypoxia in single ventricular myocyte. METHODS: The model of myocardial hypoxia was induced by unmixed and saturated nitrogen. IK_~-ATP activities were measured by whole-cell patch clamp recording. RESULTS: Activities of IK_~-ATP in the cell membrane of hypoxia ventricular myocyte significantly increased, compared to that in the normal. Extracellular injection of taurine (5,10,20 mmol/L) inhibited the increase in the IK_~-ATP activity in the hypoxia myocardium in a concentration-depend manner. Injection of taurine also recovered shorten APD during hypoxia. CONCLUSIONS: Taurine produces its cardioprotective effect by inhibiting the activity of IK_~-ATP in the hypoxia cardiomycytes of guinea pig. The results suggest that the depletion of taurine during myocardial hypoxia contributes to the early activation of the K_~ATP channel. [