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目的 观察肿瘤坏死因子 -α(TNF-α)对人脐静脉内皮细胞株 ECV30 4钙激活钾通道 (BKca)的影响以及 G蛋白是否在此过程中起作用。方法 细胞贴附式膜片箝技术。结果 发现 ECV30 4细胞膜上存在大电导钙激活钾通道 (BKca) ,它的电导是 (2 0 2 .5 4± 16 .6 2 ) p S,其活动可被 2 0 0 U / m l TNF-α增强 ,G蛋白在此过程中起介导作用。结论 TNF-α作用于内皮细胞 ,快速激活 BKca,促进钾离子大量外流 ,使细胞膜发生超极化 ,增大静息钙离子内流的电化学驱动力 ,开放静息钙通道升高静息胞内钙离子浓度。G蛋白可增强此激活效应。
Objective To investigate the effect of tumor necrosis factor-α (TNF-α) on the ECV30 4 calcium-activated potassium channel (BKca) in human umbilical vein endothelial cells and whether G-protein plays a role in this process. Methods Cell attachment patch clamp technique. The results showed that there is a large conductance calcium-activated potassium channel (BKca) on the ECV30 4 membrane and its conductance is (20.254 ± 16.62) pS, and its activity can be increased by 200 U / ml TNF-α Enhanced, G protein plays a mediating role in this process. Conclusions TNF-α acts on endothelial cells and rapidly activates BKca, promotes the outflow of potassium ions, hyperpolarizes the cell membrane, increases the electrochemical driving force of resting calcium influx, and opens up a resting calcium channel to elevate the resting cells Calcium ion concentration. G protein enhances this activation effect.