| 肿瘤坏死因子—α激活ECV304钙激活钾主G蛋白的增强效应 |
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| 作者姓名： | Lin L Zheng Y Qu J Bao G |
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| 作者单位： | 中国医学科学院中国协和医科大学基础医学研究所生理研究室!北京100005(林琳,郑永芳,屈金河),中国医学科学院中国协和医科大学基础医学研究所生理研究室!北(鲍光宏) |
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| 基金项目： | 国家自然科学基金重点项目!(39730 2 2 0 ) |
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| 摘 要： | 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。
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| 关 键 词： | 钙激活钾通道 肿瘤坏死因子－α G蛋白 增强效应 |
| 修稿时间： | 1999-07-14 |
G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304 |
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| Lin L,Zheng Y,Qu J,Bao G.G-protein potentiates the activation of TNF-alpha on calcium-activated potassium channel in ECV304[J].Acta Academiae Medicinae Sinicae,2000,22(3):232-236. |
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| Authors: | Lin L Zheng Y Qu J Bao G |
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| Institution: | Department of Physiology, Institute of Basic Medical Sciences, CAMS, PUMC, Beijing 100005, China. |
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| Abstract: | OBJECTIVE: Observe the effect of tumor necrosis factor-alpha (TNF-alpha) on calcium-activated potassium channel in ECV304 and the possible involvement of G-protein mediation in the action of TNF-alpha. METHOD: Using the cell-attached configuration of patch clamp technique. RESULTS: (1) the activity of high-conductance calcium-activated potassium channel (BKca) was recorded. Its conductance is (202.54 +/- 16.62) pS; (2) the activity of BKca was potentiated by 200 U/ml TNF-alpha; (3) G-protein would intensify this TNF-alpha activation. CONCLUSIONS: TNF-alpha acted on vascular endothelial cell ECV304 could rapidly activate the activity of BKca. Opening of BKca resulted in membrane hyper-polarization which could increase electro-chemical gradient for the resting Ca2+ influx and open leakage calcium channel, thus resting cytoplasmic free Ca2+ concentration could be elevated. G-protein may exert an important regulation in this process. |
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