内皮素-1对高血压病患者肠系膜动脉平滑肌细胞钙激活钾通道活性的影响  

Regulation of calcium-activated potassium channels of mesenteric artery smooth muscle cells in patients with essential hypertension by endothelin-1

作　　者：罗兴林[1] 何川[1] 杨艳[1] 曾晓荣[1] 魏宗德[1] 

机构地区：[1]泸州医学院心血管病研究所,四川泸州646000

出　　处：《四川医学》2003年第7期697-699,共3页Sichuan Medical Journal

基　　金：卫生部默沙东基金资助项目 (1 997年 );四川省教育厅自然科学基金重点资助项目 编号 1 996 1 6

摘　　要：目的　探讨内皮素 1(ET1)对高血压病患者血管平滑肌细胞KCa通道活性的影响。方法　选择高血压病患者 18例 ,血压正常者 17例 ,两组患者均于腹部手术时取肠系膜动脉小分支用酶消化法获得单个血管平滑肌细胞。以膜片钳技术检测KCa通道的活性 ,记录不同钳制电压下单通道电流的平均开放时间 (To)、平均关闭时间 (Tc)、平均开放概率 (Po)、电流幅值 (Am) ,并绘制成电流 电压关系曲线。再分别加入Ca2 + (10 -8、10 -7、10 -6mol/L)、ET1(2× 10 9mol/L、4×10 9mol/L、6× 10 9mol/L、8× 10 9mol/L)后检测To、Tc、Po、Am等参数变化。结果　①高血压病患者KCa通道活性变化 :于细胞内面向外膜片下 ,在对称性高钾液中 ,高血压病组KCa通道平均开放概率增加 ,关闭时间延长、开放时间缩短。在浴液中分别加入Ca2 + 后 ,两组KCa通道均被明显激活 ,但血压正常组Po的增加显著高于高血压病组 (P <0 .0 0 1)。②ET1对高血压病患者KCa通道活性的影响 :血压正常者在内面向外式膜片下 ,Po、Tc均先增加后降低 ,显示低浓度时兴奋、高浓度时抑制 ,然而高血压病患者肠系膜血管平滑肌KCa通道对ET1则缺乏反应。结论　高血压病患者肠系膜动脉平滑肌细胞KCa通道活性明显高于血压正常者 ,但对Ca2 + 的敏感性降低。Objective To study the regulation of Ca 2+ activated K + channels(KCa)of mesenteric artery smooth muscle cells,(SMC)in 18 old patients with essential hypertension(EH) by endothelin-1(ET 1).Methods Mesenteric artery branch from EH patients was digested by enzyme.Patch clamp technique was used to pull cell attached and inside out patches on mesenteric artery SMC from EH patients and the normotensive patients respectively.The signal channel open probability(Po),open dwell time(To),close dwell time(Tc)and open channel number per patch were recorded.After adding Ca 2+ (10 -8 ～10 -6 mol/L)and ET 1[(2～8)×10 9/mol/L]to cytoplasm respectively,the parameters above were defermined again.Results Compared with those of the normotensive patients,the activities of KCa channels of patients with EH were at a higher rate .After adding Ca 2+ to the Po cytoplasm,KCa channels in normotensive patients increased significantly.But there were few changes in EH group.KCa channels had dual reaction to ET 1 in normotensive patients,But we have found no statistically significant difference when ET 1 present on KCa channels of EH cases.Conclusion The activities of KCa channels of patients with EH increased significantly,but the sensitivity to Ca 2+ decreased.ET 1 had little effect on KCa channels of patients with EH.

关 键 词：钙激活钾通道 膜片钳技术 肠系膜 动脉平滑肌细胞 高血压 内皮素-1 

分 类 号：R544.1[医药卫生—心血管疾病]