剪切力诱导微血管内皮细胞K^+通道的开放  

SHEAR STRESS INDUCED THE ACTIVATION OF K^+ CHANNEL INRAT BRAIN MICROVASCULAR ENDOTHELIAL CELL

作　　者：胡金麟[1] 常小飞[2] 宋晓燕[2] 李玉珍[1] 宋欣[1] 

机构地区：[1]中国人民解放军总医院微循环研究室,北京100853 [2]北京工业大学,北京100022

出　　处：《生物物理学报》2000年第2期372-379,共8页Acta Biophysica Sinica

基　　金：国家自然科学基金资助项目!(批准号 :39600040)

摘　　要：利用膜片钳及内皮细胞流动小室方法对大鼠脑微血管内皮细胞在剪切力作用下内皮细胞膜K+ 通道的开放进行了初步研究 ,结果提示脑微血管内皮细胞膜上存在剪切力敏感的K+ 通道 ,剪切力作用后 ,内皮细胞膜上K +电流明显增大 ,此电流有明显的短暂延迟现象 ,也可以被胞外施加的TEA抑制 ,符合IKv特征。流动剪切力可以通过影响内皮细胞膜上的K +通道的开放引起穿细胞的离子通透性的增加 ,进而引起细胞内Ca2 + 的变化。在K+ 、Ca2 + 等离子浓度改变的诱导下可以促使G -Actin装配为F -Actin。同时诱导内皮细胞内钙库调节机制的激活 ,这些变化都可以进一步引起细胞信号转导机制的激活。该工作为进一步开展剪切力对微血管内皮细胞信号转导机制的影响提供了实验数据。A primary study of shear stress activated K+ channel in Microvascular Endothelial Cell,MVEC using patch-clamp technique and parallel-plate flow chamber was reported in this papaer. MVEC monolayers were voltage-clamped and whole-cell currents were recorded. Cells were voltage clamped at -100mv and step depolarized to various potentials for 2100ms at 0.1Hz. Shear stress was applied with a pressure ejection micro-tube placed near the MVEC. The flow rate was 100μl/s and the diameter of that tube was 10～15μm. The shear stress were about 0.05～0.12N/m2. Whole-cell currents were observed and the currents were inhibited in a concentration-dependence manner by bath application of TEA-Cl with an IC50 approximately 2.0mmol/L. After application of shear stress, currents increased in amplitude as compared with controls. The absolute currents activated by shear stress and I-V curve with shear stress application were obtained. When MVEC membrane potential was 30mV, the potassium channel current was 54.12±24.42pA, 106.13±47.42pA at 60mV, 154.01±53.22pA at 90mV (n=3,p<0.01). These results supported that shear stress sensitive ion channel was really existed on the membrane of microvascular endothelial cell.

关 键 词：剪切力 膜片钳 K^+ 道 微血管内皮细胞 

分 类 号：Q463[生物学—生理学] Q66