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为研究睫状体色素上皮 (pigmentedciliaryepithelial,PCE)细胞容积激活性Cl-电流的特性 ,用膜片箝全细胞记录技术记录了猪的低渗液诱发的容积激活性Cl-电流。此电流外向占优势 ,几乎没有时间依赖性失活 ,电流 电压曲线显示此电流反转电位 (- 6 3± 0 5mV)很接近氯离子平衡电位的计算值 (ECl=0mV)。电流的激活依赖于细胞内ATP ,细胞外ATP抑制外向电流和内向电流 ,但外向电流抑制率大于内向电流抑制率 (92 %比 74% ,P <0 0 1)。氯离子通道阻断剂tamoxifen抑制外向电流和内向电流 ,两个抑制率几乎相等 (85 %比 87% ,P >0 0 5 )。此电流特性与其他类型细胞的P糖蛋白相关电流很相似。结果提示PCE细胞容积激活性Cl-电流的形成可能与P糖蛋白有关
To investigate the characteristics of the volume-activated Cl-current in the cells of pigmented ciliary epithelial (PCE) cells, volume-activated Cl-currents induced by hypotonic fluid in pigs were recorded using patch-clamp whole-cell recording techniques. This current is predominantly extroverted and has almost no time-dependent inactivation. The current-voltage curve shows that the current reversal potential (-63 ± 0.05mV) is close to the calculated value of the chloride equilibrium potential (ECl = 0mV). Current activation depends on intracellular ATP. Extracellular ATP inhibits outward current and inward current, but the outward current suppression rate is higher than that of inward current suppression (92% vs 74%, P <0.01). Chloride channel blocker tamoxifen inhibited outward current and inward current with almost equal inhibition rates (85% vs. 87%, P> 0.05). This current profile is very similar to the P glycoprotein-related currents in other cell types. The results suggest that the formation of PCE cell volume-activated Cl-current may be related to P-glycoprotein