Oike M, Droogmans G, Nilius B
K. U. Leuven, Laboratorium voor Fysiologie, Belgium.
Pflugers Arch. 1994 May;427(1-2):184-6. doi: 10.1007/BF00585960.
We have studied the effect of intracellular ATP on volume-activated CI(-)-currents in endothelial cells from human umbilical veins by means of the whole-cell patch-clamp technique. The run-down of this current in ruptured patches during repetitive applications of hypotonic solutions (HTS) could be significantly reduced if the cells were internally perfused with a pipette solution that contained 4 mmol/l ATP. This run-down was much less pronounced if currents were recorded using nystatin-perforated patches. The amplitude of the current was drastically reduced and its activation became slower if the cells were superfused with a glucose-free medium with 1 mmol/l KCN. Adding 4 mmol/l ATP gamma S, a poorly hydrolyzable ATP-analogue, to the patch pipette prevented run-down of the current during repetitive activations by HTS, even if the cells were superfused with glucose-free solution with 1 mmol/l KCN. It is concluded that activation of the mechanosensitive Cl- conductance in human endothelial cells requires the presence of intracellular ATP, but not its hydrolysis.
我们采用全细胞膜片钳技术研究了细胞内ATP对人脐静脉内皮细胞容积激活氯离子电流的影响。如果用含有4 mmol/L ATP的移液管溶液对细胞进行内部灌流，在重复应用低渗溶液（HTS）期间，破裂膜片中该电流的衰减可显著降低。如果使用制霉菌素穿孔膜片记录电流，这种衰减则不那么明显。如果用含有1 mmol/L KCN的无糖培养基对细胞进行灌流，电流幅度会急剧降低，其激活也会变慢。向膜片移液管中添加4 mmol/L ATPγS（一种难水解的ATP类似物）可防止在HTS重复激活期间电流衰减，即使细胞用含有1 mmol/L KCN的无糖溶液灌流也是如此。得出的结论是，人内皮细胞中机械敏感性氯离子通道的激活需要细胞内ATP的存在，但不需要其水解。
