Butt A G, McLaughlin C W, Bowler J M, Purves R D, Macknight A D
Department of Physiology, University of Otago Medical School, Dunedin, New Zealand.
J Membr Biol. 1994 Oct;142(1):9-20. doi: 10.1007/BF00233379.
Relationships between short-circuit current (Isc), cell Cl and the mechanism(s) of Cl accumulation in toad bladder epithelial cells were investigated. In serosal Cl-free gluconate Ringer, 80% of the cell Cl (measured by x-ray microanalysis) was lost over 30-60 min with an associated decrease in cell water content. concomitantly, Isc fell to 20% of its initial value within 10 min but then recovered to 45% of its initial value despite continued Cl loss. With the reintroduction of Cl, cell Cl and Isc both recovered within 10 min. Serosal SITS (4-acetamido-4'-isothiocyano-stilbene-2,2'-disulfonate; 0.5 mM) plus bumetanide (0.1 mM), did not prevent the fall in Isc or the loss of cell Cl in gluconate medium, although they did inhibit subsequent recovery of Isc in this medium. They also prevented the recovery of Isc in Cl medium but not the reaccumulation of Cl by the cells. Although SITS and bumetanide did not prevent the loss or recovery of Cl, they modified the pattern of the ion changes. In their absence, changes in cellular Cl were twice that of the changes in measured cellular cations implicating basolateral Cl/HCO3 exchange in Cl movement. With SITS plus bumetanide present, changes of similar magnitude in Cl were associated with equivalent changes in cation, consistent with the inhibition of Cl/HCO3 exchange.
研究了蟾蜍膀胱上皮细胞中短路电流（Isc）、细胞内氯离子（Cl）以及Cl积累机制之间的关系。在无Cl的葡萄糖酸盐林格氏液中，30 - 60分钟内，80%的细胞内Cl（通过X射线微分析测量）流失，同时细胞含水量下降。相应地，Isc在10分钟内降至初始值的20%，但尽管Cl持续流失，随后又恢复到初始值的45%。重新引入Cl后，细胞内Cl和Isc在10分钟内均恢复。在葡萄糖酸盐培养基中，浆膜侧加入SITS（4 - 乙酰氨基 - 4'-异硫氰基 - 芪 - 2,2'-二磺酸盐；0.5 mM）加布美他尼（0.1 mM），虽不能阻止Isc下降或细胞内Cl流失，但能抑制该培养基中Isc随后的恢复。它们还能阻止Cl培养基中Isc的恢复，但不能阻止细胞对Cl的重新积累。尽管SITS和布美他尼不能阻止Cl的流失或恢复，但它们改变了离子变化模式。在它们不存在时，细胞内Cl的变化是所测细胞阳离子变化的两倍，这意味着Cl的转运涉及基底外侧Cl/HCO₃交换。当存在SITS加布美他尼时，Cl的相似量级变化与阳离子的等量变化相关，这与Cl/HCO₃交换受到抑制一致。
