Aickin C C, Brading A F
J Physiol. 1984 Apr;349:587-606. doi: 10.1113/jphysiol.1984.sp015175.
The Cl-depleted smooth muscle cells of guinea-pig vas deferens rapidly restore their intracellular Cl activity ( aiCl ) to a level 5 times higher than that predicted by a passive distribution when Cl- ions are readmitted to the extracellular solution. Cl reaccumulation, measured using Cl-sensitive micro-electrodes and the uptake of 36Cl, was slowed about 3-fold by the nominal absence of CO2 and HCO3 and about 10-fold by the presence of the anion exchange inhibitor DIDS (4-4'-diisothiocyanostilbene-2,2'-disulphonic acid). However, the usual level of intracellular Cl was eventually attained and neither condition reduced intracellular Cl in normal tissues. The loss of intracellular Cl that occurs when Cl- ions are removed from the extracellular solution was slowed about 3-fold by the nominal absence of CO2 and HCO3 and was accelerated by their readdition. DIDS slowed the fall in aiCl about 10-fold and reduced 36Cl efflux. Intracellular pH (pHi), measured using pH-sensitive micro-electrodes, increased by a mean of 0.73 units when Cl was removed from the superfusing solution in the presence of CO2 and HCO3, and rapidly decreased when Cl was readmitted. These changes are equivalent to an intracellular accumulation and loss of HCO3- ions respectively. The net transmembrane movement of HCO3- ions which would have caused these changes in pHi was calculated using the measured intracellular buffering power ( Aickin , 1984). 25% fewer HCO3- ions than Cl- ions were accumulated and lost and the HCO3 movement was completed 2-3 times faster than the simultaneous Cl movement under the same conditions. The changes in pHi induced by alteration of extracellular Cl were reduced by the nominal absence of CO2 and HCO3 and abolished by the presence of DIDS. The acidification recorded on readmission of Cl in the nominal absence of CO2 and HCO3 was compatible with a metabolic production of about 0.1% CO2. We conclude that Cl-HCO3 exchange plays a major role in the regulation of intracellular Cl. The exchange carrier is reversible, is completely inhibited by DIDS, and accounts for about 75% of the net Cl movement that occurs when Cl is removed from or readmitted to the extracellular solution. The mechanism which is responsible for the remaining Cl movement remains to be elucidated.
当向细胞外溶液中重新引入氯离子时，豚鼠输精管中氯离子缺失的平滑肌细胞会迅速将其细胞内氯离子活性（aiCl）恢复到比被动分布预测水平高5倍的水平。使用氯离子敏感微电极和36Cl摄取测量的氯离子重新积累，在名义上不存在二氧化碳和碳酸氢根时减慢约3倍，在存在阴离子交换抑制剂DIDS（4,4'-二异硫氰基芪-2,2'-二磺酸）时减慢约10倍。然而，最终达到了细胞内氯离子的正常水平，并且在这两种情况下，正常组织中的细胞内氯离子都没有减少。当从细胞外溶液中去除氯离子时发生的细胞内氯离子损失，在名义上不存在二氧化碳和碳酸氢根时减慢约3倍，而在重新添加它们时加速。DIDS使aiCl的下降减慢约10倍，并减少36Cl外流。使用pH敏感微电极测量的细胞内pH（pHi），在存在二氧化碳和碳酸氢根的情况下从灌注溶液中去除氯离子时平均增加0.73个单位，而在重新引入氯离子时迅速下降。这些变化分别相当于细胞内碳酸氢根离子的积累和损失。使用测量的细胞内缓冲能力计算了会导致pHi发生这些变化的碳酸氢根离子的净跨膜移动（艾金，1984年）。积累和损失的碳酸氢根离子比氯离子少25%，并且在相同条件下，碳酸氢根离子的移动比同时进行的氯离子移动快2至3倍。细胞外氯离子改变引起的pHi变化在名义上不存在二氧化碳和碳酸氢根时减少，在存在DIDS时消除。在名义上不存在二氧化碳和碳酸氢根的情况下重新引入氯离子时记录的酸化与约0.1%的二氧化碳代谢产生一致。我们得出结论，氯离子-碳酸氢根交换在细胞内氯离子调节中起主要作用。交换载体是可逆的，被DIDS完全抑制，并且占从细胞外溶液中去除或重新引入氯离子时发生的净氯离子移动的约75%。负责其余氯离子移动的机制仍有待阐明。
