Eveloff J, Warnock D G
Am J Physiol. 1987 May;252(5 Pt 2):F883-9. doi: 10.1152/ajprenal.1987.252.5.F883.
The transport pathways for chloride in basolateral membrane vesicles from the rabbit renal cortex were investigated. 36Cl uptake was stimulated by the presence of potassium in the uptake media compared with sodium or N-methyl-D-glucamine. In addition, potassium (86Rb) uptake was stimulated more by chloride than by nitrate or gluconate. Neither of these processes was further stimulated by potassium gradients plus valinomycin, suggesting the presence of an electrically neutral K-Cl cotransport system. A magnesium-induced chloride conductance was also found in the basolateral membrane vesicles. In the absence of magnesium, the chloride conductance was low; valinomycin and an inwardly directed potassium gradient did not stimulate 36Cl uptake, anthracene-9-carboxylic acid did not inhibit 36Cl uptake, and valinomycin did not stimulate chloride-dependent 86Rb uptake. However, in the presence of 1 mM magnesium, opposite results were obtained; valinomycin and an inwardly directed potassium gradient stimulated 36Cl uptake, anthracene-9-carboxylic acid inhibited 36Cl uptake, and valinomycin stimulated chloride-dependent 86Rb uptake. Therefore, an electrically neutral K-Cl cotransport and magnesium-induced chloride conductance were found in renal cortical basolateral membrane vesicles prepared from the rabbit renal cortex.
对来自兔肾皮质的基底外侧膜囊泡中氯离子的转运途径进行了研究。与钠或N-甲基-D-葡糖胺相比，摄取介质中钾的存在刺激了³⁶Cl的摄取。此外，氯离子对钾（⁸⁶Rb）摄取的刺激作用比硝酸盐或葡萄糖酸盐更强。钾梯度加缬氨霉素均未进一步刺激这两个过程，提示存在电中性的K-Cl共转运系统。在基底外侧膜囊泡中还发现了镁诱导的氯离子电导。在没有镁的情况下，氯离子电导较低；缬氨霉素和内向钾梯度不刺激³⁶Cl摄取，9-蒽羧酸不抑制³⁶Cl摄取，缬氨霉素不刺激氯离子依赖性的⁸⁶Rb摄取。然而，在存在1 mM镁的情况下，得到了相反的结果；缬氨霉素和内向钾梯度刺激³⁶Cl摄取，9-蒽羧酸抑制³⁶Cl摄取，缬氨霉素刺激氯离子依赖性的⁸⁶Rb摄取。因此，在从兔肾皮质制备的肾皮质基底外侧膜囊泡中发现了电中性的K-Cl共转运和镁诱导的氯离子电导。
