Hanrahan J W, Alles W P, Lewis S A
Proc Natl Acad Sci U S A. 1985 Nov;82(22):7791-5. doi: 10.1073/pnas.82.22.7791.
Basolateral membrane chloride permeability of surface cells from rabbit urinary bladder epithelium was studied using the patch-clamp technique. Two types of anion-selective channel were observed. One channel type showed inward rectification and had a conductance of 64 pS at-50 mV when bathed symmetrically by saline solution containing 150 mM chloride; the other resembled high-conductance voltage-dependent anion channels (VDACs). Both channels had the selectivity sequence Cl-approximately equal to Br-approximately equal to I- approximately equal to SCN- approximately equal to NO3- greater than F- greater than acetate greater than gluconate greater than Na+ approximately equal to K+ and were sensitive to the anion exchange inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Basolateral chloride conductance in urinary bladder is apparently due to the 64 pS anion channel, which is active at physiological potentials. Imperfect selectivity of this channel against cations might also account for the low, but finite, sodium permeability of the basolateral membrane.
运用膜片钳技术研究了兔膀胱上皮表层细胞基底外侧膜的氯通透性。观察到两种类型的阴离子选择性通道。一种通道类型表现出内向整流特性，当在含150 mM氯的盐溶液对称浸泡时，在-50 mV下电导为64 pS；另一种类似于高电导电压依赖性阴离子通道（VDAC）。两种通道的选择性顺序均为Cl-≈Br-≈I-≈SCN-≈NO3-＞F-＞醋酸根＞葡萄糖酸根＞Na+≈K+，且对阴离子交换抑制剂4,4'-二异硫氰基芪-2,2'-二磺酸敏感。膀胱的基底外侧氯电导显然归因于64 pS的阴离子通道，该通道在生理电位下具有活性。该通道对阳离子的选择性不完善也可能解释了基底外侧膜较低但有限的钠通透性。
