Wolosin J M, Forte J G
Am J Physiol. 1984 May;246(5 Pt 1):C537-45. doi: 10.1152/ajpcell.1984.246.5.C537.
Vesicles isolated from the apical membrane of stimulated oxyntic cells [stimulation-associated (SA) vesicles] are highly permeable to KCl. The KCl flux is coupled to an electroneutral ATP-driven H+-K+ exchange (the H+-K+-ATPase) to produce net intravesicular HCl accumulation. In the past, we observed that rates of KCl transport were not accelerated by valinomycin and that dissipation of preformed H+ gradients in the presence of a protonophore (carbonyl cyanide, m-chlorophenylhydrazone, 10 microM) required the simultaneous presence of valinomycin. Consequently the fast KCl transport was attributed to an electroneutral cotransport system. Now we have been able to elicit fast H+ gradient dissipation in the absence of valinomycin by using the protonophore tetrachlorosalicylanilide. Experiments carried out in the absence of Cl- demonstrated the existence of a specific high-conductance pathway for K+. Experiments in K+-free medium demonstrated the existence of a high Cl- conductance. Parallel experiments in the equivalent H+-K+-ATPase-rich vesicles from nonsecreting oxyntic cells showed very little K+ and Cl- conductivity, suggesting that the appearance of large ionic conductance in the membrane is associated with the stimulation of the cell.
从受刺激的壁细胞顶端膜分离出的囊泡[刺激相关（SA）囊泡]对氯化钾具有高度通透性。氯化钾通量与电中性的ATP驱动的H⁺-K⁺交换（H⁺-K⁺-ATP酶）偶联，以产生囊泡内净盐酸积累。过去，我们观察到缬氨霉素不会加速氯化钾的转运速率，并且在存在质子载体（羰基氰化物，间氯苯腙，10微摩尔）的情况下，预先形成的H⁺梯度的消散需要同时存在缬氨霉素。因此，快速的氯化钾转运归因于电中性共转运系统。现在，我们通过使用质子载体四氯水杨酰苯胺，能够在不存在缬氨霉素的情况下引发快速的H⁺梯度消散。在不存在Cl⁻的情况下进行的实验证明了存在特定的高电导钾离子通道。在无钾培养基中进行的实验证明了存在高氯离子电导。在来自非分泌性壁细胞的等效富含H⁺-K⁺-ATP酶的囊泡中进行的平行实验显示，钾离子和氯离子的电导率非常低，这表明膜中出现大的离子电导与细胞的刺激有关。
