Rehm W S, Schwartz M, Carrasquer G, Hagan E A, Dinno M A
Biochim Biophys Acta. 1987 May 12;899(1):17-24. doi: 10.1016/0005-2736(87)90234-3.
Inhibition of acid secretion of the frog fundus is generally accompanied by an increase in transmucosal resistance, Rt, and in potential difference, PD (nutrient normally positive). These results are predicted for the intact tissue by an electrogenic proton pump. It has been suggested that the increase in PD with inhibition can also be explained by a neutral proton pump. The latter model postulates a K+ diffusion potential across the secretory (lumen-facing) membrane tending to make the secretory side positive. Upon inhibition, the [K+] in the lumen is assumed to increase, which decreases the diffusion potential, resulting in an increase in the positivity of the nutrient side. To test this theory, we determined the effects of inhibition with a high [K+] on the secretory side. With a high [K+] in the lumina, inhibition would result in only a small change in the ratio of K+ in the cell to that in the lumina, and hence a small change in the diffusion potential. We found, however, that inhibition increased the PD essentially the same as in the controls. With inhibition the resistance also increased with high secretory K+. Elevating the secretory K+ during secretion produced a 44% decrease in Rt indicating a large increase in luminal K+. We conclude that the results are not compatible with the K+ diffusion potential model but are those predicted by the electrogenic concept.
青蛙胃底酸分泌的抑制通常伴随着跨黏膜电阻（Rt）和电位差（PD，营养侧通常为正）的增加。这些结果通过电生性质子泵对完整组织进行了预测。有人提出，抑制时PD的增加也可以用中性质子泵来解释。后一种模型假定跨分泌（面向管腔）膜存在K+扩散电位，倾向于使分泌侧为正。在抑制时，假定管腔内的[K+]增加，这会降低扩散电位，导致营养侧的正性增加。为了验证这一理论，我们测定了高[K+]对分泌侧的抑制作用。当管腔内有高[K+]时，抑制只会导致细胞内K+与管腔内K+的比例发生小的变化，因此扩散电位变化也很小。然而，我们发现，抑制使PD增加的幅度与对照组基本相同。在高分泌K+的情况下，抑制时电阻也会增加。分泌过程中提高分泌侧的K+会使Rt降低44%，表明管腔内K+大幅增加。我们得出结论，这些结果与K+扩散电位模型不相符，而是电生性概念所预测的结果。
