AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 5 639-G647, Copyright © 1986 by American Physiological Society
Sites of resistance changes with inhibition of acid secretion in frog stomach
W. S. Rehm, G. Carrasquer and M. Schwartz
The primary purpose of this study was to determine the sites of resistance
changes from thiocyanate inhibition of secretion to better evaluate models
of the gastric proton pump. The potential difference, resistance, and H+
secretory rate were measured with various tonicities of the secretory
fluid. Thiocyanate (SCN) inhibition generally produces a resistance
increase, but with nutrient Ba, the resistance is high and SCN decreases
it. The latter effect is also seen with cimetidine. In the secreting fundus
a hypotonic secretory solution has a small effect on resistance, but in the
inhibited fundus the effect is huge, due to increase of resistance of the
lumen-tubular cell pathway. With a hypotonic secretory solution, for
inhibited fundus (cimetidine or omeprazole) and antrum, SCN does not
decrease the resistance of the surface cells and/or the transintercellular
pathways with or without Ba. The SCN resistance decrease with Ba is via the
tubular cell pathway. With Ba the resistance of the nutrient membrane of
the tubular cells decreases after SCN or cimetidine inhibition. The
findings further support the concept that under standard conditions the
resistance via the lumina and tubular cells is low and that via the surface
cells and transintercellular pathways is high.
