AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 5 377-G388, Copyright © 1982 by American Physiological Society

ARTICLES

Mechanism of luminal alkalinization by bullfrog fundic mucosa

K. Takeuchi, A. Merhav and W. Silen

Metiamide-inhibited fundic mucosa of bullfrog secreted alkali (OH-) at 0.1-0.2 mueq.cm-2.h-1.OH- was abolished by dinitrophenol (DNP) and was decreased significantly by 4,4-didsothiocyano-2,2-disulfonate stilbene (DIDS), anoxia, or HCO3(-)-free nutrient solution. In Na+ solutions, increasing nutrient, [HCO3(-)] augmented OH- and Isc linearly while resistance (R) decreased. No such changes occurred in Na+-free nutrient solution. In all experiments, delta Isc was approximately 12 X delta OH. Replacement of Cl- in the secretory solutions or in the nutrient solutions had no significant influence on OH-. When Na+-free nutrient solutions and Cl--free secretory solutions were present, OH- decreased significantly (P less than 0.01). Increasing nutrient [Cl-] in the absence of secretory Cl- significantly (P less than 0.01) augmented OH- and Isc. In the absence of secretory Cl-, OH- and Isc were linearly related to varying nutrient [Cl-]. In tissues with nutrient solutions on the secretory side and vice versa, apparent OH- was 0.4-0.5 mueq.cm-1.h-1 and was dependent on secretory [HCO3(-)] but was not affected by DNP, DIDS, or replacement of Cl- on secretory or nutrient solutions. We conclude that 1) OH- secretion is dependent on nutrient HCO3(-) and Na+ and oxidative metabolism, 2) endogenous HCO3(-) does not contribute significantly, and 3) adequate tissue Cl- must be present for normal OH-.

This article has been cited by other articles:

				J. Xu, J. Henriksnas, S. Barone, D. Witte, G. E. Shull, J. G. Forte, L. Holm, and M. Soleimani SLC26A9 is expressed in gastric surface epithelial cells, mediates Cl-/HCO3- exchange, and is inhibited by NH4+ (Report) Am J Physiol Cell Physiol, August 1, 2005; 289(2): C493 - C505. [Abstract] [Full Text] [PDF]

				A. Allen and G. Flemstrom Gastroduodenal mucus bicarbonate barrier: protection against acid and pepsin Am J Physiol Cell Physiol, January 1, 2005; 288(1): C1 - C19. [Abstract] [Full Text] [PDF]

				S. Vidyasagar, V. M. Rajendran, and H. J. Binder Three distinct mechanisms of HCO3- secretion in rat distal colon Am J Physiol Cell Physiol, September 1, 2004; 287(3): C612 - C621. [Abstract] [Full Text] [PDF]

				J. Xu, S. Barone, S. Petrovic, Z. Wang, U. Seidler, B. Riederer, K. Ramaswamy, P. K. Dudeja, G. E. Shull, and M. Soleimani Identification of an apical Cl-/HCO3- exchanger in gastric surface mucous and duodenal villus cells Am J Physiol Gastrointest Liver Physiol, December 1, 2003; 285(6): G1225 - G1234. [Abstract] [Full Text] [PDF]

				L. Debellis, E. Papini, R. Caroppo, C. Montecucco, and S. Curci Helicobacter pylori cytotoxin VacA increases alkaline secretion in gastric epithelial cells Am J Physiol Gastrointest Liver Physiol, December 1, 2001; 281(6): G1440 - G1448. [Abstract] [Full Text] [PDF]

				T. Coskun, S. Chu, and M. H. Montrose Intragastric pH regulates conversion from net acid to net alkaline secretion by the rat stomach Am J Physiol Gastrointest Liver Physiol, October 1, 2001; 281(4): G870 - G877. [Abstract] [Full Text] [PDF]