1. Properties of gastric antrum. III. Selectivity and modification of shunt conductance
- Author
-
S C, Bajaj, J G, Spenney, and G, Sachs
- Subjects
Rana catesbeiana ,Sodium ,Biological Transport ,Hydrogen-Ion Concentration ,Lithium ,Models, Biological ,Amphibians ,Carbodiimides ,Chlorides ,Gastric Mucosa ,Carbenoxolone ,Potassium ,Pyloric Antrum ,Animals - Abstract
The permselectivity of the paracellular pathway of amphibian (Necturus and bullfrog) antrum was investigated with respect to intracationic selectivity and the K+ and Cl- permeability ratio as a function of mucosal pH. The intracationic selectivity sequence was Rb+ greater than K+ greater than Cs+ greater than Na+ greater than Li+. Both antra showed weak cationic selectivity at pH 7.4, and at pH 4.4 for bullfrog and pH 3.0 for Necturus, the ratio Pk+/P Cl- was unity. At lower mucosal pH the tissues were anion selective. Treatment of the tissue with a water-soluble carbodiimide enhanced anion selectivity at higher pH; carbenoxolone, a weak acid, resulted in maintained cation selectivity at lower pH. These data suggest that carboxyl groups play a role in determining shunt selectivity; the increase in anion selectivity below pH 2.0 suggests that phosphate or sulfate groups could also be involved.
- Published
- 1977