Sodium Transport in Rana pipiens Gastric Mucosa

Abstract

The transport properties of frog gastric mucosa in vitro have been reexamined in conditions analogous to those used in studies on mammalian systems in which net movements of sodium were observed. Net transport of sodium across frog gastric mucosa was not observed to occur when the mucosal surface was bathed with a well-buffered solution of near neutral pH, indicating that failure to demonstrate sodium transport across frog stomach in previous work could not be ascribed to the low pH value of the solution usually used as the mucosal fluid. Addition of 5 × 10^-4 M amphotericin B to the mucosal solution elicited net transport of sodium and an increase in short-circuit current. These findings indicate that sodium transport may contribute to the electrolyte physiology of frog gastric mucosa in some experimental conditions, and may limit the utility of the three-variable model proposed by Hogben.