Sodium space and acid secretion in frog gastric mucosa

¹ Department of Physiology, University of Michigan, Ann Arbor, Michigan

Inulin, arabinose, mannitol, choline, and sodium, but not radioiodinated serum albumin (RISA), penetrate a space of about 320 ml/kg in gastric mucosa of Rana pipiens. Sixty-three to seventy-eight per cent of the space not penetrated by RISA is reached by the others from the serosal side. Sodium is quickly eluted from the mucosa by sodium-free solutions, only 2 mEq/kg remaining after 1 hr. When sodium is replaced by choline or mannitol the mucosa can still secrete acid. In sodium-free solutions containing mannitol at 200 mm the tissue loses potassium and its ability to secrete, but when [K] of bathing solution is increased tissue potassium rises and secretion is possible. Optimal external [K] is 36 mm. Sodium is not essential for acid secretion; it passes through the highly permeable basal membrane of the oxyntic cells into an intracellular space where its major function is osmotic. Potassium is the more important ion for acid secretion.

This article has been cited by other articles:

				D. Heitzmann and R. Warth Physiology and Pathophysiology of Potassium Channels in Gastrointestinal Epithelia Physiol Rev, July 1, 2008; 88(3): 1119 - 1182. [Abstract] [Full Text] [PDF]