Transport in mammalian gastric mucosa

Experiments in mammalian gastric mucosae lead to the following conclusions: 1. Sodium, potassium, and chloride are all required in the serosal solution but not on the mucosal side for acid secretion to occur. The only exception to this is in the dog, for which Cl- is required on both sides. 2. Most mammalian gastric mucosa actively absorb Na+. This 2. Most mammalian gastric mucosa actively absorb Na+. This absorption can be blocked by amiloride in the mucosal solution or by ouabain on the serosal side. The Na+ absorption probably occurs in some cell type other than parital cells. 3. Sodium and chloride move through separate transport pathways across the serosal border. 4. Hydrogen and chloride secretion are closely linked; however the secretion does not appear to be in the neutral HCl form. 5. There is a ouabain-sensitive Na+-K+ pump at the serosal membrane. 6. An increase in intracellular cAMP can initiate acid secretion. In addition cAMP appears to play a role physiologically at least in the initiation of histamine-stimulated acid secretion.