Effect of Potassium on Ion Transport and Bioelectric Potentials of Frog Gastric Mucosa

Ion transport of the isolated frog gastric mucosa was studied in vitro by the chamber method. The effects of modifications in the concentrations of potassium in nutrient (Kn+) and in secretory (Ks+) solutions on net potassium flux from nutrient to secretory phases (JnsKK+) on the rate of H+ production and on the transmucosal potential difference (PD) was studied in this system. Both the rate of H+ secretion and JnsKK+ increased when Kn+ was raised and decreased when Kn+ was lowered. Reduction of Kn+ to zero produced a striking depression of H+ secretion, which was reversed by adding K+ to the nutrient phase. Serial differences in H+ production (ΔH+) were approximately proportionate to the serial changes in Kn+. Transmucosal PD varied inversely with Kn+. Modification in Ks+ failed to alter H+ production or PD, although JKnsKns+ was decreased by raising Ks+.