Acid secretion, potential, and resistance of frog stomach in K+-free solutions

Abstract

The removal of K+ from the fluids bathing the in vitro frog gastric mucosa results in a decrease of the H+ secretory rate to zero, a marked increase in electrical resistance, a transient increase in potential difference (PD), and relatively little change in the K+ content of the mucosa. The effects of K+ removal are reversed by adding K+ either to the nutrient fluid (4 mm) or to the secretory fluid (104 mm). They are not reversed by voltage clamping (nutrient positive). Following the cessation of H+ secretion, the PD gradually decreases to a level that is low but still greater than zero. The PD under these conditions can be reversibly reduced to about zero by anoxia. It is concluded that the presence of K+ in certain regions of the mucosa is necessary for the functioning of the H+ and Cl– mechanisms.