Effect of inhibitors of gastric secretion on polarization of gastric potential by voltage clamping

Abstract

Voltage clamping across the frog gastric mucosa, nutrient positive to secretory, results in an increase in the open-circuit potential difference (OCPD). The increase in OCPD, or polarization, induced by voltage clamping could be caused by a redistribution of ions across the plasma membrane or by a polarization of pump electromotive forces, such as the Na(+)-K(+)-adenosinetriphosphatase (ATPase) located in the nutrient (serosal) membrane or the proton pump located in the secretory (luminal) membrane. The polarization induced by voltage clamping was not affected by removing Cl- and Na+ or by increasing the K+ concentration to 79 mM but was markedly reduced by placing in the nutrient solution 10(-3) M famotidine or 10(-4) M omeprazole. These data suggest that there is a strong contribution of the proton pump to the polarization induced by voltage clamping with some contribution of ion redistribution and/or the Na(+)-K(+)-ATPase. The data support the electrogenicity of the proton pump.