Effect of dinitrophenol on potential, resistance, and H+ rate of frog stomach

Abstract

Gastric mucosae were mounted between chambers, some with Cl^– bathing solutions and some with Cl^–-free bathing solutions. The effect of 2,4-dinitrophenol (DNP) was determined on the potential difference (PD), resistance, and H⁺ secretory rate. In Cl^– experiments, the H⁺ rate was depressed to low levels without a marked decrease in the PD, and the PD did not vary linearly with the H⁺ rate. Neither ATP (6 mm) nor voltage clamping (nutrient + 150 mv) restored H⁺ secretion. The PD is inverted in Cl^–-free solutions (nutrient is negative), and under these conditions DNP produced a decrease in the H⁺ rate which varied linearly with the decrease in the absolute magnitude of the PD. An analysis of this latter finding, on the basis of the separate-site theory of gastric HCl formation, revealed that during inhibition of H⁺ secretion only the electrogenic H⁺ mechanism is affected; the parameters of the return circuit within the mucosa are not changed. Under Cl^–-free conditions the resistance and emf of the H⁺ mechanism were estimated; the resistance ranged from 571 to 1,350 ohm/cm², and the emf from 33 to 56 mv.