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

¹ Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, Kentucky, and Department of Physiology and Biophysics, University of Alabama Medical Center, Birmingham, Alabama

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.

Key Words: gastric acid secretion • gastric potential • DNP on gastric potential • DNP on Cl^–-free stomach • voltage clamping on DNP-inhibited stomach • resistance of gastric H⁺ mechanism • DNP inhibition of acid secretion • DNP on gastric resistance • anoxia on DNP-inhibited stomach • ATP on DNP-inhibited stomach

Submitted on June 10, 1964