Chemical concentration gradients and electrical properties of gastric mucosa

¹ Cardiovascular Research Institute and Departments of Medicine and Physiology, University of California School of Medicine, San Francisco, California

This study explored the possibility that each surface of the gastric epithelial cell contains ion transport systems contributing to the observed transmucosal potential difference (V_t). The model proposes that V_t arises from a K⁺ and Cl^– diffusion potential across the submucosal face of the epithelial cells in series with the potential generated by electrogenic transport of H⁺ and Cl^– across the mucosal face. The bio-electric effects of changes in the ionic composition of the bathing media and the tissue composition data were used to test this hypothesis. V_t varied with the log of submucosal K⁺ at constant Cl^– and with the log of submucosal Cl^– at constant K⁺; the sum of the slopes averaged 50 mv. Simultaneous tenfold changes in K⁺ and Cl^– in the submucosal solutions resulted in a 53-mv change in V_t, a reasonable agreement with the theoretical value of 58 mv for a system in which the total electrical conductance is given by the sum of the K⁺ and Cl^– conductances. Alterations in Na⁺ at either surface had no appreciable effect on V_t. Chemical analysis of gastric mucosae and plasma revealed the predicted pattern of K⁺ (mucosa) > K⁺ (extracellular), Na⁺ (mucosa) < Na⁺ (extracellular), and Cl^– (mucosa) < Cl^– (extracellular).

Key Words: oxyntic cell • gastric epithelial cell • ion transport systems • transmucosal potential • submucosal piffusion potential • mucosal electrogenic transport potential • chloride pump frog gastric mucosa • membrane potentials

Submitted on July 29, 1963

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