EFFLUX OF CHLORIDE THROUGH CELL SURFACES OF FROG GASTRIC MUCOSA.

Concentration, effluxes, and exchangeable chloride were studied in the isolated frog gastric mucosa. The tissue chloride, 51.6 ± 0.7 (se) mm/kg wet wt, is totally exchangeable. The tissue chloride concentration increases to 68.0 ± 2 2 (se) mm/kg wet wt after incubation between two chloride solutions. Using sulfate secretory solution this value became 66.9 ± 1.3 (se) mm/kg wet wt. Using sulfate nutrient solution a decrease to 126 ± 1.1 (se) mm/kg wet wt was observed. Tissue chloride effluxes were described by two exponentials; one (extracellular chloride) had a time constant of 117 ± 04 (se) hr–1; the other (cellular chloride) had a time constant of 1.13 ± 0.07 (se) hr–1. The ratio of the effluxes through both surfaces, ΔAm/ΔAs was 1.59 ± 0.16 (se) in mucosae maintained between sulfate solutions. This ratio increases to 2.13 ± 0.10 (se) by the use of histamine in both solutions or decreases to 0.51 ± 0.05 (se) by the use of chloride solutions. It is proposed that a) there exists chloride passive diffusion ...