Studies of Resting Isolated Frog Gastric Mucosa.

Abstract

Freshly isolated bullfrog (R. catesbeiana) gastric mucosa mounted between lucite chambers and bathed in Ringer''s (95% O2 - 5% CO2) solution secretes HC1; this spontaneous secretion was insensitive to exogenous histamine. Incubation of chambered mucosae in the absence of added histamine resulted in a gradual decline of acid secretion and after 16 hr., yielded viable ''near resting'' mucosae. Such mucosae were consistently stimulated to almost initial rates with exogenous histamine. The ATPase activities/mg protein of whole homogenates of resting and stimulated mucosae were the same as those of freshly isolated mucosae. Mean ATP concentration of the stimulated mucosae was slightly greater than that of resting mucosae on a gm wet wt. basis. By prolonged incubation of the mucosa in histamine-free media reproducibly resting mucosae was obtained and had afforded in vitro preparations for comparing physiological and biochemical properties of secreting versus non-secreting mucosae.