Effect of xanthines and histamine on ion transport and respiration by frog gastric mucosa

Abstract

In standard chloride solutions, methyl xanthines enhanced ion transport and oxygen consumption by frog gastric mucosa in vitro to a significantly greater extent than did histamine. Substituting glucuronate for chloride in the bathing solutions abolished ion transport, but left respiration unchanged. Caffeine and histamine had no effect on respiration in glucuronate solutions, but butyrate stimulated respiration to the same extent in chloride and glucuronate solutions. All of these effects appeared to be a function of the epithelial cells, since respiration by smooth muscle from the stomach was not affected by any of the compounds. It is postulated that the hydrogen ions of gastric secretion are derived from the dehydrogenation process during substrate oxidation. Following dehydrogenation, the methyl xanthines and histamine stimulate some step in the events that lead to the formation of hydrochloric acid. In the respiring, non-acid secreting mucosa, the hydrogen ions follow the usual intracellular pathways that lead to the formation of water.