Electrophysiological Aspects of Gastric Ion Transport

Abstract

In comparison to nerve, muscle, and numerous epithelial organs such as intestine, kidney, and exocrine glands, electrophysiological studies on gastric epithelia have been less successful in the past. The reason for this is twofold: (1) In contrast, for example, to intestine, it is quite difficult to obtain viable in vitro preparations of mammalian gastric mucosa because cessation of blood circulation apparently leads to oxygen deficiency or catabolic poisoning and tends to render the tissue unresponsive to secretory stimuli. (2) In contrast to other epithelia, gastric mucosa has a very complex architecture. Fundus mucosa consists of a layer of surface epithelial cells (SEC) that is perforated by the openings of numerous gastric glands that are densely packed underneath the SEC layer and are composed of different cell types: enzyme and HCl secreting oxyntic cells (OC) in amphibia, and separate enzyme secreting chief cells (CC) and HCl secreting parietal cells (PC) in mammals, together with mucous neck cells (MC) and endocrine cells (EC). Since virtually only SEC could be punctured in the past, a detailed analysis of the major transport events was not possible.