A flowcytometric method for evaluation of acid secretion from isolated ratgastric mucosal cells

Studies on the gastric proton pump are mostly performed on the H+, K+-ATPas e enzyme in the microsomal preparation or by aminopyrine accumulation in th e gastric parietal. cells. H+, K+-ATPase activity is estimated by both spec trophotometric and fluorimetric methods. In the present study, quenching or augmentation in acridine orange (AO) fluorescence was monitored on a flowc ytometer in rat gastric mucosal cells. Rat gastric mucosal cells were isola ted by the standard pronase-EDTA method. The effect of oleic acid, a proton pump inhibitory was evaluated on gastric parietal cell activity and was co mpared with its effect on proton transport, H+, K+-ATPase, and p-nitropheny l phosphatase (p-NPPase) activity in gastric microsomes. In addition, the e ffect of histamine and carbachol, gastric acid release inducers, was also i nvestigated by flowcytometry in isolated parietal cells. Histamine and carb achol, in a dose-dependent manner, stimulated acid release from isolated ga stric cells. Oleic acid also dose-dependently inhibited the basal and stimu lated acid release from the cells, as well as in all three enzyme preparati ons associated with gastric proton pump activity. Thus, the results suggest that flowcytometric method might be used to study basal, as well as stimul ated, proton pump activity in isolated gastric parietal cells. (C) 2001 Els evier Science Inc. All rights reserved.