The effect of omeprazole on ultrastructural changes in gastric parietal cells
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This study was designed to compare the effects of omeprazole and cimetidine on ultrastructural changes in parietal cells of guinea pigs during histamine stimulation. Both omeprazole and cimetidine remarkably inhibited acid secretion induced by histamine stimulation. Omeprazole, however, failed to prevent the morphological transition of parietal cells to an active stage during histamine stimulation, in contrast to cimetidine which inhibited the morphological transition. In addition, it was noticed that administration of omeprazole caused vacuolation in approximately 27% of all parietal cells. This phenomenon was not seen in control animals with histamine stimulation alone and only very rarely in cimetidine treated animals. Ultrastructural findings suggested that vacuoles originated in secretory canaliculi of parietal cells. These results may be the key to explain the difference of the inhibitory mechanism between omeprazole which acts on the final step of the intracellular process (so-called proton pump) and cimetidine which acts on the H2-receptor site of plasma membrane.
Key WordsCimetidine H+/K+ATPase Omeprazole Parietal cell Vacuolation
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- 9.Karasawa H: The effect of omeprazole on gastric acid secretion. Japanese J Gastroenterology 1987;84:1201–1210Google Scholar
- 11.Helander HF, Sanders SS, Rehm WS, et al: Quantitative aspects of gastric morphology. In: Sachs G, Heinz E, Ullrich KT, eds. Gastric Secretion. Academic Press, New York. 1972;69–88Google Scholar
- 14.Forte TM, Machen TE, Forte JG: Ultrastructural changes in oxyntic cells associated with secretory function: a membrane recycling hypothesis. Gastroenterogy 1977;73:941–955Google Scholar
- 15.Helander HF: The cell of the gastric mucosa. Int Rev Cytol 1981;70:271–89Google Scholar
- 19.Stachura J, Konturek SJ, Cieszkowsky M, et al: Comparison of the effect of omeprazole-a substituted benzimidazole- and ranitidine- a potent H2-receptor antagonist-on histamineinduced gastric acid secretion and the ultrastructure of canine parietal cells. Hepato-gastroenterol 1983;30:205–210Google Scholar
- 22.Kawai T, Azumi T, Inokuchi H et al: The effects of omeprazole, a proton pump inhibitor, on gastric mucosa, serum gastrin and pepsinogen activity of the rats, with special reference to neonatal development. Jpn J Gastroenterol 1986;83:2303–2309 (in Jpn)Google Scholar