ENTERIC NERVES IN GASTRIC-MUCOSA COULD BE INFLUENCED BY PROTON PUMP INHIBITORS THROUGH EFFECT ON H-ATPASE()

Omprazole and lansoprazole are potent inhibitors of H+-K+-ATPase (prot on pump inhibitor: PPI) supposedly localized in the parietal cells, wh ile recent studies have shown the localization of similar enzymes in o ther parts of the body, i.e. the colonic epithelium, kidney and unmyel inated nerve fibers. Thus, the present study was undertaken to study t he uptake sites of H-3-omeprazole and lansoprazole on the rat fundic m ucosa using the radioautographic methods. Aqueous solution of H-3-omep razole or H-3-lansoprazole was infused through the intraaortic cathete r. 30 min, 1, 12, 24 hours after the infusion, the fundic and antral t issues were taken out and cut into small tissue blocks with a razor bl ade and freeze-dried. Radioautographic procedure was performed by dire ct embedding in Epon, wet-sectioning with ethylene glycol and dry- mou nting by the wire-loop method. As a result, 30 min after the infusion, most of the uptake sites of H-3- omeprazole were seen on some of the gastric epithelial cells, mostly corresponding to the parietal cells a nd slightly recognized on the enteric nerve fibers. Few grains were on the basally granulated cells. 12 and 24 hours after the infusion, the number of the grains on the gastric epithelia significantly decreased , but the distribution pattern was not changed. From these observation s, the enteric nervous system in the gastric mucosa was shown to have the uptake sites of two proton pump inhibitors, suggesting the interve ntion of proton pump inhibitors on the entric nervous activity.