Uptake site of lansoprazole, a proton pump inhibitor, in human fundic mucosa: possible relevance with fibroblast and Helicobacter pylori.

To clarify the mechanism of the effect of lansoprazole in the healing of human gastric ulcer, the uptake sites of lansoprazole were studied using endoscopically biopsied specimens from the margin of the gastric ulcer. The specimens were incubated in a medium containing 3H-lansoprazole for 5 or 15 min., postfixed with 1% osmic acid and embedded in Epon. The semithin or ultrathin sections were made and radioautographic emulsion films were applied by the wire-loop method. 30 days after the incubation, the sections were developed, fixed and observed by light and electron microscopy. As a result, the uptake sites of lansoprazole were accumulated on the fibroblasts located near the tip portion of the gastric mucosa and on the unmyelinated nerve fibers as well as on the parietal cells. Some of the uptake sites were also observed near the plasma membrane of the bacteria in the gastric lumen. From these observations, lansoprazole uptake sites were not only on the parietal cells but on the fibroblasts and the bacteria, suggesting that the effect of lansoprazole was exerted partly through the influence on the mesenchymal cells and Helicobacter pylori-related organisms.