We examined the effect of
leminoprazole (an
acid pump inhibitor) on
reflux esophagitis induced in rats. Intragastrically administered
leminoprazole significantly and dose-dependently protected the esophageal mucosa against the reflux of gastric contents, without affecting gastric acid secretion. However, it had no effect on the
esophagitis when administered intraduodenally, despite its significant inhibition (about 40%) of gastric acid secretion.
Omeprazole significantly prevented the development of
esophagitis, most probably through potent inhibition of gastric acid secretion.
Indomethacin significantly reduced the synthesis of
prostaglandin E2 in the esophagus. Since
indomethacin pretreatment had no effect on the esophageal protection by
leminoprazole,
omeprazole or
sucralfate, the involvement of endogenous
prostaglandins can be ruled out as a possible underlying mechanism. Intragastrically, but not intraduodenally, administered
sucralfate significantly prevented the
esophagitis even at a dose not affecting gastric acid secretion. These results strongly suggest that both
leminoprazole and
sucralfate protect the esophageal mucosa directly.