Restituted gastric mucosa: tolerance against low luminal pH and restricted mucosal blood flow in the cat

This study examined the tolerance of gastric surface epithelium allowed to restitute for 90 min after damage produced by mucosal exposure to 2 M NaCl for 10 min. Cats were subjected to gastric luminal perfusion with saline at pH = 1.0 and reduction of celiac artery blood flow for 90 min. A flow reduction of 55%, as assessed by Doppler ultrasound flowmetry, was obtained by constriction of the celiac artery. These interventions alone did not produce lesions in nondamaged control cats, whereas exposure to 2 M NaCl immediately before flow reduction evoked extensive erosions as judged by gross examination and microscopy. Stomachs exposed to 2 M NaCl 90 min before flow reduction showed lesions that were clearly less in extent and number than in animals in which an intervening restitution period was not allowed. Topical dimethyl-prostaglandin E2 (50 micrograms/kg) increased the rate by which restituted surface cells were transformed to apparently normal cells. This study shows that the restituted gastric mucosa possesses a remarkably high tolerance against lowered blood flow in the presence of high luminal acidity.