GASTRIC-MOTILITY AND ISCHEMIC CHANGES IN OCCURRENCE OF LINEAR ULCER FORMATION INDUCED BY RESTRAINT-WATER IMMERSION STRESS IN RAT

The pathogenesis of linear ulceration induced by restraint water-immer sion (RWI) was investigated in view of gastric motility and early isch emic changes. After three hours of restraint-water immersion stress, t he cross-sectioned gastric body was prepared for light microscopy. Mos t lesions (90.8%) were present in the mucosal folds projecting toward the cavity. Wedge-shaped degeneration in the crest of the folds was re cognized as an ischemic lesion followed by hemorrhagic ulceration. Com pressed arterioles were frequently encountered in the muscularis mucos ae and circular muscle. Generally, mucosal folds appear merely with th e reduction of gastric content, and run along with the elevation of th e circular muscle as an anatomical structure, becoming tall and steep after RWI. Marked enhancement of contraction, observed with a strain g auge force transducer, was induced by RWI. This enhancement was suppre ssed by papaverine HCI pretreatment in accordance with suppression of the fold-related mucosal lesion even after 150 mM HCI perfusion into t he stomach. In conclusion, gastric motility appears to play an importa nt role in the pathogenesis of linear ulceration by causing ischemic c hange along the folds.