Role of gastric mucosal folds in formation of focal ulcers in the rat.

Ulcers induced in rats by a variety of techniques often have a characteristic elongated shape or are focal and follow a linear pattern. The reason for this is unknown but may be related to the presence of gastric mucosal folds. Studies utilizing a rat gastric chamber preparation demonstrate that the apex of the mucosal fold is peculiarly sensitive to injury by corrosive agents in normotensive or hypotensive animals and in the completely ischemic mucosa. Focal gastric mucosal potential difference (PD) measurements utilizing a "sucrose gap" technique demonstrate that the PD at the crest of a mucosal fold is significantly lower than in the trough at the base of the fold, suggesting a local perfusion or permeability defect. The stomachs of animals submitted to three different ulcerogenic treatment demonstrated significantly more fold-related lesions that nonfold lesions. It is concluded that although different mechanisms may be responsible for the grossly different lesions, the mucosal fold, for a variety of reasons, appears particularly sensitive to injury.