Mucous barrier and peptic ulcer of the stomach.

Mucous barrier was searched by the histochemical method of mucopolysaccharides and by the measurement of precipitated mucus of gastric juice. The neutral polysaccharide stored within the surface epithelial cells must be a source of the mucus of the gastric juice. The storage of the polysaccaride was decreased by a long-term stimulation by histamine, and the precipitated mucus volume was also decreased shortly after the stimulation. Therefore, some kind of the stimulation for the gastric secretion must be avoided for prevention of peptic ulcer. The oral administration of the sulfuric polysaccharide extracted from seaweed prevented the occurrence of experimental ulcer. It may be concluded that the exogeneous polysaccaride can take the place of the endogenous polysaccharide.