On the possible role of intestinal hormones as the diarrhoeagenic messenger in cholera.

Cholera enterotoxin introduced into the duodenum of young rabbits causes severe degranulation of the enterochromaffin (EC) cells as revealed by electron microscopy. In the mucosal epithelium fixed mainly 1 hr after toxin administration, many of the basal granules of the EC cells are swollen up and open to the basal and lateral cell surface. The EC cells of the rabbit, as it is the rule for intestinal endocrine cells in mammals, are open to the lumen with an apical process covered by microvilli. A hypothesis is proposed that cholera toxin stimulates this apical receptor of the EC cells and that the aminic (serotonin) and polypeptide (motilin?) products of the cells released by the stimulus may mediate the diarrhoeagenic action of cholera enterotoxin.