Application of immunohistochemistry to the isolated mucosa of the mouse gastrointestinal tract, with special reference to somatostatin cells

In the present study, in order to easily grasp whole images of somatostatin (D) cells, the isolated mucosa of the mouse gastrointestinal tract was immunohistochemically treated. The present study revealed that: (1) in the stomach, small-intestinal villi and colon, about 20% of the D cells extrude basal cytoplasmic processes, showing terminal expansions in many cases; on the other hand, in the crypts of the small intestine, few D cells possess basal processes, and (2) in the stomach, there is no determined tendency in the direction of the basal processes of the D cells; on the other hand, in the small-intestinal villi and colon, most D cell basal processes run toward the villus base and colon crypt bottoms. The direction of the basal processes of the D cells in the gastrointestinal tract seems to be mostly in favor of the migration pattern of epithelial cells described previously. It is likely that, if the targets of the D cells are near the D cells, the basal process is not necessary for local secretion of somatostatin. During migration, however, D cells might extrude basal processes to keep relationships with their targets.