Serotonin Immunoreactive Cells and Nerve Fibers in the Mucosa of the Rat Stomach

The current study has showed the morphological features of serotonin (5-hydroxytryptamine) immunoreactivity in the pyloric mucosa of the rat stomach. The immunoreactive elements included the endocrine cells, mast cells and mucosal nerve fibers in the lamina propria. The immunopositive endocrine cells were oval in shape and located mostly in the basal part of the gastric glands. The cell contained a central non-staining area and the peripheral staining zone. The mast cells stained homogenously and appeared to be oval-round in shape. They were located in the upper, middle and basal parts of the mucosa. Serotonin immunoreactive nerve fibers with varicosities were located in the space between the gastric glands in the lamina propria. They appeared not to be in contact with the immunopositive endocrine and mast cells. The current study shows that serotonin may be released by the immunoreactive elements in the stomach and that future work is needed to characterize the ultrastructural features of serotonin positive nerve fibers in the pyloric mucosa.