Fine structure of the gastric epithelium of the coral fish, Chelmon rostratus Cuvier

Abstract

The gastric epithelium of the tropical fish, Chelmon rostratus Cuvier was studied with the electron microscope. At least 6 different types of cells could be distinguished. These are, lining the mucosal surface and gastric pits, the epithelial cells, 'rodlet cells' and 3 kinds of argentaffin like cells, and lining the gastric gland, the secretory cells. The tall columnar epithelial cell shows a basal nucleus. It is rich in organelles and contains periodic acid Schiff positive secretory granules in the apical zone. Lodged between the epithelial cells are pyriform 'rodlet' cells which exist singly. They both share a common desmosome. The 'rodlet' cells contain a variable number of rod like bodies in the supranuclear zone. The peripheral region of the cell is specialized to form a thick capsular coat. The 3 types of argentaffin like cells are sequestered in the basal region of the epithelial cells. Each of the cell types contains characteristic granularites. Finally, lining the gastric gland are the secretory cells. The luminal half of these cells is packed with abundant tubular structures which seem to communicate with the external medium. Basally, the cytoplasm is loaded with secretory granules. They are released apically by the process of exocytosis.