Ultrastructure of the gastric mucosa of normal laboratory ferrets

Abstract

An ultrastructural study of the normal laboratory ferret has been made. Cytological features of the surface mucous cell, parietal cell, and chief cell are described. Fine fibrils were seen running from the desmosomes on the lateral surface of surface mucous cells beneath the nucleus and on toward desmosomes on the opposite side of the cell. Mucous granules are produced in the area of the Golgi, and evidence is presented that secretion is brought about by solubilization in the apical cytoplasm prior to release through the plasma membrane. The secretory canaliculi of the parietal cell are “open” and run deep into the cell, often isolating the nucleus and a number of mitochondria in the center of the cell. Narrow cytoplasmic strands traverse the canaliculi and connect the peripheral cytoplasm with the centrally located cytoplasm containing the nucleus. The peripheral cytoplasm is engorged with mitochondria. Both endoplasmic reticulum and vacuoles are sparse but ribosomes are seen free in the cytoplasm around the mitochondria. Basal folds and secretory canaliculi come into close apposition at the base of the cell having only a narrow isthmus of cytoplasm between them. The chief cell contains a rich rough endoplasmic reticulum in the basal cytoplasm which produces small smooth-membraned vesicles in the area of the Golgi. These vesicles apparently fuse with vacuoles from the Golgi to produce the zymogen granules. The zymogen granule is secreted by fusion of its membrane with the apical plasma membrane and release of its contents into the lumen of the gland. Argentaffin cells with microvilli extending into the lumen of the gland were observed.