Fine structure of the oxynticopeptic cell in the gastric glands of an elasmobranch species (Halaelurus chilensis).

Gastric mucosa of an elasmobranch species was examined by electron microscope. The gastric glands contain one form of cell whose fine structure is similar to the cell that secretes both hydrochloric acid and pepsinogen of the amphibian gastric glands proper. The oxynticopeptic cells are characterized by: (a) a luminal surface with long projections of cytoplasm having dilatations in their thickness; (b) a tubulo-vesicular system in the apical cytoplasm; (c) a great number of mitochondria, some of which are of great length; (d) a well developed granular endoplasmic reticulum and a conspicuous Golgi apparatus; and (e) a large nucleus with a conspicuous nucleolus. A fourth part of the cells are binucleated. Physiological implications of some of these ultrastructural features are discussed.