Ultrastructure of the submandibular gland in the Korean spider shrew, Sorex caecutiens

Abstract

The ultrastructure of submandibular gland was examined in the Korean spider shrew, Sorex caecutiens. The submandibular gland was composed of acini and salivary ducts. A submadibular acinus was a mixed gland having serous demilune cells and mucous cells that were filled with well developed rER, mitochondria and large amount of dense secretory granules. Serous acinar granules were oval shape without distinct limiting membrane on the border and it had only coarse specks with various density. Mucous acinar granules were oval shape without distinct limiting membrane and had a variety pattern with several thin or transparent bands into the homogeneous dense matrix. Thus submandibular acinar granules of S. caecutiens belonging to subfamily Soricinae were distinct from the other mammalian species including Crocidurinae, because of the absence of limiting membrane of acinar granules and specific pattern of mucous acinar granules. Granular duct cells had large amount of small granular vesicles and several characteristic structures of granule which were covered with stratified limiting membranes and filled with coarse serous-like granules or homogeneous matrix.