Morphologic diversity of the minor salivary glands of the rat: fertile ground for studies in gene function and proteomics

Abstract

In this article the locations and histologic and ultrastructural features of all of the minor salivary glands of the rat are presented; similarities and differences among them are highlighted. These glands are almost as diverse morphologically as the major salivary glands of the rat. The acini of von Ebner's glands are serous; those of the anterior and posterior buccal glands and minor sublingual glands are mucous; and those of the glossopalatal, palatal, and Weber's glands are mucous with serous demilunes. The anterior buccal, minor sublingual and von Ebner's glands have striated and stratified columnar ducts, while only the minor sublingual and von Ebner's glands have intercalated ducts. The glossopalatal, palatal, posterior buccal and Weber's glands have none of these ducts; the tubulo-acini drain abruptly into short terminal ducts composed of stratified squamous epithelium. All of the mucous acini react with an antibody to a mucin (Muc19) of the rat major sublingual gland, but in some of the glands the reaction varies in intensity among the acinar cells. Ultrastructurally, the mucous secretory granules of the anterior buccal, glossopalatal, palatal and Weber's glands are biphasic, while those of the minor sublingual and posterior buccal glands are monophasic. Although there is a considerable body of literature concerning the development, innervation, physiology and proteomics of von Ebner's glands, investigation of the other minor salivary glands of the rat ranges from modest to nearly nonexistent.

Developmental Morphology of the Palatine Glands in Rats: An Electron Microscope Study

“…Several previous publications have disputed the presence of intercalated ducts in the palatine glands. In most of the studies in rats, intercalated ducts were not seen, suggesting an immediate transition of the secretory endpieces into the excretory ducts (Butcher and Mitchell, ; Nakamura et al, ; Srivastava and Vyas, ; Redman, ). In human palatine glands, convoluted intercalated ducts have been observed communicating with some mucous acini (Black, ).…”

“…Among those the palate is considered the most common location of both benign and malignant minor salivary gland tumors, accounting for 10–25% of all salivary gland tumors (Pires et al, ; Mejía‐Velázquez et al, ). Nevertheless, palatine glands have received considerably less attention than the major glands and other minor glands, perhaps owing to their more difficult accessibility (Izutsu et al, ; Redman, ).…”

Nonproliferative and Proliferative Lesions ofthe Gastrointestinal Tract, Pancreas andSalivary Glands of the Rat and Mouse

“…The minor salivary glands lack a true connective tissue capsules and are usually located within the submucosa or are interspaced between connective tissue stroma or muscle fibers. The glands are morphologically diverse and are organized into distinct serous (von Ebner’s glands), mucous (anterior and posterior buccal glands and minor sublingual glands) or mucous glands with serous demilunes (glossopalatal, palatal, and Weber’s glands, Figure 155 ) glands ( Redman 2011 ). The acini are organized into lobule-like structures and collections of secretory end pieces and ducts open onto the mucosal surface.…”

Analysis of Histone H2BGFP Retention in Mouse Submandibular Gland Reveals Actively Dividing Stem Cell Populations

“…A recent study using K5 promoter and a similar H2BGFP pulse-chase strategy in minor SGs (palatal) has localized a population of quiescent stem cells to the basal layer of the lower excretory ducts and MECs in the acini [42]. Although the contribution of each of these cell populations to normal gland renewal and regeneration needs to be determined, the apparent differences in ductal cell dynamics observed between the palatal and SMGs may be explained by their distinct embryonic origin and significant structural differences [43,44].…”