Heterogeneous localization of muscarinic cholinoceptor M 1 in the salivary ducts of adult mice

• Published in: Archives of oral biology Vol. 100; p. 14
• Main Authors: Rawangwong, Atsara, Khrongyut, Suthankamon, Chomphoo, Surang, Konno, Kohtaro, Yamasaki, Miwako, Watanabe, Masahiko, Kondo, Hisatake, Hipkaeo, Wiphawi
• Format: Journal Article
• Language: English
• Published: England 01.04.2019
• Subjects: Acinar Cells - metabolism; Animals; Mice; Microscopy, Immunoelectron; Receptor, Muscarinic M1 - metabolism; Salivary Ducts - metabolism; Salivary gland; Mice; Localization; Mreceptor
• ISSN: 1879-1506
• DOI: 10.1016/j.archoralbio.2019.02.001

We hypothesize variation in expression and localization, along the course of the glandular tubule, of muscarinic cholinergic receptor M which plays as a distinct contribution, though minor in comparison with M receptor, in saliva secretion. Localization of the M receptor was examined using immunohistochemistry in three major salivary glands. Although all glandular cells were more or less M -immunoreactive, acinar cells were weakly immunoreactive, while ductal cells exhibited substantial M -immunoreactivity. Many ductal cells exhibited clear polarity with higher immunoreactivity in their apical/supra-nuclear domain. However, some exhibited indistinct polarity because of additional higher immunoreactivity in their basal/infra-nuclear domain. A small group of cells with intense immunoreactivity was found, mostly located in the intercalated ducts or in portions of the striated ducts close to the intercalated ducts. In immuno-electron microscopy, the immunoreactive materials were mainly in the cytoplasm including various vesicles and vacuoles. Unexpectedly, distinct immunoreactivity on apical and basal plasma membranes was infrequent in most ductal cells. The heterogeneous localization of M -immunoreactivity along the gland tubular system is discussed in view of possible modulatory roles of the M receptor in saliva secretion.