Myoepithelial cells and innervation in the infraorbital gland of the Japanese serow (Capricornis crispus).

Both the apocrine and the sebaceous portions of the infraorbital gland of the Japanese serow were examined to obtain morphological evidence related to the mechanism of secretion. The examination was carried out by an immunohistochemical method using antibodies against alpha-smooth muscle actin for myoepithelial cells and protein gene product 9.5 for nerve fibers. Immunostaining for alpha-smooth muscle actin was apparent in the myoepithelial cells of apocrine tubules and varied within the same glands and among individual glands. Immunostaining for protein gene product 9.5 revealed the presence of nerve fibers around apocrine tubules. The immunoreactive nerve fibers were fine or varicose. In the sebaceous glands of the ordinary type and of the modified type, no immunoreactivity specific for alpha-smooth muscle actin or protein gene product 9.5 was observed. These results suggest that apocrine tubular activity of the infraorbital gland occurs independently in each tubule and that secretion by the apocrine tubules is controlled by the myoepithelial cells via nerve fibers.