Immunohistochemical Study of Nitric Oxide Synthase in Lacrimal Gland and Salivary Gland

Park, Kyung Ho; Pyo, Chang Hae; Ko, Jeong Sik; Ahn, E Tay

Abstract

Endogenous nitric oxide (NO) has been known to regulate the salivary secretion and glandular blood flow. However, nitric oxide synthase (NOS) responsible for NO synthesis has not been well studied in lacrimal glands. The present study was aimed to investigate the distribution of nitric oxide synthase isoforms (endothelial, neuronal, and inducible NOS). Immunohistochemistry, using monoclonal mouse anti-endothelial NOS, anti-neuronal NOS, and anti-inducible NOS, was performed in exorbital lacrimal glands of the rat. Endothelial NOS (eNOS)-positive immunoreactivity was observed in vascular endothelium, intralobular duct and interlobular duct of the exorbital lacrimal gland of the rats, and also in the 3 major salivary glands of the rat. eNOSpositive immunoreactivity was most prominent in the intralobular and interlobular duct was well concentrated in cytoplasm of columnar epithelial duct cell. However, eNOS-positive immunoreactivity of the intercalated duct and serous acinus was absent. Neuronal NOS (nNOS)-positive immunoreactivity was seen in ganglion cells of exorbital lacrimal gland. iNOS or nNOS-positive immunoreactivy was not detected either in excretory ducts or in acinar cells. Inducible NOS-positive immunoreactivity was not seen. There results reveal the presence of eNOS and nNOS in the exorbital lacrimal gland, which may be related with regulation of the glandular secretion and blood flow.