DIFFERENTIAL DISTRIBUTION OF NEURONAL MARKERS AND NEUROPEPTIDES IN THE HUMAN LACRIMAL GLAND

Background: The present study was untertaken in an attempt to broaden the spectrum of known neuronal markers and neuropeptides in the main l acrimal gland of the human by light-microscopic immunohistochemistry. Methods: Using antisera against the neuronal markers protein gene prod uct (PGP) and S-100 protein (S-100), the distribution of nerve fibers in the human main lacrimal gland was studied. Vasoactive intestinal po lypeptide (VIP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and tyrosine hydroxylase (TH) were identified by their specifi c antisera. Results: The nerve fibers are distributed throughout the i nterstice between the glandular tubules. Associations were also found between nerve fibers and both the interlobular ductal system and blood vessels (mainly arterioles). Within the glandular lobules isolated gr oups of secretory cells stained positive for S-100 protein. Nerve fibe rs situated in the glandular interstice between the tubules showed pre dominantly positive immunoreactions for the neuropeptide VIP, while on ly very few fibers stained positive for CGRP, NPY and the catecholamin e marker TH. Nerve fibers associated with interlobular blood vessels w ere mainly CGRP and NPY positive and stained only very rarely for VIP. The epithelia of interlobular ducts and excretory ducts were associat ed with CGRP-immunoreactive nerve fibers. Conclusion: The neuropeptide s identified in the lacrimal,oland indicate the complexity with which a variety of biologic signals regulate and modulate the lacrimal gland .