Abstract
Distribution of nerve fibers containing catecholamine, 5-hydroxytryptamine (5-HT), gamma-aminobutyric acid (GABA) and neuropeptides such as vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), and substance P (SP) ; and interactions between these nerve fibers and glandular cells, myoepithelial cells, or blood vessels in the submandibular gland of the rat were examined by means of light and electron microscopic immunohistochemistry using tyrosine hydroxylase (TH), 5-HT, GABA, VIP, NPY and SP antisera. TH-, 5-HT-, GABA-, VIP-, NPY-, and SP-like immunoreactive nerve fibers were distributed around the acini, the excretory ducts and the blood vessels in the interstitial tissue. VIP-like immunoreactive nerve terminals penetrating into the acinus, were found to make synaptic contacts with both seromucous and mucous glandular cells. In the interstitial tissue, TH-like immunoreactive nerve fibers were found, in part, to make synaptic contact with the smooth muscle cells surrounding blood vessels. These findings suggest that VIP-containing neurons may be important in salivary secretion, and catecholamine- and NPY-containing neurons may contribute to the control of blood flow.
