[Immunohistochemical studies on the peptidergic nerve distribution in hard palate mucosa and gingiva of the rat].

The present study demonstrates the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), neurokinin A (NKA), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) in the hard palate mucosa and gingiva of the rat by the use of an indirect immunofluorescence method. Nerve fibers containing CGRP, SP and NKA showed very similar distribution patterns. Numerous nerve fibers containing CGRP, SP and NKA were observed in the lamina propria of hard palate mucosa. They formed dense subepithelial plexuses in incisive papilla and transverse palatine ridges. Some of them penetrated deeply into the epithelium and terminated as free nerve endings. In gingiva, nerve fibers containing these peptides were found especially near gingival sulcus. They were abundantly distributed beneath the junctional epithelium and formed nerve plexus. In all sampling regions, these nerve fibers were seen around the large- and medium-sized blood vessels in lamina propria and submucosal layer. NPY- and VIP-containing nerve fibers were observed in close association with blood vessels of hard palate mucosa. These nerve fibers were located around the large-sized blood vessels in the submucosal layer of hard palate and a few fibers were seen running along the small blood vessels in the lamina propria of the anterior half of hard palate mucosa. Nerve fibers containing these peptides were never found in gingiva.