Immunohistochemical study of the innervation of the boundary area of the hard and soft palates of the rat

The palatal mucosa plays an important role for patients using full dentures . The posterior ridge of the denture is designed to fit on the border betwe en the hard and soft palates; accordingly, this boundary area is of importa nce when the outline of the denture is designed. In the present study, a ri ch supply of nerve libers was found in the mucosa of the boundary area of t he hard and soft palates of the rat. An immunocytochemical examination reve aled nerve fibers containing protein gene product 9.5 (PGP 9.5), calcitonin gene-related peptide (CGRP), substance P (SP), pituitary adenylate cyclase -activating peptide, vasoactive intestinal polypeptide (VIP), C-terminal fl anking peptide of neuropeptide Y (c-PON), or nitric oxide synthase (NOS). T hin nerve fibers with PGP 9.5, CGRP, or SP penetrated into the epithelium, reaching beneath the cornified layer and terminated as fi ee nerve endings. VIP-, c-PON- and NOS-containing nerve fibers were distributed in the conne ctive tissue. Many of the VIP- and c-PON-containing nerve fibers were assoc iated with blood vessels. In addition, nerve fibers containing PGP 9.5, COR P SP and c-PON were observed around, and penetrating into, the taste buds i n the boundary area.