IMMUNOHISTOCHEMICAL STUDIES OF NEUROCHEMICAL MARKERS IN NORMAL HUMAN BUCCAL MUCOSA

The content of various substances, such as regulatory peptides, hormon es and structural proteins, was investigated in normal buccal mucosa u sing indirect immunofluorescence. Thin nerve fibres, which from a morp hological point of view were most probably sensory, showed immunoreact ivity for substance P (SP), calcitonin gene-related peptide (CGRP), ne uropeptide K (NPK) and neurokinin A (NKA). Also galanin (GAL), gamma-m elanocyte stimulating hormone (gamma-MSH) and somatostatin (SOM) stain ed thin fibres were found in the propria, which were, however, few in number and the gamma-MSH staining was weak. CGRP, vasoactive intestina l polypeptide (VIP), peptide histidine isoleucine amide (PHI) and neur opeptide Y (NPY) immunoreactive nerve fibres were observed in close co nnection to blood vessels. SOM positive cells with processes were foun d, mostly scattered, in the connective tissue. A population of cells w ithin the epithelium also showed somatostatin immunoreactivity. Protei n S-100 (S-100) stained distinct populations of cells at two separate locations. In the propria, cells with one or two slender processes wer e seen, being mostly single but sometimes forming groups. In the epith elium, dendritic cells with many processes with or without 'spines' we re observed, mainly located to the basal layer of the lamina epithelia lis. Single nerve fibres and nerve bundles were also stained. Neurofil ament (NF) positive fibres, singly and in bundles, as well as endorgan -like structures were seen. Neuron-specific enolase (NSE) and protein gene product 9.5 (PGP 9.5) both stained the same structures, namely si ngle fibres, nerve bundles, nerves surrounding vessels and innervating muscles and glands (if present in the section), as well as Merkel cel ls. Also with these two markers endorgan-like structures were seen. No clear innervation of the epithelium could be observed with the marker s used. No methionine-enkephalin (ENK) or synaptophysin (SYN) immunore active material was found.