NERVE-FIBERS IMMUNOREACTIVE TO PROTEIN GENE PRODUCT-9.5, CALCITONIN-GENE-RELATED PEPTIDE, SUBSTANCE-P, AND NEUROPEPTIDE-Y IN THE DENTAL-PULP, PERIODONTAL-LIGAMENT, AND GINGIVA IN CATS

The distribution patterns of nerve fibers immunoreactive (IR) to calci tonin gene-related peptide (CGRP), substance P (SP), and neuropeptide Y (NPY) in the dental pulp, periodontal ligament (PDL), and gingiva we re studied and compared with the complete innervation visualized by an tibody to protein gene product (PGP) 9.5 in adult cats. The pulp showe d considerably denser nerve supply for PGP 9.5, CGRP, and SP than the periodontal tissues. Most of the pulpal fibers were CGRP-IR, and appro ximately three to four times more IR fibers were labeled with CGRP tha n SP. Most fibers in the odontoblast area penetrating into the dentin tubules were CGRP-IR. NPY-IR nerves were mainly observed in connection with the larger blood vessels in pulp and PDL. In the PDL most nerves were localized in the apical third in connection with blood vessels, but CGRP-IR fibers extending close to root cementum were often observe d. Immunoreactivity to PGP 9.5 and CGRP was frequently found in cell-l ike structures in connection with Malassez epithelium in the PDL and i n some round epithelial-like cells located in the base of gingival ret e pegs.