title: Nerve fibres and cells immunoreactive to neurochemical markers in developing rat molars and supporting tissues.
abstract: The distribution of nerve fibres immunoreactive to calcitonin gene-related peptide (CGRP), substance P (SP) and neuropeptide Y (NPY) was compared to the general neurochemical markers for nerves and neuroendocrine cells protein gene product 9.5 (PGP 9.5) and neurone-specific enolase (NSE), by use of the avidin-biotin peroxidase complex method in developing dental structures in rats aged 13 to 27 days. A substantially greater part of the nerve fibres was immunoreactive to CGRP and SP than to NPY. In the bell stage, nerve fibres immunoreactive to PGP 9.5, CGRP and SP were found in the dental follicle but not in the dental papilla and stellate reticulum. In the advanced bell stage, after initiation of dentine and enamel formation, PGP 9.5, CGRP- and SP-immunoreactive fibres were found in the dental papilla, while the first NPY-immunoreactive fibres were observed in the papilla when root formation started. Concomitant with the beginning of root development, a subodontoblastic nerve plexus was gradually formed and PGP 9.5-, CGRP- and SP-immunoreactive fibres were found within the dentinal tubules. From the start of root formation, CGRP-, SP- and NPY-immunoreactive nerves were shown in the developing periodontal ligament, although a mature distribution pattern was not observed until root formation was nearly completed. Ameloblasts, odontoblasts and cell-like structures in the outer enamel epithelium and within the dental lamina were PGP 9.5-immunoreactive at the bell stage. As the tooth matured, the immunolabelling gradually decreased, but was still present in some odontoblasts after tooth eruption. NSE-immunoreactive, cell-like structures were found in the periphery of the dental follicle, and persisted close to alveolar bone in the periodontal ligament when the tooth reached occlusion. Hence, it may be concluded that sensory nerves containing SP and CGRP are present in the pulp in advance of sympathetic nerves immunoreactive to NPY.
authors.affiliation: Department of Cariology and Endodontics, School of Dentistry, Medical Faculty, University of Bergen, Norway.
authors.forename: I
authors.initials: I
authors.lastname: Fristad
authors.forename: K J
authors.initials: KJ
authors.lastname: Heyeraas
authors.forename: I
authors.initials: I
authors.lastname: Kvinnsland
mesh_terms: D000539:Alveolar Process / Q000098:blood supply / Q000294:innervation; D000565:Ameloblasts / Q000737:chemistry; D000818:Animals; D015415:Biomarkers; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D003782:Dental Pulp / Q000098:blood supply / Q000294:innervation; D003795:Dental Sac / Q000098:blood supply / Q000294:innervation; D005260:Female; D007124:Immunoenzyme Techniques; D007797:Laminin / Q000032:analysis; D008963:Molar / Q000294:innervation; D009478:Neuropeptide Y / Q000032:analysis; D009479:Neuropeptides / Q000032:analysis*; D009804:Odontoblasts / Q000737:chemistry; D009805:Odontogenesis / Q000502:physiology; D010513:Periodontal Ligament / Q000098:blood supply / Q000254:growth & development / Q000294:innervation; D010519:Periodontium / Q000098:blood supply / Q000254:growth & development / Q000294:innervation*; D010751:Phosphopyruvate Hydratase / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000032:analysis; D013869:Thiolester Hydrolases / Q000032:analysis; D013997:Time Factors; D014083:Tooth Germ / Q000098:blood supply / Q000294:innervation*; D014092:Tooth Root / Q000098:blood supply / Q000254:growth & development / Q000294:innervation; D043222:Ubiquitin Thiolesterase
chemical_list: D015415:Biomarkers; D007797:Laminin; D009478:Neuropeptide Y; D009479:Neuropeptides; D013373:Substance P; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase; D010751:Phosphopyruvate Hydratase; D015740:Calcitonin Gene-Related Peptide