title: Growth-associated protein (GAP-43)-like immunoreactivity in primary and permanent tooth pulp nerve fibers of the cat.
abstract: GAP-43-like immunoreactivity in developing and mature incisor and canine tooth pulp nerve fibers in the cat was examined with fluorescence immunohistochemistry and pre-embedding immunogold electron microscopy. As expected, pulpal and periodontal nerve fibers in primary teeth aged 2-3 weeks showed strong immunoreactivity. Double-labeling experiments demonstrated that 50-70% of primary pulpal GAP-43-positive nerve fibers showed CGRP-like immunoreactivity. However, in adult permanent teeth the vast majority of pulpal nerve fibers also displayed intense GAP-43-like immunoreactivity both when surrounding pulpal blood vessels and in the subodontoblast/odontoblast region. There was a high degree (90-95%) of simultaneous expression of GAP-43-like immunoreactivity and CGRP-like immunoreactivity in adult permanent pulps. Immunogold GAP-43 labeling was mainly associated with the cytoplasmic side of axonal membranes. However, occasional examples of immunolabeled Schwann cells were also found. High levels of GAP-43 in normal mature permanent pulpal nerves may facilitate neural plasticity after dental wear or injury.
authors.affiliation: Department of Anatomy, Karolinska Institutet, Stockholm, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Fried
authors.forename: M
authors.initials: M
authors.lastname: Risling
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis*; D002415:Cats; D003782:Dental Pulp / Q000294:innervation*; D019922:GAP-43 Protein; D006133:Growth Substances / Q000032:analysis*; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000032:analysis*; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D009412:Nerve Fibers / Q000737:chemistry*; D009419:Nerve Tissue Proteins / Q000032:analysis*
chemical_list: D019922:GAP-43 Protein; D006133:Growth Substances; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D015740:Calcitonin Gene-Related Peptide