title: Immunohistochemical localization of SNARE proteins in dental pulp and periodontal ligament of the rat incisor.
abstract: Distribution of three soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (SNARE) proteins, syntaxin-1, synaptosomal-associated protein of 25 kDa (SNAP-25), and vesicle-associated membrane protein-2 (VAMP-2), was examined in dental pulp and periodontal ligament of the rat incisor. In the trigeminal ganglion, syntaxin-1 and SNAP-25 immunoreactivity was predominately detected in medium- to large-sized neurons. Most syntaxin-1 immunoreactive neurons expressed SNAP-25. In contrast, VAMP-2 was localized in small- to medium-sized neurons and in slender-shaped cells surrounding SNAP-25-immunopositive neurons. When the inferior alveolar nerve, one of the mandibular nerve branches innervating the dental pulp and periodontal ligament, was ligated, SNARE proteins accumulated at the site proximal to the ligation. In the incisor dental pulp, all nerve fibers displayed immunoreactivity for syntaxin-1, SNAP-25, and VAMP-2. In the periodontal ligament of the incisor, almost all nerve fibers displayed both syntaxin-1 and SNAP-25 immunoreactivity, but lacked VAMP-2 immunoreactivity. SNAP-25 protein expression was localized around the vesicle membranes at the axon terminal of the periodontal mechanoreceptors. These present data suggest that these three SNARE proteins are synthesized at the trigeminal ganglion, transported centrally and peripherally, and expressed in sensory endings where apparent synapses are not present. Because those proteins participate in docking and exocytosis of synapse vesicles in the central nervous system, they might also contribute to vesicle exocytosis at receptive fields where apparent synapses are not present.
authors.affiliation: Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, Osaka, Japan. honma@dent.osaka-u.ac.jp
authors.forename: Shiho
authors.initials: S
authors.lastname: Honma
authors.forename: Kunitaka
authors.initials: K
authors.lastname: Taki
authors.forename: Shi
authors.initials: S
authors.lastname: Lei
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Niwa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakisaka
mesh_terms: D000818:Animals; D003782:Dental Pulp / Q000737:chemistry* / Q000294:innervation / Q000378:metabolism*; D007150:Immunohistochemistry; D007180:Incisor / Q000737:chemistry* / Q000294:innervation / Q000378:metabolism*; D008297:Male; D009412:Nerve Fibers / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D010513:Periodontal Ligament / Q000737:chemistry* / Q000294:innervation / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050600:SNARE Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D013569:Synapses / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D050825:Synaptosomal-Associated Protein 25 / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D050827:Syntaxin 1 / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D014276:Trigeminal Nerve / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D050988:Vesicle-Associated Membrane Protein 2 / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D050600:SNARE Proteins; C494210:Snap25 protein, rat; D050825:Synaptosomal-Associated Protein 25; D050827:Syntaxin 1; D050988:Vesicle-Associated Membrane Protein 2