title: Ruffini endings are absent from the periodontal ligament of trkB knockout mice.
abstract: To clarify the role of neurotrophin receptors in the development of Ruffini endings, periodontal ligaments and trigeminal ganglia of trkA, trkB, and trkC knockout mice were immunostained for protein gene product 9.5 (PGP 9.5), calcitonin gene-related peptide (CGRP), parvalbumin (PV), and calretinin (CR). Innervation patterns of PGP 9.5- and CGRP-immunoreactive fibers were examined in the periodontal ligament of the knockout mice. PGP 9.5-positive fibers in the incisal periodontal ligaments of trkA and trkC knockout mice form Ruffini endings distinguished by dendritic ramifications and branches. However, Ruffini endings were not present in the periodontal ligament of trkB knockout mice. Only free nerve endings were observed in tissue of trkB knockout mice. Compared with trkA and trkC knockouts, the proportion of CR-positive neurons in mandibular and maxillary regions of the trigeminal ganglion of trkB knockout mice is decreased. These findings indicate that the development of periodontal Ruffini endings is regulated by trkB-dependent and CR-coexpressing neurons.
authors.affiliation: Department of Toxicology, Veterinary Science, Osaka Prefecture University Graduate School of Agriculture and Biological Sciences, Sakai, Japan.
authors.forename: Saburou
authors.initials: S
authors.lastname: Matsuo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Silos-Santiago
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Kiyomiya
authors.forename: Masaru
authors.initials: M
authors.lastname: Kurebe
authors.forename: Joop J A
authors.initials: JJ
authors.lastname: Arends
authors.forename: Mark F
authors.initials: MF
authors.lastname: Jacquin
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D008465:Mechanoreceptors / Q000002:abnormalities / Q000502:physiology* / Q000648:ultrastructure; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D009411:Nerve Endings / Q000648:ultrastructure; D009412:Nerve Fibers / Q000502:physiology; D010513:Periodontal Ligament / Q000294:innervation* / Q000378:metabolism; D020917:Receptor, trkA / Q000172:deficiency / Q000235:genetics; D020813:Receptor, trkB / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D020812:Receptor, trkC / Q000172:deficiency / Q000235:genetics; D013869:Thiolester Hydrolases / Q000378:metabolism; D043222:Ubiquitin Thiolesterase
chemical_list: D020917:Receptor, trkA; D020813:Receptor, trkB; D020812:Receptor, trkC; D013869:Thiolester Hydrolases; D043222:Ubiquitin Thiolesterase; D015740:Calcitonin Gene-Related Peptide