title: How many hair follicles are innervated by one afferent axon? A confocal microscopic analysis of palisade endings in the auricular skin of thy1-YFP transgenic mouse.
abstract: Hairs are known as a sensory apparatus for touch. Their follicles are innervated predominantly by palisade endings composed of longitudinal and circumferential lanceolate endings. However, little is known as to how their original primary neurons make up a part of the ending. In this study, innervation of the palisade endings was investigated in the auricular skin of thy1-YFP transgenic mouse. Major observations were 1) Only a small portion of PGP9.5-immunopositive axons showed YFP-positivity, 2) All of thy1-YFP-positive sensory axons were thick and myelinated, 3) Individual thy1-YFP-positive trunk axons innervated 4-54 hair follicles, 4) Most palisade endings had a gap of lanceolate ending arrangement, 5) PGP9.5-immunopositive 10-32 longitudinal lanceolate endings were closely arranged. Only a part of them were thy1-YFP-positive axons that originated from 1-3 afferents, and 6) Single nerve bundles of the dermal nerve network included both bidirectional afferents. Palisade endings innervated by multiple sensory neurons might be highly sensitive to hair movement.
authors.affiliation: Department of Anatomy, Meiji University of Integrative Medicine, Kyoto, Japan.
authors.forename: Maasa
authors.initials: M
authors.lastname: Suzuki
authors.forename: Satomi
authors.initials: S
authors.lastname: Ebara
authors.forename: Taro
authors.initials: T
authors.lastname: Koike
authors.forename: Sotatsu
authors.initials: S
authors.lastname: Tonomura
authors.forename: Kenzo
authors.initials: K
authors.lastname: Kumamoto
mesh_terms: D000818:Animals; D001369:Axons / Q000502:physiology*; D018859:Hair Follicle / Q000294:innervation*; D008164:Luminescent Proteins / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D009411:Nerve Endings / Q000502:physiology*; D009475:Neurons, Afferent / Q000166:cytology*; D018800:Thy-1 Antigens / Q000235:genetics*; D014110:Touch / Q000502:physiology
chemical_list: D008164:Luminescent Proteins; D018800:Thy-1 Antigens