title: Sympathetic and parasympathetic neurons are likely to be absent in the human vestibular and geniculate ganglia: an immunohistochemical study using elderly cadaveric specimens.
abstract: The vestibular and geniculate ganglia of the ear in experimental animals carry both of the tyrosine hydroxylase (TH)-positive sympathetic neurons and the neuronal nitric oxide synthase (nNOS)-positive parasympathetic neurons. With an aid of immunohistochemistry, we examined these ganglia as well as the horizontal part of the facial nerve using specimens from 10 formalin-fixed elderly cadavers. The submandibular ganglion from the same cadavers was used for the positive control for both markers. Although there was a nonspecific reaction in nuclei for the present antibody of nNOS, these ganglia were unlikely to contain either nNOS- or TH-positive neurons. However, we did not deny a possibility that the absence was a result of degeneration with aging. In contrast, the facial nerve horizontal part consistently contained both of TH-positive- and nNOS-positive fibers. These fibers might regulate blood supply to the facial nerve and the dysregulation leads to edema to elevate pressure on the nerve within its osseous canal.
authors.affiliation: Department of Anatomy, Tokyo Dental College.
authors.forename: Masato
authors.initials: M
authors.lastname: Yamauchi
authors.forename: Masahito
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Kei
authors.initials: K
authors.lastname: Kitamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kasahara
authors.forename: Satoru
authors.initials: S
authors.lastname: Matsunaga
authors.forename: Gen
authors.initials: G
authors.lastname: Murakami
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Abe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005726:Ganglia, Parasympathetic / Q000166:cytology*; D005728:Ganglia, Sympathetic / Q000166:cytology*; D005830:Geniculate Ganglion / Q000166:cytology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D009412:Nerve Fibers; D009474:Neurons / Q000166:cytology*; D014722:Vestibule, Labyrinth / Q000166:cytology*