title: Localization of fibroblast growth factor-1 in cholinergic neurons innervating the rat larynx.
abstract: Cholinergic neurons in the dorsal motor nucleus of the vagus (DMNV) are particularly vulnerable to laryngeal nerve damage, possibly because they lack fibroblast growth factor-1 (FGF1). To test this hypothesis, we investigated the localization of FGF1 in cholinergic neurons innervating the rat larynx by immunohistochemistry using central-type antibodies to choline acetyltransferase (cChAT) and peripheral type (pChAT) antibodies, as well as tracer experiments. In the DMNV, only 9% of cChAT-positive neurons contained FGF1, and 71% of FGF1-positive neurons colocalized with cChAT. In the nucleus ambiguus, 100% of cChAT-positive neurons were FGF1 positive. In the intralaryngeal ganglia, all ganglionic neurons contained both pChAT and FGF1. In the nodose ganglia, 66% of pChAT-positive neurons were also positive for FGF1, and 90% of FGF1-positive ganglionic cells displayed pChAT immunoreactivity. Neuronal tracing using cholera toxin B subunit (CTb) demonstrated that cholinergic neurons sending their axons from the DMNV and nucleus ambiguus to the superior laryngeal nerve were FGF1 negative and FGF1 positive, respectively. In the nodose ganglia, some FGF1-positive cells were labeled with CTb. The results indicate that for innervation of the rat larynx, FGF1 is localized to motor neurons, postganglionic parasympathetic neurons, and sensory neurons, but expression is very low in preganglionic parasympathetic cholinergic neurons.
authors.affiliation: Molecular Neuroscience Research Center, Shiga University of Medical Science, Setatsukinowa-cho, Otsu 520-2192, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okano
authors.forename: Ken-ichiro
authors.initials: K
authors.lastname: Toyoda
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Bamba
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Hisa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Oomura
authors.forename: Toru
authors.initials: T
authors.lastname: Imamura
authors.forename: Shoei
authors.initials: S
authors.lastname: Furukawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kimura
authors.forename: Ikuo
authors.initials: I
authors.lastname: Tooyama
mesh_terms: D000818:Animals; D002772:Cholera Toxin; D002795:Choline O-Acetyltransferase / Q000276:immunology / Q000378:metabolism*; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism*; D005726:Ganglia, Parasympathetic / Q000378:metabolism; D007150:Immunohistochemistry; D007823:Laryngeal Nerves / Q000378:metabolism*; D007830:Larynx / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009620:Nodose Ganglion / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016220:Fibroblast Growth Factor 1; D002772:Cholera Toxin; D002795:Choline O-Acetyltransferase