title: Expression of Fos protein in brainstem after application of l-menthol to the rat nasal mucosa.
abstract: There are two functional pathways for the nasotrigeminal reflex: the spinal nucleus of trigeminal nerve (SPV) to the Kölliker-Fuse (KF) nucleus and the nucleus of solitary tract (NTS) to the lateral parabrachial nucleus (PBl). Although stimulation of the nasal mucosa by cool temperature induces respiratory depression, it is still unknown whether these nuclei are activated. In the present study, we examined the expression of Fos protein in rat brainstem neurons after nasal application of l-menthol, which is known to activate cold-sensitive nasal receptors. Application of l-menthol, but not paraffin oil, decreased the respiratory rate from 99.7+/-15.6 to 78.5+/-7.3 min(-1). Furthermore, a significantly higher density of Fos-immunoreactive cells was observed in the SPV and KF in the l-menthol rats than in the controls. In the SPV, the density of Fos-immunoreactive cells was highest at approximately 0.5mm rostral to the obex in both the l-menthol (48.5+/-11.5 cells/section) and paraffin oil (26.0+/-9.6 cells/section) groups. In the KF, the mean density of Fos-immunoreactive cells was highest at approximately 5.0mm rostral to the obex in both groups (l-menthol: 67.8+/-14.0 cells/section, control: 41.0+/-12.7 cells/section). The present study suggests that the SPV-KF pathway is important for the cold-induced respiratory depression.
authors.affiliation: Laboratory of Veterinary Biochemistry and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Wakai
authors.forename: Katsuaki
authors.initials: K
authors.lastname: Yoshizaki
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Taniguchi
authors.forename: Misuzu
authors.initials: M
authors.lastname: Yamaguchi-Yamada
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D000982:Antipruritics / Q000494:pharmacology*; D001931:Brain Mapping; D001933:Brain Stem / Q000378:metabolism*; D002452:Cell Count; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D008610:Menthol / Q000494:pharmacology*; D009297:Nasal Mucosa / Q000187:drug effects* / Q000502:physiology; D009833:Olfactory Pathways / Q000502:physiology; D016761:Oncogene Proteins v-fos / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012119:Respiration / Q000187:drug effects
chemical_list: D000982:Antipruritics; D016761:Oncogene Proteins v-fos; D008610:Menthol