title: Immunohistochemical distribution of inwardly rectifying K+ channels in the medulla oblongata of the rat.
abstract: The inwardly rectifying K+ channels, Kir1.1, Kir2.3 and Kir4.1-Kir5.1, are the candidate chemosensory molecules for CO2/H+. We determined the mRNA expression and immunohistochemical localization of these channels in the medulla oblongata of the rat. RT-PCR analysis revealed mRNAs of Kir1.1, Kir2.3, Kir4.1 and Kir5.1 were detected in the medulla. The immunoreactivities for Kir1.1, Kir2.3, Kir4.1, and Kir5.1 were observed in the medulla, and immunolabeling pattern was varied by the subunit. Immunoreactivities for Kir1.1 and Kir2.3 were observed in the nerve cell bodies and glial cells both in the chemosensory areas [nucleus tractus solitarius (NTS), nucleus raphe obscurus (RO), pre-Bötzinger complex (PreBötC)] and non-chemosensory area [hypoglossal nucleus (XII), inferior olive nucleus (IO)]. Kir4.1 immunoreactivity was observed in the glial cells and neuropil, especially in XII and IO. Kir5.1 immunoreactivity was observed in the nerve cell bodies in the XII, RO, and PreBötC, but not in the NTS or IO. In the NTS, a dense network of varicose nerve fibers showed immunoreactivity for Kir5.1. Our findings suggest that Kir channels may not act specific to the central chemoreception, but regulate the ionic properties of cellular membranes in various neurons and glial cells.
authors.affiliation: Laboratory of Veterinary Biochemistry and Cell Biology, Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan. yyoshio@iwate-u.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Ryota
authors.initials: R
authors.lastname: Ishikawa
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Omoe
authors.forename: Norie
authors.initials: N
authors.lastname: Yoshikawa
authors.forename: Misuzu
authors.initials: M
authors.lastname: Yamaguchi-Yamada
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Taniguchi
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000235:genetics; D007150:Immunohistochemistry; D008526:Medulla Oblongata / Q000166:cytology* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger