Expression of inwardly rectifying K+ channels in the carotid body of rat
Y. Yamamoto1, R. Ishikawa2, K. Omoe3 and K. Taniguchi2
1Laboratory of Veterinary Biochemistry and Cell Biology, 2Laboratory of Veterinary Anatomy, and 3Laboratory of Veterinary Food Safety Science, Faculty of Agriculture, Iwate University, Morioka, Japan.
Offprint requests to: Prof. Dr. Yoshio Yamamoto, Laboratory of Veterinary Biochemistry and Cell Biology, Faculty of Agriculture, Iwate University, 18-3 Ueda 3-chome, Morioka, Iwate 020-8550, Japan. e-mail: yyoshio@iwate-u.ac.jp
Summary. The inwardly rectifying K+ channels, Kir1.1, Kir2.3, Kir4.1-Kir5.1, and Kir4.2-Kir5.1, are candidate chemosensory molecules for CO2/H+. Here, we determined the mRNA expression and immunohistochemical localization of these channels in the carotid body (CB) and petrosal ganglion (PG) of the rat. RT-PCR analysis revealed mRNA expression of Kir4.1 and Kir5.1 in CB, and Kir1.1, Kir4.1, and Kir5.1 in PG. Immunohistochemistry identified the glomus cells in CB to express both Kir4.1 and Kir5.1 protein, while the nerve fibers in CB were immunoreactive for Kir1.1, Kir4.1, and Kir5.1. In the PG, immunoreactivity for Kir1.1, Kir4.1, and Kir5.1 was observed in some ganglion cells. Our findings suggest that Kir channels in the peripheral chemoreceptors play a role in sensing hypercapnic acidosis and maintaining the resting membrane potentials. Histol Histopathol 23, 799-806 (2008)
Key words: Hypercapnic acidosis, Inwardly rectifying K+ channel, Carotid body, Petrosal ganglion, Chemoreceptor
DOI: 10.14670/HH-23.799