Molecular diversity of K-V alpha- and beta-subunit expression in canine gastrointestinal smooth muscles

Citation
A. Epperson et al., Molecular diversity of K-V alpha- and beta-subunit expression in canine gastrointestinal smooth muscles, AM J P-GAST, 40(1), 1999, pp. G127-G136
Citations number
51
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
ISSN journal
01931857 → ACNP
Volume
40
Issue
1
Year of publication
1999
Pages
G127 - G136
Database
ISI
SICI code
0193-1857(199907)40:1<G127:MDOKAA>2.0.ZU;2-5
Abstract
Voltage-activated K+ (Kv) channels play an important role in regulating the membrane potential in excitable cells. In gastrointestinal (GI) smooth mus cles, these channels are particularly important in modulating spontaneous e lectrical activities. The purpose of this study was to identify the molecul ar components that may be responsible for the Ky currents found in the cani ne GI tract. In this report, we have examined the qualitative expression of eighteen different Ky channel genes in canine GI smooth muscle cells at th e transcriptional level using RT-PCR analysis. Our results demonstrate the expression of K(V)1.4, K(V)1.5, K(V)1.6, K(V)2.2, and K(V)4.3 transcripts i n all regions of the GI tract examined. Transcripts encoding K(V)1.2, K(V)b eta 1.1, and K(V)beta 1.2 subunits were differentially expressed. K(V)1.1, K(V)1.3, K(V)2.1, K(V)3.1, K(V)3.2, K(V)3.4, K(V)4.1, K(V)4.2, and K(V)beta 2.1 transcripts were not detected in any GI smooth muscle cells. We have a lso determined the protein expression for a subset of these Ky channel subu nits using specific antibodies by immunoblotting and immunohistochemistry. Immunoblotting and immunohistochemistry demonstrated that K(V)1.2, K(V)1.4, K(V)1.5, and K(V)2.2 are expressed at the protein level in GI tissues and smooth muscle cells. K(V)2.1 was not detected in any regions of the GI trac t examined. These results suggest that the wide array of electrical activit y found in different regions of the canine GI tract may be due in part to t he differential expression of Ky channel subunits.