Molecular basis of ATP-sensitive K+ channels in rat vascular smooth muscles.
ATP-sensitive K+ (K(ATP)) channels couple metabolic changes to membrane excitability in vascular smooth muscle cells (SMCs). While the electrophysiological properties of K(ATP) channels have been examined, little is known about the molecular basis of K(ATP) complex in vascular SMCs. We identified and cloned four K(ATP) subunit genes from rat mesenteric artery, namely rvKir6.1, rvKir6.2, rvKirSUR1, and rvSUR2B. These clones showed over 99.6% amino acid sequence identity with other previously reported isoforms. The mRNA expression patterns of the K(ATP) subunits varied among rat aorta, mesenteric artery, pulmonary artery, tail artery, hepatic artery, and portal vein. Heterologous co-expression of rvKir6.1 and rvSUR2B yielded functional K(ATP) channels that were inhibited by glibenclamide, and opened by pinacidil. Our results for the first time reported the expression of four K(ATP) subunits in same vascular tissues, unmasking the diversity of native K(ATP) channels in vascular SMCs.
Cao
Kun
K
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Tang
Guanghua
G
Hu
Dahai
D
Wang
Rui
R
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000378:metabolism; D001921:Brain / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D005905:Glyburide / Q000378:metabolism; D006801:Humans; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D020110:Pinacidil / Q000378:metabolism; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014665:Vasodilator Agents / Q000378:metabolism
D000889:Anti-Arrhythmia Agents; D024661:Potassium Channels, Inwardly Rectifying; D021122:Protein Subunits; D014665:Vasodilator Agents; D020110:Pinacidil; D000255:Adenosine Triphosphate; D005905:Glyburide