Contributions of Kv1.2, Kv1.5 and Kv2.1 subunits to the native delayed rectifier K(+) current in rat mesenteric artery smooth muscle cells.
A large array of voltage-gated K(+) channel (Kv) genes has been identified in vascular smooth muscle tissues. This molecular diversity underlies the vast repertoire of native Kv channels that regulate the excitability of vascular smooth muscle tissues. The contributions of different Kv subunit gene products to the native Kv currents are poorly understood in vascular smooth muscle cells (SMCs). In the present study, Kv subunit-specific antibodies were applied intracellularly to selectively block various Kv channel subunits and the whole-cell outward Kv currents were recorded using the patch-clamp technique in rat mesenteric artery SMCs. Anti-Kv1.2 antibody (8 microg/ml) inhibited the Kv currents by 29.2 +/- 5.9% (n = 6, P < 0.05), and anti-Kv1.5 antibody (6 microg/ml) by 24.5 +/- 2.6% (n = 7, P < 0.05). Anti-Kv2.1 antibody inhibited the Kv currents in a concentration-dependent fashion (4-20 microg/ml). Co-application of antibodies against Kv1.2 and Kv2.1 (8 microg/ml each) induced an additive inhibition of Kv currents by 42.3 +/- 3.1% (n = 7, P < 0.05). In contrast, anti-Kv1.3 antibody (6 microg/ml) did not have any effect on the native Kv current (n = 6, P > 0.05). A control antibody (anti-GIRK1) also had no effect on the native Kv currents. This study demonstrates that Kv1.2, Kv1.5, and Kv2.1 subunit genes all contribute to the formation of the native Kv channels in rat mesenteric artery SMCs.
Lu
Yanjie
Y
Department of Physiology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK, Canada S7N 5E5.
Hanna
Salma T
ST
Tang
Guanghua
G
Wang
Rui
R
D000818:Animals; D000918:Antibody Specificity; D015153:Blotting, Western; D051668:Delayed Rectifier Potassium Channels; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D066298:In Vitro Techniques; D051663:Kv1.2 Potassium Channel; D051666:Kv1.5 Potassium Channel; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000378:metabolism*; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D051381:Rats; D017207:Rats, Sprague-Dawley; D051669:Shab Potassium Channels
D051668:Delayed Rectifier Potassium Channels; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; C496972:Kcna2 protein, rat; C496983:Kcna5 protein, rat; C496991:Kcnb1 protein, rat; D051663:Kv1.2 Potassium Channel; D051666:Kv1.5 Potassium Channel; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D051669:Shab Potassium Channels