Cloning and expression of a Kv1.2 class delayed rectifier K+ channel from canine colonic smooth muscle.

• DOI: 10.1073/pnas.90.20.9659
• Publication Date: 2006-05-31T12:32:55Z
• Authors: P J Hart; K E Overturf; S N Russell; A Carl; J R Hume; K M Sanders; B Horowitz
• Keywords: 0301 basic medicine; DNA, Complementary; Potassium Channels; Microinjections; Sequence Homology, Amino Acid; Colon; Molecular Sequence Data; Electric Conductivity; Gene Expression; Muscle, Smooth; Xenopus laevis; 03 medical and health sciences; Dogs; Potassium; Animals; Tissue Distribution; Amino Acid Sequence; RNA, Messenger; 4-Aminopyridine; Cloning, Molecular; Ion Channel Gating; Sequence Alignment

A cDNA (CSMK1) encoding a delayed rectifier K+ channel of the Kv1.2 class was cloned from canine colonic circular smooth muscle and expressed in Xenopus oocytes. These channels appear to be uniquely gastrointestinal muscles may participate electrical slow wave activity. Functional expression CSMK1 oocytes demonstrated current that activated voltage-dependent manner upon depolarization. This highly sensitive 4-aminopyridine (IC50, 74 microM). low-conductance identified inside-out patches injected with CSMK1. displayed linear current-voltage relation slope conductance 14 pS. The were blocked concentration-dependent by 4-aminopyridine. Northern blot analysis is wide variety muscles. Portal vein, renal artery, uterus do not express CSMK1, suggesting that, among muscles, this restricted 91% homologous RAK, rat heart, but displays unique pharmacological properties tissue distribution.