Expression of voltage-dependent K⁺channel genes in mesenteric artery smooth muscle cells

Abstract

Molecular basis of native voltage-dependent K(+) (Kv) channels in smooth muscle cells (SMCs) from rat mesenteric arteries was investigated. The whole cell patch-clamp study revealed that a 4-aminopyridine-sensitive delayed rectifier K(+) current (I(K)) was the predominant K(+) conductance in these cells. A systematic screening of the expression of 18 Kv channel genes using RT-PCR technique showed that six I(K)-encoding genes (Kv1.2, Kv1.3, Kv1.5, Kv2.1, Kv2.2, and Kv3.2) were expressed in mesenteric artery. Although no transient outward Kv currents (I(A)) were recorded in the studied SMCs, transcripts of multiple I(A)-encoding genes, including Kv1.4, Kv3.3, Kv3.4, Kv4.1, Kv4.2, and Kv4.3 as well as I(A)-facilitating Kv beta-subunits (Kvbeta1, Kvbeta2, and Kvbeta3), were detected in mesenteric arteries. Western blot analysis demonstrated that four I(K)-related Kv channel proteins (Kv1.2, Kv1. 3, Kv1.5, and Kv2.1) were detected in mesenteric artery tissues. The presence of Kv1.2, Kv1.3, Kv1.5, and Kv2.1 channel proteins in isolated SMCs was further confirmed by immunocytochemistry study. Our results suggest that the native I(K) in rat mesenteric artery SMCs might be generated by heteromultimerization of Kv genes.

Molecular Composition of 4-Aminopyridine-Sensitive Voltage-Gated K + Channels of Vascular Smooth Muscle

“…10 -16,36 -39 Moreover, transcripts encoding Kv␤ subunits were also shown to be expressed in smooth muscle of pulmonary artery, mesenteric artery, and gastrointestinal tract. 10,12,13,38 However, Kv1.1, Kv1.3, and Kv1.6 were reported to be expressed in pulmonary 10 and/or mesenteric arteries, 12,13 but were not detected in RPV. Additionally, splice variants of Kv␤1 (ie, ␤1.1 and ␤1.2) were found in smooth muscle cells of the gastrointestinal tract, but ␤2.1 expression was not detected.…”

The Effects of the Selective Serotonin Reuptake Inhibitor Fluvoxamine on Voltage-Dependent K⁺ Channels in Rabbit Coronary Arterial Smooth Muscle Cells

“…15, 39,40) As Kv1.5 subtype is expressed in most arterial smooth muscle and fluvoxamine directly inhibited Kv1.5 channels expressed in CHO cells, 10) at least one of the main targets of fluvoxamine could be the Kv1.5 subtype, although other subtypes may also be affected. Further studies are necessary to determine which Kv subtypes interact with fluvoxamine.…”

The Mechanism of Endothelium-Independent Relaxation Induced by the Wine Polyphenol Resveratrol in Human Internal Mammary Artery

“…This peptide is a highly selective inhibitor of the K V 1 channels, especially 1.1, 1.2, 1.3, and 1.6 subtypes, but displays no affinity for the mammalian BK Ca channel (28,29). K V 1.2 and K V 1.3 channels were identified in vascular smooth muscle cell of rat mesenteric artery; K V 1.1 and K V 1.6 channels were detected in smooth muscle cells of rat aorta and rat pulmonary artery, but not in smooth muscle cells of mesenteric artery (30,31). This reflects tissue differences in expression of K V 1 channels subtypes.…”