K_ir2.1 encodes the inward rectifier potassium channel in rat arterial smooth muscle cells

Functional Expression of Inward Rectifier Potassium Channels in Cultured Human Pulmonary Smooth Muscle Cells: Evidence for a Major Role of Kir2.4 Subunits

“…Regardless of their origin within the cardiovascular system, K IR currents recorded to date are potently blocked by micromolar external Ba 2+ ions in a manner that is steeply voltage and time-dependent (Quayle et al, 1993;Robertson et al, 1996;Bradley et al, 1999;Snetkov & Ward, 1999;Sakai et al, 2002;Oonuma et al, 2002).…”

Direct Interaction between the Actin-binding Protein Filamin-A and the Inwardly Rectifying Potassium Channel, Kir2.1

“…Kir2.1 is the predominant isoform of the classical strong inward rectifier to be expressed in smooth muscle (21). Targeted disruption of the Kir2.1 gene produces arteries that fail to dilate in response to the modest elevations in extracellular K ϩ that are typically associated with periods of hypoxia and ischemia, indicating the essential role for Kir2.1 in the regulation of vascular tone under conditions of metabolic stress (22).…”

“…3B), suggesting that these two proteins form complexes within HEK293 cells. Both filamin and Kir2.1 are expressed within arterial smooth muscle (21,22,30), and we were interested in establishing whether such an interaction was likely to occur within native tissue. Fig.…”

“…Consequently, Kir channels are involved in setting and maintaining the resting membrane potential, modulation of prolonged action potentials in electrically excitable cells, and potassium homeostasis and secretion (19,20). Kir2.1 is the only isoform of the classical strong (Kir2) inward rectifier subfamily expressed in smooth muscle cells (21) and, crucially, has been shown to be an important regulator of smooth muscle membrane potential and, hence, vascular tone under conditions of metabolic stress (22). * The costs of publication of this article were defrayed in part by the payment of page charges.…”

Inward rectifier potassium conductance regulates membrane potential of canine colonic smooth muscle

“…Ba¥-sensitive inward rectifier K¤ currents have been identified in vascular smooth muscles (Quayle et al 1993;Knot et al 1996). These currents are likely to be due to the expression of Kir2.1 mRNA (Bradley et al 1999), but this conductance has not been reported in GI muscles to date. Although referred to as 'inward rectifiers,' these conductances carry small outward currents at potentials positive to EK, and this current contributes to the negative membrane potentials of several cell types, including cardiac muscle, mast cells and neurones (see Jan & Jan, 1997, for review).…”