The 2TM domain family of K channels are also known as the inward-rectifier channel family. This includes strong (Kir2.x) that constitutively active, G-protein-activated (Kir3.x) and ATP-sensitive (Kir6.x, which combine with sulphonylurea receptors (SUR1-3)). pore-forming α subunits form tetramers, heteromeric may be formed within subfamilies (e.g. Kir3.2 Kir3.3).

RATIONALE The mitochondrial ATP sensitive potassium channel (mK(ATP)) is implicated in cardioprotection by ischemic preconditioning (IPC), but the molecular identity of the channel remains controversial. The validity of current methods to assay mK(ATP) activity is disputed. OBJECTIVE We sought to develop novel methods to assay mK(ATP) activity and its regulation. METHODS AND RESULTS Using a...

Effects of K-262a, (8R*, 9S*, llP)-(-)-Q-hydroxyD-methoxycarbonyl-8-methyl-2,3,9,lO-tetrahydro-8, Il-epoxy-1H,8H,11H-2,7b,lla-triazadibenzo[a,g]cycloocta [cdeltrinden1-one, purified from the culture broth of Nocardiopsis sp., on the activity of myosin light chain kinase were investigated. 1) K-262a (1 X lo-’ M) affected three characteristic properties of chicken gizzard myosin-B, natural actomy...

The novel sulfonylthiourea 1-[[5-[2-(5-chloro-o-anisamido)ethyl]-2-methoxyphenyl]sulfonyl]-3-methylthiourea (HMR 1883), a blocker of ATP-sensitive K(+) channels (K(ATP) channels), has potential against ischemia-induced arrhythmias. Here, the interaction of HMR 1883 with sulfonylurea receptor (SUR) subtypes and recombinant K(ATP) channels is compared with that of the standard sulfonylurea, glibe...

The primase fragment of bacteriophage T7 gene 4 protein catalyzes the synthesis of oligoribonucleotides in the presence of ATP, CTP, Mg(2+) (or Mn(2+)), and DNA containing a primase recognition site. During chain initiation, ATP binds with a K(m) of 0.32 mM, and CTP binds with a K(m) of 0.85 mM. Synthesis of the dinucleotides proceeds at a rate of 3.8/s. The dinucleotide either dissociates or i...

Endotoxemia induces a hemodynamic form of acute renal failure (ARF; renal vasoconstriction +/- reduced glomerular ultrafiltration coefficient, K(f); minimal/no histological damage). We tested whether levosimendan (LS), an ATP-sensitive K+ (K(ATP)) channel opener with cardiac ionotropic and possible anti-inflammatory properties, might have utility in combating this form of ARF. CD-1 mice were in...

ATP-sensitive K+ (K(ATP)) channels link metabolic state to cell excitability. Here, we examined regulation of K(ATP) channels in substantia nigra dopamine neurons by hydrogen peroxide (H2O2), which is produced in all cells during aerobic metabolism. Blockade of K(ATP) channels by glibenclamide (100 nM) or depletion of intracellular H2O2 by including catalase, a peroxidase enzyme, in the patch p...