Mg2+ sensitizes KATP channels to inhibition by DIDS: dependence on the sulphonylurea receptor subunit.

ABSTRACT: 1. ATP-sensitive potassium channels (K(ATP) channels) consist of pore-forming Kir6.x subunits and of sulphonylurea receptors (SURs). In the absence of Mg(2+), the stilbene disulphonate, DIDS, irreversibly inhibits K(ATP) channels by binding to the Kir subunit. Here, the effects of Mg(2+) on the interaction of DIDS with recombinant K(ATP) channels were studied in electrophysiological and [(3)H]-glibenclamide binding experiments. 2. In inside-out macropatches, Mg(2+) (0.7 mM) increased the sensitivity of K(ATP) channels towards DIDS up to 70 fold (IC(50)=2.7 micro M for Kir6.2/SUR2B). Inhibition of current at DIDS concentrations > or =10 micro M was irreversible. 3. Mg(2+) sensitized the truncated Kir6.2Delta26 channel towards inhibition by DIDS only upon coexpression with a SUR subunit (SUR

SUBMITTER: Gojkovic-Bukarica L 

PROVIDER: S-EPMC1573525 | biostudies-literature | 2002 Oct

REPOSITORIES: biostudies-literature