Glimepiride block of cloned beta-cell, cardiac and smooth muscle K(ATP) channels.

ABSTRACT: 1. We examined the effect of the sulphonylurea glimepiride on three types of recombinant ATP-sensitive potassium (K(ATP)) channels. 2. K(ATP) channels share a common pore-forming subunit, Kir6.2, which associates with different sulphonylurea receptor isoforms (SUR1 in beta-cells, SUR2A in heart and SUR2B in smooth muscle). 3. Kir6.2 was coexpressed with SUR1, SUR2A or SUR2B in Xenopus oocytes and macroscopic K(ATP) currents were recorded from giant inside-out membrane patches. Glimepiride was added to the intracellular membrane surface. 4. Glimepiride inhibited Kir6.2/SUR currents by interaction with two sites: a low-affinity site on Kir6.2 (IC(50)= approximately 400 microM) and a high-affinity site on SUR (IC(50)=3.0 nM for SUR1, 5.4 nM for SUR2A and 7.3 nM for SUR2B). The potency of glim

SUBMITTER: Song DK 

PROVIDER: S-EPMC1572773 | biostudies-literature | 2001 May

REPOSITORIES: biostudies-literature