Inhibition of ATP-sensitive K+ channels by taurine through a benzamido-binding site on sulfonylurea receptor 1

Biochem Pharmacol. 2004 Mar 15;67(6):1089-96. doi: 10.1016/j.bcp.2003.11.003.


ATP-sensitive potassium (K(ATP)) channels in pancreatic beta-cells comprise sulfonylurea receptor (SUR) 1 and inwardly-rectifying potassium channel (Kir) 6.2 subunits. We have evaluated the effect of intracellular taurine on K(ATP) channel activity in rat pancreatic beta-cells using the patch-clamp technique. The mechanism of taurine action was also examined using recombinant K(ATP) channels. The islets and single beta-cells from male Sprague-Dawley rats were collected by collagenase digestion technique. Single K(ATP) channel currents were recorded by the inside-out mode at a membrane potential of -60mV. Cytosolic free-Ca(2+) concentration ([Ca(2+)](c)) and insulin secretory capacity were measured by the dual-excitation fluorimetry and radioimmunoassay, respectively. The native beta-cell K(ATP) channel was directly inhibited by taurine in a dose-dependent manner. Taurine did not influence ATP-mediated inhibition or MgADP-induced activation of the channel activity. The sensitivity of the K(ATP) channel to glybenclamide, but not gliclazide, was enhanced by taurine. Glybenclamide elicited a greater increase in [Ca(2+)](c) and increased insulin secretion in the beta-cells when pretreated with taurine. Taurine did not inhibit Kir6.2DeltaC36 currents, a truncated form of Kir6.2, expressed in Xenopus oocytes without SUR. These results demonstrate that taurine inhibits the K(ATP) channel activity in the beta-cells, interacting with a benzamido-binding site on SUR1, but not Kir6.2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / metabolism
  • Animals
  • Binding Sites
  • Drug Interactions
  • Glyburide / pharmacology
  • Insulin / metabolism
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / metabolism
  • Male
  • Membrane Proteins / antagonists & inhibitors*
  • Membrane Proteins / metabolism
  • Potassium Channels
  • Potassium Channels, Inwardly Rectifying / antagonists & inhibitors
  • Potassium Channels, Inwardly Rectifying / metabolism*
  • Protein Subunits / antagonists & inhibitors
  • Protein Subunits / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sulfonylurea Compounds / pharmacology
  • Taurine / pharmacology*


  • Insulin
  • Membrane Proteins
  • Potassium Channels
  • Potassium Channels, Inwardly Rectifying
  • Protein Subunits
  • Sulfonylurea Compounds
  • mitochondrial K(ATP) channel
  • Taurine
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Glyburide