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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.BP

Abstract

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.

Authors+Show Affiliations

Chronic Disease Research Center, Keimyung University School of Medicine, 194 Dongsan-Dong, Jung-Gu, Daegu 700-712, South Korea.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15006545

Citation

Park, Eun-Jee, et al. "Inhibition of ATP-sensitive K+ Channels By Taurine Through a Benzamido-binding Site On Sulfonylurea Receptor 1." Biochemical Pharmacology, vol. 67, no. 6, 2004, pp. 1089-96.
Park EJ, Bae JH, Kim SY, et al. Inhibition of ATP-sensitive K+ channels by taurine through a benzamido-binding site on sulfonylurea receptor 1. Biochem Pharmacol. 2004;67(6):1089-96.
Park, E. J., Bae, J. H., Kim, S. Y., Lim, J. G., Baek, W. K., Kwon, T. K., Suh, S. I., Park, J. W., Lee, I. K., Ashcroft, F. M., & Song, D. K. (2004). Inhibition of ATP-sensitive K+ channels by taurine through a benzamido-binding site on sulfonylurea receptor 1. Biochemical Pharmacology, 67(6), 1089-96.
Park EJ, et al. 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. PubMed PMID: 15006545.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Inhibition of ATP-sensitive K+ channels by taurine through a benzamido-binding site on sulfonylurea receptor 1. AU - Park,Eun-Jee, AU - Bae,Jae Hoon, AU - Kim,So-Yeon, AU - Lim,Jeong-Geun, AU - Baek,Won-Ki, AU - Kwon,Taeg Kyu, AU - Suh,Seong-Il, AU - Park,Jong-Wook, AU - Lee,In-Kyu, AU - Ashcroft,Frances M, AU - Song,Dae-Kyu, PY - 2003/07/14/received PY - 2003/11/03/accepted PY - 2004/3/10/pubmed PY - 2004/4/13/medline PY - 2004/3/10/entrez SP - 1089 EP - 96 JF - Biochemical pharmacology JO - Biochem Pharmacol VL - 67 IS - 6 N2 - 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. SN - 0006-2952 UR - https://www.unboundmedicine.com/medline/citation/15006545/Inhibition_of_ATP_sensitive_K+_channels_by_taurine_through_a_benzamido_binding_site_on_sulfonylurea_receptor_1_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0006295203008852 DB - PRIME DP - Unbound Medicine ER -