ATP-sensitive K+ channels from aortic smooth muscle incorporated into planar lipid bilayers

Richard Kovacs, M. T. Nelson

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Glibenclamide binding sites were identified in a membrane preparation from canine aortic smooth muscle. The dissociation constant for [3H]glibenclamide binding was 10 ± 2 nM, with a density of 420 ± 108 fmol/mg protein. The properties of ATP-sensitive potassium (K(ATP)) channels from the same membrane preparation incorporated into planar lipid bilayers were investigated. ATP was a potent inhibitor of the channels with half-maximal inhibition of channel activity by 41 μM ATP. Glibenclamide inhibited channel activity, and cromakalim activated the channel in the presence of ATP. Blockers of Ca2+-activated K+ (K(Ca)) channels (charybdotoxin and tetraethylammonium ions) did not affect K(ATP) channels in concentrations that caused significant block of K(Ca) channels in bilayers. This membrane preparation should allow further biochemical and functional characterization of K((ATP) channels and glibenclamide receptors in arterial smooth muscle.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume261
Issue number2 30-2
StatePublished - 1991
Externally publishedYes

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Lipid Bilayers
Smooth Muscle
Adenosine Triphosphate
Glyburide
Membranes
Cromakalim
Charybdotoxin
Purinergic P2 Receptors
KATP Channels
Tetraethylammonium
Canidae
Binding Sites
Proteins

Keywords

  • Cromakalim
  • Glibenclamide
  • Potassium channels
  • Sulfonylurea

ASJC Scopus subject areas

  • Physiology

Cite this

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AU - Nelson, M. T.

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N2 - Glibenclamide binding sites were identified in a membrane preparation from canine aortic smooth muscle. The dissociation constant for [3H]glibenclamide binding was 10 ± 2 nM, with a density of 420 ± 108 fmol/mg protein. The properties of ATP-sensitive potassium (K(ATP)) channels from the same membrane preparation incorporated into planar lipid bilayers were investigated. ATP was a potent inhibitor of the channels with half-maximal inhibition of channel activity by 41 μM ATP. Glibenclamide inhibited channel activity, and cromakalim activated the channel in the presence of ATP. Blockers of Ca2+-activated K+ (K(Ca)) channels (charybdotoxin and tetraethylammonium ions) did not affect K(ATP) channels in concentrations that caused significant block of K(Ca) channels in bilayers. This membrane preparation should allow further biochemical and functional characterization of K((ATP) channels and glibenclamide receptors in arterial smooth muscle.

AB - Glibenclamide binding sites were identified in a membrane preparation from canine aortic smooth muscle. The dissociation constant for [3H]glibenclamide binding was 10 ± 2 nM, with a density of 420 ± 108 fmol/mg protein. The properties of ATP-sensitive potassium (K(ATP)) channels from the same membrane preparation incorporated into planar lipid bilayers were investigated. ATP was a potent inhibitor of the channels with half-maximal inhibition of channel activity by 41 μM ATP. Glibenclamide inhibited channel activity, and cromakalim activated the channel in the presence of ATP. Blockers of Ca2+-activated K+ (K(Ca)) channels (charybdotoxin and tetraethylammonium ions) did not affect K(ATP) channels in concentrations that caused significant block of K(Ca) channels in bilayers. This membrane preparation should allow further biochemical and functional characterization of K((ATP) channels and glibenclamide receptors in arterial smooth muscle.

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