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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
3
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pubmed:dateCreated |
1996-11-15
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pubmed:abstractText |
We have studied potassium currents through a cloned Ca(2+)-dependent K+ channel (hslo) from human myometrium. Currents were recorded in inside-out macropatches from membranes of Xenopus laevis oocytes. In particular, the inactivation-like process that these channels show at high positive potentials was assessed in order to explore its molecular nature. This current inhibition conferred a bell shape to the current-voltage curves. The kinetic and voltage dependence of this process suggested the possibility of a Ba2+ block. There were the following similarities between the inactivation process observed at zero-added Ba2+ and the internal Ba2+ block of hslo channels: (a) in the steady state, the voltage dependence of the current inhibition observed at zero-added Ba2+ was the same as the voltage dependence of the Ba2+ block; (b) the time constant for recovery from current decay at zero-added Ba2+ was the same as the time constant for current recovery from Ba2+ blockade; and (c) current decay was largely suppressed in both cases by adding a Ba2+ chelator [(+)-18-crown-6-tetracarboxylic acid] to the internal solution. In our experimental conditions, we determined that the Kd for the complex chelator-Ba2+ is 1.6 x 10(-10) M. We conclude that the current decay observed at zero-added Ba2+ to the internal solution is due to contaminant Ba2+ present in our solutions (approximately 70 nM) and not to an intrinsic gating process. The Ba2+ blocking reaction in hslo channels is bimolecular. Ba2+ binds to a site (Kd = 0.36 +/- 0.05 mM at zero applied voltage) that senses 92 +/- 25% of the potential drop from the internal membrane surface.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-1279807,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-1529355,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-1931050,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2122519,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2435161,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2437523,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2443608,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2580269,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2582128,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-2653189,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-3235973,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-4541078,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-6248618,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-6266531,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-6300405,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-6315858,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-6330754,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7518702,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7612822,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7687074,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7716526,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7917297,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-7993625,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-8038378,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8868050-8821792
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
Mar
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pubmed:issn |
0022-1295
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
107
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
399-407
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:8868050-Animals,
pubmed-meshheading:8868050-Barium,
pubmed-meshheading:8868050-Calcium,
pubmed-meshheading:8868050-Chelating Agents,
pubmed-meshheading:8868050-Cloning, Molecular,
pubmed-meshheading:8868050-Electrophysiology,
pubmed-meshheading:8868050-Ethers, Cyclic,
pubmed-meshheading:8868050-Humans,
pubmed-meshheading:8868050-Lipid Bilayers,
pubmed-meshheading:8868050-Membrane Potentials,
pubmed-meshheading:8868050-Muscle, Smooth,
pubmed-meshheading:8868050-Oocytes,
pubmed-meshheading:8868050-Patch-Clamp Techniques,
pubmed-meshheading:8868050-Potassium Channels,
pubmed-meshheading:8868050-Xenopus laevis
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pubmed:year |
1996
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pubmed:articleTitle |
Interaction of internal Ba2+ with a cloned Ca(2+)-dependent K+ (hslo) channel from smooth muscle.
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pubmed:affiliation |
Centro de Estudios Cientificos de Santiago, Universidad de Chile.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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