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rdf:type |
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lifeskim:mentions |
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pubmed:dateCreated |
1999-3-22
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pubmed:abstractText |
1. Sodium channel ionic current (INa) and gating current (Ig) were compared for rat skeletal (rSkM1) and human heart Na+ channels (hH1a) heterologously expressed in cultured mammalian cells at approximately 13 C before and after modification by site-3 toxins (Anthopleurin A and Anthopleurin B). 2. For hH1a Na+ channels there was a concordance between the half-points (V ) of the peak conductance-voltage (G-V) relationship and the gating charge-voltage (Q-V) relationship with no significant difference in half-points. In contrast, the half-point of the Q-V relationship for rSkM1 Na+ channels was shifted to more negative potentials compared with its G-V relationship with a significant difference in the half-points of -8 mV. 3. Site-3 toxins slowed the decay of INa in response to step depolarizations for both rSkM1 and hH1a Na+ channels. The half-point of the G-V relationship in rSkM1 Na+ channels was shifted by -8.0 mV while toxin modification of hH1a Na+ channels produced a smaller hyperpolarizing shift of the V by -3.7 mV. 4. Site-3 toxins reduced maximal gating charge (Qmax ) by 33% in rSkM1 and by 31% in hH1a, but produced only minor changes in the half-points and slope factors of their Q-V relationships. In contrast to measurements in control solutions, after modification by site-3 toxin the half-points of the G-V and the Q-V relationships for rSkM1 Na+ channels demonstrated a concordance similar to that for hH1a. 5. Qmax vs. Gmax for rSkM1 and hH1a Na+ channels exhibited linear relationships with almost identical slopes, as would be expected if the number of electronic charges (e-) per channel was comparable. 6. We conclude that the faster kinetics in rSkM1 channels compared with hH1a channels may arise from inherently faster rate transitions in skeletal muscle Na+ channels, and not from major differences in the voltage dependence of the channel transitions.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-1244888,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-1314510,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-1346508,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-1660285,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-1851958,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2157792,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2435840,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2457660,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2536799,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2551998,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2559760,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-2578549,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-6316158,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-7807059,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8013069,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8061191,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8576699,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8576700,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8770089,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8770201,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8785328,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8786350,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8786356,
http://linkedlifedata.com/resource/pubmed/commentcorrection/9852324-8843731
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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 |
Jan
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pubmed:issn |
0022-3751
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:day |
15
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pubmed:volume |
514 ( Pt 2)
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
425-36
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:9852324-Animals,
pubmed-meshheading:9852324-Cell Line,
pubmed-meshheading:9852324-Heart,
pubmed-meshheading:9852324-Humans,
pubmed-meshheading:9852324-Ion Channel Gating,
pubmed-meshheading:9852324-Mammals,
pubmed-meshheading:9852324-Membrane Potentials,
pubmed-meshheading:9852324-Muscle, Skeletal,
pubmed-meshheading:9852324-Papillary Muscles,
pubmed-meshheading:9852324-Quaternary Ammonium Compounds,
pubmed-meshheading:9852324-Rats,
pubmed-meshheading:9852324-Recombinant Fusion Proteins,
pubmed-meshheading:9852324-Sodium Channels,
pubmed-meshheading:9852324-Transfection
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pubmed:year |
1999
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pubmed:articleTitle |
Gating of skeletal and cardiac muscle sodium channels in mammalian cells.
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pubmed:affiliation |
The Nora Eccles Harrison Cardiovascular Research & Training Institute and Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA. michael@cvrti.uath.edu
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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