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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 |
2002-2-25
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pubmed:abstractText |
The widely accepted model to explain the positive inotropic effect of cardiac glycosides invokes altered Na+-Ca2+ exchange activity secondary to Na+ pump inhibition. However, proof of this model is lacking and alternative mechanisms have been proposed. We directly tested the role of the Na+-Ca2+ exchanger in the action of the glycoside ouabain using Na+-Ca2+ exchanger knockout mice. Ablation of the exchanger is embryonic lethal, but contractility can be studied in embryonic heart tubes at day 9.5 postcoitum. Heart tubes isolated from homozygous Na+-Ca2+ exchanger knockout mice (NCX-/-) display surprisingly normal Ca2+ transients. Removal of extracellular Na+ induces Ca2+ overload in wild-type heart tubes but does not alter the Ca2+ transients of NCX-/- heart tubes. Similarly, ouabain, at levels causing Ca2+ overload in wild-type heart tubes, has no effect on NCX-/- heart tubes. We conclude that in embryonic mouse myocytes the Na+-Ca2+ exchanger is absolutely required for the effect of cardiac glycosides on Ca2+(i).
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pubmed:grant |
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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 |
Feb
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pubmed:issn |
1524-4571
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pubmed:author |
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pubmed:issnType |
Electronic
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pubmed:day |
22
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pubmed:volume |
90
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
305-8
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:11861419-Animals,
pubmed-meshheading:11861419-Calcium,
pubmed-meshheading:11861419-Calcium Signaling,
pubmed-meshheading:11861419-Cardiac Glycosides,
pubmed-meshheading:11861419-Cardiotonic Agents,
pubmed-meshheading:11861419-Electrophysiologic Techniques, Cardiac,
pubmed-meshheading:11861419-Heart,
pubmed-meshheading:11861419-Heterozygote,
pubmed-meshheading:11861419-Homozygote,
pubmed-meshheading:11861419-Ion Transport,
pubmed-meshheading:11861419-Mice,
pubmed-meshheading:11861419-Mice, Knockout,
pubmed-meshheading:11861419-Models, Animal,
pubmed-meshheading:11861419-Myocardial Contraction,
pubmed-meshheading:11861419-Ouabain,
pubmed-meshheading:11861419-Sodium,
pubmed-meshheading:11861419-Sodium-Calcium Exchanger
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pubmed:year |
2002
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pubmed:articleTitle |
The Na+-Ca2+ exchanger is essential for the action of cardiac glycosides.
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pubmed:affiliation |
Department of Physiology, UCLA School of Medicine, Los Angeles, Calif 90095-1760, USA.
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pubmed:publicationType |
Journal Article,
In Vitro,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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