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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
1 Pt 2
|
| pubmed:dateCreated |
1995-2-27
|
| pubmed:abstractText |
Sodium flux rate and energy consumption of the Na(+)-K+ pump in vascular endothelial cells of porcine aorta grown on micro-carrier beads were studied using a combination of nuclear magnetic resonance spectroscopy of intracellular 23Na and microcalorimetry. The Na+ flux into the cells was determined in the presence of the shift reagent Dy(P3O10)2(7-), while the Na(+)-K+ pump was inhibited with ouabain. Basal Na+ influx was 17 +/- 3 nmol.min-1.mg protein-1, and intracellular Na+ concentration was 23.5 +/- 3.8 mM, resulting in a complete exchange of intracellular Na+ within 5-6 min. Spin-lattice relaxation time (T1) measurements of intracellular Na+ showed a T1 of 19 +/- 1 ms under basal conditions and a T1 of 26.2 +/- 1.6 ms after pump inhibition with 50 microM ouabain. Such an increase is typical for a system in which the total amount of Na+ increases but where the amount of bound Na+ remains constant. The Na+ ionophore nystatin maximally increased the Na(+)-K+ pump rate about twofold, whereas the amount of intracellular Na+ only increased 14%. With microcalorimetry a cellular heat flux of 183 +/- 18 microW per mg endothelial protein was determined, which relates to 7.6 microW/mg endothelial protein generated by the Na(+)-K(+)-adenosinetriphosphatase. Our data demonstrate that small intracellular changes of Na+ can stimulate the endothelial Na(+)-K+ pump activity. The contribution of the Na(+)-K+ pump to total endothelial energy expenditure is approximately 4-5%.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:citationSubset |
IM
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| pubmed:chemical | |
| pubmed:status |
MEDLINE
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| pubmed:month |
Jan
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| pubmed:issn |
0002-9513
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| pubmed:author | |
| pubmed:issnType |
Print
|
| pubmed:volume |
268
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| pubmed:owner |
NLM
|
| pubmed:authorsComplete |
Y
|
| pubmed:pagination |
H351-8
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| pubmed:dateRevised |
2007-11-15
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| pubmed:meshHeading |
pubmed-meshheading:7840283-Animals,
pubmed-meshheading:7840283-Aorta,
pubmed-meshheading:7840283-Calorimetry,
pubmed-meshheading:7840283-Cells, Cultured,
pubmed-meshheading:7840283-Endothelium, Vascular,
pubmed-meshheading:7840283-Energy Metabolism,
pubmed-meshheading:7840283-Kinetics,
pubmed-meshheading:7840283-Magnetic Resonance Spectroscopy,
pubmed-meshheading:7840283-Microspheres,
pubmed-meshheading:7840283-Nystatin,
pubmed-meshheading:7840283-Ouabain,
pubmed-meshheading:7840283-Sodium,
pubmed-meshheading:7840283-Sodium-Potassium-Exchanging ATPase,
pubmed-meshheading:7840283-Swine,
pubmed-meshheading:7840283-Time Factors
|
| pubmed:year |
1995
|
| pubmed:articleTitle |
Na(+)-K(+)-ATPase in endothelial cell energetics: 23Na nuclear magnetic resonance and calorimetry study.
|
| pubmed:affiliation |
Department of Physiology I, Heinrich Heine University Düsseldorf, Germany.
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| pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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