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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
5
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pubmed:dateCreated |
2003-10-28
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pubmed:abstractText |
Formamide-induced detubulation of rat ventricular myocytes was used to investigate the functional distribution of the Na/Ca exchanger (NCX) and Na/K-ATPase between the t-tubules and external sarcolemma. Detubulation resulted in a 32% decrease in cell capacitance, whereas cell volume was unchanged. Thus, the surface-to-volume ratio was used to assess the success of detubulation. NCX current (I(NCX)) and Na/K pump current (I(pump)) were recorded using whole-cell patch clamp, as Cd-sensitive and K-activated currents, respectively. Both inward and outward I(NCX) density was significantly reduced by approximately 40% in detubulated cells. I(NCX) density at 0 mV decreased from 0.19 +/- 0.03 to 0.10 +/- 0.03 pA/pF upon detubulation. I(pump) density was also lower in detubulated myocytes over the range of voltages (-50 to +100 mV) and internal [Na] ([Na](i)) investigated (7-22 mM). At [Na](i) = 10 mM and -20 mV, I(pump) density was reduced by 39% in detubulated myocytes (0.28 +/- 0.02 vs. 0.17 +/- 0.03 pA/pF), but the apparent K(m) for [Na](i) was unchanged (16.9 +/- 0.4 vs. 17.0 +/- 0.3 mM). These results indicate that although thet-tubules represent only approximately 32% of the total sarcolemma, they contribute approximately 60% to the total I(NCX) and I(pump). Thus, the functional density of NCX and Na/K pump in the t-tubules is 3-3.5-fold higher than in the external sarcolemma.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-10024300,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-10444485,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-10473671,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-11053140,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-11310434,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-11351025,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-11834711,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-11850507,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-12193464,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-12650868,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-12770918,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-1373142,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-1514597,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-2059429,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-2314460,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-364994,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-376173,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-5283936,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-7730403,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-8413629,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-8576849,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-8865063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-8928749,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-9575295,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-9746552,
http://linkedlifedata.com/resource/pubmed/commentcorrection/14581240-9815123
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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 |
Nov
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pubmed:issn |
0006-3495
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
85
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
3388-96
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:14581240-Animals,
pubmed-meshheading:14581240-Calcium,
pubmed-meshheading:14581240-Cell Size,
pubmed-meshheading:14581240-Cells, Cultured,
pubmed-meshheading:14581240-Electric Capacitance,
pubmed-meshheading:14581240-Heart Ventricles,
pubmed-meshheading:14581240-Membrane Potentials,
pubmed-meshheading:14581240-Myocytes, Cardiac,
pubmed-meshheading:14581240-Rats,
pubmed-meshheading:14581240-Sarcolemma,
pubmed-meshheading:14581240-Sodium,
pubmed-meshheading:14581240-Sodium-Potassium-Exchanging ATPase,
pubmed-meshheading:14581240-Tissue Distribution,
pubmed-meshheading:14581240-Ventricular Function
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pubmed:year |
2003
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pubmed:articleTitle |
Na/Ca exchange and Na/K-ATPase function are equally concentrated in transverse tubules of rat ventricular myocytes.
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pubmed:affiliation |
Department of Physiology, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153, USA.
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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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