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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2 Pt 2
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pubmed:dateCreated |
1997-9-25
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pubmed:abstractText |
Previous studies suggesting a greater functional role of cardiac Na+/Ca2+ exchange at birth were performed using tightly buffered free cytosolic Ca2+ concentration ([Ca2+]i). Because Na+/Ca2+ exchange current (INaCa) is influenced by physiological fluctuations in [Ca2+]i, we used conditions of minimally buffered [Ca2+]i to simultaneously record INaCa and cell contractions in single ventricular myocytes isolated from 1 to 27-day-old and adult rabbits. With conventional Cl(-)-containing solutions. Ni(2+)-sensitive outward and inward charge movements were unbalanced, suggesting the presence of a contaminating current (presumably the Ca(2+)-activated Cl- current). Removing Cl- abolished this discrepancy in all age groups and allowed for the accurate quantitation of INaCa. Under Cl(-)-free conditions, outward and inward charge movements were high at birth (4 days: 0.42 +/- 0.03 and -0.38 +/- 0.04 pC/pF, respectively) and decreased postnatally (adult: 0.08 +/- 0.01 and -0.07 +/- 0.01 pC/pF, respectively). Newborn but not adult myocytes contracted during depolarizations in the presence of nifedipine, ryanodine, and thapsigargin. The magnitudes of outward charge movement (Ca2+ influx) and cell shortening exhibited similar voltage dependence, consistent with INaCa-mediated contractions. These results indicate that INaCa can directly support contraction in newborn rabbit ventricular myocytes.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Chlorides,
http://linkedlifedata.com/resource/pubmed/chemical/Nickel,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium-Calcium Exchanger,
http://linkedlifedata.com/resource/pubmed/chemical/Solutions
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pubmed:status |
MEDLINE
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pubmed:month |
Aug
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pubmed:issn |
0002-9513
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
273
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
H837-46
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:9277501-Aging,
pubmed-meshheading:9277501-Animals,
pubmed-meshheading:9277501-Carrier Proteins,
pubmed-meshheading:9277501-Cell Separation,
pubmed-meshheading:9277501-Chlorides,
pubmed-meshheading:9277501-Electric Conductivity,
pubmed-meshheading:9277501-Electrophysiology,
pubmed-meshheading:9277501-Myocardial Contraction,
pubmed-meshheading:9277501-Myocardium,
pubmed-meshheading:9277501-Nickel,
pubmed-meshheading:9277501-Rabbits,
pubmed-meshheading:9277501-Reaction Time,
pubmed-meshheading:9277501-Sodium-Calcium Exchanger,
pubmed-meshheading:9277501-Solutions
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pubmed:year |
1997
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pubmed:articleTitle |
Na+/Ca2+ exchange current and contractions measured under Cl(-)-free conditions in developing rabbit hearts.
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pubmed:affiliation |
Department of Pediatrics, New York University Medical Center, New York 10016, USA.
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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