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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1999-7-7
pubmed:abstractText
A Na/Ca exchange current can be elicited in voltage clamped single ventricular myocytes by the abrupt removal of extracellular Na+ by means of a rapid switcher device. We measured this reverse Na/Ca exchange current in isolated mouse ventricular myocytes from wild-type mice, and from transgenic mice with hearts overexpressing the Na/Ca exchanger. In mouse ventricular myocytes, the current was sensitive to nickel, and was eliminated by removal of intracellular Na+. It was not influenced by 3 m m ouabain, and thus not contaminated by Na pump currents. The magnitude of the current reached a plateau within 10-15 min after obtaining a whole cell patch with the pipettes containing EGTA, to buffer [Ca2+]i and in zero extracellular K+ concentration to completely inhibit the Na pump, and allow equilibration of pipette Na+ with subsarcolemmal [Na+]. The magnitude of the current increased with increases in pipette [Na+]. Comparison of the current magnitudes in wild-type and transgenic myocytes showed a 2.5 and 2.7 fold increase in the current in transgenic myocytes at pipette [Na+] of 10 and 20 m m. The magnitude of this increase in Na/Ca exchanger currents in single transgenic myocytes compares well with the reported 2.5 fold increase in Na+-dependent 45Ca2+ uptake measured in ventricular sarcolemmal vesicles obtained from transgenic animals. With this approach, we found variation in exchanger current densities in different species, with values for mouse>rat>rabbit>dog>human. This technique should also be useful in quantifying changes in Na/Ca exchanger current density as a consequence of pathologic processes, and exposure to drugs.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-2828
pubmed:author
pubmed:copyrightInfo
Copyright 1999 Academic Press.
pubmed:issnType
Print
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1125-35
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1999
pubmed:articleTitle
Quantitation of Na/Ca exchanger function in single ventricular myocytes.
pubmed:affiliation
Division of Cardiology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't