| Na(+)/Ca(2+) exchanger expression and function in a rabbit model of myocardial infarction. | |
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MedLine Citation:
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PMID: 16686683 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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INTRODUCTION: In general, sarcolemmal Na(+)/Ca(2+) exchanger (NCX) protein and activity is increased in hearts with ventricular dysfunction. However, in a subset of studies, reduced activity of NCX has been reported. Left ventricular dysfunction (LVD) was induced in the rabbit eight weeks after an apical myocardial infarction. METHODS: Using single microelectrode voltage clamp to assess the NCX activity in isolated ventricular cells, a decrease in NCX activity by approximately 30% was observed. Immunoblot analysis indicated increased NCX protein levels by approximately 20% in the LVD group. The cause of this paradox is unknown. Overexpression of the protein sorcin increased the activity of NCX without affecting NCX protein levels. RESULTS: Sorcin protein (dimer) levels were significantly lower in the LVD group (0.67+/-0.05 n=15, P<0.05) compared to sham (1.0+/-0.16, n=15). Sorcin monomer levels were not significantly different (sham: 1.0+/-0.26, LVD: 0.83+/-0.13). Mathematical modeling of NCX suggests that a reduction of NCX activity during diastole to that in LVD could be achieved by holding the diastolic membrane potential at -60 mV instead of -80 mV. Holding E(m) at -60 mV decreased NCX-mediated Ca(2+) efflux rates to values comparable to those seen in LVD and increased SR Ca(2+) content and peak systolic [Ca(2+)] in sham and LVD cardiomyocytes. CONCLUSIONS: In conclusion, reduced sorcin expression may be linked to the lower NCX activity in the rabbit model of LVD. Reduced NCX activity during diastole increases SR Ca(2+) content and Ca(2+) transient amplitude. |
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Authors:
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Godfrey L Smith; Elspeth E B Elliott; Sarah Kettlewell; Susan Currie; Francis R Quinn |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of cardiovascular electrophysiology Volume: 17 Suppl 1 ISSN: 1045-3873 ISO Abbreviation: J. Cardiovasc. Electrophysiol. Publication Date: 2006 May |
Date Detail:
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Created Date: 2006-05-11 Completed Date: 2006-10-31 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9010756 Medline TA: J Cardiovasc Electrophysiol Country: United States |
Other Details:
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Languages: eng Pagination: S57-S63 Citation Subset: IM |
Affiliation:
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Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, UK. g.smith@bio.gla.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Calcium / metabolism* Calcium-Binding Proteins / metabolism* Cells, Cultured Computer Simulation Disease Models, Animal* Gene Expression Male Membrane Potentials Models, Cardiovascular* Myocardial Infarction / metabolism* Myocytes, Cardiac / metabolism* Rabbits Sodium-Calcium Exchanger / metabolism* Tissue Distribution |
| Chemical | |
Reg. No./Substance:
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0/Calcium-Binding Proteins; 0/Sodium-Calcium Exchanger; 7440-70-2/Calcium |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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