The Cardiac Conduction System in the Rat Expresses the α2 and α3 Isoforms of the Na+, K+-ATPase

The sodium pump is crucial for the function of the heart and of the cardiac conduction system, which initiates the heartbeat. The α (catalytic) subunit of this pump has three isoforms; the α1 isoform is ubiquitous, but the α2 and α3 isoforms are localized to excitable tissue. Because rodent α2 and α...

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Published inProceedings of the National Academy of Sciences - PNAS Vol. 89; no. 1; pp. 99 - 103
Main Authors Zahler, Raphael, Brines, Michael, Kashgarian, Michael, Benz, E. J., Gilmore-Herbert, Maureen
Format Journal Article
LanguageEnglish
Published Washington, DC National Academy of Sciences of the United States of America 01.01.1992
Subjects
Analytical, structural and metabolic biochemistry
Biological and medical sciences
Body tissues
Enzymes and enzyme inhibitors
Fundamental and applied biological sciences. Psychology
Heart
In situ hybridization
Messenger RNA
Myocardium
Oligonucleotide probes
Oligonucleotides
Protein isoforms
Pumps
RNA probes
Transferases
Heart
Vertebrata
Molecular form
Mammalia
Enzymatic activity
Rat
Enzyme
Rodentia
Na,K-ATPase
Tissue specificity
Diaphragm pump
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Summary:The sodium pump is crucial for the function of the heart and of the cardiac conduction system, which initiates the heartbeat. The α (catalytic) subunit of this pump has three isoforms; the α1 isoform is ubiquitous, but the α2 and α3 isoforms are localized to excitable tissue. Because rodent α2 and α3 isoforms are relatively sensitive to ouabain, which also slows cardiac conduction, we studied heart-cell-specific expression of pump isoform genes. Multiple conduction-system structures, including sinoatrial node, bundle branches, and Purkinje strands, had prominent, specific hybridization signal for α2 and α3 isoforms compared with adjacent working myocytes. This gene-expression approach may be useful for labeling conduction tissue and also for localizing specific membrane channels and receptors in this system.
ISSN:0027-8424
1091-6490