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Aldosterone Regulation of the Cardiac Sodium‐Calcium Exchanger
Author(s) -
Hadley Robert W,
Simmerman Linda
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.lb105-c
Subject(s) - aldosterone , calcium , sodium calcium exchanger , chemistry , endocrinology , mineralocorticoid , medicine , mineralocorticoid receptor , spironolactone , sodium , cytosol , calcium metabolism , sodium–hydrogen antiporter , biochemistry , biology , enzyme , organic chemistry
The objective of this study was to determine whether the protein expression and functional activity of the cardiac sodium‐calcium exchanger was subject to regulation by activation of mineralocorticoid receptors. The studies were carried out in cultured adult rat ventricular myocytes. Protein expression was evaluated by Western blotting, using a monoclonal antibody to the NCX1 protein (R3F1, Swant, Switzerland). Functional activity of the sodium‐calcium exchanger was evaluated by first inducing reverse‐mode exchanger activity and then using fluorescent calcium indicators to measure changes in cytosolic calcium. Aldosterone strongly inhibited exchanger protein expression in a dose‐dependent manner (0.1–10 nM). This effect depended on mineralocorticoid activation, as it could be blocked by spironolactone. Cytosolic calcium measurements confirmed that the decreased protein expression seen with 10 nM aldosterone was accompanied by a significant inhibition of sodium‐calcium exchanger functional activity. This work was supported by NHLBI R01HL056910 (RWH).