Increased expression of the Na(+)/Ca(2+) exchanger in the rat heart after immobilization stress is not induced by cortisol.
Calcium homeostasis is crucial for the proper function of cardiac cells. Since the Na(+)/Ca(2+) exchanger is an important modulator of calcium homeostasis especially in the heart, the objective of this study was to investigate the effect of immobilization stress on the high capacity Na(+)/Ca(2+) exchanger in rat heart ventricles and atria. Repeated immobilization stress increased both the mRNA and the protein level and the activity of the Na(+)/Ca(2+) exchanger in the left, but not the right ventricle of rat heart. Since corticosterone is rapidly increased during the stress stimulus, it might be assumed that mRNA of the Na(+)/Ca(2+) exchanger is increased through a glucocorticoid responsive element. However, we have found that cortisol did not change the Na(+)/Ca(2+) exchanger at the mRNA or protein levels. These results clearly show that this effect of stress is not mediated via cortisol.
Zacikova
L
L
Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, Vlarska 5, 833 34, Bratislava, Slovak Republic.
Kvetnansky
R
R
Krizanova
O
O
D000818:Animals; D015153:Blotting, Western; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D006854:Hydrocortisone / Q000378:metabolism / Q000494:pharmacology*; D007103:Immobilization / Q000009:adverse effects; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D019831:Sodium-Calcium Exchanger / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological / Q000209:etiology / Q000378:metabolism*
D012333:RNA, Messenger; D019831:Sodium-Calcium Exchanger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006854:Hydrocortisone