| Title | Effects of Aldosterone on Cx43 Gap Junction Expression in Neonatal Rat Cultured Cardiomyocytes. | | Author(s) | Suzuki S, Ohkusa T, Sato T, Yoshida M, Yasui K, Miwa K, Lee JK, Yano M, Kodama I, Matsuzaki M | | Institution | Division of Cardiology, Department of Medicine and Clinical Science, Yamaguchi University Graduate School of Medicine. | | Source | Circ J 2009 Jun 16. | | Abstract | Background: The renin-angiotensin-aldosterone system affects cellular morphology and function in the heart under a variety of pathologic conditions. In the present study the effects of aldosterone on the expression of connexin (Cx) 43 gap junctions in cardiomyocytes were investigated.
Methods and Results: Cultured rat ventricular myocytes were exposed to aldosterone for 24 h. The protein and mRNA expression of Cx43 was estimated. Propagation of excitation was visualized by a multiple electrode array system. Treatment of the myocytes with 10(-8) mol/L aldosterone resulted in a significant upregulation of Cx43 (by ~1.5-fold in protein and by ~1.2-fold in mRNA). The immunoreactive signal of Cx43 was also increased. Conduction velocity (CV) was increased by ~24%. Treatment of the myocytes with aldosterone at higher concentrations (10(-6)-10(-4) mol/L) caused a significant downregulation of Cx43 protein (by ~0.3-fold) without affecting Cx43 mRNA levels, and decreased the CV by ~23%. The Cx43 upregulation and CV acceleration at 10(-8) mol/L aldosterone were prevented by pretreatment with eplerenone, but unaffected by mifepristone. Pretreatment of the myocytes with eplerenone or mifepristone did not prevent the Cx43 downregulation by aldosterone at 10(-6)-10(-4) mol/L.
Conclusions: Aldosterone may be involved in arrhythmogenic gap junction remodeling through its dual effects on the expression of Cx43. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19531903 |
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