CAMP-independent activation of protein kinase A by the peroxynitrite generator SIN-1 elicits positive inotropic effects in cardiomyocytes.

ABSTRACT: The phosphatase vs. kinase equilibrium plays a critical role in the regulation of myocardial contractility. Previous studies have demonstrated that peroxynitrite exerts a biphasic effect on cardiomyocyte contraction, such that high peroxynitrite reduced beta-adrenergic-stimulated myocyte contraction by inducing the dephosphorylation of phospholamban (PLB) via phosphatase activation. Conversely, low peroxynitrite increased basal and beta-adrenergic-stimulated contraction also through a PLB-dependent mechanism. However, previous studies have not elucidated the mechanism underlying the positive effects of low peroxynitrite on myocyte contraction. In the current study, we examined the phosphatase vs. kinase equilibrium as a potential mechanism underlying the positive effects of peroxynitrite.

SUBMITTER: Kohr MJ 

PROVIDER: S-EPMC2837779 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature