Gene expression of natriuretic peptides and their receptors type-A and -C after myocardial infarction in rats

The purpose of this study was to investigate myocardial mRNA expression of brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) in dif ferent regions of the heart at three different time points after induction or myocardial infarction (MI) in rats. Furthermore. we examined putative ch anges in mRNA expression of natriuretic peptide receptors (NPRs), NPR-A and NPR-C, in myocardium and peripheral organs. Substantial increase in the mR NA levels of both BNP and ANP in the infarcted as well as non-infarcted reg ions were observed after induction of MI. These findings were paralleled by elevated circulating concentrations of ANP, BNP and N-terminal proANP (Nt- proANP). In addition, the mRNA levels of the clearance receptor. NPR-C, wer e augmented in the infarcted and non-infarcted regions of the left ventricu lar wall (LV), while it was decreased in the kidneys and lungs 28 days post -MI. Based on these data, we propose that, in addition to increased myocard ial secretion of BNP and ANP, reduced peripheral clearance by NPR-C may con tribute to the observed increase in circulating plasma concentrations of th e natriuretic peptides after induction of MI in rats.