Hemodynamic effects of centrally administered adrenomedullin (13-52) in anesthetized rats

This study was conducted to investigate the effect of intracerebroventricular administration of adrenomedullin (13-52) [ADM(13-52)], a novel hypotensive peptide, on the hemodynamic parameters of anesthetized rats. ADM(13-52) was administered centrally in a dose of 0.4-3.2 nmol/kg. It provoked marked, prolonged and dose-dependent increases in mean arterial blood pressure, heart rate, stroke volume, cardiac index, left ventricular pressure, left ventricular dp/dtmax and dp/dtmin, but reduction in total peripheral resistance index. In addition, intracerebroventricular administration of ADM(13-52; 1.6 nmol/kg) provoked a marked increase in renal sympathetic nerve activity. Intracerebroventricular administration of artificial cerebrospinal fluid had no effect on the hemodynamic parameters and renal sympathetic nerve activity. The results indicate that ADM(13-52) exerts a central action on the cardiovascular system. The mechanisms of hemodynamic changes induced by central ADM(13-52) were preliminarily analyzed in this study. ADM might play a role in the central control of the cardiovascular system, although the confirmed mechanisms and the physiological implications are undetermined.