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/dt_maxand dp/dt_min 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.