Administration of a vascular vasopressin antagonist in rabbits with adriamycin-induced heart failure decreased blood pressure and peripheral resistance, and increased cardiac output.
Does a specific vascular vasopressin antagonist improve hemodynamics in an experimental rabbit model of adriamycin-induced congestive heart failure?
In an experimental rabbit model of heart failure, vasopressin plays a role in maintaining blood pressure by increasing total peripheral resistance, despite normal plasma levels, due to increased vascular sensitivity.
The hemodynamic and hormonal changes produced by adriamycin-induced cardiomyopathic congestive heart failure in rabbits were studied. Adriamycin cardiomyopathy in rabbits led to ventricular dilatation, pleural and pericardial effusions, hepatic congestion, and ascites. These pathological changes were associated with the maintenance of a normal blood pressure but a lowered cardiac output and increased total peripheral resistance. Plasma renin activity and plasma norepinephrine were increased twofold in rabbits with congestive cardiac failure. However, plasma vasopressin and osmolality were normal, whereas an increased vascular sensitivity to the infusion of exogenous vasopressin was demonstrated. Despite the normal levels of plasma vasopressin, administration of a specific vascular vasopressin antagonist led to a fall in blood pressure, a significant increase in cardiac output, and a decrease in total peripheral resistance. No such hemodynamic changes occurred on infusing normal rabbits with the vascular vasopressin antagonist, nor did any significant hemodynamic changes occur on injecting vehicle in rabbits with heart failure. These results suggest that in adriamycin-induced cardiomyopathic heart failure in rabbits, there is activation of the renin-angiotensin system and the sympathetic nervous system together with an increased sensitivity to vasopressin. These three hormonal systems help to maintain blood pressure by increasing total peripheral resistance in this experimental model of heart failure.
Johnston et al. (Wed,) conducted a other in Adriamycin-induced cardiomyopathic congestive heart failure. Specific vascular vasopressin antagonist vs. Vehicle was evaluated on Hemodynamic changes (blood pressure, cardiac output, total peripheral resistance). Administration of a vascular vasopressin antagonist in rabbits with adriamycin-induced heart failure decreased blood pressure and peripheral resistance, and increased cardiac output.