Different response of the rat left and right heart to norepinephrine

• Published in: Cardiovascular research 1996-01, Vol.31 (1), p.157-162
• Main Authors: Irlbeck, M., Mühling, O., Iwai, T., Zimmer, H.-G.
• Format: Article
• Language: English
• Subjects: Cardiac hypertrophy; Left ventricle; Norepinephrine; Rats; Right ventricle
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1016/S0008-6363(95)00188-3

The in vivo hemodynamic and morphologic responses of the rat left (LV) and right (RV) ventricle to continuous long-term i.v. infusion of norepinephrine (NE) at different dosages and for different durations of infusion were studied. Female Sprague-Dawley rats received continuous intravenous infusion of norepinephrine from infors® syringe pumps for 24, 48 and 72 h at a dose of 200 μg · kg−1 · h−1. Furthermore, NE was infused for 72 h at dosages of 50, 100 and 200 μg · kg−1 · h−1. The beta-adrenergic blocker and vasodilator with alpha1-blocking activity carvedilol (0.5 mg · kg−1 · h−1) was coinfused with NE for 72 h. The hemodynamic effects were measured on intact, anesthetized rats with special Millar® ultraminiature pressure tip catheters, and the weights of the left and right ventricles were measured. NE increased heart rate at any time or dose, whereas cardiac output and total peripheral resistance remained unchanged. LV and RV dP/dtmax were nearly doubled as compared to control values and RVSP was elevated by more than 100%. The effect of NE on LVSP was much less pronounced (