Comparison of Effects of Angiotensin and Norepinephrine on Pulmonary Circulation, Systemic Arteries and Veins, and Systemic Vascular Capacity in the Dog

In dog experiments, angiotensin II and norepinephrine were compared in regard to some components of the generalized pressor response each of these agents produces. It was found that angiotensin II has no direct effect on pulmonary blood vessels, in contrast to the pulmonary vasoconstrictor effect of norepinephrine. Angiotensin II appeared to have no effects on veins or the systemic vascular capacity, while norepinephrine was a potent venoconstrictor with, therefore, a marked ability to reduce the systemic vascular capacity.