Increased Vascular Reactivity in Experimental Hypertension

¹ Department of Physiology, University of Miami School of Medicine Coral Gables, Florida

The responsiveness to norepinephrine of aortic strips from hypertensive rats and from normotensive rats was compared. The strips were set up in a bath of Krebs-Ringer solution, and isometric tension development upon addition of norepinephrine was recorded. The hypertensive strips produced the greatest tension, indicating a greater reactivity to norepinephrine. It was found that the initial tension exerted upon the strip greatly influenced its response, there being an optimal initial tension at which the greatest active response was obtained. These results support the hypothesis that hypertension may be due to an excessive reactivity of vascular smooth muscle.