Sensitivity of the Large Blood Vessels of the Rabbit to l -Epinephrine and l -Norepinephrine

Abstract

Some of the pharmacological properties of the smooth muscle of 17 anatomically different vessels of the adult rabbit have been compared using helical strips under in vitro conditions. Using the median effective dose and the slope of the logarithm dose-probit response curve for l -epinephrine and l -norepinephrine as criteria, these vessels may be divided into two groups. The vascular muscle of the thoraeic and abdominal aorta, the femoral, main pulmonary and lobar pulmonary arteries, some preparations of the renal arteries and the inferior vena cava exhibit, within 95 per cent confidence limits, identical characteristics. They are more sensitive to l -norepinephrine than l -epinephrine, and the slopes of thc dose-response curves to these amines are the same. The muscle of the common carotid and saphena arteries and the external jugular vein is very similar to this group, but not identical. The vascular muscle of the common iliac, brachial, facial, anterior and posterior mesenteric, and celiac arteries, and the portal vein is less sensitive, and the slope of the dose-response curve more steep to these amines than the previous group. They are more sensitive to l -epinephrine than l -norepinephrnie and the slopes of the dose-response curves for these amines are not the same.