The use of the rabbit ear artery in the bioassay of catecholamines in urine

Abstract

Abstract Urine causes transient constriction of the isolated central artery of the rabbit ear. The substance responsible is qualitatively indistinguishable from noradrenaline when assessed by α-adrenergic blockade, sensitivity to oxidation by ferricyanide, behaviour on alumina, and comparison of dose response curves. The artery is equally sensitive to noradrenaline and adrenaline and approximately one hundred times less sensitive to dopamine. The results of bioassay, and chemical assay using the trihydroxyindole method, indicate that the constrictor response of the artery provides a useful guide to the urinary content of noradrenaline plus adrenaline.