THE INFLUENCE OF PHENOXYBENZAMINE ON THE STORAGE OF NORADRENALINE IN RAT AND CAT TISSUES

Abstract

In the cat, phenoxybenzamine prevented the uptake of noradrenaline by the kidney but not by the uterus; dichloroisoprenaline prevented the uptake of noradrenaline by the uterus but not by the kidney. In the rat, a single dose of phenoxybenzamine prevented the uptake of noradrenaline by the heart, spleen and uterus and reduced the uptake by the duodenum. Prolonged treatment with phenoxybenzamine prevented the uptake by the heart and uterus but not by the spleen or duodenum. Both phenoxybenzamine and dichloroisoprenaline lowered the noradrenaline content of some tissues of the rat. Phenoxybenzamine did not antagonize the responses to noradrenaline of the nonpregnant cat uterus in situ, nor the responses of rat isolated ventricles, uterus or duodenum. It is concluded that the way in which these noradrenaline antagonists affect the storage sites for noradrenaline varies between organs. The effects of the drugs on the receptors for noradrenaline are not related to their effects on storage sites.