Studies on the Role of Noradrenaline in the Pathogenesis of Hypertension

The role of noradrenaline in essential hypertension was studied and the following results were obtained. (1) Hypertensive subjects except the patient with pheochronnocytoma were found more sensitive to the infusion of noradrenaline than normotensives. But in the cases with pheochromocytoma the sensitivity was weaker than in normotensives. (2) There was no relation between the blood pressure and its response to Regitine. (3) A negative correlation was observed between blood pressure and urinary excretion of noradrenaline. From these experiments it may be concluded that hypertension (except in the case of pheochromocytoma) does not result from the excess of noradrenaline. Rather, in hypertensive subjects, it seems to be likely that the secretion of noradrenaline is reflexly decreased in order to adapt to their hypertensive state. On the other hand, the sensitivity to noradrenaline is obviously excessive in hypertensives. But the cause and the role of this hypersensitivity are entirely unknown to date. These problems await future study.