Role of Noradrenaline and Angiotensin on Cerebral Circulation in Juvenile Essential Hypertension

Cases of essential hypertension are predominant among the so-called hypertensive. However, its etiology still remains unclarified, since it is likely to be with various factors. Hemodynamically essential hypertension resembles conditions following injection of noradrenaline. Since the study of experimental hypertension caused by a stricture of the renal artery, a role played by the renin-angiotensin system has been considered to be of importance in developing essential hypertension. It is known, that cases of essential hypertension show an accelerated pressure response to catecholamines and angiotensin although there is no increase in either of these agents. It is of interest to find reports that hypertension was induced in dogs by a constriction of the internal carotid artery or ligation of the basilar artery, and that angiotensin enhanced pressor response following a constriction of cerebral blood vessels and it had central hypertensive effect. It is thus considered that cerebral circulation plays a very important role in the etiology of hypertension. The present study was carried out in solving that problem. Materials and Methods 1. Cerebral circulation in patients with juvenile essential hypertension Patients with juvenile essential hypertension below 34 years of age were studied in comparison with normotensive subjects about the same age. Older subjects were excluded, because their cerebral blood flow tends to decrease as their age advance and their cerebral vascular reactivity is affected by organic changes in cerebral blood vessels. The cerebral blood flow was measured by the nitrous oxide method of KETY and SCHMIDT, as modified by AIZAWA or SCHEINBERG and STEAD, blood gas analysis was made by the manometric technique of VAN SLYKE and NEILL, and measurements of blood pH and blood gas tension were made by means of an I.L. meter.