Hypertension and Cerebral Blood Vessels

Abstract

The present report dealt with hypertrophy and acute vascular lesions of cerebral arterioles in hypertensive rabbits. Hypertension was produced by clipping of the renal artery with intact contralateral kidney (two-kidney hypertension) or with contralateral nephrectomy (one-kidney hypertention).
(1) Wall areas of cerebral arterioles were measured in 47 animals which had been killed one week after clipping of the renal artery (two-kidney hypertension) or sham-operation. The wall areas were calculated from the external and internal diameter of arterioles in hypocampus on coronal sections of the brain. The incidence of arterioles with greater wall areas was significantly increased in hypertensive animals as compared with normotensive ones. These results indicate that hypertrophy of cerebral arterioles develops already in the early stage of hypertension.
(2) Acute vascular lesions and increase in vascular permeability were studied in one-kidney hypertensive rabbits with or without cerebral hemorrhage. Colloidal carbon technique was used to detect increase in vascular permeability. Necrotic changes of cerebral arterioles were found in 14 of 18 animals with cerebral hemorrhage, but was found in none of 15 animals without it. Arteriolar necrotic changes of other organs were frequently found in both animals with and without cerebral hemorrhage. Increase in vascular permeability of arterioles was more widely distributed than the necrotic changes. Vascular permeability was increased not only in arterioles but also in larger arteries including aorta and carotid artery in some of animals with cerebral hemorrhage.