CAROTID-ARTERY CONSTRICTION IN ACUTE HYPERTENSION

  • 1 January 1981
    • journal article
    • research article
    • Vol. 103  (2) , 226-233
Abstract
The effects of carotid artery constriction on cerebrovascular ultrastructure and permeability in acute hypertension were assessed. The right common carotid artery of 26 male Wistar-Kyoto normotensive rats was constricted with a silver wire clip. These animals received an angiotensin amide injection (1 .mu.g/kg body wt) or infusion for 3-4 h (0.5 or 1.7 .mu.g/min per kg body wt) or were subjected to subdiaphragmatic aortic constriction 48 h later. All animals were injected with horseradish peroxidase (HRP) (20 mg/100 g body wt) and sacrificed after 5-15 min. Parietal cortex from both hemispheres was processed for light microscopy and EM examination. The arterial vessels of the right hemisphere from animals given injections of or infused with angiotensin II exhibited increased permeability to HRP, as manifested by the presence of reaction product in interendothelial cell clefts, in subendothelial space, in endothelial and smooth muscle cell pinocytotic vesicles and along smooth muscle cell basal laminas. No alterations in the permeability of ipsilateral vessles were seen in rats with aortic constriction. Cerebral cortical arterial vessels from the left hemisphere in all groups of animals exhibited segmental dilatation and constriction and abnormal permeability to HRP. Angiotensin administration apparently can produce increased permeability of cerebral cortical vessels in the absence of elevated blood pressure.