Morphometric study of cerebral arteries from spontaneously hypertensive and stroke-prone spontaneously hypertensive rats

OBJECTIVE: The importance of sympathetic innervation for the development of structural changes in the cerebral arteries of hypertensive animals was studied. DESIGN: Sympathetic denervation was induced with combined treatment from birth of antibody against nerve growth factor and guanethidine. Previous studies from our laboratory showed that this procedure not only caused a permanent denervation of the mesenteric arteries, but also prevented the development of hypertension in spontaneously hypertensive rats (SHR). METHODS: Morphometric measurement of the structural changes was carried out in the basilar, superior cerebellar, posterior cerebral and middle cerebral arteries from 28-week-old SHR, stroke-prone SHR, and normotensive Wistar-Kyoto rats. The results were compared with those obtained from cerebral arteries of sympathectomized rats. RESULTS: Total vascular wall cross-sectional area was significantly larger in the basilar and superior cerebellar arteries from hypertensive rats compared with normotensives. The change was characterized by an increase in the number of smooth muscle cell layers. There were also differences between the two hypertensive groups in some arteries. Sympathetic denervation attenuated the development of hypertension and vascular changes in some arteries. There was a positive linear correlation between blood pressure and medial cross-sectional area, and between blood pressure and the number of smooth muscle cell layers for the four arteries analysed. CONCLUSION: Sympathetic nerves have a trophic influence upon the remodelling of some cerebral arteries during the development of genetic hypertension.