title: Effect of chronic sympathetic denervation on cerebrovascular hypertrophy during the development of hypertension in rats.
abstract: The present study was designed to examine the trophic effect of sympathetic nerves on cerebrovascular hypertrophy in developmental hypertension. Unilateral superior cervical ganglionectomy was performed in spontaneously hypertensive rats at 4 weeks of age, and wall-to-lumen ratios of cerebral arteries were determined at 5 weeks, 2 months or 5 months after denervation. To estimate the thickness of the vessel wall, a freeze substitution technique was used for the preparation of cerebral arteries. Basal mean arterial blood pressure measured through cannulated femoral artery was 127 +/- 2, 146 +/- 7 and 168 +/- 6 mm Hg (mean +/- S.E.M.) at 9 weeks, 3 months and 6 months of age, respectively. The wall-to-lumen ratios in the denervated and innervated hemispheres were 0.124 +/- 0.004 and 0.129 +/- 0.005 at 9 weeks, 0.127 +/- 0.003 and 0.169 +/- 0.004 (P less than 0.02 vs denervated) at 3 months, and 0.194 +/- 0.007 and 0.222 +/- 0.006 (P less than 0.05 vs denervated) at 6 months. The effect of denervation was more significant in downstream vessels (diameter less than or equal to 100 microns) than larger ones. We conclude that wall-to-lumen ratio is correlated well with a rise in basal blood pressure, and chronic interruption of the sympathetic nerves attenuates normal occurrence of vascular hypertrophy during the development of hypertension.
mesh_terms: D000818:Animals; D001794:Blood Pressure; D002539:Cerebral Arterial Diseases / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology; D005612:Freeze Drying; D006973:Hypertension / Q000473:pathology / Q000503:physiopathology*; D006984:Hypertrophy; D008856:Microscopy, Fluorescence; D009638:Norepinephrine / Q000032:analysis; D051381:Rats; D011918:Rats, Inbred SHR; D013562:Sympathectomy; D013997:Time Factors
chemical_list: D009638:Norepinephrine