Analysis of cerebrovascular sympathetic nerve density in relation to stroke development in spontaneously hypertensive rats.
Previous studies have shown that elevating the K+ levels from 0.75% to 2.11% in the diet of stroke-prone spontaneously hypertensive rats significantly retards the development of stroke and increases their lifespan. On the other hand, stroke-resistant spontaneously hypertensive rats fail to develop stroke even if they are fed the low-K+ version of this diet. Since sympathetic nerves surrounding the cerebral vasculature play an important role in protecting the brain from stroke during hypertension, I studied whether changes in sympathetic nerve density accounted for the differing incidences of stroke in stroke-prone spontaneously hypertensive rats fed high- and low-K+ diets and in stroke-resistant and stroke-prone spontaneously hypertensive rats fed a low-K+ diet. At 14 weeks of age, all 11 stroke-prone rats fed the low-K+ diet had evidence of cerebral hemorrhage while such lesions were virtually absent in the 11 littermates fed the high-K+ diet and totally absent in the eight stroke-resistant rats fed the low-K+ diet. Stroke-prone (regardless of diet) but not stroke-resistant rats exhibited greater sympathetic nerve densities in the left hemisphere than in the right. When stroke-prone rats were compared, in some areas of the cerebrovasculature, rats fed the high-K+ diet had greater mean sympathetic nerve densities than those fed the low-K+ diet. On the other hand, stroke-resistant and stroke-prone rats fed the low-K+ diet exhibited comparable sympathetic nerve densities in most cerebral arteries studied.(ABSTRACT TRUNCATED AT 250 WORDS)
Smeda
J S
JS
Department of Anaesthesia, Faculty of Health Sciences, McMaster University, Hamilton, Canada.
D000818:Animals; D001808:Blood Vessels / Q000294:innervation; D002536:Cerebral Arteries / Q000294:innervation; D002560:Cerebrovascular Circulation; D002561:Cerebrovascular Disorders / Q000209:etiology*; D004032:Diet; D004198:Disease Susceptibility; D008297:Male; D011188:Potassium / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR / Q000033:anatomy & histology* / Q000502:physiology; D011919:Rats, Inbred Strains / Q000033:anatomy & histology*; D013564:Sympathetic Nervous System / Q000033:anatomy & histology*
D011188:Potassium