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Selective Increase in Renal Arcuate Innervation Density and Neurogenic Constriction in Chronic Angiotensin II-Infused Rats

 

作者: Helena,   Parkington Jonathan,   Dodd Susan,   Luff Katrina,   Worthy Harold,   Coleman Marianne,   Tare Warwick,   Anderson Amanda,  

 

期刊: Hypertension: Journal of The American Heart Association  (OVID Available online 2004)
卷期: Volume 43, issue 3  

页码: 643-648

 

ISSN:0194-911X

 

年代: 2004

 

出版商: OVID

 

关键词: sympathetic nervous system;endothelium

 

数据来源: OVID

 

摘要:

Abstract—This study investigated the effects of angiotensin II “slow pressor” hypertension on structure and function of nerves supplying the renal vasculature. Low-dose angiotensin II (10 ng/kg per minute, initially sub-pressor) or saline vehicle was infused intravenously for 21 days in rats, and the effects were compared in renal and mesenteric arteries. Mean arterial pressure averaged 12±2 mm Hg higher than in vehicle-infused rats at 21 days. Using electron microscopy, the innervation density of renal arcuate, but not mesenteric arteries of equivalent size, was significantly higher in angiotensin II-infused than in vehicle-infused rats. Functional testing on a pressure myograph revealed that constrictions evoked by nerve stimulation in arcuate arteries were 2.3±0.7-fold greater in vessels from angiotensin II-infused compared with vehicle-infused rats (P<0.0001), whereas there was no significant difference in nerve-induced constrictions in mesenteric arteries. Sensitivity to and maximum amplitude of constrictions evoked by phenylephrine were not different in renal or mesenteric arteries between groups, suggesting that the increased neurally evoked constriction in renal arcuate arteries was not caused by postsynaptic changes. Endothelium-dependent vasorelaxation and the vessel wall physical properties were not different between the two groups in either artery. Thus, angiotensin II infusion appeared to evoke renal-specific increases in vessel innervation and increased vasoconstriction to nerve stimulation. These changes appear early and occur before changes in renal endothelial function are apparent. Thus, “slow pressor” angiotensin II hypertension is associated with increased renal innervation, compatible with a pathogenetic role.

 

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