Acute production of vascular superoxide by angiotensin II but not by catecholamines
作者:
Takeshi Kawazoe,
Hiroaki Kosaka,
Hirohito Yoneyama,
Yuiro Hata,
期刊:
Journal of Hypertension
(OVID Available online 2000)
卷期:
Volume 18,
issue 2
页码: 179-185
ISSN:0263-6352
年代: 2000
出版商: OVID
关键词: angiotensin II;superoxide;hypertension;aortic ring;norepinephrine;isometric tension
数据来源: OVID
摘要:
ObjectiveTo determine whether vascular superoxide is rapidly released by angiotensin II and is involved in vascular contraction.DesignThe effect of superoxide dismutase (SOD) on angiotensin II induced elevation of mean arterial blood pressure was measured. Subsequently, acute production of vascular superoxide by angiotensin II and its effect on isometric tension were measured in rat aortic rings. The effects of catecholamines were concomitantly measured.Methodsand results The acute pressor effects of angiotensin II were significantly reduced when rats were pretreated intravenously with SOD. When angiotensin II was added on aortic segments in the presence ofCypridina luciferinanalog, immediate elevations of chemiluminescence were observed which were inhibited by SOD. Furthermore, angiotensin II-induced elevations of isometric tension in aortic rings were significantly reduced by SOD. The effects of epinephrine and norepinephrine were concomitantly measured and were not significant.ConclusionsThe acute superoxide producing effect is likely to be specific to angiotensin II, because such a significant modification of the effects was not observed for catecholamines. Our results suggest that angiotensin II causes acute vascular superoxide production, which may be involved in the acute pressor effects.
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