摘要：

Superoxide anion (O_2~-) plays a key role in the endogenoussuppression of endothelium-derived nitric oxide (NO) bioactivity andhas been implicated in the development of hypertension. In previousstudies, we found that O_2~- is produced predominantly in theadventitia of isolated rabbit aorta and acts as a barrier to NO. Inthe present studies, we characterize the enzyme responsible for O_2~-production in the adventitia and show that this enzyme is aconstitutively active NADPH oxidase with similar composition as thephagocyte NADPH oxidase. Constitutive O_2~--generating activity waslocalized to aortic adventitial fibroblasts and was enhanced by thepotent vasoconstrictor angiotensin II.

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