Abstract
Arginine analogs are commonly used as inhibitors of the synthesis of endothelium-derived relaxing factor, nitric oxide. However, their effect on nitric oxide levels is rarely measured. Using a chemiluminescence assay for nitric oxide, we found that NG-monomethyl-L-arginine enhanced, rather than reduced, nitric oxide synthesis in pulmonary arterial and aortic rings. NG-monomethyl-L-arginine inhibited relaxation to the endothelium-dependent vasodilator A23187 in aortic but not pulmonary arterial rings. In contrast, N omega-nitro-L-arginine did not stimulate nitric oxide synthesis and it inhibited relaxation to A23187 in all rings. We conclude that NG-monomethyl-L-arginine is a partial agonist for nitric oxide synthesis.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Aorta, Abdominal / drug effects*
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Aorta, Abdominal / metabolism
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Aorta, Abdominal / physiology
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Arginine / analogs & derivatives*
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Arginine / pharmacology
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Calcimycin / pharmacology
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Endothelium, Vascular / physiology
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In Vitro Techniques
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Muscle, Smooth, Vascular / drug effects*
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Muscle, Smooth, Vascular / metabolism
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Muscle, Smooth, Vascular / physiology
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Nitric Oxide / metabolism*
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Nitroarginine
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Phenylephrine / pharmacology
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Pulmonary Artery / drug effects*
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Pulmonary Artery / metabolism
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Pulmonary Artery / physiology
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Rats
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Rats, Sprague-Dawley
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Vasoconstriction / drug effects
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Vasodilation / drug effects
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omega-N-Methylarginine
Substances
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Phenylephrine
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Nitroarginine
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omega-N-Methylarginine
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Nitric Oxide
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Calcimycin
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Arginine