ID | 111318 |
Author |
Yin, Hua
The University of Tokushima
Mawatari, Kazuaki
The University of Tokushima
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Yasui, Sonoko
The University of Tokushima
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Segawa, Hiroko
The University of Tokushima
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Takahashi, Akira
The University of Tokushima
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Oshita, Shuzo
The University of Tokushima
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Nakaya, Yutaka
The University of Tokushima
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|
Keywords | L-DOPA
aortic rings
nitric oxide
vasorelaxation
reactive oxygen species
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Content Type |
Journal Article
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Description | Objectives : To clarify the underlying mechanisms of L-DOPA induced vasoconstriction in rat aorta. Methods : The effect of L-DOPA on phenylephrine-induced contractile force of blood vessels was examined in vitro using rat aortic ring preparations by isometric tension experiment. Involvement of nitric oxide (NO) in the effect of L-DOPA on vascular smooth muscle was studied by using Nω-Nitro-L-arginine (L-NNA), Sodium nitroprusside (SNP) in endothelium-intact and endothelium-denuded aortic rings. Results : L-DOPA potentiated α-adrenergic receptor- and depolarization-induced vascular contraction and inhibited acetylcholine-induced vasorelaxation. This effect was diminished by pretreatment of the aortic rings with L-NNA, an inhibitor of NO synthesis, or by removing the endothelium from the ring preparations. In endothelium-denuded rings, L-DOPA inhibited exogenous NO-dependent but not cGMP-mediated vasorelaxation. Increases in cGMP levels in response to an NO donor were attenuated by L-DOPA in cultured rat aortic smooth muscle cells. L-DOPA could not contract rings (without endothelium) pretreated with 3-(5’-hydroxymethyl- 2’-furyl)-1-benzyl indazole (YC-1), an activator of guanylyl cyclase, but SOD (150 U/ml) pretreatment of rings with endothelium inhibited contraction by L-DOPA. Conclusions : These results suggest that L-DOPA inhibits nitric-dependent vasorelaxation on vascular smooth muscle cells via production of reactive oxygen species.
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Journal Title |
The Journal of Medical Investigation
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ISSN | 13496867
13431420
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NCID | AA11166929
AA12022913
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Publisher | Faculty of Medicine Tokushima University
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Volume | 56
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Issue | 3-4
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Start Page | 120
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End Page | 129
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Sort Key | 120
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Published Date | 2009-08
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EDB ID | |
DOI (Published Version) | |
URL ( Publisher's Version ) | |
FullText File | |
language |
eng
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TextVersion |
Publisher
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departments |
Medical Sciences
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