ID 111318
Author
Yin, Hua The University of Tokushima
Harada, Nagakatsu The University of Tokushima KAKEN Search Researchers
Keywords
L-DOPA
aortic rings
nitric oxide
vasorelaxation
reactive oxygen species
Content Type
Journal Article
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.
Journal Title
The Journal of Medical Investigation
ISSN
13496867
13431420
NCID
AA11166929
AA12022913
Publisher
Faculty of Medicine Tokushima University
Volume
56
Issue
3-4
Start Page
120
End Page
129
Sort Key
120
Published Date
2009-08
EDB ID
DOI (Published Version)
URL ( Publisher's Version )
FullText File
language
eng
TextVersion
Publisher
departments
Medical Sciences