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Pathways of dopamine oxidation mediated by nitric oxide
Daniel Rettori1, Yue Tang, Lauro C Dias
1Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, CA 90033, USA.
Free Radical Biology & Medicine
|September 5, 2002
Summary
This study reveals how dopamine interacts with nitric oxide (NO). At high NO levels, dopamine is nitrosated and nitrated, while at low NO levels, dopaminochrome forms, involving specific intermediates.
Area of Science:
- Biochemistry
- Chemical Biology
- Neuroscience
Background:
- Dopamine is a crucial neurotransmitter.
- Nitric oxide (NO) plays diverse physiological roles.
- The interaction between dopamine and NO is not fully understood.
Purpose of the Study:
- To investigate the interaction between dopamine and nitric oxide.
- To elucidate the mechanistic pathways of this interaction.
- To identify reactive intermediates and products.
Main Methods:
- Electron paramagnetic resonance (EPR) spin trapping and stabilization.
- AM1 semiempirical calculations for heats of formation.
- Enzymatic assays using superoxide dismutase and catalase.
Main Results:
- At high NO concentrations, dopamine undergoes nitrosation and nitration.
- At low NO concentrations, dopaminochrome formation occurs via two o-semiquinone intermediates.
- Peroxynitrite was identified as the source of hydroxyl radicals.
Conclusions:
- A detailed mechanism for dopamine-NO interaction is proposed.
- Reaction products and intermediates depend on NO concentration.
- This interaction involves complex redox chemistry with biological implications.