title: Study on the ability of 1,2,3,4-tetrahydropapaveroline to cause oxidative stress: Mechanisms and potential implications in relation to parkinson's disease.
abstract: Tetrahydropapaveroline (THP) is a compound derived from dopamine monoamine oxidase-mediated metabolism, particularly present in the brain of parkinsonian patients receiving L-dopa therapy, and is capable of causing dopaminergic neurodegeneration. The aim of this work was to evaluate the potential of THP to cause oxidative stress on mitochondrial preparations and to gain insight into the molecular mechanisms responsible for its neurotoxicity. Our data show that THP autoxidation occurs with a continuous generation of hydroxyl radicals (*OH) and without the involvement of the Fenton reaction. The presence of ascorbate enhances this process by establishing a redox cycle, which regenerates THP from its quinolic forms. It has been shown that the production of *OH is not affected by the presence of either ferrous or ferric iron. Although THP does not affect lipid peroxidation, it is capable of reducing the high levels of thiobarbituric acid-reactive substances obtained in the presence of ascorbate and/or iron. However, THP autoxidation in the presence of ascorbate causes both an increase in protein carbonyl content and a reduction in protein-free thiol content. THP also increases protein carbonyl content when the autoxidation occurs in the presence of iron. The remarkable role played by ascorbate in the production of oxidative stress by THP autoxidation is of particular interest.
authors.affiliation: Grupo de Neuroquímica, Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Universidad de Santiago de Compostela, San Francisco 1, E-15782 Santiago de Compostela, Spain.
authors.forename: Ramón
authors.initials: R
authors.lastname: Soto-Otero
authors.forename: Carolina
authors.initials: C
authors.lastname: Sanmartín-Suárez
authors.forename: Sofía
authors.initials: S
authors.lastname: Sánchez-Iglesias
authors.forename: Alvaro
authors.initials: A
authors.lastname: Hermida-Ameijeiras
authors.forename: Inés
authors.initials: I
authors.lastname: Sánchez-Sellero
authors.forename: Estefanía
authors.initials: E
authors.lastname: Méndez-Alvarez
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D010300:Parkinson Disease / Q000378:metabolism*; D050050:Protein Carbonylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013765:Tetrahydropapaveroline / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D013765:Tetrahydropapaveroline