Monoamine Metabolism Provides an Antioxidant Defense in the Brain Against Oxidant- and Free Radical-Induced Damage

Liu, Jiankang; Mori, Akitane

doi:10.1006/abbi.1993.1189

Cited by 141 publications

(69 citation statements)

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“…Dopamine is known to be an antioxidant and to protect neurocytes from oxidative stress [15][16][17] by scavenging reactive oxygen species. Meanwhile, dopamine also acts as a prooxidant through a reaction with molecular oxygen that produces reactive oxygen species.…”

Section: Discussionmentioning

confidence: 99%

“…It acts as an antioxidant by scavenging free radicals. [15][16][17] Recently, it was found that dopamine spontaneously react with molecular oxygen to produce reactive oxygen species and semiquinone dopamine radical, 18,19) which are toxic to catecholamine neurons. [20][21][22][23] However, there is no evidence that sulfate conjugated dopamine acts as an antioxidant or a prooxidant.…”

Section: )mentioning

confidence: 99%

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Electron Paramagnetic Resonance Study on Free Radical Scavenging and/or Generating Activity of Dopamine-4-O-sulfate.

Kirima

Tsuchiya

Yoshizumi

et al. 2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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With the increasing understanding of the cytotoxicity of free radicals and other reactive oxygen species as a major cause of human disease and aging, the roles of endogenous antioxidants have drawn attentions. Uric acid, 1) vitamin E, 2) vitamin C, 3) ubiquinone, 4) SH-compounds, 5) bilirubin, 6) and pyruvate 7) are recognized as endogenous non-enzymatic antioxidants, while catalase, superoxide dismutase and glutathione peroxidase are known to be enzymatic antioxidants.Dopamine is the immediate metabolic precursor of norepinephrine and epinephrine. Dopamine interacts with dopamine receptors, then exerts its pharmacological effects.In human and experimental animals, dopamine is present almost entirely as a sulfate conjugated form in the circulation, 8,9) and very little of the free form is presented in the plasma.10) The physiological roles of sulfate conjugated dopamine are still unclear. Pharmacologically, conjugated dopamine has convulsive effects, 11) inhibits aldosterone secretion from cultured bovine adrenal cells, 12) and induces a constriction of some vascular beds. 13) One study, however, found that sulfate conjugated dopamine has no physiological activity. 14)From the viewpoint of free radical chemistry, dopamine can serve electrons via its oxidation pathway (Chart 1). This enables dopamine to act as both an antioxidant and a prooxidant. It acts as an antioxidant by scavenging free radicals. [15][16][17] Recently, it was found that dopamine spontaneously react with molecular oxygen to produce reactive oxygen species and semiquinone dopamine radical, 18,19) which are toxic to catecholamine neurons. [20][21][22][23] However, there is no evidence that sulfate conjugated dopamine acts as an antioxidant or a prooxidant. Therefore, in the present report, we compared dopamine and dopamine-4-O-sulfate for susceptibility to enzymatic and non-enzymatic oxidization in vitro using alkaline solution, horseradish peroxidase, UV irradiation, hydroxyl radical, superoxide anion radical, and sodium periodate. ExperimentalChemicals Dopamine, hypoxanthine, xanthine oxidase (from butter milk), and peroxidase (from horseradish) were purchased from Sigma Chemical Co., (MO, U.S.A.), hydrogen peroxide from Wako Pure Chemical Industries Ltd. (Osaka, Japan), and sodium metaperiodate from Acros Organics (NJ, U.S.A.). Dopamine-4-O-sulfate was kindly donated by Kyowa Hakko Kogyo Co., Ltd. (Tokyo, Japan). Other reagents were of the highest quality available from Wako Pure Chemical Industries Ltd.Free Radical Analysis Using EPR Spectroscopy The free radical metabolites of dopamine and dopamine-4-O-sulfate were examined with an EPR spectrometer (JES-TE 300, JEOL Co., Ltd., Tokyo, Japan) equipped with a cavity and an aqueous quartz flat cell (JEOL Co., Ltd., Tokyo, Japan) at X-band (9.5 GHz). EPR data were analyzed by a computer (HP Apollo 9000 Series 400) with the software, ESPRIT 432 ( JEOL Co., Ltd., Tokyo, Japan). Typical operating conditions of the EPR spectrometer were: power, 5 mW; center field, 3360 G; sweep width, 20 G; modulat...

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Section: Discussionmentioning

confidence: 99%

Section: )mentioning

confidence: 99%

Electron Paramagnetic Resonance Study on Free Radical Scavenging and/or Generating Activity of Dopamine-4-O-sulfate.

Kirima

Tsuchiya

Yoshizumi

et al. 2001

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…In Ref. [21] the structural and magnetic characteristics of the ZnMnO nanoclusters synthesized by the sol-gel method were investigated. A small quantity of ZnMn 2 O 4 phase was also present in the studied samples.…”

Section: Resultsmentioning

confidence: 99%

“…The paramagnetic centres were assumed to exist in the interior and near the surface of the crystals. The magnetization curve measured at room temperature showed a hysteresis loop arising probably due to the presence of the ZnMn 2 O 4 phase [21]. Nanoparticles of Mn 3 O 4 produced by a novel, environmentally friendly, room-temperature route using an ionic liquid have been studied by EPR method in Ref.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Resonance Study of MnO/ZnO Nanopowders

et al. 2011

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Fine particles n(MnO)/(1 − n)ZnO (n = 0.05 to 0.95) were prepared by wet chemistry method. According to X-ray diffraction analysis the obtained samples with n = 0.95, 0.90, 0.80, 0.70, 0.60 contained Mn 3 O 4 and ZnMn 2 O 4 phases, while samples with n = 0.05, 0.10, 0.20, 0.30, 0.40 and 0.50 contained ZnMnO 3 and ZnO phases. The mean crystalline size of ZnMnO 3 varied from 8 to 13 nm. The magnetic resonance investigations have been carried out at room temperature. Slightly asymmetric, broad and intense magnetic resonance line is recorded for all samples. The magnetic resonance spectra parameters showed marked differences depending on the composition index n. This could be explained by the variation of the magnetic susceptibility and a much slower evolution of spin relaxation, associated with the interaction of crystal field and superexchange interactions. Taking into account the values of magnetic resonance parameters, the investigated samples could be divided into two groups: these with the composition index n < 0.50 and those with n > 0.50. A detailed discussion of the magnetic properties of different phases in the n(MnO)/(1 − n)ZnO system is presented.

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“…This action was probably mediated by pro-oxidant effects that induced DNA oxidative damage, while apomorphine was an antimutagen, inhibiting by up to 80% hydrogen peroxide (H 2 O 2 ) and t-butylhydroperoxide (t-BOOH)-induced mutagenicity in all strains, possibly due to an antioxidant property (25). Compounds with a catechol structure such as apomorphine have metal chelating properties and can act as reducing agents and radical scavengers (30). However, as a reducing agent, apomorphine can also contribute to the generation of highly toxic hydroxyl radical by maintaining iron in the ferrous state.…”

Section: Mutagenicitymentioning

confidence: 99%

Genotoxic, neurotoxic and neuroprotective activities of apomorphine and its oxidized derivative 8-oxo-apomorphine

Picada

Roesler

Henriques

2005

Braz J Med Biol Res

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Apomorphine is a dopamine receptor agonist proposed to be a neuroprotective agent in the treatment of patients with Parkinson's disease. Both in vivo and in vitro studies have shown that apomorphine displays both antioxidant and pro-oxidant actions, and might have either neuroprotective or neurotoxic effects on the central nervous system. Some of the neurotoxic effects of apomorphine are mediated by its oxidation derivatives. In the present review, we discuss recent studies from our laboratory in which the molecular, cellular and neurobehavioral effects of apomorphine and its oxidized derivative, 8-oxo-apomorphine-semiquinone (8-OASQ), were evaluated in different experimental models, i.e., in vitro genotoxicity in Salmonella/ microsome assay and WP2 Mutoxitest, sensitivity assay in Saccharomyces cerevisiae, neurobehavioral procedures (inhibition avoidance task, open field behavior, and habituation) in rats, stereotyped behavior in mice, and Comet assay and oxidative stress analyses in mouse brain. Our results show that apomorphine and 8-OASQ induce differential mutagenic, neurochemical and neurobehavioral effects. 8-OASQ displays cytotoxic effects and oxidative and frameshift mutagenic activities, while apomorphine shows antimutagenic and antioxidant effects in vitro. 8-OASQ induces a significant increase of DNA damage in mouse brain tissue. Both apomorphine and 8-OASQ impair memory for aversive training in rats, although the two drugs showed a different dose-response pattern. 8-OASQ fails to induce stereotyped behaviors in mice. The implications of these findings are discussed in the light of evidence from studies by other groups. We propose that the neuroprotective and neurotoxic effects of dopamine agonists might be mediated, in part, by their oxidized metabolites. Correspondence

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Monoamine Metabolism Provides an Antioxidant Defense in the Brain Against Oxidant- and Free Radical-Induced Damage

Cited by 141 publications

References 0 publications

Electron Paramagnetic Resonance Study on Free Radical Scavenging and/or Generating Activity of Dopamine-4-O-sulfate.

Electron Paramagnetic Resonance Study on Free Radical Scavenging and/or Generating Activity of Dopamine-4-O-sulfate.

Magnetic Resonance Study of MnO/ZnO Nanopowders

Genotoxic, neurotoxic and neuroprotective activities of apomorphine and its oxidized derivative 8-oxo-apomorphine

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