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Coupling of Dopamine Oxidation (Monoamine Oxidase Activity) to Glutathione Oxidation Via the Generation of Hydrogen Peroxide in Rat Brain Homogenates
Author(s) -
Maker Howard S.,
Weiss Cipora,
Silides Demetra J.,
Cohen Gerald
Publication year - 1981
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1981.tb01631.x
Subject(s) - monoamine oxidase , hydrogen peroxide , dopamine , chemistry , coupling (piping) , glutathione , biochemistry , monoamine neurotransmitter , neuroscience , enzyme , serotonin , biology , materials science , receptor , metallurgy
Abstract: Homogenates of perfused rat brain generated oxidized glutathione from reduced glutathione during incubation with dopamine or serotonin. This activity was blocked by pargyline. a monoamine oxidase inhibitor, or by catalase, a scavenger of hydrogen peroxide. These results demonstrate formation of hydrogen peroxide by monoamine oxidase and the coupling of the peroxide to glutathione peroxidase activity. Oxidized glutathione was measured fluorometrically via the oxidation of NADPH by glutathione reductase. In the absence of added dopamine or serotonin, a much smaller amount of reduced glutathione was oxidized: this activity was blocked by catalase, but not by pargyline. Therefore, endogenous production of hydrogen peroxide, not linked to monoamine oxidase activity, was present. These results indicate that glutathione peroxidase (linked to hexose monophosphate shunt activity) can function to eliminate hydrogen peroxide generated by monoamine oxidase and other endogenous sources in aminergic neurons.