The mitochondrial electron transfer alteration as a factor involved in the brain aging
G Benzi1, O Pastoris, F Marzatico
1Institute of Pharmacology, University of Pavia, Italy.
Neurobiology of Aging
|May 1, 1992
Summary
Brain aging reduces reduced glutathione (GSH) and mitochondrial cytochrome aa3. Peroxidative stress also depletes GSH and disrupts electron transfer carriers, suggesting a link between GSH and mitochondrial function.
Area of Science:
- Biochemistry
- Neuroscience
- Aging Research
Background:
- Brain aging is associated with oxidative stress and mitochondrial dysfunction.
- Reduced glutathione (GSH) plays a crucial role in cellular defense against oxidative damage.
- Mitochondrial electron transport chain (ETC) components are vital for cellular energy production and can be targets of oxidative stress.
Purpose of the Study:
- To investigate the impact of aging and induced peroxidative stress on mitochondrial components and GSH levels in rat brains.
- To evaluate the effects of chronic pharmacological treatments on these parameters during aging and stress.
- To explore the functional relationship between GSH and mitochondrial ETC carriers.
Main Methods:
- Biochemical analysis of reduced glutathione (GSH) and ETC components (ubiquinone, cytochromes b, c1, c, aa3) in rat forebrain mitochondria.
- Induction of peroxidative stress using cyclohexene-1-one in aged rats.
- Pretreatment of rats with pharmacological agents targeting macrocirculation, carbohydrate metabolism, lipid metabolism, energy transduction, and the dopaminergic system.
Main Results:
- Brain aging led to decreased GSH and cytochrome aa3 levels, with stable ubiquinone and cytochrome b.
- Peroxidative stress induced GSH depletion and disrupted ETC carrier concentrations.
- Cytochrome aa3 appeared to retain oxygen intermediates, while electron leakage from cytochrome b and ubiquinone was hypothesized to increase reactive oxygen species.
- Pharmacological treatments indicated a functional link, but not interdependence, between GSH and mitochondrial ETC carriers.
Conclusions:
- Brain aging and oxidative stress significantly impact mitochondrial function and GSH levels.
- Mitochondrial electron transfer chain components, particularly cytochrome aa3, are sensitive to aging and oxidative insults.
- GSH and mitochondrial ETC carriers are functionally connected in maintaining brain homeostasis, though not directly interdependent.
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