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Age effect on brain pH during ischemia/reperfusion and pH influence on peroxidation
T Funahashi1, R A Floyd, J M Carney
1Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City 73104.
Neurobiology of Aging
|March 1, 1994
Summary
Older gerbils show increased sensitivity to brain ischemia/reperfusion injury (IRI). Lower brain pH during IRI exacerbates oxidative damage, with older gerbils exhibiting impaired recovery and mitochondrial function.
Area of Science:
- Neuroscience
- Biochemistry
- Gerontology
Background:
- Ischemia/reperfusion injury (IRI) disproportionately affects older individuals.
- Brain acidification during IRI is a critical factor in neuronal damage.
- Age-related decline in mitochondrial function may impair recovery from oxidative stress.
Purpose of the Study:
- To investigate age-related differences in brain response to IRI.
- To explore the role of pH and high-energy phosphates in IRI-induced brain damage.
- To determine the impact of reduced pH on oxidative damage in brain homogenates.
Main Methods:
- Utilized 31P-NMR to monitor in vivo brain pH and high-energy phosphates during IRI in young and old gerbils.
- Assessed peroxidation rates in young and old brain homogenates at different pH levels.
- Investigated the effect of ADP/Fe/Ascorbate system on peroxidation.
Main Results:
- Older gerbils exhibited prolonged recovery of brain pH and high-energy phosphates post-IRI compared to younger gerbils.
- Decreased pH (6.4 vs. 7.4) significantly increased peroxidation rates in both young and old brain homogenates.
- The enhancement of peroxidation by ADP/Fe/Ascorbate was less pronounced at lower pH.
Conclusions:
- IRI-induced brain acidification exacerbates oxidative damage, potentially by increasing iron availability.
- Older gerbils demonstrate impaired recovery from IRI, suggesting reduced mitochondrial capacity to handle oxidative stress.
- Age-related mitochondrial dysfunction contributes to increased susceptibility to IRI.