Age-related changes in mitochondrial function and oxygen radical production in synaptic and non-synaptic brain cortex mitochondria.

LORES-ARNAIZ, S.; CICERCHIA, DANIELA; LOMBARDI, P.; BUSTAMANTE, JUANITA

Buenso Aires

Congreso; VIII International Congress Society for Free Radical Biology and Medicine South American Group; 2013

Society for Free Radical Biology and Medicine - South American Goup

Brain aging has been associated with mitochondrial dysfunction and oxygen radicals generation at nerve terminals. The aim of this study was to evaluate the susceptibility of brain cortex synaptic and non-synaptic (NS) mitochondria to aging-dependent dysfunction. Male Swiss mice of 3, 14 or 17 months of age were used. Brain cortex synaptosomes and NS mitochondria were isolated by Ficoll gradient procedures. Mitochondrial respiration and oxygen radicals generation were determined. State 3 respiration was 40% decreased in brain cortex synaptosomes from aged animals, but was not significantly affected by aging in NS mitochondria. Complex IV activity was decreased by 25-35% in synaptosomes from aged animals. Synaptosomes were more susceptible than NS mitochondria to calcium-induced depolarization in 14 months-old animals. Superoxide levels were lower in brain cortex synaptosomes and NS mitochondria from 17 months-old mice as compared with young animals. Increased hydrogen peroxide (H2O2) production rates were observed in synaptosomes from aged mice, while a 44% decrease in H2O2 production was found in NS mitochondria. MAO activity was 62% higher only in synaptosomes from 17-months old mice, as compared with young animals. The results of this study suggest that mitochondria present at nerve terminals would be more susceptible than NS mitochondria to suffer age-dependent dysfunction.