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Cytosolic and mitochondrial calcium in synaptosomes during aging
J Satrústegui1, M Villalba, R Pereira
1Department of Molecular Biology, Center of Molecular Biology "Severo Ochoa" Autonomous University of Madrid, Spain.
Life Sciences
|January 1, 1996
Summary
Aging increases synaptosomal calcium levels in rat hippocampus due to impaired calcium buffering and extrusion. This age-related decline in calcium homeostasis may heighten neuronal vulnerability to excitotoxicity.
Area of Science:
- Neuroscience
- Cell Biology
- Aging Research
Background:
- Synaptosomal intracellular calcium ([Ca2+]i) levels are critical for neuronal function.
- Altered calcium homeostasis is implicated in age-related cognitive decline and neurodegeneration.
Purpose of the Study:
- To investigate age-dependent changes in synaptosomal calcium handling in the rat hippocampus.
- To determine the mechanisms underlying increased [Ca2+]i in aging.
Main Methods:
- Measurement of synaptosomal [Ca2+]i under basal and depolarization conditions.
- Assessment of calcium buffering capacity and extrusion mechanisms.
- Evaluation of mitochondrial calcium uptake and uniporter activity.
Main Results:
- Old rats exhibited elevated basal and depolarization-induced synaptosomal [Ca2+]i in the hippocampus.
- Reduced cytosolic calcium binding capacity and impaired mitochondrial calcium compartmentation were observed in aged synaptosomes.
- Decreased activity of the mitochondrial calcium uniporter was associated with aging.
Conclusions:
- Aging deteriorates cellular calcium homeostatic mechanisms, leading to increased synaptosomal [Ca2+]i.
- Impaired calcium buffering and extrusion, rather than increased influx, contribute to elevated [Ca2+]i in aged neurons.
- These calcium dysregulations may increase neuronal susceptibility to excitotoxicity in old age.