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Synaptic mechanisms and calcium binding proteins in the aged rat brain
P Krzywkowski1, B Potier, J M Billard
1INSERM Unité 161, Paris, France.
Life Sciences
|January 1, 1996
Summary
Aging significantly impairs synaptic function in rat hippocampus, affecting cholinergic excitation and GABAergic inhibition. These changes are linked to altered muscarinic receptors, reduced acetylcholine release, and decreased calbindin in GABAergic interneurons, potentially impacting cognitive function.
Area of Science:
- Neuroscience
- Aging Research
- Synaptic Plasticity
Background:
- Age-related cognitive decline is often associated with hippocampal dysfunction.
- Synaptic transmission alterations are key mechanisms underlying cognitive impairments in aging.
Purpose of the Study:
- To investigate age-related changes in synaptic mechanisms within the rat hippocampus.
- To identify the molecular and cellular basis of impaired synaptic function in aged rats.
Main Methods:
- Ex vivo electrophysiological recordings of CA1 pyramidal neurons in aged rat hippocampus slices.
- Intracellular recordings to measure excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs).
- Immunohistochemical analysis of calcium-binding proteins (calbindin, parvalbumin, calretinin) in aged rat brain tissue.
Main Results:
- A significant depression of slow cholinergic EPSPs and slow GABAB-mediated IPSPs was observed in aged rats across three strains.
- Mechanisms include altered postsynaptic muscarinic receptor properties and possibly acetylcholine release.
- Reduced calbindin immunoreactivity in hippocampal CA1 pyramidal neurons and interneurons, and reduced parvalbumin in the medial septal area and cingulate cortex were noted.
Conclusions:
- Age-related synaptic alterations in the hippocampus may contribute to cognitive deficits.
- Reduced calbindin impacts GABAergic inhibition and neuronal calcium buffering, increasing vulnerability to insults.
- These findings highlight critical neurobiological changes associated with brain aging.