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NMDA receptor activation in the aged rat hippocampus
B Potier1, F Poindessous-Jazat, P Dutar
1Dynamique des Systèmes Neuroendocriniens, INSERM U159, 2ter rue d'Alesia, 75014, Paris, France.
Experimental Gerontology
|December 13, 2000
Summary
Aging impairs N-methyl-D-aspartate receptor (NMDAr) function in rat hippocampus, evidenced by smaller synaptic potentials. However, synaptic plasticity remains unaffected, suggesting compensatory mechanisms in aged brains.
Area of Science:
- Neuroscience
- Aging Research
- Synaptic Physiology
Background:
- N-methyl-D-aspartate receptors (NMDAr) play crucial roles in synaptic plasticity and cognitive functions.
- Age-related cognitive decline is often associated with alterations in NMDAr function.
Purpose of the Study:
- To investigate age-related changes in NMDAr activation and synaptic plasticity in the rat hippocampus.
- To determine if NMDAr function is altered in aged rats compared to young rats.
Main Methods:
- Ex vivo extracellular electrophysiological recordings from hippocampal slices of young and aged Sprague-Dawley rats.
- Measurement of NMDAr-mediated field excitatory postsynaptic potentials (fEPSPs) under specific ionic and pharmacological conditions.
- Assessment of short-term potentiation (STP) to evaluate synaptic plasticity.
Main Results:
- Aged rats exhibited significantly smaller NMDAr-mediated fEPSPs compared to young rats.
- Presynaptic fiber response and the effects of magnesium (Mg2+) on NMDAr function were not significantly different between age groups.
- No age-related alterations were observed in the magnitude or time course of short-term potentiation (STP).
Conclusions:
- While NMDAr-mediated synaptic transmission is reduced in aged rats, synaptic plasticity remains intact.
- The findings suggest the presence of compensatory mechanisms in the aged hippocampus to maintain synaptic function despite reduced NMDAr signaling.