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PubMed · 11113601

NMDA receptor activation in the aged rat hippocampus.

B Potier·F Poindessous-Jazat·P Dutar·J M Billard
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Abstract

Age-related alterations of N-methyl-D-aspartate receptor (NMDAr) activation were investigated in the CA1 field of hippocampal slices from young (3-6 months old) and aged (25-33 months old) Sprague-Dawley rats by using ex vivo extracellular electrophysiological recording techniques. NMDAr-mediated field excitatory postsynaptic potentials (fEPSPs) were induced by electrical stimulation of glutamatergic fibers in a magnesium (Mg(2+))-free medium supplemented with the non-NMDAr antagonist CNQX. The fEPSPs were significantly smaller in aged rats, whereas the response of presynaptic afferent fibers remained unaffected. No significant age-related differences were found in the ability of Mg(2+) to depress the magnitude of NMDAr-mediated fEPSPs. The responsiveness of postsynaptic NMDAr to the agonist was assessed in both groups of animals. No age-related differences were recorded either in the depolarizing effect of bath-applied NMDA or in the magnitude of the depolarization after altering extracellular Mg(2+) concentration. Finally, short-term potentiation (STP) of excitatory transmission was studied in young and aged rats considering the pivotal role of NMDAr in synaptic plasticity. No age-related alterations of the magnitude and the time course of STP in response to 10 or 30Hz conditioning stimulation were found. Because of the decrease in the magnitude of NMDAr-mediated synaptic transmission in aged animals, the absence of obvious modifications of synaptic plasticity suggests the occurrence of compensatory mechanisms that are discussed.

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6-Cyano-7-nitroquinoxaline-2,3-dioneAgingAnimalsElectrophysiologyExcitatory Amino Acid AntagonistsExcitatory Postsynaptic PotentialsHippocampusIn Vitro TechniquesMagnesiumMaleN-MethylaspartateRatsRats, Sprague-DawleyReceptors, N-Methyl-D-AspartateSynapsesTime FactorsJournal Article

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B Potier, F Poindessous-Jazat, P Dutar, J M Billard. 2000. NMDA receptor activation in the aged rat hippocampus.. https://doi.org/10.1016/s0531-5565(00)00122-4

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