NMDA receptor activation in the aged rat: electrophysiological investigations in the CA1 area of the hippocampal slice ex vivo.
The effects of aging on activation of N-methyl-D-aspartate (NMDA) receptors were studied in the CA1 field of hippocampal slices from young (2-4 months old) and aged (25-32 months old) Sprague-Dawley rats with the use of ex vivo extra- and intracellular electrophysiological recording techniques. No significant age-related changes of the unitary NMDA-receptor mediated excitatory postsynaptic potentials (EPSPs), recorded from the pyramidal cells after stimulation of the stratum radiatum in a magnesium-free medium and isolated in the presence of the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione, were found. Simultaneously, the magnitude of synaptic plasticity which involved NMDA receptor activation was not altered. No significant age-related modifications in the mechanisms controlling glutamate release and of postsynaptic NMDA receptor responsiveness were revealed. Considering the 30-40% decrease in NMDA binding sites in the aged hippocampus, our results suggest the occurrence of compensatory mechanisms which are discussed.
Billard
J M
JM
Laboratoire de Physiopharmacologie du Système Nerveux, INSERM U 161, Paris, France.
Jouvenceau
A
A
Lamour
Y
Y
Dutar
P
P
D000375:Aging / Q000502:physiology*; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology; D009473:Neuronal Plasticity / Q000502:physiology; D017966:Pyramidal Cells / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000502:physiology*; D013569:Synapses / Q000502:physiology
D018690:Excitatory Amino Acid Agonists; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate