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Influence of age on N‐methyl‐D‐aspartate antagonist binding sites in the rat brain studied by in vitro autoradiography
Author(s) -
Miyoshi Rie,
Kito Shozo,
Doudou Naomi,
Nomoto Teruko
Publication year - 1991
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890080307
Subject(s) - nmda receptor , glycine , glutamate receptor , receptor , nucleus accumbens , chemistry , hippocampus , antagonist , binding site , cerebral cortex , neuroscience , biophysics , biology , medicine , biochemistry , amino acid
The N‐methyl‐D‐aspartate (NMDA) receptor complex has been considered to consist of an L‐glutamate recognition site, a strychine‐insensitive glycine modulatory site, and a voltage‐dependent cation channel. In this study, an effect of age on NMDA antagonist binding sites was investigated through quantitative in vitro autoradiography with 3 H‐3‐((+)‐2‐carboxypiperazin‐4‐yl)propyl‐1‐phosphonic acid (CPP). 3 H‐CPP binding sites were most concentrated in the hippocampus and cerebral cortex where NMDA receptors have been demonstrated to be involved in synaptic transmission. In aged rats, 3 H‐CPP binding sites in the hippocampus and cerebral cortex were not significantly changed. As for other brain regions, there was an age‐dependent decline of binding sites only in the caudate‐putamen and nucleus accumbens. Our previous study revealed that strychine‐insensitive glycine receptors were markedly reduced in telencephalic regions in the aged rat brain. Taking these findings into consideration, is concluded that glycine receptors but not NMDA antagonist binding sites are severely altered in telencephalic regions of aged animals. It is considered that within the NMDA receptor complex, glycine receptors may be selectively affected in the aging process.