N-METHYL-D-ASPARTATE RECEPTOR-BINDING IN BRAINS OF RATS AT DIFFERENT AGES

Potential age differences in N-methyl-D-aspartate (NMDA) receptor bind ing were evaluated in rat brain using [H-3]dizocilpine and 3]D,L-(E)-2 -amino-4-propyl-5-phosphono-3-pentanoic acid (CGP 39653) as the radiol igands. Neither [H-3]dizocilpine nor [H-3]CGP 39653 binding in hippoca mpus revealed any age difference (7 vs. 23-25 months) in B-max or K-d. High-affinity [H-3]dizocilpine binding showed a developmental increas e (8 vs. 2 months) in hippocampus but not in frontal cortex. No senesc ence-related change (25 vs. 8 months) was observed in either region. T he lack of senescence-related differences in these biochemical markers does not preclude the possibility of functional changes in the NMDA r eceptor with aging. Published by Elsevier Science Inc.