Effect of antemortem and postmortem factors on [3H]glutamate binding in the human brain.

The effect of a number of antemortem and postmortem factors on both N-methyl-D-aspartate (NMDA) sensitive and NMDA insensitive [3H]glutamate binding was investigated in the frontal cortex and putamen of human brains. There was a high correlation between both binding sites (r = 0.86, P less than 0.001) and both binding sites increased during the early postnatal period reaching a maximum between age 1 and 2 years. After age 10 years NMDA sensitive sites disappeared at 9.2% per decade while the NMDA insensitive sites disappeared at 7.4% per decade only. Therefore, the ratio between NMDA sensitive and NMDA insensitive sites changed in favor of the NMDA insensitive site with increasing age. The storage time of brain tissue had a strong reducing effect on both binding sites, again affecting the NMDA sensitive sites more severely. There was no obvious effect of gender, brain weight or postmortem time interval on either binding site. Furthermore, there was no difference between frontal cortex and putamen. Both binding sites were bilateral symmetrically distributed in either frontal cortex and putamen.