D-ASPARTATE BINDING TO THE GLUTAMATE UPTAKE SITE IN HUMAN BRAIN-TISSUE - EFFECTS OF LEUKOTOMY

Binding of [H-3]D-aspartate, as an indicator of glutamate uptake sites , was investigated in post-mortem human brain tissue by use of a centr ifugation assay to separate free and bound ligand. Binding was displac eable, apparently saturable and to a single site, with mean K(D) and B max values of 2.3 muM and 40.3 nmol/g tissue in the frontal cortex. Th e method was applied to the study of tissue from frontal and temporal cortices and the caudate nucleus of five psychiatric patients who had undergone a frontal leucotomy. The effects of this neurosurgical proce dure were to diminish by almost 50% the density of D-aspartate binding sites in the frontal cortex and caudate nucleus, while the temporal c ortex was less affected. It is concluded that the method provides a po tentially useful correlate of glutamatergic innervation in human brain tissue.