EXCITATORY AND INHIBITORY AMINO-ACID BINDING-SITES IN HUMAN DENTATE NUCLEUS

Autoradiography of excitatory and inhibitory amino acid binding sites in human dentate nuclei indicated virtually no binding to N-methyl-D-aspartate (NMDA) or gamma-aminobutyric acid(B) (GABA(B)) binding sites, and a low density of kainate binding sites. alpha-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid, metabotropic-quisqualate, benzodiazepine, and gamma-aminobutyric acid(A) (GABA(A)) binding sites were present in moderate abundance. Our NMDA results differ from those found previously in rodents. GABA(A) receptors are probably the primary mediators of inhibitory neurotransmission and alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid and metabotropic-quisqualate receptors are probably the primary mediators of excitatory neurotransmission within the human deep cerebellar nuclei.