AUTORADIOGRAPHIC VISUALIZATION OF [H-3] DTG BINDING TO SIGMA-RECEPTORS, [H-3] TCP BINDING-SITES, AND L-[H-3]GLUTAMATE BINDING TO NMDA RECEPTORS IN HUMAN CEREBELLUM

The autoradiographic distributions of [H-3]1,3-di-ortho-tolyguanidine ([H-3]DTG), [H-3]1-[1-(2-thienyl) cyclohexyl] piperidine ([H-3]TCP) and L-[H-3]glutamate were studied in the human cerebellum. [H-3]DTG is a selective label for the sigma receptor, while L-[H-3]glutamate binding was carried out under conditions selective for the N-methyl-D-aspartate (NMDA) receptor. [H-3]TCP binding sites and sigma receptors showed marked enrichment in the Purkinje cell layer, while L-[H-3]glutamate-labelled NMDA receptors showed virtually no binding in the Purkinje cell layer. The results confirm the existence of [H-3]TCP binding sites which are not linked to NMDA receptors in the human cerebellum, having a distribution which is more similar to that of the haloperidol-sensitive sigma receptor.