Autoradiographic visualisation of [ 3H]DTG binding to σ receptors, [ 3H]TCP binding sites, and l-[ 3H]glutamate binding to NMDA receptors in human cerebellum

Abstract

The autoradiographic distributions of [ 3H]1,3-di- ortho-tolyguanidine ([ 3H]DTG), [ 3H]1-[1-(2-thienyl) cyclohexyl] piperidine [ 3H]TCP) and l-[ 3H]glutamate were studied in the human cerebellum. [ 3H]DTG is a selective label for the σ receptor, while l-[ 3H]glutamate binding was carried out under conditions selective for the N- methyl- d-aspartate (NMDA) receptor. [ 3H]TCP binding sites and σ receptors showed marked enrichment in the Purkinje cell layer, while l-[ 3H]glutamate-labelled NMDA receptors showed virtually no binding in the Purkinje cell layer. The results confirm the existence of [ 3H]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 σ receptor.