[Specific binding of 3H-domperidone--a selective ligand of D2-dopamine receptors--by the human caudate nucleus].

Specific binding of 3H-domperidone was detected in a homogenate of human caudate nucleus tissue obtained from mentally healthy people and schizophrenic patients postmortem. Analysis of Scatchard's graph revealed only one type of binding sites with a dissociation constant of about 17 nM and the maximal number of binding sites about 87 pmol/g of the initial tissue. According to the current concepts, 3H-domperidone is a selective ligand of D2 dopamine receptors mediating the psychotropic effect of neuroleptics. The use of human brain for the investigation of these receptors may contribute to the elucidation of the mechanism of action of psychotropic drugs.