Mu opioid receptor binding sites in human brain.

Our experiments focused on the examination of the distribution of mu opioid receptor binding sites in normal human brain using the highly selective ligand [3H]DAGO, in both membrane binding assay and in vitro receptor autoradiography. Mu opioid binding sites are very discretely distributed in human brain with high densities of sites found in the posterior amygdala, caudate, putamen, hypothalamus and certain cortical areas. Moreover the autoradiographic distribution of [3H]DAGO binding sites clearly reveals the discrete lamination (layers I and III-IV) of mu sites in cortical areas.