title: Characterization of type 2 opiate receptors.
abstract: Recent evidence suggests that the Type 1 opiate receptor (in rat striatal patches) is a mobile receptor which is able to adopt a mu, delta, or kappa opiate receptor ligand selectivity pattern under appropriate conditions. In this paper, we have investigated such a possibility for Type 2 opiate receptors which are visualized diffusely over rat striatum. Ligand selectivity analysis suggested that the Type 2 opiate binding site is equivalent to a delta opiate receptor. The auto-radiographic distribution of Type 2 opiate binding sites is diffuse over most areas of rat brain. Thus, Type 2 opiate binding sites are different from Type 1 opiate receptors which are very discretely distributed in rat brain. Our results suggest that Type 2 opiate receptors, unlike Type 1 opiate receptors, are receptors locked in a delta-like ligand selectivity conformation.
mesh_terms: D000818:Animals; D001345:Autoradiography; D003342:Corpus Striatum / Q000032:analysis; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008024:Ligands; D008345:Manganese / Q000494:pharmacology; D051381:Rats; D011957:Receptors, Opioid / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D014018:Tissue Distribution
chemical_list: D008024:Ligands; D011957:Receptors, Opioid; D008345:Manganese; D004743:Enkephalin, Leucine; D016308:Enkephalin, Leucine-2-Alanine; D006160:Guanosine Triphosphate; D012964:Sodium