Synthesis and brain distribution of carbon-11 labeled analogs of antagonists for the NMDA receptor coupled PCP-binding site

Two phencyclidine (PCP) analogs, 3 and 4, and one thienylcyclohexyl-piperidine (TCP) analog, (±)6, were labeled with positron emitter carbon-11. These compounds displayed higher in vitro binding affinities than PCP itself for the PCP-binding site located inside the ion channel on the N-methyl-D-aspartate (NMDA) receptors. Brain distribution studies in mice showed different uptake characteristics between the PCP and TCP analogs, indicating their different in vivo interactions with the brain components including the PCP-binding site probably due to the different physicochemical properties of the molecules.