ABP688, a novel selective and high affinity ligand for the labeling of mGlu5 receptors: identification, in vitro pharmacology, pharmacokinetic and biodistribution studies.

[(11)C]ABP688 (2) has recently been demonstrated to be a useful PET tracer for in vivo imaging of the metabotropic glutamate receptors type 5 (mGluR5) in rodents. We describe here the identification and preclinical profiling of ABP688 and its tritiated version [(3)H]ABP688, and show that its high affinity (K(d)=2nM), selectivity, and pharmacokinetic properties fulfill all requirements for development as a PET tracer for clinical imaging of the mGlu5 receptor.