METHODOLOGICAL ASPECTS FOR IN-VITRO CHARACTERIZATION OF RECEPTOR-BINDING USING C-11 LABELED RECEPTOR LIGANDS - A DETAILED STUDY WITH THE BENZODIAZEPINE RECEPTOR ANTAGONIST [C-11] RO-15-1788

As a complement to in vivo studies with positron emission tomography ( PET), it is desirable to perform in vitro characterization of newly de veloped C-11 tracers. In this report we describe the technique for det ermination of receptor-ligand kinetics utilizing ligands labeled with the short lived radionuclide C-11. The limitations and advantages are discussed. The benzodiazepine antagonist [C-11]Ro 15-1788 was used as a model substance, and the use of storage phosphor plates for quantifi cation of radioactivity was validated, Storage phosphor plates showed an excellent linear range (similar to 10(3)) and acceptable resolution (similar to 0.5 mm). Receptor-ligand kinetics, including depletion, a ssociation and dissociation, saturation and displacement were evaluate d with good results through the use of short lived radiotracers and st orage phosphor plates. (C) 1997 Elsevier Science Inc.