Biodistribution of [F-18] SR144385 and [F-18] SR147963: Selective radioligands for positron emission tomographic studies of brain cannabinoid receptors

[F-18] SR144385 and [F-18] SR147963 were synthesized in a multistep reactio n in which fluorine-18 was introduced by nucleophilic halogen displacement on a bromo precursor. The fluorine-18 labeled intermediate was deprotected and coupled with the appropriate alkyl amine to give the final products. Bo th radioligands had appropriate regional brain distribution for cannabinoid receptors with a target to nontarget ratio of 1.7 for [F-18] SR147963 and 2.5 for [F-18] SR144385 at 60 and 90 min postinjection, respectively. The u ptake of both tracers was blocked with a 1 mg/kg dose of SR141716A. NUCL ME D BIOL 27;8:757-762, 2000. (C) 2000 Elsevier Science Inc. All rights reserv ed.