Biological evaluation of a technetium-99m-labeled integrated tropane-BAT and its piperidine congener as potential dopamine transporter imaging agents

Both 99mTc-TropaBAT complexes exhibit similar diffusion into brain as 99mTc-TRODAT-1, and ex vivo autoradiography shows significant striatal uptake. However, the inferior striatum/cerebellum activity ratio, the striatal uptake in mice pretreated with FP-β-CIT or haloperidol, and the lack of striatal uptake during in vitro incubation prove that the DAT is not targeted. Brain uptake disappears when the tropane skeleton is replaced by a piperidine ring, and also in this case no striatal uptake is found in vitro.