The potential of o ‐bromo‐ trans ‐decalinvesamicol as a new PET ligand for vesicular acetylcholine transporter imaging

We investigated the characteristics of the regional rat brain distribution of radio‐brominated o ‐bromo‐decalinvesamicol (OBDV) in vivo to evaluate its potential as a PET ligand for vesicular acetylcholine transporter (VAChT). In in vivo biodistribution study, the specific brain regional accumulation of [ 77 Br]OBDV was revealed 30 min after intravenous injection. The specific brain regional accumulation of [ 77 Br]OBDV was significantly inhibited by co‐injection of (+/−)‐vesamicol. In contrast, no significant inhibition of the uptake of [ 77 Br]OBDV in all brain regions was observed with co‐injection of (+)‐pentazocine (selective σ‐1 receptor agonist) and (+)−3‐(3‐hydroxyphenyl)‐ N ‐propylpiperidine, [(+)−3‐PPP] (σ‐1 and σ‐2 receptor agonist) with [ 77 Br]OBDV. [ 77 Br]OBDV accumulation in VAChT‐rich brain regions was observed in ex vivo autoradiography. These results showed that [ 77 Br]OBDV selectively bound to VAChT with high affinity in rat brain in vivo . Hence, OVBDV radiolabelled with more suitable 76 Br was suggested to be a potent VAChT ligand for PET. Synapse 68:445–453, 2014 . © 2014 Wiley Periodicals, Inc.