Comparative in vivo study of iodine-123-labeled β-cit and nor-β-cit binding to serotonin transporters in rat brain

✍ Scribed by Liesbeth Reneman; Jan Booij; Jules Lavalaye; Kora De Bruin; Frederik A. De Wolff; Richard P. Koopmans; Johannes C. Stoof; Gerard J. Den Heeten

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 462 KB
• Volume: 34
• Category: Article
• ISSN: 0887-4476
• DOI: 10.1002/(sici)1098-2396(199910)34:1<77::aid-syn9>3.0.co;2-y

✦ Synopsis

Both iodine-123-labeled ␤-CIT (2␤-carbomethoxy-3␤-(4-iodophenyl)tropane) and nor-␤-CIT (2␤-carbomethoxy-3␤-(4-iodophenyl)nortropane) have shown to be suitable radioligands for imaging serotonin (5-HT) transporters. [ 123 I]nor-␤-CIT has the highest in vitro affinity for 5-HT transporters among ␤-CIT analogs reported so far. However, no direct comparison-studies of these two radiotracers as to their in vivo binding to 5-HT transporters have been reported so far. Therefore, it is still unclear which of the two radiotracers is more suitable for single photon emisison computed tomograpy (SPECT) imaging of 5-HT transporters. The purpose of this study was to compare directly in a controlled design the in vivo [ 123 I]␤-CIT and [ 123 I]nor-␤-CIT binding to 5-HT transporters under the same conditions in rats with the focus on brain kinetic characteristics by means of a two-compartment analysis. We observed that [ 123 I]␤-CIT has a higher binding potential and faster kinetics for 5-HT transporters than [ 123 I]nor-␤-CIT, suggesting that [ 123 I]␤-CIT may be a more suitable radioligand than [ 123 I]nor-␤-CIT for imaging 5-HT transporters with SPECT. Synapse 34:77-80, 1999.