Iodine-123 labelled nor-beta-CIT binds to the serotonin transporter in vivo as assessed by biodistribution studies in rats

Eur J Nucl Med. 1998 Dec;25(12):1666-9. doi: 10.1007/s002590050346.


Iodine-123 labelled 2beta-carbomethoxy-3beta-4-iodophenylnortropane (nor-beta-CIT), a radioiodinated cocaine analogue, was evaluated as an agent for the in vivo labelling of serotonin transporters by biodistribution studies in rats. Intravenous injection of [123I]nor-beta-CIT resulted in high accumulation of radioactivity in brain areas with high densities of serotonin (hypothalamus) and dopamine transporters (striatum), although the binding was less pronounced in the hypothalamus. While binding of [123I]nor-beta-CIT in the hypothalamus was blocked significantly by fluvoxamine (a selective serotonin transporter blocker) but not by GBR12,909 (a selective dopamine transporter blocker), the opposite was observed in the striatum. The results of this study indicate that [123I]nor-beta-CIT, although not being a selective radioligand, binds specifically to serotonin transporters in the hypothalamus in vivo and thus suggest that [123I]nor-beta-CIT promises to be a suitable radioligand for single-photon emission tomography imaging of serotonin transporters in humans.

MeSH terms

  • Animals
  • Brain / diagnostic imaging*
  • Brain / metabolism*
  • Carrier Proteins / metabolism*
  • Cocaine / analogs & derivatives
  • Dopamine Uptake Inhibitors / pharmacology
  • Fluvoxamine / pharmacology
  • Iodine Radioisotopes / pharmacokinetics*
  • Male
  • Membrane Glycoproteins / metabolism*
  • Membrane Transport Proteins*
  • Nerve Tissue Proteins*
  • Piperazines / pharmacology
  • Radionuclide Imaging
  • Rats
  • Rats, Wistar
  • Selective Serotonin Reuptake Inhibitors / pharmacology
  • Serotonin / metabolism*
  • Serotonin Plasma Membrane Transport Proteins
  • Tropanes / pharmacokinetics*


  • Carrier Proteins
  • Dopamine Uptake Inhibitors
  • Iodine Radioisotopes
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Nerve Tissue Proteins
  • Piperazines
  • Serotonin Plasma Membrane Transport Proteins
  • Serotonin Uptake Inhibitors
  • Slc6a4 protein, rat
  • Tropanes
  • 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane
  • Serotonin
  • vanoxerine
  • Cocaine
  • Fluvoxamine