[¹²³I]FP-CIT binding in rat brain after acute and sub-chronic administration of dopaminergic medication

Abstract.

The recently developed radioligand [¹²³I]FP-CIT is suitable for clinical single-photon emission tomography (SPET) imaging of the dopamine (DA) transporter in vivo. To date it has remained unclear whether dopaminergic medication influences the striatal [¹²³I]FP-CIT binding. The purpose of this study was to investigate the influence of this medication on [¹²³I]FP-CIT binding in the brain. We used an animal model in which we administered dopaminomimetics, antipsychotics and an antidepressant. In vivo [¹²³I]FP-CIT binding to the DA and serotonin transporters was evaluated after sub-chronic and acute administration of the drugs. The administered medication induced small changes in striatal [¹²³I]FP-CIT binding which were not statistically significant. As expected, the DA reuptake blocker GBR 12,909 induced a significant decrease in [¹²³I]FP-CIT binding. [¹²³I]FP-CIT binding in the serotonin-rich hypothalamus was decreased only after acute administration of fluvoxamine. The results of this study suggest that dopaminergic medication will not affect the results of DA transporter SPET imaging with [¹²³I]FP-CIT.