A PET study of
Several radiolabelled cocaine analogues have been proposed for brain imaging of the dopamine transporter in research on neuropsychiatric disorders and drug abuse. In a recent positron emission tomography (PET) study we labelled the cocaine analogue ß-CIT-FE with carbon-11 and demonstrated high specific binding in the monkey striatum. In the present study, the selectivity of [11C]ß-CIT-FE binding in the primate brain was examined by pretreatment experiments with reference ligands for the dopamine, serotonin and norepinephrine transporter. In three healthy human subjects the regional binding of [11C]ß-CIT-FE was analysed using equilibrium and kinetic analyses. A Scatchard analysis showed that [11C]ß-CIT-FE bound in a saturable manner yielded a density value of the same order as that reported in vitro. The pharmacological characterization indicated that a high degree of [11C]-CIT-FE binding in the primate striatum represents the dopamine transporter. In human subjects the radioligand provided high brain uptake and reached peak equilibrium within 1 hour after i.v. injection. Different quantitative approaches gave similar values for the binding potential. The results support the view that [11C]ß-CIT-FE is a suitable radioligand for clinical studies of the dopamine transporter. In particular for studies requiring short data acquisition or repeated PET measurements on the same day.
Farde
Lars
L
Ginovart
Nathalie
N
Halldin
Christer
C
Chou
Yuan-Hwa
YH
Olsson
Hans
H
Swahn
Carl-Gunnar
CG