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A longitudinal [18F]FDOPA-PET study on nicotine addicted patients before and after long-term abstinence

2013; Society of Nuclear Medicine and Molecular Imaging; Volume: 54; Linguagem: Inglês

1535-5667

Ingo Vernaleken, Lena Rademacher, Karsten Henkel, Claudia Dietrich, Susanne Prinz, Oliver Winz, Jörn Schmaljohann, Siamak Mohammadkhani Shali, Felix M. Mottaghy, Gerhard Gruender,

Functional Brain Connectivity Studies

31 Objectives Previous studies on addiction suggest disturbances in the dopamine transmission system. This [18F]FDOPA-PET investigation aims to detect nicotine related changes during continued smoking, after acute withdrawal, and after long-term abstinence. The latter condition should simulate the situation before the substance-dependent behaviour became apparent. The reversible inlet/outlet model for [18F]FDOPA-PET analysis was applied for characterization of divers presynaptic kinetic parameters. Methods 30 male nicotine dependent subjects (28.3±7.0 yrs) and 15 non-smoking subjects (27.9±7.5 yrs) were included. Half of the patients underwent a first scan under acute withdrawal the other half under smoking conditions. Afterwards, all patients attended at a smoking cessation program. 16/30 patients remained abstinent for at least 3 months. This group underwent a second [18F]FDOPA scan (124 min., bolus infusion 228±32 MBq [patients]; arterial blood withdrawal; metabolite detection). The reversible inlet/outlet model of Kumakura et al. (2005) was applied in order to obtain the net blood/brain clearance (K), the loss of fluorinated metabolites (kloss), and the total distribution volume (VD). Results Positive correlations between the dopamine transmission and cognitive performance could be replicated (TMT-B vs. VD in vNC: r=-0.631, p=0.016). Smoking patients showed a reduced dopamine synthesis capacity in particular in the right (-16%, p=0.045) and left ventral caudate nucleus (-16%, p=0.050). The kloss sowed a reduction on trend-level. The long-term smoking cessation, nevertheless, normalized all presynaptic dopaminergic parameters. The state of acute withdrawal showed a tendency toward reduced K and kloss. Conclusions Ongoing nicotine consumption results in a down-regulation of dopamine-synthesis capacity and turn-over. The complete normalization after 3 months of abstinence, however, was unexpected and does not claim an inefficient dopamine system to be a strong trait toward nicotine dependence.