ArticlesUse of Positron Emission Tomography to Study the Dynamics of Psychostimulant-Induced Dopamine Release
Section snippets
Radiosynthesis
The synthesis of [18F]FCP was accomplished via N-alkylation of the corresponding des-benzyl precursor with [18F]4-fluorobenzyliodide ([18F]FBI), as described previously 24, 26. The synthesis time was ∼120 min, and the overall yield ranged from 10 to 56%; the specific activity of the final product ranged from 1000 to 5000 mCi/μmol.
PET Data Acquisition in Rhesus Monkeys
Images were acquired on a Siemens CTI 951/31 PET Scanner. The in-plane resolution of the scanner was measured to be 6.0–6.5 mm full width at half maximum (FWHM) in the
Results
The results of a PET imaging study, coregistered with an MRI image of the test subject, are shown in Fig. 2. Note the high uptake of [18F]FCP in the basal ganglia, a brain region expressing a high density of dopamine D2 receptors. Representative tissue–time activity curves from a dynamic imaging study are shown in Fig. 3. There is a high accumulation of radiotracer in the BG (Fig. 3, open triangles) and a low uptake and rapid rate of washout of radioactivity from the Cb, a reference region
Discussion
It is now generally accepted that the positive reinforcing effects of psychostimulants are mediated, in large part, through the elevation of synaptic dopamine concentrations in the mesocorticolimbic dopaminergic system. Although the principal site of action for many psychostimulants resides on molecular targets located on the presynaptic dopaminergic terminal, the reinforcing effects of psychostimulants are mediated, in large part, through the interaction of the elevated synaptic dopamine with
Acknowledgements
We thank Mr. Brian Whirrett, Ms. Virginia Kirby, Mr. Clifford Hubbard, Ms. Debbie Gibbons, Ms. Holly Choate, and Ms. Joanne Dow for their excellent technical assistance. This research was funded by grant NS 31907 awarded by the National Institutes of Health.
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