Effects of Club Drugs on Dopaminergic and Serotonergic Systems: Use of [18F]FDOPA, [99mTc]TRODAT-1, and [i]ADAM

The acute effects and side effects of recreational drugs such as ketamine, cocaine, and methamphetamine on dopamine neurons and tissues/organs are evaluated using [¹⁸F]fluoro-3,4-dihydroxyphenyl-l-alanine ([¹⁸F]FDOPA) combined with positron emission tomography and quantitative autoradiography. Images obtained from both approaches are used for determining the specific binding ratios of striatum and cerebellum, the latter is the reference region. Significant accumulation of [¹⁸F]FDOPA-derived radioactivity in the striatum was observed. Blocking images markedly eliminate the specific binding of [¹⁸F]FDOPA in the striatum and in peripheral organs such as stomach, intestine, and kidneys. Among these recreational drugs, ketamine was shown with the highest inhibition effect on the striatal [¹⁸F]FDOPA-derived radioactivity followed by cocaine and methamphetamine. Here [¹⁸F]FDOPA is demonstrated as a useful radiopharmaceutical for investigating the effects of recreational drugs on dopaminergic neurons in central nervous system and on peripheral tissues/organs in drug abusers. Applications of [^99mTc]TRODAT-1 and [I?]ADAM for imaging the dopamine transporter and serotonin transporter and their related symptoms, respectively, are also briefly reviewed.