[18F]MPPF as a tool for the in vivo imaging of 5-HT1A receptors in animal and human brain

Serotonin (5-hydroxytryptamine, 5-HT) and its various receptors are involved in numerous CNS functions and psychiatric disorders. 5-HT1A, the best-characterized subtype of currently known 5-HT receptors, is tightly implicated in the pathogenesis of depression, anxiety, epilepsy and eating disorders. It thus represents an important target for drug therapy. Specific radioligands and positron emission tomography (PET) allow for a quantitative imaging of brain 5-HT1A receptor distribution in living animals and humans. Recently, the selective 5-HT1A receptor antagonist, MPPF, has been successfully labeled with [18F]fluorine ([18F]MPPF), and an increasing number of academic and industry centres have used this radiotracer in preclinical and clinical studies. After a brief account of some of the structural, distributional and electrophysiological characteristics of brain 5-HT1A receptors, this review focuses on studies conducted with [18F]MPPF, with emphasis on preclinical results illustrating the actual and potential value of this PET radioligand for clinical research and drug development.