Effects of Fluvoxamine Treatment on the in Vivo Binding of [F-18]FESP in Drug Naive Depressed Patients: A Pet Study

Abstract

Thisstudy investigates the effect of chronic treatment with Fluvoxamine, a potent and specific serotonin reuptake sites inhibitor (SSRI), on 5HT2 serotonin and D2 dopamine receptors in the brain of drug naive unipolar depressed patients. Drug effect was evaluated in different cortical areas and in the basal ganglia by positron emission tomography (PET) and fluoro-ethyl-spiperone ([18F]FESP), an high affinity 5HT2 serotonin and D2 dopamine receptors antagonist. Patients underwent a PET study at recruitment and after clinical response to Fluvoxamine treatment. Nine of the 15 patients recruited completed the study. Fluvoxamine treatment significantly improved clinical symptoms and modified [18F]FESP binding in the frontal and occipital cortex of all of the nine patients who completed the study; in these regions a mean 31% increase in the in vivo [18F]FESP binding was found (P < 0.01). On the contrary, no significant changes in the in vivo [18F]FESP binding were found in the basal ganglia where [18F]FESP binds mainly to D2 dopamine receptors. Chronic treatment with Fluvoxamine significantly increases the in vivo binding of [18F]FESP in the frontal and occipital cortex of drug naive unipolar depressed patients. The increase of the in vivo binding of [18F]FESP may reflect a modification in 5HT2 binding capacity secondary to changes in cortical serotonin activity.