Archival ReportDecreased [18F]MPPF Binding Potential in the Dorsal Raphe Nucleus After a Single Oral Dose of Fluoxetine: A Positron-Emission Tomography Study in Healthy Volunteers
Section snippets
Subjects
The study was carried out in accordance with the Declaration of Helsinki and was approved by the Montreal Neurological Institute Research Ethics Board. Eight men, 19 to 35 years old (mean: 25 ± 6) were recruited via advertisements on a local website. All were physically healthy and drug-free, as determined by a physical examination and standard laboratory tests, including a urine drug screen (Biosite Diagnosis, San Diego, California) on the morning of each PET scan. Personal history of
Results
All procedures were well tolerated by the subjects, who did not differ significantly between sessions (placebo vs. fluoxetine) for mood, subjective behavioral effects, and vital signs. Fluoxetine and norfluoxetine were detected in the plasma of every subject, 5 hours and 6 hours after fluoxetine intake, at similar levels at both time points (fluoxetine: 19.98 ± 7.39 ng/mL; norfluoxetine: 5.37 ± 3.41 ng/mL; means ± SD).
The rank order of regional distribution and range values of [18F]MPPF BP
Discussion
The selective decreases in [18F]MPPF BP here observed and measured with PET in the DRN of healthy human subjects administered a single oral dose of the SSRI fluoxetine were presumably imputable to 5-HT1A autoreceptor internalization, in keeping with earlier results in animals (6, 24, 25) showing that 5-HT1A autoreceptor internalization is associated with parallel decreases in the in vivo binding of the 5-HT1A receptor radioligand [18F]MPPF in the DRN.
Considering that the DRN nucleus is not
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