Decreased [18F]MPPF Binding Potential in the Dorsal Raphe Nucleus After a Single Oral Dose of Fluoxetine: A Positron-Emission Tomography Study in Healthy Volunteers

Igor Sibon, Chawki Benkelfat, Paul Gravel, Nicolas Aznavour, Nicolas Costes, Shadrek Mzengeza, Linda Booij, Glen Baker, Jean-Paul Soucy, Luc Zimmer, Laurent Descarries
Biological Psychiatry. 2008-06-01; 63(12): 1135-1140
DOI: 10.1016/j.biopsych.2007.11.016

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1. Biol Psychiatry. 2008 Jun 15;63(12):1135-40. doi: 10.1016/j.biopsych.2007.11.016.
Epub 2008 Jan 14.

Decreased [18F]MPPF binding potential in the dorsal raphe nucleus after a single
oral dose of fluoxetine: a positron-emission tomography study in healthy
volunteers.

Sibon I(1), Benkelfat C, Gravel P, Aznavour N, Costes N, Mzengeza S, Booij L,
Baker G, Soucy JP, Zimmer L, Descarries L.

Author information:
(1)Department of Psychiatry, McGill University, Montreal, Quebec, Canada.

BACKGROUND: Brain serotonin-1A (5-HT(1A)) autoreceptors internalize when
activated by agonist or by their endogenous ligand, serotonin. This
positron-emission tomography (PET) study tested the hypothesis that 5-HT(1A)
autoreceptor internalization might be indexed in vivo by a decrease in the
specific binding of the 5-HT(1A) radioligand,
4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1
piperazinyl]ethyl-N-2-pyridinyl-benzamide ([(18)F]MPPF), in the dorsal raphe
nucleus (DRN) of healthy adult men administered a single oral dose of the
selective serotonin reuptake inhibitor, fluoxetine.
METHODS: [(18)F]MPPF binding potential was measured in the DRN and other brain
regions endowed with 5-HT(1A) receptors in eight healthy volunteers, 5 hours
after the randomized, double-blind administration of fluoxetine (20 mg) or
placebo.
RESULTS: In every subject, [(18)F]MPPF binding potential was decreased in the DRN
only (44% +/- 22 SD), in response to fluoxetine.
CONCLUSIONS: Imaging the functional state of 5-HT(1A) autoreceptors (i.e.,
internalization) in the human brain, using [(18)F]MPPF/PET, may represent a
promising avenue for investigating the neurobiology of serotonin-related
disorders and notably of major depression.

DOI: 10.1016/j.biopsych.2007.11.016
PMID: 18191817 [Indexed for MEDLINE]

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