Title
Significant decreases in frontal and temporal [11C]-raclopride binding after THC challenge.
Abstract
Δ9-tetrahydrocannabinol (THC) increases prefrontal cortical dopamine release in animals, but this is yet to be examined in humans. In man, striatal dopamine release can be indexed using [11C]-raclopride positron emission tomography (PET), and recent reports suggest that cortical [11C]-raclopride binding may also be sensitive to dopaminergic challenges. Using an existing dataset we examined whether THC alters [11C]-raclopride binding potential (BPND) in cortical regions. Thirteen healthy volunteers underwent two [11C]-raclopride PET scans following either oral 10mg THC or placebo. Significant areas of decreased cortical [11C]-raclopride BPND were identified using whole brain voxel-wise analysis and quantified using a region of interest (ROI) ratio analysis. Effect of blood flow on binding was estimated using a simplified reference tissue model analysis. Results were compared to [11C]-raclopride test–retest reliability in the ROIs identified using a separate cohort of volunteers. Voxel-wise analysis identified three significant clusters of decreased [11C]-raclopride BPND after THC in the right middle frontal gyrus, left superior frontal gyrus and left superior temporal gyrus. Decreases in [11C]-raclopride BPND following THC were greater than test–retest variability in these ROIs. R1, an estimate of blood flow, significantly decreased in the left superior frontal gyrus in the THC condition but was unchanged in the other ROIs. Decreased frontal binding significantly correlated to catechol-o-methyl transferase (COMT) val108 status. We have demonstrated for the first time significant decreases in bilateral frontopolar cortical and left superior temporal gyrus [11C]-raclopride binding after THC. The interpretation of these findings in relation to prefrontal dopamine release is discussed.
Year
DOI
Venue
2010
10.1016/j.neuroimage.2010.04.274
NeuroImage
Keywords
Field
DocType
Cannabis,PET,Dopamine,Extrastriatal,THC,[11C]-raclopride
Developmental psychology,Blood flow,Raclopride,Dopaminergic,Psychology,Dopamine,Positron emission tomography,Region of interest,Binding potential,Placebo
Journal
Volume
Issue
ISSN
52
4
1053-8119
Citations 
PageRank 
References 
2
0.56
2
Authors
8
Name
Order
Citations
PageRank
Paul R A Stokes1184.12
Alice Egerton2153.33
Ben Watson3665.30
Alistair Reid420.90
Gerome Breen551.81
Anne Lingford-Hughes6202.72
David J. Nutt7274.57
Mitul A Mehta87612.54