Dopamine D1 receptor binding in the striatum of patients with obsessive-compulsive disorder.
BACKGROUND
Obsessive-compulsive disorder (OCD) is a chronic anxiety disorder of unknown aetiology. Psychopharmacological studies have suggested a role for the neurotransmitter serotonin however further evidence for serotonin in the aetiology of OCD is conflicted. The authors used positron emission tomography (PET) to examine the binding of the dopamine D(1) receptor antagonist [(11)C]-SCH23390 to D(1) receptors in the striatum of drug-free OCD patients compared with healthy controls.


METHODS
Seven drug-free patients (two drug naïve) with OCD and seven age, gender and education matched healthy controls underwent positron emission tomography with [(11)C]-SCH23390. Binding Potentials (BP) at D(1) receptors were calculated for the caudate nucleus and putamen. Correlations between BP values for basal ganglia regions and clinical measures were performed in OCD patients.


RESULTS
The BP for [(11)C]-SCH23390 at D(1) receptors in OCD patients was significantly reduced in both caudate nucleus (0.59+/-0.06 vs 0.88+/-0.06, p<0.05) and putamen (0.89+/-0.06 vs 1.14+/-0.06, p<0.05) compared with healthy controls. No correlations were found between D(1) BP and symptom measures.


CONCLUSIONS
The main limitations of this study are the small sample size and the PET methodology which does not allow for disaggregation of Bmax and Kd values for D(1) receptor binding of [(11)C]-SCH23390.


CONCLUSIONS
The finding of downregulation of D(1) receptors in the striatum of OCD patients suggests increased nigrostriatal dopaminergic drive in OCD. If confirmed, this finding provides support for trials of novel treatments in OCD based on dopaminergic system blockade.
Olver
James S
JS
Department of Psychiatry, University of Melbourne, Heidelberg, Victoria, Australia. jamesso@unimelb.edu.au
O'Keefe
Graeme
G
Jones
Gareth R
GR
Burrows
Graham D
GD
Tochon-Danguy
Henri J
HJ
Ackermann
Uwe
U
Scott
Andrew
A
Norman
Trevor R
TR
D000328:Adult; D000368:Aged; D001552:Benzazepines / Q000493:pharmacokinetics*; D002250:Carbon Radioisotopes; D016022:Case-Control Studies; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000493:pharmacokinetics*; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000000981:diagnostic imaging / Q000378:metabolism*; D049268:Positron-Emission Tomography; D011569:Psychiatric Status Rating Scales; D011699:Putamen / Q000000981:diagnostic imaging / Q000378:metabolism*; D017447:Receptors, Dopamine D1 / Q000378:metabolism*; D055815:Young Adult
D001552:Benzazepines; D002250:Carbon Radioisotopes; D018492:Dopamine Antagonists; D017447:Receptors, Dopamine D1; C534628:SCH 23390