title: Serotonin 2A receptors in obsessive-compulsive disorder: a positron emission tomography study with [11C]MDL 100907.
abstract: BACKGROUND
  Serotonergic abnormalities are hypothesized to contribute to obsessive-compulsive disorder (OCD). This study used positron emission tomography with the radioligand [11C]MDL 100907 to examine whether the distribution of serotonin 2A (5-HT(2A)) receptors is altered in OCD.
  
  
  METHODS
  Nineteen OCD subjects, free of psychiatric medications and depression, and 19 matched healthy subjects underwent positron emission tomography scans following injection of [11C]MDL 100907. Total distribution volumes were derived by kinetic analysis using the arterial input function. Two measures of 5-HT(2A) availability were computed: the ratio at equilibrium of specifically bound radiotracer either to nondisplaceable radiotracer in tissue (BP(ND)) or to unmetabolized tracer in arterial plasma (BP(p)). Groups were compared using a region of interest (ROI) analysis and voxelwise analysis of spatially normalized parametric maps. ROIs included cortical (orbitofrontal, dorsolateral prefrontal, medial prefrontal, anterior cingulate, temporal, parietal, occipital, and insular cortex) and limbic (entorhinal cortex, parahippocampal gyrus, and medial temporal lobe) regions.
  
  
  RESULTS
  No significant group differences were observed in [11C]MDL 100907 BP(ND) or BP(p) in the ROIs or in the voxelwise analysis of BP(ND) maps. There was a significant correlation in the orbitofrontal cortex between [11C]MDL 100907 binding and age of onset, with earlier age of onset associated with higher binding.
  
  
  CONCLUSIONS
  Adults with OCD are not characterized as a group by major changes in 5-HT(2A) availability in cortical or limbic brain regions. Further research is warranted to examine potential differences in 5-HT(2A) availability between early- and late-onset OCD and to assess 5-HT(2A) function in relation to other neurotransmitter systems implicated in OCD.
authors.affiliation: Department of Psychiatry, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA. simpson@nyspi.columbia.edu
authors.forename: Helen Blair
authors.initials: HB
authors.lastname: Simpson
authors.forename: Mark
authors.initials: M
authors.lastname: Slifstein
authors.forename: James
authors.initials: J
authors.lastname: Bender
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Xu
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hackett
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Maher
authors.forename: Anissa
authors.initials: A
authors.lastname: Abi-Dargham
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D005260:Female; D005464:Fluorobenzenes; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007553:Isotope Labeling; D008032:Limbic System / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009771:Obsessive-Compulsive Disorder / Q000000981:diagnostic imaging* / Q000378:metabolism; D010880:Piperidines; D049268:Positron-Emission Tomography; D011569:Psychiatric Status Rating Scales; D019275:Radiopharmaceuticals; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism / Q000502:physiology*; D012702:Serotonin Antagonists; D055815:Young Adult
chemical_list: D005464:Fluorobenzenes; D010880:Piperidines; D019275:Radiopharmaceuticals; D044402:Receptor, Serotonin, 5-HT2A; D012702:Serotonin Antagonists; C079049:volinanserin