title: Dopamine transporters, D2 receptors, and dopamine release in generalized social anxiety disorder.
abstract: BACKGROUND
  Dopamine D2 receptor and dopamine transporter (DAT) availability in the striatum (STR) have each been reported abnormal in generalized social anxiety disorder (GSAD) in studies using single photon emission computerized tomography (SPECT). D2 receptors and DAT have not previously been studied within the same GSAD subjects, however, and prior GSAD studies have not assessed dopamine release or subdivided the STR into functional subregions.
  
  
  METHODS
  Unmedicated adults with GSAD (N=17) and matched healthy comparison (HC) subjects (N=13) participated in this study. Of these, 15 GSAD and 13 HC subjects completed baseline assessment of D2 receptor availability using positron emission tomography (PET) with the radiotracer [11C]raclopride. Twelve GSAD and 13 HC subjects completed a repeat scan after intravenous administration of d-amphetamine to study dopamine release. Twelve of the GSAD subjects and 10 of the HC subjects also completed SPECT with the radiotracer [123I] methyl 3beta-(4-iodophenyl) tropane-2beta-carboxylate ([123I]beta-CIT) to assess DAT availability.
  
  
  RESULTS
  GSAD and HC groups did not differ significantly in striatal DAT availability, the overall striatal or striatal subregion D2 receptor availability at baseline, or change in D(2) receptor availability after d-amphetamine. Receptor availability and change after d-amphetamine were not significantly associated with severity of social anxiety or trait detachment.
  
  
  CONCLUSIONS
  These findings do not replicate previous findings of altered striatal DAT and D2 receptor availability in GSAD subjects assessed with SPECT. The differences from results of prior studies may be due to differences in imaging methods or characteristics of samples.
authors.affiliation: Anxiety Disorders Clinic, New York State Psychiatric Institute, Unit 69, 1051 Riverside Drive, New York, NY 10032, USA. frs1@columbia.edu
authors.forename: Franklin R
authors.initials: FR
authors.lastname: Schneier
authors.forename: Anissa
authors.initials: A
authors.lastname: Abi-Dargham
authors.forename: Diana
authors.initials: D
authors.lastname: Martinez
authors.forename: Mark
authors.initials: M
authors.lastname: Slifstein
authors.forename: Dah-Ren
authors.initials: DR
authors.lastname: Hwang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Liebowitz
authors.forename: Marc
authors.initials: M
authors.lastname: Laruelle
mesh_terms: D000328:Adult; D002250:Carbon Radioisotopes; D003042:Cocaine / Q000031:analogs & derivatives; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D003913:Dextroamphetamine; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D009042:Motivation; D009714:Nucleus Accumbens / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D010555:Personality Inventory / Q000706:statistics & numerical data; D010698:Phobic Disorders / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000523:psychology; D049268:Positron-Emission Tomography; D011594:Psychometrics; D020891:Raclopride; D017448:Receptors, Dopamine D2 / Q000187:drug effects / Q000502:physiology*; D012201:Reward; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; D050483:Dopamine Plasma Membrane Transport Proteins; D017448:Receptors, Dopamine D2; D020891:Raclopride; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine; D003913:Dextroamphetamine; D004298:Dopamine