title: Striatal dopamine transporter availability in unmedicated bipolar disorder.
abstract: OBJECTIVE
  Dopamine transmission abnormalities have been implicated in the etiology of bipolar disorder (BPD). However, there is a paucity of receptor imaging studies in BPD, and little information is available about the dopamine system in BPD. Reuptake of synaptic dopamine by the dopamine transporter (DAT) is the principal mechanism regulating dopamine neurotransmission, and is often used as a marker for presynaptic dopamine function. This positron emission tomography (PET) study investigated whether DAT availability differed between BPD and healthy control subjects.
  
  
  METHODS
  A total of 11 unmedicated BPD patients in either the euthymic or depressed phase and 13 closely matched healthy subjects underwent PET imaging with the DAT-selective radiotracer [(11) C]CFT and a structural magnetic resonance imaging (MRI) scan. Striatal binding potential (BP(ND) ) was estimated using the multilinear reference tissue model. Region of interest and analyses were conducted to test for differences in [(11) C]CFT BP(ND) between groups.
  
  
  RESULTS
  Unmedicated BPD subjects had significantly lower DAT availability relative to healthy controls in bilateral dorsal caudate.
  
  
  CONCLUSIONS
  The results of this study support the hypothesis that there are abnormalities in the dopaminergic system in BPD, and suggest that DAT availability may be related to the neuropathology of BPD. Future studies are needed to determine if DAT availability cycles with disease phase.
authors.affiliation: Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA. aanand@iupui.edu
authors.forename: Amit
authors.initials: A
authors.lastname: Anand
authors.forename: Gavriel
authors.initials: G
authors.lastname: Barkay
authors.forename: Mario
authors.initials: M
authors.lastname: Dzemidzic
authors.forename: Daniel
authors.initials: D
authors.lastname: Albrecht
authors.forename: Harish
authors.initials: H
authors.lastname: Karne
authors.forename: Qi-Huang
authors.initials: QH
authors.lastname: Zheng
authors.forename: Gary D
authors.initials: GD
authors.lastname: Hutchins
authors.forename: Marc D
authors.initials: MD
authors.lastname: Normandin
authors.forename: Karmen K
authors.initials: KK
authors.lastname: Yoder
mesh_terms: D000293:Adolescent; D000328:Adult; D001714:Bipolar Disorder / Q000000981:diagnostic imaging / Q000473:pathology*; D002247:Carbon Isotopes; D003042:Cocaine / Q000031:analogs & derivatives; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D011569:Psychiatric Status Rating Scales; D055815:Young Adult
chemical_list: D002247:Carbon Isotopes; D050483:Dopamine Plasma Membrane Transport Proteins; D018765:Dopamine Uptake Inhibitors; C021279:(1R-(exo,exo))-3-(4-fluorophenyl)-8-methyl-8- azabicyclo(3.2.1)octane-2-carboxylic acid, methyl ester; D003042:Cocaine