title: Associations between dopamine D2 receptor availability and BMI depend on age.
abstract: OBJECTIVE
  The dopamine D2/3 receptor subtypes (DRD2/3) are the most widely studied neurotransmitter biomarker in research on obesity, but results to date have been inconsistent, have typically involved small samples, and have rarely accounted for subjects' ages despite the large impact of age on DRD2/3 levels. We aimed to clarify the relation between DRD2/3 availability and BMI by examining this association in a large sample of subjects with BMI spanning the continuum from underweight to extremely obese.
  
  
  METHODS
  130 healthy subjects between 18 and 81years old underwent PET with [18F]fallypride, a high affinity DRD2/3 ligand.
  
  
  RESULTS
  As expected, DRD2/3 availability declined with age. Critically, age significantly interacted with DRD2/3 availability in predicting BMI in the midbrain and striatal regions (caudate, putamen, and ventral striatum). Among subjects under 30years old, BMI was not associated with DRD2/3 availability. By contrast, among subjects over 30years old, BMI was positively associated with DRD2/3 availability in the midbrain, putamen, and ventral striatum.
  
  
  CONCLUSIONS
  The present results are incompatible with the prominent dopaminergic hypofunction hypothesis that proposes that a reduction in DRD2/3 availability is associated with increased BMI, and highlights the importance of age in assessing correlates of DRD2/3 function.
authors.affiliation: Department of Psychology, Vanderbilt University, 219 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA. Electronic address: linh.dang@vanderbilt.edu.
authors.forename: Linh C
authors.initials: LC
authors.lastname: Dang
authors.affiliation: Department of Psychology, Yale University, 2 Hillhouse Avenue, New Haven, CT 06520, USA.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Samanez-Larkin
authors.affiliation: Department of Psychology, Vanderbilt University, 219 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA.
authors.forename: Jaime J
authors.initials: JJ
authors.lastname: Castrellon
authors.affiliation: Department of Psychology, Vanderbilt University, 219 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA.
authors.forename: Scott F
authors.initials: SF
authors.lastname: Perkins
authors.affiliation: Department of Psychiatry, Vanderbilt University School of Medicine, 1601 23rd Ave South, Nashville, TN 37212, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, 1211 Medical Center Drive, Nashville, TN 37232, USA.
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Cowan
authors.affiliation: Department of Psychology, Vanderbilt University, 219 Wilson Hall, 111 21st Avenue South, Nashville, TN 37203, USA; Department of Psychiatry, Vanderbilt University School of Medicine, 1601 23rd Ave South, Nashville, TN 37212, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Zald
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D001549:Benzamides / Q000493:pharmacokinetics*; D001682:Biological Availability; D015992:Body Mass Index; D001921:Brain / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D057054:Molecular Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods; D011759:Pyrrolidines / Q000493:pharmacokinetics*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D001549:Benzamides; C094948:N-((1-allyl-2-pyrrolidinyl)methyl)-5-(3-fluoropropyl)-2,3-dimethoxybenzamide; D011759:Pyrrolidines; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3
keywords: Aging; BMI; Dopamine D2 receptor; Midbrain; Obesity; Striatum