title: Age-related decline in striatal dopamine transporter binding with iodine-123-beta-CITSPECT.
abstract: The effect of age on human striatal dopamine (DA) transporters was investigated with SPECT using the ligand [123I]2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([123I]beta-CIT).
  
  
  METHODS
  Iodine-123-beta-CIT binding in the striatum was examined in 28 healthy human subjects (14 men, 14 women) who ranged in age from 18 to 83 yr. Following injection with [123I]beta-CIT (mean +/- s.d. = 9.9 +/- 1.2 mCi), subjects were scanned with the brain-dedicated CERASPECT camera. A reconstructed transaxial slice 13.3-mm thick at the level of maximal striatal activity was used to determine tracer uptake in striatal and occipital regions of interest. The stability of regional uptake on Day 2 (approximately 18-24 hr postinjection) permitted estimation of the specific-to-nondisplaceable equilibrium partition coefficient: V3", calculated as (striatal--occipital)/occipital uptake at equilibrium.
  
  
  RESULTS
  Values of V3" ranged from 3.6 to 11.4 for this sample (6.7 +/- 1.9). V3" showed a significant inverse correlation with age (r = -0.73, n = 28, p < 0.0001). Linear regression analysis revealed that V3" declined by 51% over the age range studied or approximately 8% per decade.
  
  
  CONCLUSIONS
  These findings confirm postmortem reports of dopamine transporter loss with aging. In vivo methodologies may permit the age-related degeneration of dopamine nerve terminals to be studied in relation to the cognitive and motor deficits that occur in normal aging.
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: van Dyck
authors.forename: J P
authors.initials: JP
authors.lastname: Seibyl
authors.forename: R T
authors.initials: RT
authors.lastname: Malison
authors.forename: M
authors.initials: M
authors.lastname: Laruelle
authors.forename: E
authors.initials: E
authors.lastname: Wallace
authors.forename: S S
authors.initials: SS
authors.lastname: Zoghbi
authors.forename: Y
authors.initials: Y
authors.lastname: Zea-Ponce
authors.forename: R M
authors.initials: RM
authors.lastname: Baldwin
authors.forename: D S
authors.initials: DS
authors.lastname: Charney
authors.forename: P B
authors.initials: PB
authors.lastname: Hoffer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives*; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D002352:Carrier Proteins; D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine; D004298:Dopamine