title: Asymmetry in dopamine D(2/3) receptors of caudate nucleus is lost with age.
abstract: Molecular and functional imaging techniques reveal evidence for lateralization of human cerebral function. Based on animal data, we hypothesized that asymmetry in dopamine neurotransmission declines during normal aging. In order to test this hypothesis, we measured dopamine D2/3 receptor availability with [18F]desmethoxyfallypride-PET (DMFP) in putamen and caudate nucleus (NC) of 21 healthy, right-handed males (24-60 years; 35+/-10). For volumetric analysis, high-resolution T1-weighted MR-images were obtained in 18 of the PET-subjects in order to assess possible age-related decreases in NC and putamen volume. The calculated DMFP binding potentials (BP) showed a right-ward asymmetry in NC of young subjects that decreased with age (r = 0.577, p = 0.006; Pearson correlation; two-tailed). An age-independent analysis showed a right-ward asymmetry in NC of the whole subject group (left: 1.49+/-0.35; right: 1.65+/-0.43 [mean+/-S.D.]; p = 0.020). No such side lateralization or age-effects could be found in the putamen. Volumes tended to be asymmetric in the putamen (right: 4.85+/-0.56 cm3; left: 4.64+/-0.86 cm3 [mean+/-S.D.]; p = 0.063), but not in NC. The decline of putamen volume during aging was significant in the right putamen (r = -0.613; p = 0.007; Pearson correlation; two-tailed). There were no other significant correlations between striatal volumes and age or BP. Because ventral striatal dopamine neurotransmission is involved in cognitive processes, this loss of physiological asymmetry in NC dopamine transmission during aging might be involved in age-related declines of cognitive performance.
authors.affiliation: Department of Psychiatry and Psychotherapy, RWTH Aachen University, Germany Pauwelsstrasse 30, 52074 Aachen, Germany. ivernaleken@ukaachen.de
authors.forename: Ingo
authors.initials: I
authors.lastname: Vernaleken
authors.forename: Carsten
authors.initials: C
authors.lastname: Weibrich
authors.forename: Thomas
authors.initials: T
authors.lastname: Siessmeier
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Buchholz
authors.forename: Frank
authors.initials: F
authors.lastname: Rösch
authors.forename: Andreas
authors.initials: A
authors.lastname: Heinz
authors.forename: Paul
authors.initials: P
authors.lastname: Cumming
authors.forename: Peter
authors.initials: P
authors.lastname: Stoeter
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gründer
mesh_terms: D000328:Adult; D000375:Aging / Q000378:metabolism*; D002421:Caudate Nucleus / Q000000981:diagnostic imaging / Q000378:metabolism*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000378:metabolism*; D012457:Salicylamides / Q000493:pharmacokinetics*; D014018:Tissue Distribution
chemical_list: D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; D012457:Salicylamides; C100958:desmethoxyfallypride