Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2002-7-11
pubmed:abstractText
In the present study, age-related changes in the striatal dopaminergic system were examined in the living brains of conscious young (6.2 +/- 1.5 years old) and aged (20.2 +/- 2.6 years old) monkeys (Macaca mulatta) using positron emission tomography (PET). L-[beta-(11)C]DOPA and [(11)C]beta-CFT were applied to determine dopamine presynaptic functions such as synthesis rate and transporter (DAT) availability, respectively. Striatal dopamine D(1)- (D(1)R) and D(2)-like receptor (D(2)R) binding were measured with [(11)C]SCH23390 and [(11)C]raclopride, respectively. Although the markers of presynaptic terminals showed parallel age-related declines, the reduction of dopamine synthesis rate measured with L-[beta-(11)C]DOPA was slightly smaller than that of DAT determined with [(11)C]beta-CFT. The binding of [(11)C]raclopride to D(2)R in vivo was significantly reduced with aging, while that of [(11)C]SCH23390 to D(1)R showed no such marked age-related reduction. When the DAT inhibitor GBR12909 (0.5 and 5 mg/kg) was administered, DAT availability, dopamine synthesis, and D(2)R binding were significantly decreased in a dose-dependent manner in both age groups; however, the degrees of the decreases in these parameters were significantly higher in young rather than in aged animals. Dopamine concentration in the striatal extracellular fluid (ECF), as measured by microdialysis, was increased by administration of GBR12909 in a dose-dependent manner and the degree of the increase in dopamine level decreased with age. These results demonstrate that age-related changes of dopamine neuronal functions were not limited to the resting condition but were also seen in the functional responses to the neurotransmitter modulation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0887-4476
pubmed:author
pubmed:copyrightInfo
Copyright 2002 Wiley-Liss, Inc.
pubmed:issnType
Print
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
38-45
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Age-related changes in the striatal dopaminergic system in the living brain: a multiparametric PET study in conscious monkeys.
pubmed:affiliation
Central Research Laboratory, Hamamatsu Photonics K.K., Shizuoka 434-8601, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't