Relationship of striatal dopamine synthesis capacity to age and cognition.
Relationship of striatal dopamine synthesis capacity to age and cognition.
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DOI：
10.1523/jneurosci.3729-08.2008
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发表时间：
2008-12-24
期刊：
影响因子：
--
通讯作者：
Jagust WJ
中科院分区：
文献类型：
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作者：
Braskie MN;Wilcox CE;Landau SM;O'Neil JP;Baker SL;Madison CM;Kluth JT;Jagust WJ
Past research has demonstrated that performance on frontal lobe-dependent tasks is associated with dopamine system integrity, and that various dopamine system deficits occur with aging. The positron emission tomography (PET) radiotracer 6-[18F]-fluoro-L-m-tyrosine (FMT) is a substrate of the dopamine-synthesizing enzyme, aromatic amino acid decarboxylase (AADC). Studies using 6-[18F]fluorodopa (FDOPA) (another AADC substrate) to measure how striatal PET signal and age relate have had inconsistent outcomes. The varying results occur in part from tracer processing that renders FDOPA signal subject to aspects of post-release metabolism, which may themselves change with aging. In contrast, FMT remains a purer measure of AADC function. We used partial volume corrected FMT PET scans to measure age-related striatal dopamine synthesis capacity in 21 older (mean 66.9) and 16 younger (mean 22.8) healthy adults. We also investigated how striatal FMT signal related to a cognitive measure of frontal lobe function. Older adults showed significantly greater striatal FMT signal than younger adults. Within the older group, FMT signal in dorsal caudate (DCA) and dorsal putamen (DPUT) was greater with age, suggesting compensation for deficits elsewhere in the dopamine system. In younger adults, FMT signal in DCA was lower with age, likely related to ongoing developmental processes. Younger adults who performed worse on tests of frontal lobe function showed greater FMT signal in right DCA, independent of age effects. Our data suggest that higher striatal FMT signal represents non-optimal dopamine processing. They further support a relationship between striatal dopamine processing and frontal lobe cognitive function.
