This study evaluates the effects of age on DA D2 receptors in extrastriatal regions. DA D2 receptor availability was evaluated in 42 healthy male subjects (mean age 41±16, range 21 - 86 year old) with positron emission tomography (PET) and [11C]raclopride. Estimates of B(max.)/K(d) were obtained using the ratio of the distribution volume in the region of interest (caudate, putamen, thalamus, frontal, occipital cortices, temporal insula, cingulate and orbitofrontal gyri) to that in cerebellum. Correlations between age and D2 receptors were significant in putamen (r = -0.58, p ≤ 0.0001), caudate (r = -0.54, p ≤ 0.0002), thalamus (r = -0.33, p ≤ 0.03) and temporal insula (r = -0.39, p ≤ 0.01) but not in any of the frontal regions. The decrease in DA D2 receptor availability was 6.6% per decade in caudate, 8.2% in putamen, 7.6% in thalamus and 13% in temporal insula. This study indicates that D2 losses with age are not limited to striatum and involve also thalamic as well as temporal cortical regions.
- extrastriatal dopamine receptors
- positron emission tomography
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)