Abstract
AbstractAlterations in serotonin (5-HT) function have been hypothesized to underlie a range of physiological, emotional, and cognitive changes in older age. Here, we conducted a quantitative synthesis and comparison of the effects of age on 5-HT receptors and transporters from cross-sectional PET and SPECT imaging studies. Random-effects meta-analyses of 31 studies including 1087 healthy adults yielded large negative effects of age in 5-HT-2A receptors (largest in global cortex), moderate negative effects of age in 5-HT transporters (largest in thalamus), and small negative effects of age in 5-HT-1A receptors (largest in parietal cortex). Presynaptic 5-HT-1A autoreceptors in raphe/midbrain, however, were preserved across adulthood. Adult age differences were significantly larger in 5-HT-2A receptors compared to 5-HT-1A receptors. A meta-regression showed that 5-HT target, radionuclide, and publication year significantly moderated the age effects. The findings overall identify reduced serotonergic signal transmission in healthy aging. The evidence for the relative preservation of 5-HT-1A compared to 5-HT-2A receptors may partially explain psychological age differences, such as why older adults use more emotion-focused rather than problem-focused coping strategies.
Publisher
Cold Spring Harbor Laboratory
Reference63 articles.
1. Aghajanian, G.K. , 1995. Electrophysiology of serotonin receptor subtypes and signal transduction pathways., in: Bloom, F.R. , Kupfer, D.J . (Eds.), Psychopharmacology: The Fourth Generation of Progress. Raven, New York, pp. 1451–1459.
2. 123 I-5-I-R91150, a new single-photon emission tomography ligand for 5-HT 2A receptors: influence of age and gender in healthy subjects
3. A review of central 5-HT receptors and their function
4. Operating Characteristics of a Rank Correlation Test for Publication Bias
5. A basic introduction to fixed-effect and random-effects models for meta-analysis