Age effects on serotonin receptor 1B as assessed by PET

Abstract

Previous imaging studies have suggested that there is an agerelated decline in brain serotonin (5-hydroxytryptamine) measures in healthy subjects. This paper addresses whether the availability of 5-hydroxytryptamine receptor 1B (5-HT 1B) is seen to decrease with aging via PET imaging. Methods: Forty-eight healthy control subjects (mean age ± SD, 30 ± 10 y; age range, 18-61 y; 33 men, 15 women) underwent 11C-P943 scanning on a high-resolution PET tomograph. Regions were examined with and without gray matter masking, the latter in an attempt to control for age-related gray matter atrophy on nondisplaceable binding potential (BP ND) as determined by a validated multilinear reference tissue model. Results: 5-HT 1B BP ND decreased in the cortex at an average rate of 8% per decade without and 9% with gray matter masking. A negative association with age was also observed in all individual cortical regions. Differences in the putamen and pallidum (positive association) were significant after adjustment for multiple comparisons. No sex- or race-related effects on 5-HT 1B BP ND were found in any regions. Conclusion: These findings indicate that age is a relevant factor for 5-HT 1B in the cortex of healthy adults. Copyright © 2012 by the Society of Nuclear Medicine and Molecular Imaging, Inc.