Age-related reduction in dopamine D1 receptors in the human brain: from late childhood to adulthood, a positron emission tomography study.

Age-dependent decrease in dopamine receptor density throughout adulthood is well described, meanwhile less is known about development of dopamine system in humans and in vivo it has not been investigated. We examined dopamine D1 receptor (D1DR) binding in the cerebral cortex and striatum of 12 adolescents (mean age 13.5+/-1.8 years) and 18 young adults (25+/-2.3 years) using positron emission tomography (PET) and radioligand [(11)C]SCH23390. Over the age span of 10-30 years [(11)C]SCH23390 binding (binding potential, BP) declined in all brain regions. The rate of BP decline was age-segment and brain region dependent. Most pronounced decline in BP was observed in the cortical regions during adolescence (mean BP in adults lower by 14-26% as compared to adolescents, P<0.0001). Significantly slower rate of decline in BP was observed in two cortical regions (orbitofrontal and posterior cingulate cortices) and striatal regions. The present PET-study provides new evidence on the development of D1DR in humans in vivo which is of critical importance for understanding of the biology of neurodevelopmental disorders.