Developmental and age-related changes of dopamine transporter, and dopamine D1 and D2 receptors in human basal ganglia

The developmental and age-related changes of the dopamine transporter (DAT) , and the dopamine D1 and D2 receptor (D1R and D2R) subtypes were investiga ted in basal ganglia (BG) of human brain. DAT immunostaining was mainly obs erved in the neuropil, neurons, and glia of the striatum. The DAT-positive neuropil was detectable at 32 GW, a peak being reached at 9-10 years of age , with a decrease to 50-63 years of age. The developmental pattern of DAT i mmunoreactivity in neuron was similar to that of the neuropil. DAT-positive glia were observed in the BG at 32 GW, which increased slightly at 38-40 G W, and then did not obviously change until 6-8 months after birth. D2R-posi tive neurons were clearly observed at 19 GW, a peak being reached at 32 GW and 1-3 months of age in the globus pallidus and striatum, respectively, wi th a decrease after 9-10 years of age. DIR was expressed as early as D2R, b ut decreased after 6-8 months. Our results suggest that DIR and D2R express ion is an intrinsic property of striatal neurons and is independent of dopa minergic innervation. DIR may play a more important role in neuronal matura tion of the BG than D2R. D2R may be closely correlated with late neuronal d evelopment. The higher expression of DAT during adolescence may be related to function of the BG which learns complex behavioral patterns. The signifi cance of the age-related decreases in DAT, DIR and D2R in the BG remains to be further investigated. (C) 1999 Published by Elsevier Science B.V. All r ights reserved.