Developmental regulation of the dopamine D₁ receptor in human caudate and putamen

Perturbations in the developmental regulation of the dopaminergic system have been hypothesized to participate in the age-dependent onset of schizophrenia. Although data from studies of non-human primates suggest that dopamine D₁-like receptors decrease during adolescence, less information is available concerning changes in human brain. The present study employed quantitative receptor autoradiography to measure D₁-like receptor density and affinity in human caudate and putamen. Samples were obtained postmortem from 15 subjects (9 weeks to 49 years), and grouped a priori into three classes: infants, adolescents, and adults. Receptor density and affinity were assessed by saturation binding with [³H]-SCH23390, a D₁ receptor antagonist. A decrease in D₁ receptor density was observed from infancy to adulthood, with no change in receptor affinity. The temporal pattern of D₁- like receptor expression during maturation may play a role in the interaction of dopamine with other neurotransmitter systems, and in the occurrence and pharmacotherapy of neurological and neuropsychiatric disorders.