Differential expression of dopaminergic D2 receptor messenger RNAs during development

To define the possible roles of multiple types of dopamine D2 receptors, mRNA levels for two forms of D2 receptor were determined during a variety of developmental stages. Transcripts encoding the 444 amino acid form appear as early as embryonic day 14. In contrast, the mRNA encoding the 415 amino acid form of the receptor does not appear until embryonic day 17, and remains a minor form throughout prenatal development. The adult levels of the mRNAs of these two D2 receptor forms are not attained until long after birth.