General Sources of Dopamine As a Potential Morphogenic Factor in the Developing Striatum of Rats

In the striatum of rats at different stages of development, we determined the content of tyrosine hydroxylase and aromatic L-amino acids decarboxylase using double immunohistochemical labeling and estimated the expression level of their transcripts by real-time PCR. We found that, in different periods of development, there are three sources of dopamine in the striatum of rats: bienzymatic nerve fibers (throughout ontogeny), bienzymatic neurons (appear on day 18 of embryonic development), and monoenzymatic neurons (in adult animals). Dopamine, which is synthesized in the striatal neurons in the prenatal period, may function as a morphogenetic factor.