Aromatic L-amino-acid decarboxylase (DOPA decarboxylase) gene expression in dopaminergic and serotoninergic cells of the rat brainstem.

In situ hybridization was performed in the rat brain to detect aromatic L-amino acid decarboxylase (AADC) mRNA using 35S-labeled oligonucleotide probes derived from rat kidney AADC cDNA. Results demonstrated AADC mRNA in areas containing dopaminergic and serotoninergic cell bodies. Combined immunohistochemistry for tyrosine- or tryptophan hydroxylase and in situ hybridization for AADC mRNA demonstrated the dopaminergic or serotoninergic nature of cells containing AADC mRNA. Tyrosine hydroxylase-positive mesencephalic neurons containing a very low or no AADC mRNA signal were also observed.