SOME NEURONS OF THE MOUSE CORTEX AND CAUDO-PUTAMEN CONTAIN AROMATIC L-AMINO-ACID DECARBOXYLASE BUT NOT MONOAMINES

Neurons containing the enzyme aromatic L-amino acid decarboxylase (AADC) but lacking tyrosine hydroxylase, dopamine and serotonin were found for the first time in the cortex and caudoputamen (CP) of 1 month-old mice by light and electron microscopic immunocytochemistry. These AADC-like immunoreactive cells appeared from postnatal (P) 12 days, reached maximum in number at P30 days and reduced cell numbers till the adult stage. The majority of these cells in the cortex localized in layers III approximately IV. On the other hand, no particular topography was found in the distribution of these cells which were clustered throughout the CP. Ultrastructurally AADC-like immunoreactivity was found in the thin neuronal cytoplasm but not in the nucleus, Golgi apparatus, mitochondria, nor glia.