AROMATIC AMINO-ACID DECARBOXYLASE (AADC) IMMUNOHISTOCHEMISTRY IN VERTEBRATE BRAIN-STEM WITH AN ANTISERUM RAISED AGAINST AADC MADE IN ESCHERICHIA-COLI

Aromatic L-amino acid decarboxylase (AADC) is involved in the biosynth esis of catecholamines and indolamines. AADC is present in the nervous system, in the chromaffin cells, and in non-neuronal tissues. We test ed the capacity of a new polyclonal antibody, obtained by immunization of rabbits with a recombinant protein beta-galactosidase-AADC, to det ect monoaminergic neurons in the brainstem as well as monoaminergic pa raneurons in the adrenal medulla from goldfish, frog, skink, quail, an d mouse. In the adrenal gland we found an immunoreactivity that was co nsistent with the distributions of the chromaffin cells previously rep orted. In the brainstem, groups of immunoreactive neurons and several labelled fibers were observed in the five species studied. The raphe r egion showed cell bodies and processes similar to those previously ide ntified as monoaminergic by other authors. In addition, in medulla obl ongata and isthmic tegmentum we found, in goldfish, skink, and quail, neuronal groups similar to mammalian D groups which contain AADC but a re devoided of serotonin and catecholamines.