AbstractStudies on neuronal control mechanisms of neurotransmitters biosynthesis during the development of peripheral and centralautonomic synapses are reviewed. Particular emphasis is placed on investigations of developing peripheral sympathetic ganglia and brain in chick embryo and chick.Studies on the development of autonomic neurons and synapses under different pharmacological conditions are reported. Principally the effect of (a) the administration of drugs and precursors such L‐dopa,3H‐dopa, 6‐OH dopa; (b) the prenatal administration of reserpine; (c) the blockade of cholinergic receptors; (d) the nerve growth factor (NGF) is analyzed.Results of developmental studies on chick ciliary ganglia are summarized.The review particulary underlines the importance of combining the use of sensitive microchemical methods to pharmacological tools in exploring the development of regulatory mechanisms at the cellular