Biochemical and developmental studies of acetylcholine metabolism in the central nervous system of the moth Manduca sexta

1. Acetylcholine and its biosynthetic and degradative enzymes (choline acetyltransferase and acetylcholinesterase, respectively) were quantified in several defined structures from the central nervous system of the tobacco hornworm Manduca sexta at various times during postembryonic development. 2. Activity of choline acetyltransferase, the key enzyme of the cholinergic pathway, changes roughly synchronously and similarly in the protocerebrum and subesophageal, prothoracic, and third abdominal ganglia, and it increases dramatically in developing antennal and optic lobes. 3. Levels of acetylcholine and of specific acetylcholinesterase, which is the principal cholinesterase in the nervous system, also rise greatly during metamorphosis of the central nervous regions. 4. The major changes in the activity of choline acetyltransferase correlate with known developmental endocrine events.