Biogenic amines in the brain of Manduca sexta during larval-pupal metamorphosis

1. The extracts of brains (cerebral ganglion) of the tobacco hornworm larvae contain octopamine, dopamine and 5-hydroxytryptamine, but not norepinephrine via analysis using a 16-channel electrochemical array HPLC system. 2. A comprehensive daily analysis reveals the patterns of biogenic amine levels in the brain during larval—pupal metamorphosis. 3. Monoamine oxidase-based amine metabolites are not present at detectable levels. N-β-Alanyldopamine is the predominant metabolite of dopamine present in the brain during the postwandering phase of the last larval stadium.