Simultaneous determination of the rates of synthesis and metabolism of dopamine in various areas of the rat brain: application to the effects of (+)-amphetamine.

A method is described in which two different dopamine turnover estimations are combined. The method is based on coadministration of a DOPA-decarboxylase inhibitor and a monoamine-oxidase inhibitor. This approach allows the simultaneous calculation of the biosynthesis rate of dopamine, as well as the formation rate of its main metabolite 3,4-dihydroxyphenylacetic acid. No mutual interference of the two turnover methods was observed. The method was applied in a dose-effect study of the influence of (+)-amphetamine on the synthesis and metabolism of dopamine.