Influence of monoamine oxidase inhibition on the release of 3H-dopamine elicited by potassium and by amphetamine from the rat substantia nigra and corpus striatum

Abstract

The effects of monoamine oxidase inhibition on the release of 3H-dopamine induced by exposure to amphetamine or to potassium were studied in the corpus striatum and in the substantia nigra of the rat using identical in vitro experimental conditions. Marked differences between the two areas of the dopaminergic neurone were found. In the corpus striatum, release of 3H-dopamine was observed during exposure to low concentrations of amphetamine, while considerably higher concentrations of amphetamine were required to elicit 3H-dopamine release from the substantia nigra. The difference in the effects of amphetamine on the release of 3H-dopamine from the substantia nigra and the rat corpus striatum was observed independently of whether monoamine oxidase activity was intact or inhibited by pargyline. Exposure to potassium was also more effective in inducing 3H-dopamine release from the striatum than from the substantia nigra, but the difference was less pronounced than that observed for amphetamine.