EFFECT OF VINCONATE ON THE EXTRACELLULAR LEVELS OF DOPAMINE AND ITS METABOLITES IN THE RAT STRIATUM - MICRODIALYSIS STUDIES

The effects of (+/-)-methyl-3-ethyl-2,3,3a,4-tetrahydro-1H-indolo[3,2,1-de][1,5]naphthyridine-6-carboxylate hydrochloride (vinconate), an indolonaphthyridine derivative, on the extracellular levels of dopamine and its metabolites in the rat striatum were examined using brain microdialysis. Single administration of vinconate (10, 100 mg/kg i.p.) increased the extracellular level of dopamine and its metabolites. This enhancing effect of vinconate was antagonized by scopolamine (10 mu M), a muscarinic receptor antagonist, which was added to the perfusate from 30 min before vinconate treatment. These findings suggest that vinconate, even when systemically administered, enhances the endogenous release of dopamine in the striatum, probably via the stimulation of presynaptic muscarinic receptors.