EFFECTS OF DRUGS ON THE FORMATION OF 3-METHOXYTYRAMINE, A DOPAMINE METABOLITE, IN THE SUBSTANTIA NIGRA, STRIATUM, NUCLEUS ACCUMBENS AND TUBERCULUM OLFACTORIUM OF THE RAT

3‐Methoxytyramine (3‐MT) was assayed with a sensitive and rapid liquid chromatographic separation on a Sephadex G 10 column in combination with a fluorimetric detection in a continuous flow system. The method made it possible to measure pargyline‐induced 3‐MT concentrations in various regions of a single rat brain. After haloperidol, morphine or sulpiride treatment, pargyline‐induced 3‐MT concentrations in the striatum, nucleus accumbens, tuberculum olfactorium and substantia nigra of the rat were comparable with reported changes of homovanillic acid concentrations. Dose‐response curves for 3‐MT increase in various brain regions after (+)‐amphetamine pretreatment were studied. The effect of (+)‐amphetamine on 3‐MT formation was much more pronounced in nerve terminal areas, especially in the mesolimbic structures. The influence of apomorphine, γ‐hydroxybutyric acid, haloperidol, reserpine or combined treatment of haloperidol and (+)‐amphetamine revealed pronounced differences on regional 3‐MT concentrations, indicating important differences between the regulation of dopamine metabolism in the substantia nigra and nerve terminal areas. 1979 Royal Pharmaceutical Society of Great Britain