13 research outputs found
Effect of Various Centrally Acting Drugs on the Efflux of Dopamine Metabolites from the Rat Brain
The influence of chlorpromazine, haloperidol, morphine, chloral hydrate, Îłâbutyrolactone, probenecid, kainic acid, oxotremorine, pargyline, yohimbine, (+)âamphetamine, and cocaine on the efflux rate of 3,4âdihydroxyphenylacetic acid (DOPAC) from four brain areas was studied. All drugs studied except pargyline and morphine had an effect on the transport of DOPAC and homovanillic acid (HVA) from the brain. Nine drugs inhibited the efflux of DOPAC and HVA, whereas (+)âamphetamine stimulated this transport. These data suggest that most centrally acting drugs can interfere with the elimination of 3,4âdihydroxyphenylethylamine (DA or dopamine) metabolites from the brain. These effects are heterogeneously distributed throughout the brain and are probably related to indirect nonspecific drug effects. This implies that drugâinduced changes in DA metabolite concentrations, especially when these changes are slight to moderate, cannot directly be translated to changes in the production rate of these metabolites. By studying five control groups, we concluded that formation and transport of DOPAC are not synchronized in the various brain area