Effects of chronic bupropion on interstitial concentrations of dopamine in rat nucleus accumbens and striatum.

Bupropion is a novel atypical antidepressant that inhibits dopamine (DA) uptake. The present experiments investigated the effects of acute (10 mg/kg, twice daily for 2 days) and chronic (10 mg/kg, twice daily for 21 days) bupropion treatment on interstitial DA concentrations using simultaneous in vivo microdialysis in the nucleus accumbens (NAC) and striatum of awake freely moving rats. Compared to animals that had not previously been exposed to the drug, bupropion (25 mg/kg, IP) induced increases in extracellular DA were significantly enhanced in the NAC of the chronic but not the acute bupropion group. This effect was regionally selective, as it was not observed in the striatum. In accordance with previous reports, concurrent behavioral measurements indicated that the locomotor stimulant effects of bupropion were also enhanced in the chronic group. These results demonstrate that bupropion-induced behavioral sensitization is accompanied by a selective potentiation of the effects of this compound on interstitial DA concentrations in the NAC.