Quinpirole attenuates the striatal immediate early gene expression, but not the hyperactivity, induced by the serotonin agonist RU-24969

Systemic administration of the mixed 5-HT1A/1B agonist RU-24969 has been sh own to produce a dramatic increase in locomotor activity and to induce robu st c-Fos expression in the rat striatum. Previous studies have also shown t hat pretreatment with the D-2-like dopamine agonist quinpirole virtually ab olishes RU-24969-induced striatal c-Fos expression. The present study was u ndertaken to determine whether the effects of RU-24969 on immediate early g ene expression extend to the additional Fos family transcription factors Fo sB and Fra-2. Additionally, this study quantitatively examined the effect o f quinpirole pretreatment on the ability of RU-24969 to induce both locomot or hyperactivity and striatal immediate early gene expression. RU-24969 alo ne produced elevations in locomotor activity and induced clear expression o f c-Fos, FosB and Fra-2 throughout the entire striatal complex. Quinpirole pretreatment virtually abolished RU-24969-induced expression of all three t ranscription factors, but did not alter the elevated locomotor activity pro duced by RU-24969. These results demonstrate that the effects of RU-24969 o n locomotor activity can be dissociated from its effects on immediate early gene expression within the striatum. (C) 2000 Elsevier Science B.V. All ri ghts reserved.