SCH 23390-induced behavioral supersensitivity is not related to striatal c-fos levels.

Stereotyped behavior and striatal c-fos levels induced by chronic treatment with the D1 dopamine antagonist SCH 23390 have been investigated in rats which received subsequent subacute dopamine agonist treatment. SCH 23390 treatment (0.5 mg/kg/day) for 21 days increased both apomorphine-induced orofacial stereotypies and striatal c-fos levels. Treatment with the D1 dopamine agonist SKF 38393 (10 mg/kg/day) and the combination of SKF 38393 with the D2 dopamine agonist quinpirole (1 mg/kg/day), for 5 consecutive days, attenuated apomorphine-induced stereotypies without changing c-fos levels in rats previously treated with SCH 23390. These findings suggest that SCH 23390-induced behavioral supersensitivity and the increased striatal c-fos levels are concomitant but unrelated phenomena.