RGS mRNA expression in rat striatum: modulation by dopamine receptors and effects of repeated amphetamine administration.

摘要: Single injections of cocaine, amphetamine, or methamphetamine increased RGS2 mRNA levels in rat striatum by two- to fourfold. The D1 dopamine receptor-selective antagonist SCH-23390 had no effect itself but strongly attenuated induction amphetamine. In contrast, the D2 raclopride induced when administered alone and greatly enhanced stimulation To examine effects repeated amphetamine on expression, rats were treated with escalating doses (1.0-7.5 mg/kg) for 4 days, followed 8 days multiple daily (7.5 mg/kg/2 h x four injections). Twenty hours after last injection animals challenged vehicle killed 1 later. drug-naive animals, acute expression RGS2, 3, 5 immediate early genes c-fos zif/268. RGS4 not affected. Prior treatment suppressed RGS5 a challenge dose sharp prior exposure did reduce RGS3 mRNAs indicating that control these is resistant amphetamine-induced tolerance. These data establish role receptors regulation suggest 3 might mediate some aspects