REGULATORS OF G-PROTEIN SIGNALING - RAPID CHANGES IN MESSENGER-RNA ABUNDANCE IN RESPONSE TO AMPHETAMINE

This study examined mRNAs encoding regulators of G protein signaling ( RGSs) expressed within the striatum and determined whether their expre ssion in the caudate putamen was altered by amphetamine. RT-PCR techni ques were used to clone cDNA probes of RGSs expressed within the rat s triatum. Northern blot analysis of caudate putamen and nucleus accumbe ns RNA determined the relative abundance of RGS mRNA expressed within the caudate putamen and adjacent nucleus accumbens to be RGS 2 > RGS 5 > RGS 16 > RGS 4 = RGS 9 > RGS 8 = RGS 3. A single injection of amphe tamine rapidly and transiently induced RGS 2 mRNA. The temporal patter n of induction of RGS 2 strongly resembled that of the immediate early gene c-fos. Levels of mRNAs of RGS 3 and 5 steadily increased over a 4-h interval, as did that of the 6.6-kb transcript of RGS 8. The level of RGS 9 mRNA, which shows strong striatal-specific expression, stead ily decreased over a 4-h interval, whereas RGS 4 and 16 and the 3.9-kb transcript of RGS 8 were not significantly affected at any point exam ined. The ability of amphetamine to alter RGS mRNA expression within t he caudate putamen suggests these proteins may play an important role in adaptive processes to psychostimulant exposure.