Co-stimulation of D-1/D-5 and D-2 dopamine receptors leads to an increase in c-fos messenger RNA in cholinergic interneurons and a redistribution of c-fos messenger RNA in striatal projection neurons

The anatomical subdivision of striatum in patch and matrix compartments pla ys an important role for the processing of neurotransmission through the ba sal ganglia in primates and rodents. Here we report that co-administration of D-1/D-5 and D-2 receptor agonists, which induces a heterogenous and patc hy pattern of c-Sos messenger RNA expression in striatum, stimulates c-fos messenger RNA expression in cholinergic interneurons. Moreover, this treatm ent induces c-fos messenger RNA in projection neurons containing D-1-, rath er than D-2-receptor messenger RNA. The preferential induction of c-fos mes senger RNA in patches does not depend upon a higher degree of co-localizati on between D-1 and D-2 receptors in this area, since double in situ hybridi zation experiments showed a large segregation of D-1 and D-2 receptor messe nger RNAs in the patch as well as the matrix compartments. By contrast, tre atment with a full D-1/D-5 receptor agonist up-regulates striatal c-Sos mes senger RNA homogenously and in similar proportions of D-1 and D-2 receptor messenger RNA-containing projection neurons in both medial and lateral stri atum, but has only minor effects on c-fos messenger RNA expression in choli nergic interneurons. These results provide a neuroanatomical/neurochemical correlate to the well -known behavioral interaction between dopamine D-1/D-5 agonists and dopamin e D-2 agonists. They also suggest that there may be a relation between a he terogenous, patch-enriched c-Sos messenger RNA expression and an increased expression of this immediate early gene in cholinergic interneurons. (C) 20 00 IBRO. Published by Elsevier Science Ltd. All rights reserved.