The activity-regulated cytoskeletal-associated protein arc ps expressed in different striosome-matrix patterns following exposure to amphetamine and cocaine

activity-regulated, cytoskeletal-associated gene, are, is a brain-enriched immediate-early gene whose expression is rapidly induced in the striatum by dopamine receptor agonists. This rapid induction of are in the striatum is similar to that of other early response genes such as c-fos, junB, Delta fosB, fra, and NGFI-A, which code for transcription factors. Unlike these proteins, however, Are is a cytoskeletal protein expressed not only in the nucleus of neurons but also in their dendrites. We investigated the patterns of Are expression evoked in the rat striatum by acute exposures to two psychomotor stimulants, cocaine and amphetamine. Cocaine induced are in striatal neurons that were broadly distributed within both striosome and matrix compartments of the caudoputamen. Amphetamine also evoked Are expression in striatal projection neurons, but these were heavily concentrated in the striosomal compartment and only sparsely in the matrix compartment in the rostral striatum. The contrasting patterns of Are expression evoked by cocaine and amphetamine parallel those of c-Fos, JunB, FRA, and NGFI-A expression induced by these two psychomotor stimulants. This difference in the action of cocaine and amphetamine at the level of protein expression may be linked to the different effects of these psychomotor stimulants on behavior.