The activity-regulated cytoskeletal-associated protein arc ps expressed indifferent 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 f osB, fra, and NGFI-A, which code for transcription factors. Unlike these pr oteins, however, Are is a cytoskeletal protein expressed not only in the nu cleus of neurons but also in their dendrites. We investigated the patterns of Are expression evoked in the rat striatum by acute exposures to two psyc homotor stimulants, cocaine and amphetamine. Cocaine induced are in striata l neurons that were broadly distributed within both striosome and matrix co mpartments of the caudoputamen. Amphetamine also evoked Are expression in s triatal projection neurons, but these were heavily concentrated in the stri osomal compartment and only sparsely in the matrix compartment in the rostr al striatum. The contrasting patterns of Are expression evoked by cocaine a nd amphetamine parallel those of c-Fos, JunB, FRA, and NGFI-A expression in duced by these two psychomotor stimulants. This difference in the action of cocaine and amphetamine at the level of protein expression may be linked t o the different effects of these psychomotor stimulants on behavior.