SHORT-TERM COCAINE SELF-ADMINISTRATION ALTERS STRIATAL GENE-EXPRESSION

Rats self-administered cocaine or received saline during 3 daily 5 h s essions and were euthanized 1 h after the final session. Quantitative in situ hybridization revealed that cocaine self-administration increa sed levels of preprodynorphin, but not preproenkephalin, c-fos, or zif /268 mRNAs in a patchy pattern in the dorsal striatum. These data demo nstrate that the regulation of preprodynorphin gene expression is diss ociable from that of c-fos and zif/268 in dorsal striatum following sh ort-term cocaine self-administration.