CONVULSANT DOSES OF COCAINE ALTER IMMEDIATE-EARLY GENE AND OPIOID PEPTIDE EXPRESSION IN RAT LIMBIC FOREBRAIN

Rats were treated with escalating doses of cocaine until they experien ced a convulsion and were euthanized 1 or 3 h after the last injection . Quantitative in situ hybridization histochemistry revealed that c-fo s and zif/268 mRNAs were induced at 1 h in many limbic structures and declined 3 h after cocaine-induced convulsions. Preprodynorphin and pr eproenkephalin signals increased in many of the same structures 3 h, b ut not 1 h, after cocaine-induced convulsions.