NICOTINE REINFORCEMENT IN RATS WITH HISTORIES OF COCAINE SELF-ADMINISTRATION

Few reports have described conditions under which nicotine self-admini stration occurs in rats. In this study, rats which initially lever pre ssed for cocaine infusion (0.05 mg/kg) during 1 h experimental session s continued to obtain similar infusion numbers when nicotine (0.03 mg/ kg) was available. When saline was substituted for nicotine, infusions decreased from 11.8 +/- 4.5/h to 5.4 +/- 1.1/h but returned to pre-sa line levels when it was re-introduced (12.0 +/- 5.5/h). These results indicate that nicotine can serve as a positive reinforcer for rats und er the historical and schedule conditions described.