Repeated nicotine injections decrease operant ethanol self-administration

Abstract

Nicotine and alcohol are two of the most used drugs in the United States. However, it is not clear whether the co-use of these drugs is due to pharmacological or environmental reasons, or perhaps related to both. Although results from previous studies in animal models seem to indicate that nicotine has an effect on ethanol consumption, little has been done to determine how nicotine affects appetitive and consummatory phases of ethanol self-administration. In this study, we examined the effect of repeated treatment with nicotine (0, 0.35, and 0.7 mg/kg, s.c.), given 30 min before a daily operant session, on appetitive and consummatory phases of Long–Evans rats self-administering 10% (vol./vol.) ethanol in a sipper-tube model. Ethanol intake (consummatory phase) decreased at both doses of nicotine tested, and lever pressing (appetitive phase) decreased after injection of the high dose of nicotine. These results support the suggestion that nicotine affects ethanol self-administration. However, in this model, the findings demonstrate a reduction in drinking, rather than the enhancement that has been shown in findings obtained from other studies.