Following the termination of the nicotine treatment all rats exhibiting increased 20% ethanol operant responding returned immediately to pretreatment operant self-administration levels (data not shown), which is consistent with previous reports (Lê et al., 2003). In contrast to these findings, studies have shown that nicotine, administered 30 minutes prior to the self-administration session (Sharpe and Samson, 2002) or after daily ethanol self-administration sessions (Nadal and Samson, 1999), reduces ethanol consumption and lever responding in rats. Furthermore, following the termination of nicotine administration, the increase (Blomqvist et al., 1996) or the decrease (Sharpe and Samson, 2002) in ethanol intake has been reported to persist for at least a week. These discrepancies could be due to experimental factors such as difference in the strain of rats, dosages used, the history of ethanol self-administration prior to nicotine treatment and/or the amount of ethanol access time given during each self-administration session following nicotine treatment.
