In the present study, we show that 0.8mg/kg nicotine administration in SD rats induced a steady escalation in ethanol intake that was statistically significant within the first week of nicotine pretreatment. Chronic nicotine (0.8mg/kg) caused a significant increase in ethanol intake by the third day of treatment that was maintained throughout the remainder of the treatment regimen with the average operant ethanol consumption of daily nicotine administration to be 2.09 ± 0.14 g/kg/60min. We also found that administration of a lower dose of nicotine (0.2mg/kg) induces an escalation in ethanol intake, however, this increase in ethanol intake was modest and far less robust in comparison to the higher dose. These findings support previous studies that have reported increased levels of ethanol consumption and self-administration following acute or chronic nicotine treatment (Blomqvist et al., 1996; Ericson et al., 2000; Le et al., 2000; Le et al., 2010; Le et al., 2003; Olausson et al., 2001; Potthoff et al., 1983; Smith et al., 1999). Acute administration of nicotine and ethanol has been shown to increase dopamine release in the nucleus accumbens, and when nicotine and ethanol are co-administered, there is an additive increase in dopamine release (Tizabi et al., 2007).
