An examination of the impact of nicotine exposure during periadolescence and early adulthood on the aversive and physiological effects of ethanol

The majority of smokers begin their habit during adolescence, which often precedes experimentation with alcohol. Interestingly, very little preclinical work has been done examining how exposure to nicotine during periadolescence impacts the affective properties of alcohol in adulthood. Understanding how periadolescent nicotine exposure influences the aversive effects of alcohol might help to explain why it becomes more acceptable to this preexposed population. Thus, Experiment 1 exposed male Sprague Dawley rats to either saline or nicotine (0.4 mg/kg, IP) from postnatal day 34 to 43 (periadolescence) and then examined changes in the aversive effects of alcohol (vehicle, 0.56, 1.0 & 1.8 g/kg, IP) in adulthood using the conditioned taste aversion (CTA) design. Changes in blood alcohol concentration (BAC), EtOH-induced hypothermia and locomotor activity were also assessed. To determine if changes seen were specific to nicotine exposure during periadolescence, the procedures were replicated in adults (Experiment 2). Nicotine preexposure during periadolescence attenuated the acquisition of the alcohol-induced CTAs (at 1.0 g/kg) and the hypothermic effects of alcohol (1.0 g/kg). Adult nicotine preexposure produced similar attenuation in alcohol's aversive (at 1.8 g/kg) and hypothermic (1.8 g/kg) effects. Neither adolescent nor adult nicotine preexposure altered BACs or locomotor activity. These results suggest that nicotine can alter the aversive and physiological effects of alcohol, regardless of the age at which exposure occurs, possibly increasing its overall reinforcing value and making it more likely to be consumed.