Preexposure effects of nicotine and acetaldehyde on conditioned taste aversion induced by both drugs

Previous assessments have demonstrated an interaction between ethanol and n icotine in the conditioned taste-aversion (CTA) paradigm. The present study assessed whether acetaldehyde, the primary reinforcing metabolite of ethan ol, would interact with nicotine as well. In six experiments, water-deprive d male Wistar rats were preexposed to either acetaldehyde (0.2 or 0.3 g/kg, IP) or nicotine (0.8, 1.2, or 2 mg/kg, SC) for 3 consecutive days and then subsequently conditioned, 24 h later, with either nicotine (0.8, 1.2, or 2 mg/kg, SC) or acetaldehyde (0.2 or 0.3 g/kg, IF), respectively. There were 4 conditioning days and 4 drug-free test days, each spaced 72 h apart. On test days. animals were offered a free choice between water and saccharin. The results of the following set of experiments demonstrated a dose-related interaction between nicotine and acetaldehyde, where lower doses of each d rug failed to attenuate CTA induced by one another, but a higher nicotine d ose (2 mg/kg) attenuated the formation of a CTA induced by acetaldehyde (0. 3 g/kg). It was argued that the primary metabolite of ethanol may play a ro le in the interaction between nicotine and ethanol previously observed. (C) 2000 Elsevier Science Inc.