Nicotine-induced conditioned place preference and conditioned place aversion in mice.

The motivational effects of nicotine were examined in mice using an unbiased place conditioning design. Swiss-Webster mice received four 15-min parings of a tactile stimulus with different doses of nicotine (0.25-2.0 mg/kg, IP). A different tactile stimulus was paired with saline injections. During conditioning, nicotine produced locomotor depression at the 2.0-mg/kg dose, with the greatest reduction in activity occurring during the latter part of each nicotine conditioning session. After four trials, nicotine produced increases in locomotor activity during the initial part of the nicotine sessions at doses 0.5 mg/kg or above. Upon testing, nicotine-induced conditioned place preference was noted in mice receiving 0.5 mg/kg nicotine. Conditioned place aversion was noted in mice receiving 2.0 mg/kg nicotine whereas doses of 0.25 and 1.0 mg/kg produced no conditioning. These results indicate that nicotine has dose-dependent rewarding and aversive effects measured in an unbiased place conditioning paradigm using mice.