Rats were prepared with nicotine or saline pumps and locomotor activity (A, B) and rearing (C, D) was investigated on day 13. A) Pound signs indicate a larger distance traveled compared to rats in the male nicotine group, plus signs indicate a larger distance traveled compared to rats in the female saline group, and asterisks indicate a larger distance traveled compared to rats in the male saline group. **, ##, ++ P<0.01; + P<0.05. N=7–8/group. Data are expressed as means ± SEM.