Fig. 2.

Influence of metyrapone on the expression of nicotine-induced CPP in stressed rats after 2 days of conditioning. Rats were subjected to the CUMS protocol for 21 days. Place preference procedure consisted of pre-conditioning, two conditioning sessions with nicotine (0.175 mg/kg, i.p.) and post-conditioning test. Metyrapone (50 mg/kg) was administered on the test day 60 min before the test. Data represent means ± S.E.M. and are expressed as the difference (in s) between post-conditioning and pre-conditioning time spent in the drug-associated compartment. n = 8–12 rats per group; ***P < 0.001 vs. stressed saline-conditioned rats; #P < 0.05 vs. stressed nicotine-conditioned rats (Tukey’s test)