Figure 2.

The effects of different doses of naloxone (0.05, 0.1, 0.2 and 0.4 mg/Kg; SC.) on the expression of morphine-induced place preference when challenged with the downward point dose of morphine (5 mg/Kg). Data are shown as mean ± SEM for 6-8 rats, *p < 0.05, **p < 0.01 different from the saline control group