Figure 2

Expression of Oprk1 gene in the striatum (a), hypothalamus (b), and PAG (c) in OVX female rats. The W group remained undisturbed. The SS group received saline solution 54 and 2 h before the experiments. The SM group received saline 54 h and 3.5 mg/kg morphine 2 h before the experiments. The ES group received estrogen (50 µg/kg, i.p.) 54 h before testing and saline 2 h before the experiments. The EM group received estrogen (50 µg/kg, i.p.) 54 h before testing and 3.5 mg/kg morphine 2 h before the experiments. *p < 0.05, compared with SS group. The data are expressed as mean ± SEM (ANOVA followed by Tukey’s multiple-comparison test).