Figure 3.

Chronic cebranopadol treatment on cocaine self-administration. Two groups of rats with similar baseline of cocaine intake received cebranopadol (25 µg/kg) or its vehicle for seven consecutive sessions. The number of cocaine infusions earned by the cebranopadol-treated group decreased during treatment in respect to baseline, and returned to pretreatment level from the first day posttreatment. In the vehicle-treated group, cocaine self-administration remained stable throughout the experiment. Data are presented as mean ± SEM and show the last 2 days of pretreatment, 7 days of treatment, and 2 days of posttreatment. Statistical differences: *p < 0.05, **p < 0.01, and ****p < 0.0001 vs. the last day pretreatment.