Figure 1.

Experimental design. Separate groups of adolescent (postnatal day (PD)-35) and adult (PD70) female C57BL/6 mice received vehicle (VEH) or fluoxetine (FLX; 250 mg/mL, in their drinking water) for 15 consecutive days. Twenty-one days later, mice were tested on their preference for cocaine (0, 2.5, 5, or 7.5 mg/kg) using the place conditioning test, or sucrose (1%) preference using the two-bottle choice test. Specifically, (a) adolescent FLX pretreated animals initiated behavioral testing at PD70, while (b) adult FLX pre-exposed mice initiated behavioral testing at PD105.