Core body temperatures (mean ± S.E.M.; n = 5–12) of animals that received systemic injections of saline (4 × 1 mL/kg, subcutaneous at 2-hour intervals) or METH (4 × 10 mg/kg, subcutaneous at 2-hour intervals). Treatment group designations in the legend indicate PND60 treatment:PND90 treatment, resulting in the four treatment groups. Rectal temperatures were obtained 30 minutes before the first injection [baseline (BL)] and 1 hour after each subsequent injection. X-axis values represent minutes after the first injection, and arrows represent the time of each saline or METH injection. (A and C) Temperatures recorded during treatment on PND60 of animals sacrificed 1 hour (A) or 48 hours (C) after the last injection on PND90. (B and D) Temperatures recorded during treatment on PND90 of animals sacrificed 1 hour (B) or 48 hours (D) after the last injection on PND90. *P < 0.05; ***P < 0.001 indicate that groups receiving METH were significantly hyperthermic, relative to groups receiving saline.