Top panels – Locomotor effects of 10 mg/kg MDPV when preceded by 3 days of pretreatment with saline (circles), 100 mg/kg p-CPA (triangles), or 100 mg/kg α-MPT (squares) at an ambient temperature of 20°C (left panel, white symbols) or 28°C (right panel, black symbols) in NIH Swiss mice (n=5–6). Abscissa: ‘BL’ denotes 30 min baseline data before injection. Numbers refer to time, in minutes, following MDPV administration. Ordinate: mean activity counts calculated in 30 min bins. Lower panel – Locomotor effects of MDPV following pretreatment with saline or a monoamine synthesis inhibitor at an ambient temperature of 20°C (white bars) or 28°C (black bars). Abscissa: ‘SAL,’ ‘p-CPA,’ and ‘α-MPT’ represent MDPV challenge data in mice pretreated as described above. Ordinate: mean total activity recorded across the 6 hours immediately following MDPV administration.