(Left panel) Discriminative stimulus effects of cocaine, mephedrone, naphyrone, MDMA, METH, and morphine in mice trained to discriminate 10 mg/kg cocaine from saline. Abscissa: SAL represents test injection of saline and TD represents administration of the cocaine training dose. Numbers refer to doses of drugs during substitution sessions, expressed as milligram per kilogram on a log scale. Ordinate: percent of total responses emitted on the cocaine-appropriate lever. (Right panel) Response rates following administration of saline, cocaine, mephedrone, naphyrone, MDMA, METH, or morphine during substitution sessions. The abscissa is as described above. Ordinate: response rates, expressed as lever presses per second. Asterisks adjacent to points indicate generalization at this dose. Errors bars depict means ±SEM. The “n = 4” designation indicates only four mice were included in the data point (responding was suppressed in one mouse at 10 mg/kg MDMA).