Fig. 3.

Dose-response curves for morphine to induce locomotor sensitization 3 days after its repeated administration in adolescent, late adolescent, and adult male C57/BL6J mice. Ordinate: sensitization, measured by the difference between the area under the curve (AUC) for the morphine dose-response curve obtained after repeated treatment with morphine and the morphine dose-response curve obtained after repeated treatment with saline (shown in Fig. 2). Abscissa: dose of morphine that was administered repeatedly. Dose-response data were analyzed by fitting straight lines through the ascending and descending parts of the curves.