Fig. 4.

Mean values (n = 8; ±1 SEM) are shown from the self-administration sessions for trials worked for drug (upper left), trials worked for money (upper right), money earned (lower left), and trials not worked (lower right) which are displayed as a function of tradipitant and oxycodone dose condition. There was a main effect of oxycodone for all four outcomes (trials worked for drug F_(2,14) = 38.4, p < 0.0001; trials worked for money F_(2,14) = 5.2, p = 0.02; money earned F_(2,14) = 5.2, p = 0.02; trials not worked F_(2,14) = 16.2, p = 0.0002). Asterisks (*) indicate a significant difference from the placebo within tradipitant dose condition (Tukey post hoc, p < 0.05)