Fig. 4: Effect of HF diet and adiposity on AMPH-induced locomotor activity and AMPH levels in plasma and brain.

A The baseline locomotor activity was lower in WT mice fed the HF diet (HF), compared to those that were given limited access to HF diet (LMHF). n = 8/group. B The normalized locomotor response to AMPH is higher in HF mice compared to Chow or LMHF mice. Two-way ANOVA with RM revealed a significant effect of time (p < 0.0001), a significant effect of group (p = 0.0015), as well as a significant interaction between the time X group (p = 0.0001). Different letters indicate statistically significant differences (p < 0.05) at individual time points based on Bonferroni post-hoc testing. C Adiposity (% Fat Mass) values for each mouse used for locomotor testing. D Correlation between % fat mass and AMPH locomotor activity for mice in all three groups falls just outside the significance threshold (p = 0.0568). E Limiting correlation to HF mice yields a p value (0.0466) just within the threshold for significance. F Adiposity (% Fat Mass) values for each mouse used for determination of amphetamine levels are shown. Adiposity of the HF group is significantly greater than that of the LMHF group. n = 6/group. G Panel at left shows that plasma amphetamine levels are higher in Chow or HF groups compared to LMHF group. The right panel shows a strong correlation between % fat mass and plasma amphetamine levels (p < 0.0001). H Panel at left shows that brain amphetamine levels in the HF group are higher than those in the LMHF group. The panel at right shows a strong correlation between % fat mass and brain amphetamine levels (p = 0.0005).