Figure 5.

A – Consumption of water (open circles) or 0.30 mg/ml MDPV solution (filled circles) during 3 hour fluid access period for 10 consecutive days. Points at “C” represent the mean fluid consumption measured over 3 days of 3 hour water access for both groups. Abscissa: consecutive days of water or 0.30 mg/ml MDPV solution availability, with water control solutions presented for both groups at the “C” point. Ordinate: Mean fluid consumption. Consumption of water was significantly greater than MDPV on day 1 (q=4.151, P<0.05), but no other between-group comparisons were significant, nor was there a significant effect of day. B – Escalating intake of MDPV over consecutive days of 0.30 mg/ml MDPV solution access. Abscissa: Consecutive days. Ordinate: Total MDPV intake during the 3 hour access period, expressed as mg/kg. Asterisks represent significant differences from day 1 consumption, and dashed line represents the best fit linear regression (r²=0.60) indicating a significant positive slope. C – Assessment of locomotor activity during 3 hour access to and for 3 hours following consumption of water (open circles) or 0.30 mg/ml MDPV solution (closed circles) over 10 consecutive days. Points at “C” represent locomotor activity measured over 3 days of water access for both groups. Abscissa: as described in panel A. Ordinate: 6 hour activity counts. MDPV consumption elicited significantly more activity than water consumption on all days except for day 9 (P<0.05 for all comparisons except day 9). D – Comparison of locomotor effects following consumption of 0.30 mg/mL MDPV on day 1 (filled circles) and day 10 (open circles) across the 24 hour recording period. The white bar from 0 min to 180 min indicates the period of MDPV availability. Abscissa: experimental time, in minutes. Ordinate: mean activity counts, expressed as 30 min sums.