Spinophilin KO or WT control littermates were injected with saline or d-amphetamine daily for 5 days. Immediately following injection, animals were placed in an open-field chamber and total distance traveled over 60 minutes was evaluated. Amphetamine treated WT animals had increasing levels of distance traveled on days 2–5 compared to day 1 ($ symbols). In contrast, spinophilin KO mice had no change in travel on days 2–4 and a decrease in distance traveled on day 5 (# symbol). Moreover, there was a greater distance traveled in the WT compared to KO spinophilin mice on days 3, 4, and 5 (* symbols). (#P<0.05, ** and $$ P< 0.01, *** P<0.001, and $$$$ P<0.0001).