GW842166x (GW) treatment decreased spontaneous and amphetamine-induced rotations. (a) Mice unilaterally injected with 6-OHDA exhibited an increase in spontaneous rotations compared to vehicle-injected mice (** p = 0.009, n = 13–13). GW without AM630 (AM) co-treatment did not significantly alter the number of spontaneous rotations relative to control mice (p = 0.484, n = 10–13). GW plus AM co-treatment significantly increased the number of spontaneous rotations relative to 6-OHDA controls (* p = 0.011, n = 11–13). (b) Unilateral 6-OHDA injection increased amphetamine-induced (5 mg/kg, i.p.) net rotations relative to control mice (*** p < 0.001, n = 13–13). This increase in rotations was attenuated by GW treatment (*** p < 0.001, n = 10–13), and the effect of GW was prevented by AM co-treatment (*** p = 0.004, n = 10–11).