Figure 3.

Rotational behavior in response to amphetamine (4 mg/kg) was tested pretransplantation (pre TP) and at 5, 7, and 9 weeks postgrafting. A significant decrease in absolute numbers of amphetamine-induced turning was seen in animals with ES cell neural DA grafts in the striatum (n = 9) compared with control animals that received sham surgery (n = 13). Animals with sham surgery showed no change in rotational score over time (t = 1.51, P = 0.14). In contrast, animals with ES cell-derived neural grafts showed a significant reduction in rotations over time (t = −5.16, P < 0.001). We then examined at what time point rotational decrease was reduced significantly compared with pretransplantation scores. Because we performed post hoc comparisons, Bonferroni correction was applied to the significance criterion (adjusted criterion, P = 0.05/3 = 0.017). At 5 weeks postgrafting, ES cell-grafted animals showed no significant difference in rotations compared with pretransplantation scores (808 ± 188 vs. 924 ± 93 rotations, t = −0.62, P = 0.58). However, a clear and significant difference was evident at 7 weeks (530 ± 170 vs. 924 ± 93 rotations, t = −3.66, P = 0.0064) and further at 9 weeks (413 ± 154 vs. 924 ± 93 rotations, t = −4.30, P = 0.0026). *, P < 0.01.