Figure 2. Quantitative parameters of locomotor activities and asymmetrical movements in hemiparkinsonian rats.

NMDA receptor blockers AP5 (n = 13 different rats) and CGS (n = 9), AMPA receptor blocker CNQX (n = 21), a mixture of AP5 and CNQX (A + C, n = 18), and nonselective dopamine receptor agonist apomorphine (Apo, n = 13) were locally delivered to the STN. Each drug (colored bars) had a paired control with aCSF microinfusion (black bars). Movement distance (A), movement duration (B), and rearing score (C) demonstrate movement ability. Performance of the normal rats (n = 12) is also shown for reference. Rotational bias (D), head position bias (E), and net asymmetrical climbing (F) indicate asymmetrical movements due to unilateral 6-OHDA lesions. The same parameters were also documented for systemic s.c. injection of apomorphine (Apo s.c., n = 11, gray bars) and a paired control with s.c. injection of saline (white bars). Note that NMDA, but not AMPA, receptor antagonists improved all locomotor parameters and ameliorated asymmetrical motor deficits. Subthalamic apomorphine had an effect similar to that of NMDA receptor blockers. However, systemic apomorphine induced strong paradoxical movements, which included unilateral rotation (D), paradoxical head deviation (E), and worsening of asymmetrical climbing (F). Statistical analyses were performed using a nonparametric Wilcoxon signed-rank test. Data represent the mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001.