Figure 1.

Schematic illustrating the experimental timeline. A, All rats received bilateral motor cortex microdialysis guide cannulae and underwent 6-OHDA lesion or sham surgery. After recovery, rats were treated with daily l-DOPA or vehicle (Veh), during which time motor impairment was scored using the FAS test and dyskinesia was rated with the AIMs scale. Microdialysis for glutamate and GABA was performed over 2 d. Long-term changes in basal glutamate and GABA efflux were measured on the first day of dialysis before drug injection. Rapid changes due to drug treatment were measured after l-DOPA or Veh injection on both days of dialysis. B, All rats received bilateral microinjection guide cannulae and a 6-OHDA lesion. After recovery, rats were treated with daily l-DOPA and behaviorally examined for motor impairment and dyskinesia. Later, rats received M1 microinjections (on 3 d over a 5 d period) immediately before l-DOPA treatment and were subsequently rated for FAS and AIMs.