FIGURE 1.

Schematic representation of the experimental design. At the beginning of the three experiments, animals received a vehicle or 6‐OHDA injection into the right medial forebrain bundle. Three weeks later, dopaminergic depletion was evaluated by different asymmetry tests (cylinder or bar and drag test). After that, rats received a 21‐day treatment of daily l‐DOPA injections (6 plus 12 mg·kg⁻¹ benserazide). Abnormal involuntary movements (AIMs) were scored at baseline and at the end of the treatment. In experiments 1 and 2, electrophysiological recordings and microdialysis assays in the SNr were performed after the l‐DOPA chronic treatment. Finally, animals were perfused transcardially and processed for histological examination. In experiment 3, sacrifice and tissue processing was performed after chronic treatment. ^*The group was divided into three subgroups with the respective sizes indicated by bold numbers. TH, tyrosine hydroxlase