Fig. 1: 6-OHDA Models.

A Scheme representing the timeline of the experimental procedures. Rats were unilaterally injected in the left hemisphere with 6-OHDA in the MFB. After 2 weeks from the injection, rats were subjected to an apomorphine test (APO-Test). Fully-lesioned (Full) animals were treated for 3 weeks with L-Dopa.  Twenty min after the last L-Dopa treatment, rats were sacrificed for electrophysiological and immunohistochemical analysis. B Quantification of the number of TH⁺ cells in the SNpc after 3 weeks of L-Dopa treatment in the contralateral (Control) and ipsilateral (Lesion) hemispheres to the lesion (n = 4 rats; unpaired t-test Lesion vs. Control; t = 8.029, df = 6, ***P < 0.001). C Optical density (O.D.) of TH⁺ fibers in the contralateral and ipsilateral striatum after L-Dopa treatment (n = 5 rats; unpaired t-test Lesion vs. Control; t = 24.95, df = 8, ***P < 0.001). D Experimental plan of the procedures. Rats were unilaterally injected in the left hemisphere with 6-OHDA in the MFB. After 2 weeks from the injection, rats were subjected to an apomorphine test. Partially-lesioned (Partial) animals were divided into two groups: the first group was subjected to L-Dopa for 3 weeks, while the second group was treated for 6 weeks. Twenty min after the last L-Dopa administration, animals were sacrificed for electrophysiological and immunohistochemical analysis. E Quantification of the number of TH⁺ cells in the SNpc after L-Dopa treatment in the contralateral (Control) and ipsilateral (Lesion) hemispheres to the lesion (n = 5 rats; unpaired t-test Lesion vs. Control; t = 9.596, df = 8, ***P < 0.001). F Optical density of TH⁺ fibers in the contralateral and ipsilateral striatum of the lesion after L-Dopa treatment (n = 4 rats; unpaired t-test Lesion vs. Control; t = 13.93, df = 6, ***P < 0.0001).