To assess the extent of the DA lesion induced by 6-OHDA injections, one 50 μm-thick section was selected from the pre-commissural striatum (0.14 mm from bregma) and from the SNc (−3.52 mm from bregma), in each mouse. These sections were immunostained for TH, the catalytic enzyme of DA synthesis, by using a polyclonal antibody (catalog no. AB152; Millipore Corporation, Billerica, USA) raised in rabbit. Briefly, the free-floating sections were sequentially incubated in (i) a blocking solution of PBS containing 2% normal goat serum and 0.01% Triton X-100 (1 h, RT); (ii) the same solution containing a 1/1000 dilution of rabbit polyclonal antibody against TH (overnight, 4 °C); and (iii) a 1/500 solution of biotinylated goat anti-rabbit (catalog no. BA-1000; Vector Laboratories, Burlingame, CA, USA) diluted in the same blocking solution (2 h at room temperature (RT)). After rinses in PBS, sections were incubated for 1 h at RT in an avidin-biotin-peroxydase complex solution (Vector Laboratories) diluted 1/100 in the blocking solution. Sections were then rinsed and the bound peroxidase revealed by incubating the sections for 3 min at RT in
