**2.5 TH immunocytochemistry**

For immunocytochemistry, coronal sections (50 μm) were obtained on a vibrating microtome through the mesencephalon. Tyrosine hydroxylase (Chemicon International, Inc. CA, USA, 1:1000) immunostaining with the ABC detection method (Vector Lab MI, USA) was performed for light microscope analysis. The analysis was conducted with a computer-assisted system (Image-Pro Plus, Media Cybernetics, L. P. del Mar, CA, USA) connected by a CCD camera to Optiphot 2 microscope (Nikon, Japan). The number of TH+ - positive neurons was counted in 1500 μm<sup>2</sup> from seven SNc sections of each mouse [66].
