To eliminate endogenous peroxidase activity prior to immunohistochemical staining, prefrontal cortical (PFC) tissue sections were treated with 3% hydrogen peroxide. For antigen retrieval, the slides were rinsed three times in PBS (pH 7.4) and then inoculated in sodium citrate buffer (0.01 M, pH 6.0) for 30 minutes in a water bath (95 °C). The slides were inoculated with bovine serum albumin (BSA) (1%, 1 hour) after reaching room temperature, and subsequently with the principal antibodies (4 C, overnight): anti-caspase-3 (ab2302, Abcam- Cambridge, UK, 1:100) (ab2302, Abcam- Cambridge, UK, 1:100) (23 (link)) or recombinant anti-tyrosine hydroxylase antibody (ab137869, Abcam, Cambridge-UK, 1:200) (24 (link)). Secondary antibodies conjugated with horseradish peroxidase were incubated on the sections for 0.5 hours at 37 °C, followed by labeled streptavidin-biotin (0.5 h) (DETHP1000, Sigma-Aldrich). Finally, we used hematoxylin as a counterstain and diaminobenzidine (DAB: 3 min) to envision the reaction.