Paraformaldehyde-fixed, paraffin-embedded Rat Brain tissue; Antigen retrieval by boiling in sodium citrate buffer (0.01M, pH6) for 15 minutes; Block endogenous peroxidase by 3% hydrogen peroxide for 30 minutes; Blocking buffer (3% BSA) at room temperature for 30 minutes; Antibody incubation with Parvalbumin Polyclonal Antibody, Unconjugated (bs-1299R) at 1:400 overnight at 4°C, followed by incubation with a conjugated secondary antibody, DAB and counterstaining.