Quantification of Dopamine and Metabolites by HPLC‐ED

Right striata were sonicated in ice‐cold 0.2 M perchloric acid and centrifuged (15.500 × g, 7 min, 4°C), and the supernatants were used to determine the content of dopamine (DA) and metabolites 3,4‐dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) by high‐performance liquid chromatography (HPLC‐ED) with an electrochemical detector, as previously described ²², ²³. The pellet was resuspended in 1 M NaOH and stored at −80°C for total protein quantification by the bicinchoninic acid (BCA) protein assay (Thermo Fisher Scientific, MA, Waltham, USA). Concentration of DA and its metabolites were determined by comparison with peak areas of standards and expressed in nanogram per mg of protein.