The VMAT1 antiserum was quality control tested using standard immunohistochemical methods in rat adrenal medulla using biotin/avidin-HRP techniques; the antiserum shows no reactivity in rat CNS. Specificity of the antiserum was demonstrated by soluble pre-adsorption and Western blot. Tissue staining is completely eliminated by pretreatment of the diluted antibody with an excess of rat VMAT1 peptide residues 502-521. Western blot analysis of immunoprecipitated rat adrenal homogenates demonstrates a dense immunoreactive band of approximately 55 kD and a minor band of approximately 75 kD.