µ-Opioid Receptor/OPRM1 (extracellular) Blocking Peptide (#BLP-OR011) is the original antigen used for immunization during Anti-µ-Opioid Receptor (OPRM1) (extracellular) Antibody (#AOR-011) generation. The blocking peptide binds and ‘blocks’ Anti-µ-Opioid Receptor/OPRM1 (extracellular) primary antibody, this makes it a good negative reagent control to help confirm antibody specificity in western blot and immunohistochemistry applications. This control is also often called a pre-adsorption control.