β-Endorphin, equine TFA is an endogenous opioid peptide, which binds at high affinity to both μ/δ opioid receptors. β-Endorphin, equine TFA has analgesic properties[2].IC50 & Target:μ/δ opioid receptor[2]In Vitro:β-Endorphin, equine TFA (0, 0.6, 1.2 and 3 μM) inhibits the striatal dopamine release.In Vivo:β-Endorphin, equine TFA (2 or 20 μg/kg; i.p., once) effects the acquisition and retention in the rat.