β-Endorphin (rat)

β-Endorphin (β-EP) is an endogenous opioid neuropeptide derived from proopiomelanocortin, acting in both the central nervous system and peripheral tissues. Its inhibitory effects on electrically stimulated contractions, such as in the mouse vas deferens assay, are mediated via μ- and δ-opioid receptors. This peptide is widely used in research on pain modulation, stress response, and neuroimmune interactions in both in vitro and in vivo models.