β-Endorphin, human, a prominent endogenous peptide, existing in the hypophysis cerebri and hypothalamus, is an agonist of opioid receptor, with preferred affinity for μ-opioid receptor and δ-opioid receptor; β-Endorphin, human exhibits antinociception activity.

β-Endorphin, human is an agonist of opioid receptor, with preferred affinity for μ-opioid receptor and δ-opioid receptor. β-Endorphin exhibits anti-nociception activity by stimulating ε-opioid receptor, rather than μ-, δ-, and κ-opioid receptor[1]. β-Endorphin has anti-nociception activity. Firstly, β-Endorphin combines together with the opioid receptors in hyperalgesia. Further, β-Endorphin suppresses the release of substance P at the level of spinal cord and blocks the conduction of pain on the primary sensory neurons. Moreover, β-Endorphin activates the endogenous analgesia system located in the CNS. In addition, β-Endorphin inhibits the conduction of pain and agitation of nociceptors to exert an analgesic effect[2].

[1]. Narita M, et al. Evidence for the existence of the beta-endorphin-sensitive "epsilon-opioid receptor" in the brain: the mechanisms of epsilon-mediated antinociception. Jpn J Pharmacol. 1998 Mar;76(3):233-53. [2]. Luan YH, et al. Action of β-endorphin and nonsteroidal anti-inflammatory drugs, and the possible effects of nonsteroidal anti-inflammatory drugs on β-endorphin. J Clin Anesth. 2017 Feb;37:123-128.