When endorphin activity is stimulated – either naturally or by chemical means – individuals experience relief of pain and sensations of improved well-being. In Auricular Acupuncture & Addiction, 2009 The role of endorphinsĮndorphins are the body's endogenous opiates. Whether this function is actually facilitated solely by β-endorphin molecules remains in debate. Frequently, the runner’s high experienced near the end of a long, challenging race is attributed to endorphin release and a composite surge of pain-relief peptides that block sensory receptors.
In common language, an “endorphin-high” is attributed to any euphoric feeling elicited from either physical or emotional challenge, pain, or stress. Thus, the term “endorphins” has been assigned to numerous peptides with multiple functions ranging from pain cessation and analgesia to euphoria and neurotransmission. In Scotland, the laboratory of John Hughes and Hans Kosterlitz isolated a small peptide sequence from brain tissue isolated from pig and termed it “enkephalin.” 6,7 During the same period, investigators in the United States isolated an active molecule that they considered to have morphine-like activity and termed it “endorphin.” 14,17 As the field of neuropeptides blossomed, the term “endorphins” was used loosely in reference to all endogenous peptides with opioid-like activity, particularly morphine-like properties. Endogenous neuropeptides were first identified and named by two independent laboratories in the mid-1970s. The term ‘endorphins’ remains broader than the specific molecules that are truly endorphin derivatives.
Zagon, in Handbook of Biologically Active Peptides (Second Edition), 2013 HistoryĮndorphins were the first identified endogenous opioid peptides.