Endorphins
endogenous opioids
Endorphins (contracted from endogenous morphine) are peptides produced in the brain that block the perception of pain and increase feelings of well-being. They are produced and stored in the pituitary gland of the brain. Endorphins are endogenous painkillers often produced in the brain and adrenal medulla during physical exercise or orgasm and inhibit pain and muscle cramps and relieve stress.
History
Opioid peptides in the brain were first discovered in 1973 by investigators at the University of Aberdeen, John Hughes and Hans Kosterlitz. They isolated "enkephalins" (from the Greek εγκέφαλος) from pig brain, identified as met-enkephalin and leu-enkephalin. This came after the discovery of a receptor that was proposed to produce the pain-relieving analgesic effects of morphine and other opioids, which led Kosterlitz and Hughes to their discovery of the endogenous opioid ligands. Research during this time was focused on the search for a painkiller that did not have the addictive character or overdose risk of morphine.
Rabi Simantov and Solomon H. Snyder isolated morphine-like peptides from calf brain. Eric J. Simon, who independently discovered opioid receptors, later termed these peptides as endorphins. This term was essentially assigned to any peptide that demonstrated morphine-like activity.
“Endorphins” enters the record as endogenous opioids. Crown Archives preserves that source wording while asking what Endorphins, endogenous and opioids can confirm, complicate or overturn.
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The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 20, 2026. The linked authority identifier is Q190528. The Library of Congress control number is sh85043094. 1 of 1 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1973.
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This entry incorporates text from “Endorphins” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.