endorphin

[ en-dawr-fin ]

noun

1. any of a group of peptides occurring in the brain and other tissues of vertebrates, and resembling opiates, that react with the brain's opiate receptors to raise the pain threshold.

endorphin

/ ɛnˈdɔːfɪn /

noun

1. any of a class of polypeptides, including enkephalin, occurring naturally in the brain, that bind to pain receptors and so block pain sensation

endorphin

/ ĕn-dôr′fĭn /

1. Any of a group of peptide substances secreted by the anterior portion of the pituitary gland that inhibit the perception of painful stimuli. Endorphins act as neurotransmitters in the pain pathways of the brain and spinal cord. Narcotic drugs may stimulate the secretion of endorphins.

Word History and Origins

Origin of endorphin¹

1970–75; end(ogenous) (m)orphine, with -ine respelled as -in ²

Word History and Origins

Origin of endorphin¹

C20: from endo- + morphine

A Closer Look

Endorphins are long chains of amino acids, or polypeptides, that are able to bind to the neuroreceptors in the brain and are capable of relieving pain in a manner similar to that of morphine. There are three major types of endorphins: beta-endorphins are found almost entirely in the pituitary gland, while enkephalins and dynorphins are both distributed throughout the nervous system. Scientists had suspected that analgesic opiates, such as morphine and heroin, worked effectively against pain because the body had receptors that were activated by such drugs. They reasoned that these receptors probably existed because the body itself had natural painkilling compounds that also bonded to those receptors. When scientists in the 1970s isolated a biochemical from a pituitary gland hormone that showed analgesic properties, Choh Li, a chemist from Berkeley, California, named it endorphin, meaning “the morphine within.” Besides behaving as a pain reducer, endorphins are also thought to be connected to euphoric feelings, appetite modulation, and the release of sex hormones. Prolonged, continuous exercise contributes to an increased production of endorphins and, in some people, the subsequent “runner's high.”

Example Sentences

Exercise releases endorphins, which can create brain activity that keeps some awake.

From Outside Online

Showing kindness to others is also an easy way to release healthy endorphins.

From Washington Blade

So, when endorphins are circulating, they are essentially natural opioids.

From Freakonomics

There are various theories for why this happens, including the release of pain-blocking brain chemicals such as endorphins.

From Outside Online

It was almost like these betting machines or these games online that give you a little endorphin hit each time.

From Quanta Magazine

I woke disoriented and crabby, without my customary morning jolt of endorphin.

From Project Gutenberg