endogenous opioid peptide


endogenous opioid peptide

Any of a group of more than 15 substances present in the brain, certain endocrine glands, and the gastrointestinal tract. They have morphine-like analgesic properties, behavioral effects, and neurotransmitter and neuromodulator functions. Included in this group of chemicals are endorphins, enkephalins, and dynorphin. See also: peptide