- enkephalin
- en·keph·a·lin in-'kef-ə-lən, -(.)lin n either of two pentapeptides with opiate and analgesic activity that occur naturally in the brain and have a marked affinity for opiate receptors:a) LEUCINE-ENKEPHALIN
* * *
n.* * *
en·keph·a·lin (en-kefґə-lin) either of two simple pentapeptides having the formula H2N-Tyr-Gly-Gly-Phe-X, where X is leucine or methionine, referred to as leu-enkephalin and met-enkephalin. Although met-enkephalin is the N-terminal 5 residues of the endorphins and both enkephalins and endorphins bind to opioid receptors, the two groups derive from functionally and anatomically distinct groups of neurons. The enkephalins function as neurotransmitters or neuromodulators at many locations in the brain and spinal cord and play a part in pain perception, movement, mood, behavior, and neuroendocrine regulation; they are also found in nerve plexuses and exocrine glands of the gastrointestinal tract.
Medical dictionary. 2011.