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either of two pentapeptides, composed of four identical amino acids and either leucine or methionine, referred to as leu-enkephalin and met-enkephalin. The enkephalins function as neurotransmitters or neuromodulators at many locations in the brain and spinal cord and are involved with pain perception, movement, mood, behavior, and neuroendocrine regulation; they are also found in nerve plexuses and exocrine glands of the gastrointestinal tract.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
Either of two closely related pentapeptides having opiate qualities and occurring in the brain, spinal cord, and other parts of the body.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.