chronic localized pain increased the level of the opioid peptides , dynorphin ( dyn ) , alpha-neoendorphin ( aneo ) , met-enkephalin ( met ) and mets-enkephalin-arg6-gly7-leu8 ( meagl ) , in the lumbar enlargement of the rat spinal cord .
C0205753
opioid peptides
C0013355
dynorphin