the levels of m-enk-arg6-phe7 in various structures of the rat brain were compared with the levels of several other opioid peptides , including methionine-enkephalin ( m-enk ) , leucine-enkephalin ( l-enk ) , dynorphin 1-13 , and alpha-neoendorphin , which were also measured by ria .
C0205753
opioid peptides
C0013355
dynorphin