naloxone antagonized the actions of opioids and ethylketocyclazocine , and was more effective against methionine enkephalin , leucine enkephalin and [ d-ala2 , d-leu5 ] enkephalin than against alpha-neoendorphin , ethylketocyclazocine and dynorphin ( 1-13 ) .
C0014295
methionine enkephalin
C0014298
enkephalin