the antinociceptive effects of two mu-opioid receptor agonists , morphine and [ d-ala2 , mephe4 , gly-ol5 ] enkephalin ( dago ) , and a selective delta-receptor agonist , [ d-pen2 , l-pen5 ] enkephalin ( dplpe ) , were determined in c57bl/6j-bgj ( beige ) and control mice ( crs-cdl and c57bl/6by ) using a standard tail-flick assay .
C0525773
dago
C0014298
enkephalin