specifically , the ability of two mu-opioid receptor agonists , morphine and [ d-ala2 , nmephe4 , gly-ol5 ] -enkephalin ( dago ) and a selective delta-opioid receptor agonist , [ d-pen2 , l-pen5 ] -enkephalin ( dplpe ) , to inhibit colonic bead expulsion time was measured in normal ( swiss ) and mu-opioid deficient ( cxbk ) mice .
C0525773
dago
C0014298
enkephalin