bladder contractions were depressed by intracerebroventricular injections of the mu-opioid receptor agonist [ d-ala2 , mephe4 , gly ( ol ) 5 ] enkephalin ( dago ) and the delta-agonist [ 2d-penicillamine,5d-penicillamine ] enkephalin ( dpdpe ) respectively .
C0014298
enkephalin
C0525856
dpdpe