the highest affinity pd2 7.4 ) and selectivity towards mu-receptors was exhibited by tyr-d-ala-gly- ( nme ) phe-gly-ol ( dago ) , whereas [ d-pen2 , d-pen5 ] enkephalin ( dpdpe ) was found to be the most selective delta-receptor agonist ( pd2 7.3 ) .
C0525773
dago
C0014298
enkephalin