displacement studies of [ 3h ] - [ d-ala2-mephe4-gly-ol5 ] -enkephalin ( [ 3h ] -dago ) and [ 3h ] - [ d-ala2-d-leu5 ] -enkephalin ( [ 3h ] -dadl ) by the corresponding unlabeled ligands show that there are at least three classes of sites which bind these enkephalin analogs with high affinity .
C0525773
dago
C0014298
enkephalin