mu and delta receptors were labeled with the selective ligands 3h-dago ( tyr- d-ala-gly-mephe-gly-ol ) , and 3h-dpdpe ( d-pen2 , d-pen5-enkephalin ) , respectively , while the kappa receptors were labeled with 3h- ( - ) bremazocine in the presence of unlabeled dago and dpdpe .
C0014298
enkephalin
C0525856
dpdpe