dose-dependent morphine-like stimulus effects were produced over a wide range of doses ( 0.001-30 micrograms ) , depending upon ligand and animal , by morphine , by the mu-selective peptides dago [ d-ala2-nmephe4-gly ( ol ) -enkephalin ] and fk33824 [ d-ala2 , nmephe4-met ( o ) 5- ( ol ) -enkephalin ] , and by the delta-selective peptide , dadl [ d-ala2 , d-leu5 ) enkephalin ] .
C0525773
dago
C0014298
enkephalin