sentence: The inhibitory influence of opioid agonists ( IC 50 ) in electrically driven ileal mouse preparations were DADLE ( [ D-Ala 2 , D-Leu 5 ] - enkephalin ) > = met-enkephalin > = dynorphin A > = DAMGO ( [ D-Ala 2 , N-Me-Phe 4 , Glyol 5 ] - enkephalin ) > morphine > morphiceptin as nmol / L 13.9 , 17.3 , 19.5 , 23.3 , 230 , and 403 respectively .