these beta-funaltrexamine-insensitive sites appear to interact only with opioid peptides ( [ d-ala2 , d-leu5 ] enkephalin , [ d-ala2 , met5 ] enkephalinamide , tyr-d-ser-gly-phe-leu-thr and [ d-ala2 , mephe4 , gly-ol5 ] enkephalin ) but not with nonpeptide agonists .
C0205753
opioid
C0014298
enkephalin