both the mu-opioid receptor selective agonist [ d-ala2 , mephe4 , gly-ol5 ] enkephalin ( 0.01-3 microm ) and the delta-opioid receptor selective agonist [ d-phe2-d-pen5 ] enkephalin ( dpdpe , 0.01-3 microm ) inhibited the cyclic amp efflux , stimulated by 10 microm amph in the presence of ( - ) -sulpiride , by 70 to 80 % .
C0014298
enkephalin
C0525856
dpdpe