the binding of 2 nm [ 125i ] beta-endh was displaced by unlabeled damgo ( ic50 30 nm ) , [ d-ala2-d-leu5 ] enkephalin ( ic50 60 nm ) as well as by the selective delta agonists [ d-ser2 ( o-tert-butyl ) , leu5 ] enkephalyl-thr6 ( dstbulet , ic50 500 nm ) and tyr-ala-phe-asp-val-val-gly-nh2 ( ic50 700 nm ) in a monophasic manner within 2 to 3 log concentration units , suggesting an allosteric interaction between mu and delta sites labeled by [ 125i ] beta-endh under these conditions .
C0525773
damgo
C0014298
enkephalin