in contrast to the binding of the delta-selective agonist [ 3h ] [ d-penicillamine2 , d-penicillamine5 ] enkephalin to ng108-15 cell membranes , and of the mu-selective agonist [ 3h ] [ d-ala2 , mephe4 , gly-ol5 ] enkephalin to sk-n-sh cell membranes , [ 125i ] beta h-endorphin binding to ng108-15 and sk-n-sh cell membranes was not altered by guanosine triphosphate ( gtp ) or guanylyl-5'-imidodiphosphate ( gpp ( nh ) p ) in the absence of cations .
C0018353
guanosine triphosphate
C0018366
gpp ( nh ) p