the current study demonstrates that the ability of guanosine 5'-triphosphate ( gtp ) and its nonhydrolyzable analogue guanylyl-5'-imidodiphosphate ( gpp ( nh ) p ) to inhibit opiate agonist binding to rat brain membranes can be altered by two methods : by preincubating with edta , and by preincubating at ph 4.5 .
C0018353
guanosine
C0018366
gpp ( nh ) p