Proglumide antagonizes the stimulation of rabbit gallbladder by cholecystokinin

Proglumide (3 X 10(-4) to 3 X 10(-3) M) produced parallel rightward shifts in the cumulative concentration-response curves for cholecystokinin octapeptide (CCK-8) in the rabbit gallbladder. Contractile responses to acetylcholine and serotonin were inhibited noncompetitively by the highest concentration of proglumide tested. K+-induced contractions, however, were unaffected by proglumide. The results indicate that proglumide may be used as a selective, competitive antagonist of the actions of CCK-8 in the isolated rabbit gallbladder preparation.