No abstract

4 Devazepide powerfully blocked responses to CCK-8S with an affinity (pKB= 9.54) that was in agreement with reported functional data obtained in pancreatic amylase secretion studies, a system exhibiting CCKA receptor activity. Devazepide displayed lower affinity against pentagastrin than against CCK-8S. 5 CI-988 blocked responses to pentagastrin in an insurmountable manner in the presence of 3 nM devazepide; a concentration previously shown to block the CCKA receptor. The nature of the antagonism observed with L-365,260 was unaltered by the presence of devazepide. 6 The guinea-pig stomach corpus smooth muscle preparation contains both subtypes of CCK receptor and will be useful as a pharmacological tool for investigating the functional effects of novel CCK ligands.