P-10-22 - CCK-4-induced calcium mobilization in T cells is enhanced in panic disorder

Abstract

This chapter describes the radioligand binding assay methods used to identify and characterize the interaction of agents with the cholecystokinin-A (CCK-A) and CCK-B/gastrin receptor subtypes. The chapter also discusses the biochemical and pharmacological properties of nonpeptide CCK-A and CCK-B/gastrin antagonists, and their utility as radioligands. Rat pancreas and guinea pig cerebral cortex are frequently used as sources for CCK-A and CCK-B receptors, respectively. In a study described in the chapter, CCK-B/gastrin receptor antagonism was examined in vivo using the in situ perfused stomach preparation. The results of the study suggested that, as proposed for the cholinergic receptor or other receptor systems, the CCK-A receptor may have either two classes of binding sites or two conformational states that have different affinities for agonists but the same affinities for antagonists. The CCK receptor agonists, including CCK-8, CCK-8 desulfate, gastrin, and CCK-4, are also effective in inhibiting specific [3H]L-365,260 binding to guinea pig brain membranes. Removal of MgCl2 or addition of the guanyl nucleotide GppNHP results in a selective reduction of [125I]CCK-8 binding and [3H]L-365,260 binding differently.