Quantitative Structure-Activity Relationship Studies on Cholecystokinin Antagonists

A review is presented on quantitative structure-activity relationship (QSAR) studies on cholecystokinin antagonists. Cholecystokinin (CCK) is a gastrointestinal peptide hormone closely related chemically to gastrin. However, its receptors are found in both peripheral and central nervous systems. Those present in peripheral system have been termed as CCK-A receptors and those present in central nervous system as CCK-B receptors. QSAR studies verify that CCK-B receptors are closely related structurally to gastrin receptors. QSAR studies have been reported on different classes of CCK antagonists, e.g., benzodiazepine derivatives, amino acid derivatives, quinazolinones, and peptides and pseudopeptide analogs. These QSAR studies unravel the mechanisms of interactions of each category of antagonists with the CCK receptors. In the case of benzodiazepines, the hydrophobic interactions and hydrogen bondings are found to be the most important binding force, while in the case of quinazolinones, only the hydrogen bonding is found to be important. The hydrophobic as well as the dispersion interactions are shown to be important for the binding of glutamic acid analogs and steric factors appear to govern the activity of peptides and pseudopeptide analogs.