Cholecystokinin receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

Cholecystokinin receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on CCK receptors [89]) are activated by the endogenous peptides cholecystokinin-8 (CCK-8), CCK-33, CCK-58 and gastrin (gastrin-17). There are only two distinct subtypes of CCK receptors, CCK1 and CCK2 receptors [63, 123], with some alternatively spliced forms most often identified in neoplastic cells. The CCK receptor subtypes are distinguished by their peptide selectivity, with the CCK1 receptor requiring the carboxyl-terminal heptapeptide-amide that includes a sulfated tyrosine for high affinity and potency, while the CCK2 receptor requires only the carboxyl-terminal tetrapeptide shared by each CCK and gastrin peptides. These receptors have characteristic and distinct distributions, with both present in both the central nervous system and peripheral tissues.