The cholecystokinin (CCK) receptor family consists of two types: CCK1R and CCK2R, belonging to the G protein-coupled receptor (GPCR) family. They possess seven transmembrane domains and are primarily distributed in the gastrointestinal tract, central nervous system, and other tissues. These receptors participate in biological responses mediated by cholecystokinin, such as digestive fluid secretion, gastric emptying, and gallbladder contraction. By activating signaling pathways such as PLC/IP3, cAMP, and MAPK, they regulate intracellular calcium levels and gene expression. Gene expression is influenced by cell type and tissue environment, and mutations can affect receptor activity and specificity, correlating with digestive system disorders such as gastric ulcers and gallbladder diseases.