CCK (cholecystokinin) is a peptide hormone and neurotransmitter with dual functions in peripheral digestion and central nervous system signaling. In the gastrointestinal system, CCK is released from intestinal I-cells in response to dietary lipids and proteins, where it inhibits food intake and gastric emptying by targeting vagal afferent neurons 1. CCK binds to two receptor subtypes: CCK-A receptors (predominantly peripheral) stimulate pancreatic enzyme release, while CCK-B receptors (predominantly central) regulate gastric acid secretion 2. Beyond digestion, CCK plays important roles in anxiety regulation, with CCK-B receptor activity associated with human anxiety onset 34. CCK modulates dopamine release in the nucleus accumbens and interacts with multiple neurotransmitter systems including GABA, serotonin, and glutamate 4. Age-related changes in CCK sensitivity contribute to decreased appetite in elderly populations 5. In neurological diseases, CCK receptor binding is significantly reduced in Huntington's disease but remains normal in Alzheimer's disease 6. Despite extensive research, therapeutic applications remain limited, with ongoing investigations into CCK receptor ligands for various gastrointestinal and neuropsychiatric conditions 7.