Sincalide is an octapeptide fragment of cholestocystokinin (CCK) that activates the CCK receptor on immune cell surfaces. Sincalide is more potent when sulfated. Sincalide exhibits neuroprotective, immunosuppressive, and anorexigenic activities. In hippocampal neurons, sincalide increases the density of filopodia and dendritic spines. In vagal motor neurons, sincalide increases excitatory currents. In other cellular models, this compound inhibits IgG1 production and regulates transcription factor expression and activation of B cells. Sincalide also modulates hormone signaling, increasing adrenocorticotropic hormone (ACTH) secretion and altering leptin, melanocortin, and corticotropin-releasing factor (CRF) pathways. In separate animal models, sincalide decreases appetite and increases cardiac output, also increasing gastrointestinal blood flow.