CCK-4
| Clinical data | |
|---|---|
| Other names | Tetragastrin; Cholecystokinin tetrapeptide | 
| Routes of administration | Intravenous | 
| ATC code | 
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| Pharmacokinetic data | |
| Bioavailability | 100% | 
| Metabolism | Plasma protease enzymes | 
| Elimination half-life | 13 minutes | 
| Excretion | N/A | 
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| Chemical and physical data | |
| Formula | C29H35N5O7S | 
| Molar mass | 597.69 g·mol−1 | 
| 3D model (JSmol) | |
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Cholecystokinin tetrapeptide (CCK-4, tetragastrin, Trp-Met-Asp-Phe-NH2) is a peptide fragment derived from the larger peptide hormone cholecystokinin. Unlike cholecystokin which has a variety of roles in the gastrointestinal system as well as central nervous system effects, CCK-4 acts primarily in the brain as an anxiogenic, although it does retain some GI effects, but not as much as CCK-8 or the full length polypeptide CCK-58.
CCK-4 reliably causes severe anxiety symptoms when administered to humans in a dose of as little as 50 μg, and is commonly used in scientific research to induce panic attacks for the purpose of testing new anxiolytic drugs. Since it is a peptide, CCK-4 must be administered by injection, and is rapidly broken down once inside the body so has only a short duration of action, although numerous synthetic analogues with modified properties are known.