Cholecystokinin tetrapeptide<unk> , 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,<unk>  acts primarily in the brain as an anxiogenic, although it does retain some GI effects, but not as much as<unk>  or the full length polypeptide<unk> 8.<unk>  reliably causes severe anxiety symptoms when administered to humans in a dose of as little as 50μg, and is commonly used in scientific research to induce panic attacks for the purpose of testing new anxiolytic drugs. Since it is a peptide,<unk>  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.
CCK-4
Gluten exorphin
D-DIA
Incretin
OPCS-4
Beta-Endorphin
Histrelin
IMEP 