[ubiquitous 28 residue peptide which serves as an intercellular transmitter molecule in the nervous, immune, cardiovascular, digestive, and probably other systems. ( CSP )] (UMLS (NCI) C0042395) =Amino Acid, Peptide, or Protein; Neuroreactive Substance or Biogenic Amine; Hormone =gastrointestinal hormone; neuropeptide; Vasodilating Agent; gastric juice inhibitor