Neurotensin is a brain and gastrointestinal peptide that fulfils many central and peripheral functions through its interaction with specific receptors. Three subtypes of neurotensin receptors have been cloned. Two of them belong to the family of G protein-coupled receptors, whereas the third one is an entirely new type of neuropeptide receptor and is identical to gp95/sortilin, a 100,000 Da-protein with a single transmembrane domain. Neurotensin isolated primarily from the nervous system of the hypothalamus, median eminence, substantia nigra and brain stem, has many neurotransmitter-like characteristics. Neurotensin can lower blood pressure, increase vascular permeability and increase plasma levels of glucagon, glucose, growth hormone, and prolactin in rats.