This 13 amino acid peptide was first obtained from bovine hypothalamus and was named from its neuronal localization. It was detected in the central nervous system (CNS) and peripheral tissues primarily in the gastrointestinal tract. This bioactive form of neurotensin post-translationally modified at a Glu residue was obtained from porcine intestine. In the CNS, neurotensin has dual function of neuromodulator of dopamine transmission and of anterior pituitary hormone secretion. It also displays effective hypothermic and analgesic effects in the brain. Neurotensin has been implicated in the pathophysiology of schizophrenia, Huntington, and Parkinson diseases.