Neurotensin is a 13-amino-acid peptide found in the brain and spinal cord (first characterized by Carraway and Leeman). It is released by the hypothalamus and synthesized as part of a larger precursor protein that also includes the related neuropeptide neuromedin N. Neurotensin affects pituitary hormone release, interacts with the dopaminergic system, and is involved in vasodilation and hypotension. It can also modulate pain perception. Intrathecal neurotensin has also been shown to be anti-nociceptive.
Neurotensin-SAP is a chemical conjugate of neurotensin and the ribosome-inactivating protein, saporin. It specifically eliminates neurotensin receptor-expressing cells.