Targeting neurotensin receptors with agonists and antagonists for therapeutic purposes.

Neurotensin (NT) is a brain-gut tridecapeptide that fulfils a dual function, as a neurotransmitter/neuromodulator in the nervous system, and as a paracrine and circulating hormone in the periphery. Three NT receptors, NTS1, NTS2 and NTS3, have been cloned to date. NTS1 and NTS2 belong to the family of G protein-coupled receptors with seven transmembrane domains, whereas NTS3 is a single transmembrane domain protein that belongs to a recently identified family of sorting receptors. Most of the known peripheral and central effects of NT are mediated through NTS1. NTS2 might take part in the analgesic response elicited by central administration of NT; the biological roles of NTS3 are yet to be discovered. Most NT agonists and non-peptide antagonists developed to date have been studied for their NTS1-targeting abilities. Here, we will discuss the potential diagnostic and therapeutic uses of these compounds in cancer, schizophrenia, obesity and pain suppression.