Neurotensin Receptor

The neuropeptide neurotensin (NT) exerts central actionsthat include hypothermia, analgesia, and a number of effects that involve the modulation of nigrostriatal and mesocortico-limbic dopaminergic pathways. The two neurotensin receptor subtypes known to date, NTR1 and NTR2, belong to the family of G-protein-coupled receptors with seven putative transmembrane domains (TM). The NTR1 has high affinity for neurotensin, whereas the NTR2 has lower affinity for the peptide and is selectively recognized by levocabastine, an anti-histamine H1 receptor antagonist. These receptors have widespread, though not identical, central and peripheral distributions and exhibit distinct ontogenic profiles.

It is notably reported that NTR1 activation results in significant antinociception but also causes marked hypotension and hypothermia. In sharp contrast, NTR2 has emerged as an important pain target because NTR2-selective analogues exhibit potent analgesic activity in both acute and chronic pain conditions in dose-dependent analgesic effects without inducing drop in blood pressure or body temperature.