Neurotensin receptor type 1 is a protein that in humans is encoded by the NTSR1 gene. For a crystal structure of NTS1, see pdb code 4GRV. High-resolution crystal structures have been determined in complex with the peptide full agonist NT8-13, non-peptide full agonist SRI-9829, partial agonist RTI-3a, antagonists / inverse agonists SR-48692 and SR-142948, as well as in the ligand-free state. 
Neurotensin receptor 1, also called NTR1, belongs to the large superfamily of G-protein coupled receptors and is considered a class-A GPCR. NTSR1 mediates multiple biological processes through modulation by neurotensin, such as low blood pressure, high blood sugar, low body temperature, antinociception, anti-neuronal damage  and regulation of intestinal motility and secretion.