sentences:  There is more than one ligand binding domain on the NK1 receptor for the non-peptide antagonists, and these binding domains can be found in various places.The main ligand binding site is in the hydrophobic core between the loops and the outer segments of transmembrane domains 3–7 (TM3–TM7).Several residues, such as Gln165 (TM4), His197 (TM5), His265 (TM6) and Tyr287 (TM7) are involved in the binding of many non-peptide antagonists of the NK1 receptors.