W90 in loop D is critical for ligand binding and antagonists may directly contact R92. The azabicyclic ring of the competitive antagonist granisetron is located close to W183 forming a cation-pi interaction. Loop E residues Y143, G148, E149, V150, Q151, N152, Y153 and K154 may be important for granisetron binding.
The specific region of the receptor, W90 in loop D, is essential for ligand attachment and antagonists can make direct physical contact with R92. The azabicyclic ring of granisetron, a competitive antagonist, forms an important interaction with W183 through cation-pi bonding. Loop E residues Y143 to K154 may be significant for the binding of granisetron.