title: Gastrointestinal neurotensin receptors: contribution of the aromatic hydroxyl group in position 11 to peptide potency.
abstract: Neurotensin structural analogues on tyrosine11 were tested in vitro to determine their ability to contract the fundus or relax the intestine. The rank order of potency was: neurotensin greater than [Phe11]-neurotensin greater than [D-Tyr11]-neurotensin greater than [D-Phe11]-neurotensin. All peptides behaved as full agonists. It is concluded that tyrosine11 is part of the neurotensin pharmacophore; the hydroxyl group increases the affinity not the intrinsic activity of the peptide at the receptor.
mesh_terms: D000818:Animals; D004386:Duodenum / Q000187:drug effects; D005748:Gastric Fundus / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000187:drug effects*; D009496:Neurotensin / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter / Q000502:physiology*
chemical_list: D018028:Receptors, Neurotensin; D017981:Receptors, Neurotransmitter; D009496:Neurotensin