title: [TRP11]-neurotensin and xenopsin discriminate between rat and guinea-pig neurotensin receptors.
abstract: The binding and biological activities of neurotensin and two analogues, [TRP11]-neurotensin and xenopsin, in which a tryptophan replaces the neurotensin residue Tyr11, were compared in rat and guinea-pig. The binding activity of three peptides was measured as their ability to inhibit the binding of [3H]neurotensin to rat and guinea-pig brain synaptic membranes. Their biological activities were measured as their effects on the contractility of rat and guinea-pig ileal smooth muscle preparations. In binding as well as biological assays, it was found that [Trp11]-neurotensin and xenopsin were as potent as neurotensin in the rat. In contrast, the two analogues were about 10 times less potent than neurotensin in the guinea-pig. These findings reveal differences between rat and guinea-pig neurotensin receptors should be considered when comparing the activity of neurotensin analogues in assays using tissue preparations from various animal species.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D006168:Guinea Pigs; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009496:Neurotensin / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism*; D010455:Peptides; D051381:Rats; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013045:Species Specificity; D029867:Xenopus Proteins
chemical_list: D009842:Oligopeptides; D010455:Peptides; D017981:Receptors, Neurotransmitter; D029867:Xenopus Proteins; D009496:Neurotensin; C016832:xenopsin; C024309:neurotensin, Trp(11)-