Low molecular weight neurokinin NK2 antagonists

doi:10.1016/S0960-894X(00)80695-2

Bioorganic & Medicinal Chemistry Letters

Volume 3, Issue 5, May 1993, Pages 931-936

https://doi.org/10.1016/S0960-894X(00)80695-2 Get rights and content

Abstract

A deletion - optimization strategy based on an initial heptapeptide lead structure 1 led to potent and selective neurokinin NK₂ antagonists 5 (pK_B=9.3) and 9 (pK_B=7.9) of substantially reduced molecular size. Tetrapeptide 5 (0.1 μmol/Kg i.v.) potently inhibits NK₂ agonist-induced bronchoconstriction in guinea-pigs. Whilst less potent than 5 in vivo, the dipeptoid 9 (5 μmol/Kg i.v.) had a significantly longer biological half-life (> 2 h), and provides a potential lead towards non-peptide analogues.

Potent and selective tetrapeptide and pseudo-dipeptide neurokinin NK₂ antagonists are described.

References (16)

Me Logan et al.
Ann. Rep. Med. Chem.
(1991)
J-F Peyronel et al.
Bioorg Med Chem Lett
(1992)
At McKnight et al.
Regul Pept
(1988)
Nd Heindel et al.
Tetrahedron Letters
(1971)
Rm Hagan et al.
Neuropeptides
(1991)
Je Maggio
Ann Rev Neurosci.
(1988)

There are more references available in the full text version of this article.

Cited by (22)

Hybrid peptides having mixed substance P (NK1), neurokinin A (NK2) and bradykinin (BK2) antagonist properties
1996, Immunopharmacology
Probing the structure and function of the tachykinin neurokinin-2 receptor through biosynthetic incorporation of fluorescent amino acids at specific sites
1996, Journal of Biological Chemistry
A general method for understanding the mechanisms of ligand recognition and activation of G protein-coupled receptors has been developed. A study of ligand-receptor interactions in the prototypic seven-transmembrane neurokinin-2 receptor (NK2) using this fluorescence-based approach is presented. A fluorescent unnatural amino acid was introduced at known sites into NK2 by suppression of UAG nonsense codons with the aid of a chemically misacylated synthetic tRNA specifically designed for the incorporation of unnatural amino acids during heterologous expression in Xenopus oocytes. Fluorescence-labeled NK2 mutants containing an unique 3-N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-2,3-diaminopropionic acid (NBD-Dap) residue at either site 103, in the first extracellular loop, or 248, in the third cytoplasmic loop, were functionally active. The fluorescent NK2 mutants were investigated by microspectrofluorimetry in a native membrane environment. Intermolecular distances were determined by measuring the fluorescence resonance energy transfer (FRET) between the fluorescent unnatural amino acid and a fluorescently labeled NK2 heptapeptide antagonist. These distances, calculated by the theory of Förster, permit to fix the ligand in space and define the structure of the receptor in a molecular model for NK2 ligand-receptor interactions. Our data are the first report of the incorporation of a fluorescent unnatural amino acid into a membrane protein in intact cells by the method of nonsense codon suppression, as well as the first measurement of experimental distances between a G protein-coupled receptor and its ligand by FRET. The method presented here can be generally applied to the analysis of spatial relationships in integral membrane proteins such as receptors or channels.
GR159897, a potent non-peptide antagonist at tachykinin NK<inf>2</inf> receptors
1995, European Journal of Pharmacology
GR159897 ((R)-1-[2-(5-fluoro-1H-indol-3-yl)ethyl]-4-methoxy-4-[(phenylsulfinyl)methyl]piperidine) is a novel, highly potent and selective non-peptide antagonist at tachykinin NK₂ receptors. GR159897 inhibited binding of the NK₂ receptor antagonist radioligand [³H]cyclohexylcarbonyl-Gly-Ala-(d)Trp-Phe-NMe₂ ([³H]GR100679) to human ileum NK₂ receptors transfected into Chinese hamster ovary cells (pK_i 9.5) and to rat colon membranes (pK_i 10.0). GR159897 was a competitive antagonist of contractions induced by the NK₂ receptor agonist [Lys³,Gly⁸-R-γ-lactam-Leu⁹]neurokinin A-(3–10) (GR64349) in guinea-pig trachea (pA₂ 8.7), and had negligible activity at human NK₁ receptors transfected into Chinese hamster ovary cells (pK_i 5.3), NK₁ receptors in guinea-pig trachea (pK_B < 5) or NK₃ receptors in guinea-pig cerebral cortex (pK_i < 5). In vivo, in the anaesthetised guinea-pig, GR159897 (0.12 mg · kg⁻¹ i.v.) potently antagonised bronchoconstriction induced by GR64349 (dose-ratio = 28), with a long duration of action (3 h). GR159897 should be a useful tool for studying the physiological and pathophysiological role of tachykinin NK₂ receptor activation.
GR138676, a novel peptidic tachykinin antagonist which is potent at NK<inf>3</inf> receptors
1994, Neuropeptides
GR138676, a conformationally constrained analogue of neurokinin B, is a novel, potent NK₃ receptor antagonist. GR138676 was a competitive antagonist of neurokinin B-dependent arachidonic acid mobilization from prelabelled Chinese hamster ovary cells stably transfected with a human NK₃ receptor gene (pK_B 8.3) and of contractions induced by senktide in rat portal vein (pK_B 8.2). However, GR138676 was also a competitive antagonist of the increase in intracellular calcium evoked by the selective NK₁ agonist, GR73632, in the human astrocytoma U373MG cell-line (pK_B 8.3). GR138676 had little activity at NK₂ receptors, inhibiting binding of the NK₂ antagonist radioligand [³H]-GR100679 to Chinese hamster ovary cells transfected with the human ileum NK₂ receptor with a pKi of 6.0. In summary, despite its activity at NK₁ receptors, GR138676 will be a useful tool for characterizing NK₃ receptors as well as defining the physiological and pathophysiological function of this receptor subtype.
Palmitoylation but not the extreme amino-terminus of G<inf>qα</inf> is required for coupling to the NK2 receptor
1994, FEBS Letters
G_qα and G_11α differ from other G protein α subunits in that they have unique, conserved 6 residue amino-terminal extensions. Wild-type and amino-terminal mutants of G_qα expressed in COS cells were analyzed for their ability to functionally couple with co-expressed neurokinin NK2 receptor. Wild-type, T2A and Δ2–7 G_qα were able to stimulate agonist driven phospholipase C (PLC) activity in identical manners. Other activities of these two amino-terminal mutants including aluminum fluoride stimulated PLC activity, palmitoylation, interaction with G_βγ subunits and GTPγS-induced trypsin resistance are also similar to the wild-type α subunit. This demonstrates that the NK2 receptor is able to functionally interact with the α subunit of G_q and that the first seven amino-acids of G_qα are not required for any of the α subunit functions tested. In contrast to the T2A and Δ2–7 mutants, a C9,10A G_qα mutant was not able to couple to either the NK2 receptor or PLC, as assessed by high-affinity agonist binding and activation of PLC either in intact cells or in vitro. The C9,10A protein was able to assume a GTPγS-induced trypsin-resistant conformation and partitioned primarily to the pelletable fraction in a manner similar to the wild-type protein. However, it was not labeled with [³H]palmitic acid. This suggests that blocking palmitoylation at the amino-terminus of G_qα results in a loss of functional activity which reflects an inability to interact with both the receptor and downstream signaling targets.
GR159897 and related analogues as highly potent, orally active non-peptide neurokinin NK<inf>2</inf> receptor antagonists.
1994, Bioorganic and Medicinal Chemistry Letters

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Bioorganic & Medicinal Chemistry Letters

Low molecular weight neurokinin NK2 antagonists

Abstract

Ann. Rep. Med. Chem.

Bioorg Med Chem Lett

Regul Pept

Tetrahedron Letters

Neuropeptides

Ann Rev Neurosci.

Hybrid peptides having mixed substance P (NK1), neurokinin A (NK2) and bradykinin (BK2) antagonist properties

Probing the structure and function of the tachykinin neurokinin-2 receptor through biosynthetic incorporation of fluorescent amino acids at specific sites

GR159897, a potent non-peptide antagonist at tachykinin NK<inf>2</inf> receptors

GR138676, a novel peptidic tachykinin antagonist which is potent at NK<inf>3</inf> receptors

Palmitoylation but not the extreme amino-terminus of G<inf>qα</inf> is required for coupling to the NK2 receptor

GR159897 and related analogues as highly potent, orally active non-peptide neurokinin NK<inf>2</inf> receptor antagonists.

Low molecular weight neurokinin NK₂ antagonists