gw791343 has been researched along with pyridoxal-phosphate-6-azophenyl-2--4--disulfonic-acid* in 2 studies
2 other study(ies) available for gw791343 and pyridoxal-phosphate-6-azophenyl-2--4--disulfonic-acid
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Identification of regions of the P2X(7) receptor that contribute to human and rat species differences in antagonist effects.
Several P2X(7) receptor antagonists are allosteric inhibitors and exhibit species difference in potency. Furthermore, N(2)-(3,4-difluorophenyl)-N(1)-(2-methyl-5-(1-piperazinylmethyl)phenyl)glycinamide dihydrochloride (GW791343) exhibits negative allosteric effects at the human P2X(7) receptor but is a positive allosteric modulator of the rat P2X(7) receptor. In this study we have identified several regions of the P2X(7) receptor that contribute to the species differences in antagonist effects.. Chimeric human-rat P2X(7) receptors were constructed with regions of the rat receptor being inserted into the human receptor. Antagonist effects at these receptors were measured in ethidium accumulation and radioligand binding studies.. Exchanging regions of the P2X(7) receptor close to transmembrane domain 1 modified the effects of KN62, 4-(4-fluorophenyl)-2-(4-methylsulphinylphenyl)-5-(4-pyridyl)1H-imidazole (SB203580) and GW791343. Further studies, in which single amino acids were exchanged, identified amino acid 95 as being primarily responsible for the differential allosteric effects of GW791343 and, to varying degrees, the species differences in potency of SB203580 and KN62. The species selectivity of pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid was affected by multiple regions of the receptor, with potency being particularly affected by the amino acid 126 but not by amino acid 95. A further region of the rat receptor (amino acids 154-183) was identified that, when inserted into the corresponding position in the human receptor, increased ATP potency 10-fold.. This study has identified several key residues responsible for the species differences in antagonist effects at the P2X(7) receptor and also identified a further region of the P2X(7) receptor that can significantly affect agonist potency at the P2X(7) receptor. Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Allosteric Regulation; Allosteric Site; Amino Acid Sequence; Animals; Cell Line; Cloning, Molecular; Dose-Response Relationship, Drug; Glycine; Humans; Imidazoles; Molecular Sequence Data; Mutagenesis, Site-Directed; Piperazines; Plasmids; Polymorphism, Single Nucleotide; Protein Binding; Protein Structure, Tertiary; Purinergic P2 Receptor Agonists; Purinergic P2 Receptor Antagonists; Pyridines; Pyridoxal Phosphate; Radioligand Assay; Rats; Receptors, Purinergic P2; Receptors, Purinergic P2X7; Sequence Alignment; Species Specificity; Transfection | 2008 |
Negative and positive allosteric modulators of the P2X(7) receptor.
Antagonist effects at the P2X(7) receptor are complex with many behaving in a non-competitive manner. In this study, the effects of N-[2-({2-[(2-hydroxyethyl)amino]ethyl}amino)-5-quinolinyl]-2-tricyclo[3.3.1.1(3,7)]dec-1-ylacetamide (compound-17) and N (2)-(3,4-difluorophenyl)-N (1)-[2-methyl-5-(1-piperazinylmethyl)phenyl]glycinamide dihydrochloride (GW791343) on P2X(7) receptors were examined and their mechanism of action explored.. Antagonist effects were studied by measuring agonist-stimulated ethidium accumulation in cells expressing human or rat recombinant P2X(7) receptors and in radioligand binding studies.. Compound-17 and GW791343 were non-competitive inhibitors of human P2X(7) receptors. Receptor protection studies using decavanadate and pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) showed that neither compound-17 nor GW791343 competitively interacted at the ATP binding site and so were probably negative allosteric modulators of the P2X(7) receptor. GW791343 prevented the slowly reversible blockade of the human P2X(7) receptor produced by compound-17 and inhibited [(3)H]-compound-17 binding to the P2X(7) receptor suggesting they may bind to similar or interacting sites. At rat P2X(7) receptors, compound-17 was a negative allosteric modulator but the predominant effect of GW791343 was to increase agonist responses. Antagonist interaction and radioligand binding studies revealed that GW791343 did not interact at the ATP binding site but did interact with the compound-17 binding site suggesting that GW791343 is a positive allosteric modulator of the rat P2X(7) receptor.. Compound-17 was a negative allosteric modulator of human and rat P2X(7) receptors. GW791343 was a negative allosteric modulator of the human P2X(7) receptor but at the rat P2X(7) receptor its predominant effect was positive allosteric modulation. These compounds should provide valuable tools for mechanistic studies on P2X(7) receptors. Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Adenosine Triphosphate; Allosteric Regulation; Animals; Binding Sites; Cell Line; Dose-Response Relationship, Drug; Ethidium; Glycine; Humans; Molecular Structure; Piperazines; Protein Conformation; Pyridoxal Phosphate; Quinolines; Radioligand Assay; Rats; Receptors, Purinergic P2; Receptors, Purinergic P2X7; Recombinant Proteins; Species Specificity; Time Factors; Transfection; Vanadates | 2008 |