18 results on '"Poyner D"'
Search Results
2. Receptor activity‐modifying protein‐dependent effects of mutations in the calcitonin receptor‐like receptor: implications for adrenomedullin and calcitonin gene‐related peptide pharmacology
- Author
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Watkins, H A, primary, Walker, C S, additional, Ly, K N, additional, Bailey, R J, additional, Barwell, J, additional, Poyner, D R, additional, and Hay, D L, additional
- Published
- 2014
- Full Text
- View/download PDF
3. ChemInform Abstract: Synthesis of 3,4,5,6-Tetrakisphosphates of DL-1,2-Dideoxy-1,2-difluoro- myo-inositol and DL-1,2-Dideoxy-1,2-difluoro-scyllo-inositol as Analogues of DL-myo-Inositol 3,4,5,6-Tetrakisphosphate.
- Author
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SOLOMONS, K. R. H., primary, FREEMAN, S., additional, POYNER, D. R., additional, and YAFAI, F., additional
- Published
- 2010
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4. CL/RAMP2 and CL/RAMP3 produce pharmacologically distinct adrenomedullin receptors: a comparison of effects of adrenomedullin22–52, CGRP8–37 and BIBN4096BS
- Author
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Hay, D L, primary, Howitt, S G, additional, Conner, A C, additional, Schindler, M, additional, Smith, D M, additional, and Poyner, D R, additional
- Published
- 2003
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- View/download PDF
5. ChemInform Abstract: Synthesis and Iron Binding Studies of myo‐Inositol 1,2,3‐Trisphosphate and (.+‐.)‐myo‐Inositol 1,2‐Bisphosphate, and Iron Binding Studies of All myo‐Inositol Tetrakisphosphates.
- Author
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SPIERS, I. D., primary, BARKER, C. J., additional, CHUNG, S.‐K., additional, CHANG, Y.‐T., additional, FREEMAN, S., additional, GARDINER, J. M., additional, HIRST, P. H., additional, LAMBERT, P. A., additional, MICHELL, R. H., additional, POYNER, D. R., additional, SCHWALBE, C. H., additional, SMITH, A. W., additional, and SOLOMONS, K. R. H., additional
- Published
- 1996
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6. Effects of arachidonic acid upon the volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells.
- Author
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Gosling, M, primary, Poyner, D R, additional, and Smith, J W, additional
- Published
- 1996
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7. Characterization of a volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells.
- Author
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Gosling, M, primary, Smith, J W, additional, and Poyner, D R, additional
- Published
- 1995
- Full Text
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8. Investigating G protein signalling bias at the glucagon-like peptide-1 receptor in yeast.
- Author
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Weston C, Poyner D, Patel V, Dowell S, and Ladds G
- Subjects
- Glucagon-Like Peptide-1 Receptor agonists, Glucagon-Like Peptide-1 Receptor genetics, HEK293 Cells, Humans, Saccharomyces cerevisiae genetics, Signal Transduction, GTP-Binding Proteins metabolism, Glucagon-Like Peptide-1 Receptor metabolism, Saccharomyces cerevisiae metabolism
- Abstract
Background and Purpose: The glucagon-like peptide 1 (GLP-1) receptor performs an important role in glycaemic control, stimulating the release of insulin. It is an attractive target for treating type 2 diabetes. Recently, several reports of adverse side effects following prolonged use of GLP-1 receptor therapies have emerged: most likely due to an incomplete understanding of signalling complexities., Experimental Approach: We describe the expression of the GLP-1 receptor in a panel of modified yeast strains that couple receptor activation to cell growth via single Gα/yeast chimeras. This assay enables the study of individual ligand-receptor G protein coupling preferences and the quantification of the effect of GLP-1 receptor ligands on G protein selectivity., Key Results: The GLP-1 receptor functionally coupled to the chimeras representing the human Gαs, Gαi and Gαq subunits. Calculation of the dissociation constant for a receptor antagonist, exendin-3 revealed no significant difference between the two systems. We obtained previously unobserved differences in G protein signalling bias for clinically relevant therapeutic agents, liraglutide and exenatide; the latter displaying significant bias for the Gαi pathway. We extended the use of the system to investigate small-molecule allosteric compounds and the closely related glucagon receptor., Conclusions and Implications: These results provide a better understanding of the molecular events involved in GLP-1 receptor pleiotropic signalling and establish the yeast platform as a robust tool to screen for more selective, efficacious compounds acting at this important class of receptors in the future., (© 2014 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of The British Pharmacological Society.)
- Published
- 2014
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9. The Concise Guide to PHARMACOLOGY 2013/14: overview.
- Author
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Alexander SP, Benson HE, Faccenda E, Pawson AJ, Sharman JL, McGrath JC, Catterall WA, Spedding M, Peters JA, Harmar AJ, Abul-Hasn N, Anderson CM, Anderson CM, Araiksinen MS, Arita M, Arthofer E, Barker EL, Barratt C, Barnes NM, Bathgate R, Beart PM, Belelli D, Bennett AJ, Birdsall NJ, Boison D, Bonner TI, Brailsford L, Bröer S, Brown P, Calo G, Carter WG, Catterall WA, Chan SL, Chao MV, Chiang N, Christopoulos A, Chun JJ, Cidlowski J, Clapham DE, Cockcroft S, Connor MA, Cox HM, Cuthbert A, Dautzenberg FM, Davenport AP, Dawson PA, Dent G, Dijksterhuis JP, Dollery CT, Dolphin AC, Donowitz M, Dubocovich ML, Eiden L, Eidne K, Evans BA, Fabbro D, Fahlke C, Farndale R, Fitzgerald GA, Fong TM, Fowler CJ, Fry JR, Funk CD, Futerman AH, Ganapathy V, Gaisnier B, Gershengorn MA, Goldin A, Goldman ID, Gundlach AL, Hagenbuch B, Hales TG, Hammond JR, Hamon M, Hancox JC, Hauger RL, Hay DL, Hobbs AJ, Hollenberg MD, Holliday ND, Hoyer D, Hynes NA, Inui KI, Ishii S, Jacobson KA, Jarvis GE, Jarvis MF, Jensen R, Jones CE, Jones RL, Kaibuchi K, Kanai Y, Kennedy C, Kerr ID, Khan AA, Klienz MJ, Kukkonen JP, Lapoint JY, Leurs R, Lingueglia E, Lippiat J, Lolait SJ, Lummis SC, Lynch JW, MacEwan D, Maguire JJ, Marshall IL, May JM, McArdle CA, McGrath JC, Michel MC, Millar NS, Miller LJ, Mitolo V, Monk PN, Moore PK, Moorhouse AJ, Mouillac B, Murphy PM, Neubig RR, Neumaier J, Niesler B, Obaidat A, Offermanns S, Ohlstein E, Panaro MA, Parsons S, Pwrtwee RG, Petersen J, Pin JP, Poyner DR, Prigent S, Prossnitz ER, Pyne NJ, Pyne S, Quigley JG, Ramachandran R, Richelson EL, Roberts RE, Roskoski R, Ross RA, Roth M, Rudnick G, Ryan RM, Said SI, Schild L, Sanger GJ, Scholich K, Schousboe A, Schulte G, Schulz S, Serhan CN, Sexton PM, Sibley DR, Siegel JM, Singh G, Sitsapesan R, Smart TG, Smith DM, Soga T, Stahl A, Stewart G, Stoddart LA, Summers RJ, Thorens B, Thwaites DT, Toll L, Traynor JR, Usdin TB, Vandenberg RJ, Villalon C, Vore M, Waldman SA, Ward DT, Willars GB, Wonnacott SJ, Wright E, Ye RD, Yonezawa A, and Zimmermann M
- Subjects
- Humans, Ligands, Pharmaceutical Preparations chemistry, Databases, Pharmaceutical, Molecular Targeted Therapy, Pharmacology
- Abstract
The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates., (Copyright © 2013 The British Pharmacological Society.)
- Published
- 2013
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10. Receptor activity modifying proteins (RAMPs) interact with the VPAC2 receptor and CRF1 receptors and modulate their function.
- Author
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Wootten D, Lindmark H, Kadmiel M, Willcockson H, Caron KM, Barwell J, Drmota T, and Poyner DR
- Subjects
- Adrenocorticotropic Hormone blood, Animals, CHO Cells, Calcium metabolism, Cricetinae, Cricetulus, Cyclic AMP metabolism, Enzyme-Linked Immunosorbent Assay, Guanosine 5'-O-(3-Thiotriphosphate) metabolism, HEK293 Cells, Humans, Mice, Mice, Knockout, Protein Binding, Real-Time Polymerase Chain Reaction, Receptor Activity-Modifying Protein 2 genetics, Receptor Activity-Modifying Protein 2 metabolism, Transfection, Receptor Activity-Modifying Proteins metabolism, Receptors, Corticotropin-Releasing Hormone metabolism, Receptors, Vasoactive Intestinal Peptide, Type II metabolism
- Abstract
Background and Purpose: Although it is established that the receptor activity modifying proteins (RAMPs) can interact with a number of GPCRs, little is known about the consequences of these interactions. Here the interaction of RAMPs with the glucagon-like peptide 1 receptor (GLP-1 receptor), the human vasoactive intestinal polypeptide/pituitary AC-activating peptide 2 receptor (VPAC(2)) and the type 1 corticotrophin releasing factor receptor (CRF(1)) has been examined., Experimental Approach: GPCRs were co-transfected with RAMPs in HEK 293S and CHO-K1 cells. Cell surface expression of RAMPs and GPCRs was examined by ELISA. Where there was evidence for interactions, agonist-stimulated cAMP production, Ca(2+) mobilization and GTPγS binding to G(s), G(i), G(12) and G(q) were examined. The ability of CRF to stimulate adrenal corticotrophic hormone release in Ramp2(+/-) mice was assessed., Key Results: The GLP-1 receptor failed to enhance the cell surface expression of any RAMP. VPAC(2) enhanced the cell surface expression of all three RAMPs. CRF(1) enhanced the cell surface expression of RAMP2; the cell surface expression of CRF(1) was also increased. There was no effect on agonist-stimulated cAMP production. However, there was enhanced G-protein coupling in a receptor and agonist-dependent manner. The CRF(1) : RAMP2 complex resulted in enhanced elevation of intracellular calcium to CRF and urocortin 1 but not sauvagine. In Ramp2(+/-) mice, there was a loss of responsiveness to CRF., Conclusions and Implications: The VPAC(2) and CRF(1) receptors interact with RAMPs. This modulates G-protein coupling in an agonist-specific manner. For CRF(1), coupling to RAMP2 may be of physiological significance., (© 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society.)
- Published
- 2013
- Full Text
- View/download PDF
11. Lifting the lid on GPCRs: the role of extracellular loops.
- Author
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Wheatley M, Wootten D, Conner MT, Simms J, Kendrick R, Logan RT, Poyner DR, and Barwell J
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- Binding Sites, Humans, Ligands, Protein Conformation, Receptors, G-Protein-Coupled chemistry, Receptors, G-Protein-Coupled metabolism
- Abstract
GPCRs exhibit a common architecture of seven transmembrane helices (TMs) linked by intracellular loops and extracellular loops (ECLs). Given their peripheral location to the site of G-protein interaction, it might be assumed that ECL segments merely link the important TMs within the helical bundle of the receptor. However, compelling evidence has emerged in recent years revealing a critical role for ECLs in many fundamental aspects of GPCR function, which supported by recent GPCR crystal structures has provided mechanistic insights. This review will present current understanding of the key roles of ECLs in ligand binding, activation and regulation of both family A and family B GPCRs., (© 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.)
- Published
- 2012
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- View/download PDF
12. Characterization of receptors for calcitonin gene-related peptide and adrenomedullin on the guinea-pig vas deferens.
- Author
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Poyner DR, Taylor GM, Tomlinson AE, Richardson AG, and Smith DM
- Subjects
- Adrenomedullin, Amyloid pharmacology, Animals, Binding, Competitive, Calcitonin Gene-Related Peptide pharmacology, Guinea Pigs, Iodine Radioisotopes, Islet Amyloid Polypeptide, Male, Muscle Contraction drug effects, Peptide Fragments pharmacology, Peptides pharmacology, Radioligand Assay, Receptors, Adrenomedullin, Vas Deferens drug effects, Vasodilator Agents pharmacology, Membrane Proteins metabolism, Receptors, Calcitonin Gene-Related Peptide metabolism, Receptors, Peptide, Vas Deferens metabolism
- Abstract
1. The receptors which mediate the effects of calcitonin gene-related peptide (CGRP), amylin and adrenomedullin on the guinea-pig vas deferens have been investigated. 2. All three peptides cause concentration dependant inhibitions of the electrically stimulated twitch response (pD2s for CGRP, amylin and adrenomedullin of 7.90+/-0.11, 7.70+/-0.19 and 7.25+/-0.10 respectively). 3. CGRP8-37 (1 microM) and AC187 (10 microM) showed little antagonist activity against adrenomedullin. 4. Adrenomedullin22-52 by itself inhibited the electrically stimulated contractions of the vas deferens and also antagonized the responses to CGRP, amylin and adrenomedullin. 5. [125I]-adrenomedullin labelled a single population of binding sites in vas deferens membranes with a pIC50 of 8.91 and a capacity of 643 fmol mg(-1). Its selectivity profile was adrenomedullin> AC187>CGRP=amylin. It was clearly distinct from a site labelled by [125I]-CGRP (pIC50=8.73, capacity=114 fmol mg(-1), selectivity CGRP>amylin=AC187>adrenomedullin). [125I]-amylin bound to two sites with a total capacity of 882 fmol mg(-1). 6. Although CGRP has been shown to act at a CGRP2 receptor on the vas deferens with low sensitivity to CGRP8-37, this antagonist displaced [125I]-CGRP with high affinity from vas deferens membranes. This affinity was unaltered by increasing the temperature from 4 degrees C to 25 degrees C, suggesting the anomalous behaviour of CGRP8-37 is not due to temperature differences between binding and functional assays.
- Published
- 1999
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- View/download PDF
13. Structural determinants for binding to CGRP receptors expressed by human SK-N-MC and Col 29 cells: studies with chimeric and other peptides.
- Author
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Poyner DR, Soomets U, Howitt SG, and Langel U
- Subjects
- Adenylyl Cyclases metabolism, Amino Acid Sequence, Amyloid chemistry, Amyloid metabolism, Animals, Calcitonin Gene-Related Peptide pharmacology, Calcitonin Gene-Related Peptide Receptor Antagonists, Cell Line, Chemical Phenomena, Chemistry, Physical, Cyclic AMP metabolism, Humans, Islet Amyloid Polypeptide, Molecular Sequence Data, Peptide Fragments pharmacology, Radioligand Assay, Rats, Structure-Activity Relationship, Tumor Cells, Cultured, Neuropeptides chemistry, Neuropeptides metabolism, Receptors, Calcitonin Gene-Related Peptide chemistry, Receptors, Calcitonin Gene-Related Peptide metabolism, Recombinant Fusion Proteins chemistry, Recombinant Fusion Proteins metabolism
- Abstract
Structure-activity relationships for the binding of human alpha-calcitonin gene-related peptide 8-37 (halphaCGRP8-37) have been investigated at the CGRP receptors expressed by human SK-N-MC (neuroblastoma) and Col 29 (colonic epithelia) cells by radioligand binding assays and functional assays (halphaCGRP stimulation of adenylate cyclase). On SK-N-MC cells the potency order was halphaCGRP8-37 > halphaCGRP19-37 = AC187 > rat amylin8-37 > halpha[Tyr0]-CGRP28-37 (apparent pKBs of 7.49+/-0.25, 5.89+/-0.20, 6.18+/-0.19, 5.85+/-0.19 and 5.25+/-0.07). The SK-N-MC receptor appeared CGRP1-like. On Col 29 cells, only halphaCGRP8-37 of the above compounds was able to antagonize the actions of halphaCGRP (apparent pKB=6.48+/-0.28). Its receptor appeared CGRP2-like. halpha[Ala11,18]-CGRP8-37, where the amphipathic nature of the N-terminal alpha-helix has been reduced, bound to SK-N-MC cells a 100 fold less strongly than halphaCGRP8-37. On SK-N-MC cells, halphaCGRP8-18,28-37 (M433) and mastoparan-halphaCGRP28-37 (M432) had apparent pKBs of 6.64+/-0.16 and 6.42+/-0.26, suggesting that residues 19-27 play a minor role in binding. The physico-chemical properties of residues 8-18 may be more important than any specific side-chain interactions. M433 was almost as potent as halphaCGRP8-37 on Col 29 cells (apparent pKB=6.17+/-0.20). Other antagonists were inactive.
- Published
- 1998
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14. The selectivity and structural determinants of peptide antagonists at the CGRP receptor of rat, L6 myocytes.
- Author
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Howitt SG and Poyner DR
- Subjects
- Amino Acid Sequence, Animals, Cell Line, Cyclic AMP biosynthesis, Humans, Membrane Proteins agonists, Membrane Proteins antagonists & inhibitors, Membrane Proteins metabolism, Molecular Sequence Data, Muscle, Skeletal cytology, Muscle, Skeletal metabolism, Rats, Receptors, Adrenomedullin, Receptors, Calcitonin Gene-Related Peptide agonists, Receptors, Islet Amyloid Polypeptide, Receptors, Peptide agonists, Receptors, Peptide antagonists & inhibitors, Receptors, Peptide metabolism, Structure-Activity Relationship, Calcitonin Gene-Related Peptide analogs & derivatives, Calcitonin Gene-Related Peptide pharmacology, Calcitonin Gene-Related Peptide Receptor Antagonists, Muscle, Skeletal drug effects, Peptides chemistry, Peptides pharmacology
- Abstract
1. Potency orders were determined for a series of agonists and antagonists on the calcitonin gene-related peptide (CGRP) receptor of rat L6 myocytes. The agents tested were all shown to have been active against CGRP, amylin or adrenomedullin receptors. 2. AC187 had a pIC50 of 6.8 +/- 0.10, making it 14 fold less potent as an antagonist than CGRP8-37 (pIC50, 7.95 +/- 0.14). Amyline8-37 was equipotent to AC187 (pIC50, 6.6 +/- 0.16) and CGRP19-32 was 3 fold less potent than either (pIC50, 6.1 +/- 0.24). 3. [Ala11]-CGRP8-37 was 6 fold less potent than CGRP8-37, (pIC50, 7.13 +/- 0.14), whereas [Ala18]-CGRP8-37 was approximately equipotent to CGRP8-37 (pIC50, 7.52 +/- 0.15). However, [Ala11,Ala18]-CGRP8-37 was over 300 fold less potent than CGRP8-37 (pIC50, 5.30 +/- 0.04). 4. [Tyr0]-CGRP28-37, amylin19-37 and adrenomedullin22-52 were inactive as antagonists at concentrations of up to 1 microM. 5. Biotinyl-human alpha-CGRP was 150 fold less potent than human alpha-CGRP itself (EC50 values of 48 +/- 17 nM and 0.31 +/- 0.13 nM, respectively). At 1 microM, [Cys(acetomethoxy)2,7]-CGRP was inactive as an agonist. 6. These results confirm a role for Arg11 in maintaining the high affinity binding of CGRP8-37. Arg18 is of less direct significance for high affinity binding, but it may be important in maintaining the amphipathic nature of CGRP and its analogues.
- Published
- 1997
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15. Multiple receptors for calcitonin gene-related peptide and amylin on guinea-pig ileum and vas deferens.
- Author
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Tomlinson AE and Poyner DR
- Subjects
- Animals, Dose-Response Relationship, Drug, Guinea Pigs, Humans, Ileum drug effects, Ileum metabolism, Islet Amyloid Polypeptide, Male, Muscle Relaxation, Peptide Fragments pharmacology, Receptors, Islet Amyloid Polypeptide, Vas Deferens drug effects, Vas Deferens metabolism, Amyloid pharmacology, Calcitonin Gene-Related Peptide pharmacology, Muscle, Smooth drug effects, Receptors, Calcitonin Gene-Related Peptide drug effects, Receptors, Peptide drug effects
- Abstract
1. The responses of the electrically stimulated guinea-pig ileum and vas deferens to human and rat calcitonin gene-related peptide (CGRP) and amylin were investigated. 2. The inhibition of contraction of the ileum produced by human alpha CGRP was antagonized by human alpha CGRP8-37 (apparent pA2 estimated at 7.15 +/- 0.23) > human alpha CGRP19-37 (apparent pA2 estimated as 6.67 +/- 0.33) > [Tyr0]-human alpha CGRP28-37. The amylin antagonist, AC187, was three fold less potent than CGRP8-37 in antagonizing human alpha CGRP. 3. Both human beta- and rat alpha CGRP inhibited contractions of the ileum, but this was less sensitive to inhibition by CGRP8-37 than the effect of human alpha CGRP. However, CGRP19-37 was twenty times more effective in inhibiting the response to rat alpha CGRP (apparent pA2 estimated as 8.0 +/- 0.1) compared to human alpha CGRP. 4. Rat amylin inhibited contractions in about 10% of ileal preparations; this effect was not antagonized by any CGRP fragment. Human amylin had no action on this preparation. 5. Both human and rat alpha CGRP inhibited electrically stimulated contractions of the vas deferens, which were not antagonized by 3 microM CGRP8-37 or 10 microM AC187. 6. Rat amylin inhibited the stimulated contractions of the vas deferens (EC50 = 77 +/- 9 nM); human amylin was less potent (EC50 = 213 +/- 22 nM). The response to rat amylin was antagonized by 10 microM CGRP8-37 (EC50 = 242 +/- 25 nM) and 10 microM AC187 (EC50 = 610 +/- 22 nM). 7. It is concluded that human alpha CGRP relaxes the guinea-pig ileum via CGRP1-like receptors, but that human beta CGRP and rat alpha CGRP may use additional receptors. These are distinct CGRP2-like and amylin receptors on guinea-pig vas deferens.
- Published
- 1996
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16. Pharmacological characterization of a receptor for calcitonin gene-related peptide on rat, L6 myocytes.
- Author
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Poyner DR, Andrew DP, Brown D, Bose C, and Hanley MR
- Subjects
- Animals, Calcitonin Gene-Related Peptide metabolism, Cell Line, Cells, Cultured, Cyclic AMP metabolism, Inosine Triphosphate metabolism, Iodine Radioisotopes, Kinetics, Muscles cytology, Radioligand Assay, Rats, Receptors, Calcitonin, Muscles metabolism, Receptors, Cell Surface drug effects
- Abstract
1 The L6 myocyte cell line expresses high affinity receptors for calcitonin gene-related peptide (CGRP) which are coupled to activation of adenylyl cyclase. The biochemical pharmacology of these receptors has been examined by radioligand binding or adenosine 3':5'-cyclic monophosphate (cyclic AMP) accumulation. 2 In intact cells at 37 degrees C, human and rat alpha- and beta-CGRP all activated adenylyl cyclase with EC50s of about 1.5 nM. A number of CGRP analogues containing up to five amino acid substitutions showed similar potencies. In membrane binding studies at 22 degrees C in 1 mM Mg2+, the above all bound to a single site with IC50s of 0.1-0.4 nM. 3 The fragment CGRP(8-37) acted as a competitive antagonist of CGRP stimulation of adenylyl cyclase with a calculated Kd of 5 nM. The Kd determined in membrane binding assays was lower (0.5 nM). 4 The N-terminal extended human alpha-CGRP analogue Tyro-CGRP activated adenylyl cyclase and inhibited [125I]-iodohistidyl-CGRP binding less potently than human alpha-CGRP (EC50 for cyclase = 12 nM, IC50 for binding = 4 nM). 5 The pharmacological profile of the L6 CGRP receptor suggests that it most closely resembles sites on skeletal muscle, cardiac myocytes and hepatocytes. The L6 cell line should be a stable homogeneous model system in which to study CGRP mechanisms and pharmacology.
- Published
- 1992
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17. Modulation of the structure-binding relationships of antagonists for muscarinic acetylcholine receptor subtypes.
- Author
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Pedder EK, Eveleigh P, Poyner D, Hulme EC, and Birdsall NJ
- Subjects
- Animals, Centrifugation, Cerebral Cortex drug effects, Cerebral Cortex metabolism, Cholic Acids pharmacology, Digitonin pharmacology, Gallamine Triethiodide pharmacology, Heart drug effects, In Vitro Techniques, Lacrimal Apparatus drug effects, Lacrimal Apparatus metabolism, Membranes drug effects, Membranes metabolism, Myocardium metabolism, Parasympatholytics pharmacology, Piperidines pharmacology, Pirenzepine analogs & derivatives, Pirenzepine pharmacology, Rats, Structure-Activity Relationship, Muscarinic Antagonists
- Abstract
1. Membranes from rat cerebral cortex, myocardium and extraorbital lacrimal gland were used as sources of M1, M2 and M3 muscarinic acetylcholine receptors respectively and the affinities of seven antagonists for the three subtypes were examined under different experimental conditions. 2. The affinities for the membrane-bound receptors were measured at different ionic strengths and temperatures and compared with those determined on the receptor solubilised in the neutral detergent digitonin or the zwitterionic detergent, CHAPSO. 3. The range of measured affinity constants of a given antagonist for a specific subtype varied from 2 (atropine at M1 receptors) to 1000 (AF-DX 116 at M2 receptors). 4. As a consequence of these changes in affinity, which were dependent on the drug, the subtype and the experimental conditions, both the structure-binding relationships of a given subtype can be markedly changed as well as the selectivity of a drug for the different subtypes. For example it is possible to change the relative affinities of AF-DX 116 and gallamine at membrane-bound M1 receptors from 50:1 to 1:60. 5. Experimental conditions for the observation of high selectivity of pirenzepine, AF-DX 116, gallamine and hexahydrosiladiphenidol for the three subtypes are given. 6. When the receptors are removed from their membrane environment by solubilisation in detergent, antagonist affinities are changed but the subtypes still retain different structure-binding relationships. 7. In general, AF-DX 116 and the allosteric antagonist, gallamine, behave differently from the other antagonists, suggesting that they bind in different ways to muscarinic receptors. Careful attention should therefore be paid to the experimental conditions in binding assays used to assess the affinities and selectivities of new muscarinic antagonists in order to avoid misleading results. 9. The ability to produce enhanced or attenuated affinities and selectivities of antagonists, resulting from the induction of different conformations of the receptor by a variety of physical, chemical or molecular biological perturbations may lead to a better understanding of the structural basis of drug receptor interactions.
- Published
- 1991
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18. The mas oncogene as a neural peptide receptor: expression, regulation and mechanism of action.
- Author
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Hanley MR, Cheung WT, Hawkins P, Poyner D, Benton HP, Blair L, Jackson TR, and Goedert M
- Subjects
- Amino Acid Sequence, Angiotensin III metabolism, Animals, Humans, Molecular Sequence Data, Protein Conformation, Proto-Oncogene Mas, Transfection, Brain metabolism, Gene Expression Regulation, Oncogenes, Proto-Oncogenes, Receptors, Angiotensin genetics
- Abstract
The human mas oncogene, which renders transfected NIH/3T3 cells tumorigenic, was identified as a subtype of angiotensin receptor by transient expression in Xenopus oocytes and stable expression in the mammalian neuronal cell line, NG115-401L. The mas receptor preferentially recognizes angiotensin III, and is expressed at high levels in brain. The mas/angiotensin receptor functions through the breakdown of inositol lipids and can drive DNA synthesis, unlike another inositol-linked peptide receptor, that for bradykinin. Comparative analysis of several early biochemical events elicited by either angiotensin or bradykinin stimulation of mas-transfected cells has not indicated a specific difference correlated with mitogenic activity. In particular, the inositol lipid kinase, phosphatidylinositol-3-kinase, thought to be involved in the mitogenic mechanism of platelet-derived growth factor receptors, is unaffected by activation of mas. These results have shown that a proto-oncogene encodes a neural peptide receptor, indicating that peptide receptors may be involved in differentiation and proliferation processes, as are other identified proto-oncogenes.
- Published
- 1990
- Full Text
- View/download PDF
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