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Griffith DA, Edmonds DJ, Fortin JP, Kalgutkar AS, Kuzmiski JB, Loria PM, Saxena AR, Bagley SW, Buckeridge C, Curto JM, Derksen DR, Dias JM, Griffor MC, Han S, Jackson VM, Landis MS, Lettiere D, Limberakis C, Liu Y, Mathiowetz AM, Patel JC, Piotrowski DW, Price DA, Ruggeri RB, Tess DA. A Small-Molecule Oral Agonist of the Human Glucagon-like Peptide-1 Receptor. J Med Chem 2022; 65:8208-8226. [PMID: 35647711 PMCID: PMC9234956 DOI: 10.1021/acs.jmedchem.1c01856] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide agonists of the glucagon-like peptide-1 receptor (GLP-1R) have revolutionized diabetes therapy, but their use has been limited because they require injection. Herein, we describe the discovery of the orally bioavailable, small-molecule, GLP-1R agonist PF-06882961 (danuglipron). A sensitized high-throughput screen was used to identify 5-fluoropyrimidine-based GLP-1R agonists that were optimized to promote endogenous GLP-1R signaling with nanomolar potency. Incorporation of a carboxylic acid moiety provided considerable GLP-1R potency gains with improved off-target pharmacology and reduced metabolic clearance, ultimately resulting in the identification of danuglipron. Danuglipron increased insulin levels in primates but not rodents, which was explained by receptor mutagensis studies and a cryogenic electron microscope structure that revealed a binding pocket requiring a primate-specific tryptophan 33 residue. Oral administration of danuglipron to healthy humans produced dose-proportional increases in systemic exposure (NCT03309241). This opens an opportunity for oral small-molecule therapies that target the well-validated GLP-1R for metabolic health.
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Affiliation(s)
- David A Griffith
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - David J Edmonds
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Jean-Philippe Fortin
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Amit S Kalgutkar
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - J Brent Kuzmiski
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Paula M Loria
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Aditi R Saxena
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Scott W Bagley
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Clare Buckeridge
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - John M Curto
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - David R Derksen
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - João M Dias
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Matthew C Griffor
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Seungil Han
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - V Margaret Jackson
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Margaret S Landis
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Daniel Lettiere
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Chris Limberakis
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Yuhang Liu
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - Alan M Mathiowetz
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | | | - David W Piotrowski
- Pfizer Worldwide Research, Development, and Medical, Groton, Connecticut 06340, United States
| | - David A Price
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - Roger B Ruggeri
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
| | - David A Tess
- Pfizer Worldwide Research, Development, and Medical, Cambridge, Massachusetts 02139, United States
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2
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Sun EW, Iepsen EW, Pezos N, Lumsden AL, Martin AM, Schober G, Isaacs NJ, Rayner CK, Nguyen NQ, de Fontgalland D, Rabbitt P, Hollington P, Wattchow DA, Hansen T, Holm JC, Liou AP, Jackson VM, Torekov SS, Young RL, Keating DJ. A Gut-Intrinsic Melanocortin Signaling Complex Augments L-Cell Secretion in Humans. Gastroenterology 2021; 161:536-547.e2. [PMID: 33848536 DOI: 10.1053/j.gastro.2021.04.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/04/2021] [Accepted: 04/06/2021] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Hypothalamic melanocortin 4 receptors (MC4R) are a key regulator of energy homeostasis. Brain-penetrant MC4R agonists have failed, as concentrations required to suppress food intake also increase blood pressure. However, peripherally located MC4R may also mediate metabolic benefits of MC4R activation. Mc4r transcript is enriched in mouse enteroendocrine L cells and peripheral administration of the endogenous MC4R agonist, α-melanocyte stimulating hormone (α-MSH), triggers the release of the anorectic hormones Glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY) in mice. This study aimed to determine whether pathways linking MC4R and L-cell secretion exist in humans. DESIGN GLP-1 and PYY levels were assessed in body mass index-matched individuals with or without loss-of-function MC4R mutations following an oral glucose tolerance test. Immunohistochemistry was performed on human intestinal sections to characterize the mucosal MC4R system. Static incubations with MC4R agonists were carried out on human intestinal epithelia, GLP-1 and PYY contents of secretion supernatants were assayed. RESULTS Fasting PYY levels and oral glucose-induced GLP-1 secretion were reduced in humans carrying a total loss-of-function MC4R mutation. MC4R was localized to L cells and regulates GLP-1 and PYY secretion from ex vivo human intestine. α-MSH immunoreactivity in the human intestinal epithelia was predominantly localized to L cells. Glucose-sensitive mucosal pro-opiomelanocortin cells provide a local source of α-MSH that is essential for glucose-induced GLP-1 secretion in small intestine. CONCLUSION Our findings describe a previously unidentified signaling nexus in the human gastrointestinal tract involving α-MSH release and MC4R activation on L cells in an autocrine and paracrine fashion. Outcomes from this study have direct implications for targeting mucosal MC4R to treat human metabolic disorders.
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Affiliation(s)
- Emily W Sun
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Eva W Iepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Nektaria Pezos
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Amanda L Lumsden
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Alyce M Martin
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia
| | - Gudrun Schober
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Nichole J Isaacs
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia
| | - Christopher K Rayner
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Nam Q Nguyen
- Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, Australia
| | - Torben Hansen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Jens-Christian Holm
- The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark; Department of Pediatrics, Holbæk University Hospital, Holbæk, Denmark
| | - Alice P Liou
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - V Margaret Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts
| | - Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; The Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Richard L Young
- Nutrition, Diabetes and Metabolism, Lifelong Health, South Australia Health and Medical Research Institute, Adelaide, Australia; Adelaide Medical School and NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Australia.
| | - Damien J Keating
- Flinders Health and Medical Research Institute, College of Medicine and Public Health, Flinders University, Bedford Park, Australia.
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Young RL, Lumsden AL, Martin AM, Schober G, Pezos N, Thazhath SS, Isaacs NJ, Cvijanovic N, Sun EWL, Wu T, Rayner CK, Nguyen NQ, Fontgalland DD, Rabbitt P, Hollington P, Sposato L, Due SL, Wattchow DA, Liou AP, Jackson VM, Keating DJ. Augmented capacity for peripheral serotonin release in human obesity. Int J Obes (Lond) 2018; 42:1880-1889. [PMID: 29568107 DOI: 10.1038/s41366-018-0047-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 01/08/2018] [Accepted: 01/16/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND/OBJECTIVES Evidence from animal studies highlights an important role for serotonin (5-HT), derived from gut enterochromaffin (EC) cells, in regulating hepatic glucose production, lipolysis and thermogenesis, and promoting obesity and dysglycemia. Evidence in humans is limited, although elevated plasma 5-HT concentrations are linked to obesity. SUBJECTS/METHODS We assessed (i) plasma 5-HT concentrations before and during intraduodenal glucose infusion (4 kcal/min for 30 min) in non-diabetic obese (BMI 44 ± 4 kg/m2, N = 14) and control (BMI 24 ± 1 kg/m2, N = 10) subjects, (ii) functional activation of duodenal EC cells (immunodetection of phospho-extracellular related-kinase, pERK) in response to glucose, and in separate subjects, (iii) expression of tryptophan hydroxylase-1 (TPH1) in duodenum and colon (N = 39), and (iv) 5-HT content in primary EC cells from these regions (N = 85). RESULTS Plasma 5-HT was twofold higher in obese than control responders prior to (P = 0.025), and during (iAUC, P = 0.009), intraduodenal glucose infusion, and related positively to BMI (R2 = 0.334, P = 0.003) and HbA1c (R2 = 0.508, P = 0.009). The density of EC cells in the duodenum was twofold higher at baseline in obese subjects than controls (P = 0.023), with twofold more EC cells activated by glucose infusion in the obese (EC cells co-expressing 5-HT and pERK, P = 0.001), while the 5-HT content of EC cells in duodenum and colon was similar; TPH1 expression was 1.4-fold higher in the duodenum of obese subjects (P = 0.044), and related positively to BMI (R2 = 0.310, P = 0.031). CONCLUSIONS Human obesity is characterized by an increased capacity to produce and release 5-HT from the proximal small intestine, which is strongly linked to higher body mass, and glycemic control. Gut-derived 5-HT is likely to be an important driver of pathogenesis in human obesity and dysglycemia.
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Affiliation(s)
- Richard L Young
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Amanda L Lumsden
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Alyce M Martin
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Gudrun Schober
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Nektaria Pezos
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Sony S Thazhath
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nicole J Isaacs
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Nada Cvijanovic
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia
| | - Emily W L Sun
- Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia
| | - Tongzhi Wu
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Christopher K Rayner
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Nam Q Nguyen
- Adelaide Medical School, The University of Adelaide, Adelaide, SA, 5005, Australia.,NHMRC Centre of Research Excellence in Translating Nutritional Science to Good Health, The University of Adelaide, Adelaide, SA, 5005, Australia
| | - Dayan de Fontgalland
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Philippa Rabbitt
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Paul Hollington
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Luigi Sposato
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Steven L Due
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - David A Wattchow
- Department of Surgery, Flinders Medical Centre, Bedford Park, SA, 5042, Australia
| | - Alice P Liou
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 02139, USA
| | - V Margaret Jackson
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 02139, USA
| | - Damien J Keating
- Nutrition & Metabolism, South Australian Health and Medical Research Institute (SAHMRI), Adelaide, SA, 5000, Australia. .,Centre for Neuroscience & Department of Human Physiology, Flinders University, Bedford Park, SA, 5042, Australia.
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Denney WS, Sonnenberg GE, Carvajal-Gonzalez S, Tuthill T, Jackson VM. Pharmacokinetics and pharmacodynamics of PF-05190457: The first oral ghrelin receptor inverse agonist to be profiled in healthy subjects. Br J Clin Pharmacol 2016; 83:326-338. [PMID: 27621150 DOI: 10.1111/bcp.13127] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 08/25/2016] [Accepted: 09/08/2016] [Indexed: 02/06/2023] Open
Abstract
AIM To evaluate safety, tolerability and pharmacokinetics of oral PF-05190457, an oral ghrelin receptor inverse agonist, in healthy adults. METHODS Single (SAD) and multiple ascending dose (MAD) studies were randomised, placebo-controlled, double-blind studies. Thirty-five healthy men (age 38.2 ± 10.4 years; body mass index 24.8 ± 3.1 kg m-2 [mean ± standard deviation]) received ≥1 dose (2, 10, 40 [divided], 50, 100, 150, and 300 [single or divided] mg) of PF-05190457 and/or placebo in the SAD. In the MAD study, 35 healthy men (age 39.7 ± 10.1 years; body mass index 25.9 ± 3.3 kg m-2 ) received ≥1 dose (2, 10, 40 and 100 mg twice daily) of PF-05190457 and/or placebo daily for 2 weeks. RESULTS PF-05190457 absorption was rapid with a Tmax of 0.5-3 hours and a half-life between 8.2-9.8 hours. PF-05190457 dose-dependently blocked ghrelin (1 pmol kg-1 min-1 )-induced growth hormone (GH) release with (mean [90% confidence interval]) 77% [63-85%] inhibition at 100 mg. PF-05190457 (150 mg) delayed gastric emptying lag time by 30% [7-58%] and half emptying time by 20% [7-35%] with a corresponding decrease in postprandial glucose by 9 mg dL-1 . The most frequent adverse event reported by 30 subjects at doses ≥50 mg was somnolence. PF-05190457 plasma concentrations also increased heart rate up to 13.4 [4.8-58.2] beats min-1 and, similar to the effect on glucose and ghrelin-induced GH, was lost within 2 weeks. CONCLUSIONS PF-05190457 is a well-tolerated first-in-class ghrelin receptor inverse agonist with acceptable pharmacokinetics for oral daily dosing. Blocking ghrelin receptors inhibits ghrelin-induced GH, and increases heart rate, effects that underwent tachyphylaxis with chronic dosing. PF-051940457 has the potential to treat centrally-acting disorders such as insomnia.
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Affiliation(s)
- William S Denney
- Biotherapeutics Clinical Pharmacology, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, 02139, USA
| | - Gabriele E Sonnenberg
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, 02139, USA
| | - Santos Carvajal-Gonzalez
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, 02139, USA
| | - Theresa Tuthill
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, 02139, USA
| | - V Margaret Jackson
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, 02139, USA
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5
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Kong J, Chuddy J, Stock IA, Loria PM, Straub SV, Vage C, Cameron KO, Bhattacharya SK, Lapham K, McClure KF, Zhang Y, Jackson VM. Pharmacological characterization of the first in class clinical candidate PF-05190457: a selective ghrelin receptor competitive antagonist with inverse agonism that increases vagal afferent firing and glucose-dependent insulin secretion ex vivo. Br J Pharmacol 2016; 173:1452-64. [PMID: 26784385 DOI: 10.1111/bph.13439] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Ghrelin increases growth hormone secretion, gastric acid secretion, gastric motility and hunger but decreases glucose-dependent insulin secretion and insulin sensitivity in humans. Antagonizing the ghrelin receptor has potential as a therapeutic approach in the treatment of obesity and type 2 diabetes. Therefore, the aim was to pharmacologically characterize the novel small-molecule antagonist PF-05190457 and assess translational pharmacology ex vivo. EXPERIMENTAL APPROACH Radioligand binding in filter and scintillation proximity assay formats were used to evaluate affinity, and europium-labelled GTP to assess functional activity. Rat vagal afferent firing and calcium imaging in dispersed islets were used as native tissues underlying food intake and insulin secretion respectively. KEY RESULTS PF-05190457 was a potent and selective inverse agonist on constitutively active ghrelin receptors and acted as a competitive antagonist of ghrelin action, with a human Kd of 3 nM requiring 4 h to achieve equilibrium. Potency of PF-05190457 was similar across different species. PF-05190457 increased intracellular calcium within dispersed islets and increased vagal afferent firing in a concentration-dependent manner with similar potency but was threefold less potent as compared with the in vitro Ki in recombinant overexpressing cells. The effect of PF-05190457 on rodent islets was comparable with glibenclamide, but glucose-dependent and additive with the insulin secretagogue glucagon-like peptide-1. CONCLUSIONS AND IMPLICATIONS Together, these data provide the pharmacological in vitro and ex vivo characterization of the first ghrelin receptor inverse agonist, which has advanced into clinical trials to evaluate the therapeutic potential of blocking ghrelin receptors in obesity and type 2 diabetes.
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Affiliation(s)
- J Kong
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - J Chuddy
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - I A Stock
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - P M Loria
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - S V Straub
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - C Vage
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - K O Cameron
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - S K Bhattacharya
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - K Lapham
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - K F McClure
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - Y Zhang
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
| | - V M Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, Cambridge, MA, 01239, USA
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Jackson VM, Breen DM, Fortin JP, Liou A, Kuzmiski JB, Loomis AK, Rives ML, Shah B, Carpino PA. Latest approaches for the treatment of obesity. Expert Opin Drug Discov 2015; 10:825-39. [DOI: 10.1517/17460441.2015.1044966] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- V Margaret Jackson
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Danna M Breen
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Jean-Philippe Fortin
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Alice Liou
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - J Brent Kuzmiski
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - A Katrina Loomis
- 2Clinical Research, Pfizer PharmaTherapeutics, Eastern Point Road, Groton, CT 06340, USA
| | - Marie-Laure Rives
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Bhavik Shah
- 1Cardiovascular and Metabolic Diseases Research Unit, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
| | - Philip A Carpino
- 3Cardiovascular and Metabolic Diseases Medicinal Chemistry, Pfizer PharmaTherapeutics, 610 Main Street, Cambridge, MA 02139, USA
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Jackson VM, Price DA, Carpino PA. Investigational drugs in Phase II clinical trials for the treatment of obesity: implications for future development of novel therapies. Expert Opin Investig Drugs 2014; 23:1055-66. [DOI: 10.1517/13543784.2014.918952] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- V Margaret Jackson
- Cardiovascular and Metabolic Diseases Research Unit, Pfizer Worldwide Research and Development, 610 Main Street, Cambridge, MA 02139, USA
| | - David A Price
- Cardiovascular and Metabolic Diseases Medicinal Chemistry, Pfizer Worldwide Research and Development, 610 Main Street, Cambridge, MA 02139, USA
| | - Philip A Carpino
- Cardiovascular and Metabolic Diseases Medicinal Chemistry, Pfizer Worldwide Research and Development, 610 Main Street, Cambridge, MA 02139, USA
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8
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Bhattacharya SK, Andrews K, Beveridge R, Cameron KO, Chen C, Dunn M, Fernando D, Gao H, Hepworth D, Jackson VM, Khot V, Kong J, Kosa RE, Lapham K, Loria PM, Londregan AT, McClure KF, Orr STM, Patel J, Rose C, Saenz J, Stock IA, Storer G, VanVolkenburg M, Vrieze D, Wang G, Xiao J, Zhang Y. Discovery of PF-5190457, a Potent, Selective, and Orally Bioavailable Ghrelin Receptor Inverse Agonist Clinical Candidate. ACS Med Chem Lett 2014; 5:474-9. [PMID: 24900864 DOI: 10.1021/ml400473x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 02/18/2014] [Indexed: 01/15/2023] Open
Abstract
The identification of potent, highly selective orally bioavailable ghrelin receptor inverse agonists from a spiro-azetidino-piperidine series is described. Examples from this series have promising in vivo pharmacokinetics and increase glucose-stimulated insulin secretion in human whole and dispersed islets. A physicochemistry-based strategy to increase lipophilic efficiency for ghrelin receptor potency and retain low clearance and satisfactory permeability while reducing off-target pharmacology led to the discovery of 16h. Compound 16h has a superior balance of ghrelin receptor pharmacology and off-target selectivity. On the basis of its promising pharmacological and safety profile, 16h was advanced to human clinical trials.
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Affiliation(s)
- Samit K. Bhattacharya
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Kim Andrews
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Ramsay Beveridge
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Kimberly O. Cameron
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Chiliu Chen
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Matthew Dunn
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Dilinie Fernando
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Hua Gao
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - David Hepworth
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - V. Margaret Jackson
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Vishal Khot
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Jimmy Kong
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Rachel E. Kosa
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Kimberly Lapham
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Paula M. Loria
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Allyn T. Londregan
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Kim F. McClure
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Suvi T. M. Orr
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Jigna Patel
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Colin Rose
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - James Saenz
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Ingrid A. Stock
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Gregory Storer
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Maria VanVolkenburg
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Derek Vrieze
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Guoqiang Wang
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Jun Xiao
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
| | - Yingxin Zhang
- Worldwide Medicinal Chemistry, ‡Cardiovascular and
Metabolic Research Unit, §Pharmacokinetics,
Dynamics, and Metabolism, ∥Primary Pharmacology Group, and ⊥Pharmaceutical Sciences, Pfizer Global Research and Development, 620 Memorial Drive, Cambridge, Massachusetts 02139, United States
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9
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Kuc RE, Maguire JJ, Siew K, Patel S, Derksen DR, Margaret Jackson V, O'Shaughnessey KM, Davenport AP. Characterization of [¹²⁵I]GLP-1(9-36), a novel radiolabeled analog of the major metabolite of glucagon-like peptide 1 to a receptor distinct from GLP1-R and function of the peptide in murine aorta. Life Sci 2014; 102:134-8. [PMID: 24641952 DOI: 10.1016/j.lfs.2014.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 01/29/2014] [Accepted: 03/04/2014] [Indexed: 12/26/2022]
Abstract
AIMS Glucagon-like peptide 1 (GLP-1) is an insulin secretagogue, released in response to meal ingestion and efficiently lowers blood glucose in Type 2 diabetic patients. GLP-1(7-36) is rapidly metabolized by dipeptidyl peptidase IV to the major metabolite GLP-1(9-36)-amide, often thought to be inactive. Inhibitors of this enzyme are widely used to treat diabetes. Our aim was to characterize the binding of GLP-1(9-36) to native mouse tissues and to cells expressing GLP1-R as well as to measure functional responses in the mouse aorta compared with GLP-1(7-36). MAIN METHODS The affinity of [(125)I]GLP-1(7-36) and [(125)I]GLP-1(9-36) was measured in mouse tissues by saturation binding and autoradiography used to determine receptor distribution. The affinity of both peptides was compared in binding to recombinant GLP-1 receptors using cAMP and scintillation proximity assays. Vasoactivity was determined in mouse aortae in vitro. KEY FINDINGS In cells expressing GLP-1 receptors, GLP-1(7-36) bound with the expected high affinities (0.1 nM) and an EC50 of 0.07 nM in cAMP assays but GLP-1(9-36) bound with 70,000 and 100,000 fold lower affinities respectively. In contrast, in mouse brain, both labeled peptides bound with a single high affinity, with Hill slopes close to unity, although receptor density was an order of magnitude lower for [(125)I]GLP-1(9-36). In functional experiments both peptides had similar potencies, GLP-1(7-36), pD2=7.40 ± 0.24 and GLP-1(9-36), pD2=7.57 ± 0.64. SIGNIFICANCE These results suggest that GLP-1(9-36) binds and has functional activity in the vasculature but these actions may be via a pathway that is distinct from the classical GLP-1 receptor and insulin secretagogue actions.
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Affiliation(s)
- Rhoda E Kuc
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Janet J Maguire
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Keith Siew
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Sheena Patel
- Pfizer, Cardiovascular Medicine, Cambridge, MA, USA
| | | | | | | | - Anthony P Davenport
- Clinical Pharmacology Unit, Box 110, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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10
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Abstract
The small intestine is traditionally viewed as an organ that mediates nutrient digestion and absorption. This view has recently been revised owing to the ability of the duodenum to sense nutrient influx and trigger negative feedback loops to inhibit glucose production and food intake to maintain metabolic homeostasis. Further, duodenal nutrient-sensing defects are acquired in diabetes and obesity, leading to increased glucose production. In contrast, jejunal nutrient sensing inhibits glucose production and mediates the early antidiabetic effect of bariatric surgery, and gut microbiota composition may alter intestinal nutrient-sensing mechanisms to regain better control of glucose homeostasis in diabetes and obesity in the long term. This perspective highlights nutrient-sensing mechanisms in the gut that regulate glucose homeostasis and the potential of targeting gut nutrient-sensing mechanisms as a therapeutic strategy to lower blood glucose concentrations in diabetes.
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Affiliation(s)
- Danna M. Breen
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Brittany A. Rasmussen
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Clémence D. Côté
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - V. Margaret Jackson
- Department of Cardiovascular, Metabolic and Endocrine Diseases, Pfizer Global Research and Development, Cambridge, Massachusetts
| | - Tony K.T. Lam
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Medicine, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Corresponding author: Tony K.T. Lam,
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11
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Straub SV, Perez SM, Tan B, Coughlan KA, Trebino CE, Cosgrove P, Buxton JM, Kreeger JM, Jackson VM. Pharmacological inhibition of Kv1.3 fails to modulate insulin sensitivity in diabetic mice or human insulin-sensitive tissues. Am J Physiol Endocrinol Metab 2011; 301:E380-90. [PMID: 21586699 DOI: 10.1152/ajpendo.00076.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Genetic ablation of the voltage-gated potassium channel Kv1.3 improves insulin sensitivity and increases metabolic rate in mice. Inhibition of Kv1.3 in mouse adipose and skeletal muscle is reported to increase glucose uptake through increased GLUT4 translocation. Since Kv1.3 represents a novel target for the treatment of diabetes, the present study investigated whether Kv1.3 is functionally expressed in human adipose and skeletal muscle and whether specific pharmacological inhibition of the channel is capable of modulating insulin sensitivity in diabetic mouse models. Voltage-gated K(+) channel currents in human skeletal muscle cells (SkMC) were insensitive to block by the specific Kv1.3 blockers 5-(4-phenoxybutoxy)psoralen (PAP-1) and margatoxin (MgTX). Glucose uptake into SkMC and mouse 3T3-L1 adipocytes was also unaffected by treatment with PAP-1 or MgTX. Kv1.3 protein expression was not observed in human adipose or skeletal muscle from normal and type 2 diabetic donors. To investigate the effect of specific Kv1.3 inhibition on insulin sensitivity in vivo, PAP-1 was administered to hyperglycemic mice either acutely or for 5 days prior to an insulin tolerance test. No effect on insulin sensitivity was observed at free plasma PAP-1 concentrations that are specific for inhibition of Kv1.3. Insulin sensitivity was increased only when plasma concentrations of PAP-1 were sufficient to inhibit other Kv1 channels. Surprisingly, acute inhibition of Kv1.3 in the brain was found to decrease insulin sensitivity in ob/ob mice. Overall, these findings are not supportive of a role for Kv1.3 in the modulation of peripheral insulin sensitivity.
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Affiliation(s)
- Stephen V Straub
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer, Eastern Point Rd., Groton, CT 06340, USA.
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12
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Boustany-Kari CM, Jackson VM, Gibbons CP, Swick AG. Leptin potentiates the anti-obesity effects of rimonabant. Eur J Pharmacol 2011; 658:270-6. [PMID: 21371466 DOI: 10.1016/j.ejphar.2011.02.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 01/27/2011] [Accepted: 02/17/2011] [Indexed: 11/19/2022]
Abstract
We hypothesized that a combination of low doses of rimonabant and leptin would markedly reduce body weight through the modulation of neuronal activity within the hypothalamus. To this end, high fat diet-induced obese rats were randomized to receive either leptin (0.5mg/kg subcutaneously), rimonabant (3mg/kg), the combination of both, or vehicle, daily for a duration of 2 weeks. A subset of rats was pair-fed to the combination-treated animals and received either vehicle or leptin. At the end of the weight loss phase, leptin treatment was maintained for 7 days while rimonabant was discontinued to assess changes in body weight during the rebound phase. The combination of rimonabant and leptin resulted in a marked inhibition of food intake and a profound reduction in body weight that was greater than achieved with either leptin or rimonabant alone. Treatment with leptin during the rebound phase inhibited compensatory increases in body weight associated with restitution of ad libitum feeding in previously pair-fed rats. Moreover, leptin partially blunted the rebound in food intake and body weight associated with cessation of rimonabant therapy.To investigate the effect of the combination on neuronal firing in the rat hypothalamus, single unit activity was recorded from brain slices containing the ventromedial and arcuate nuclei. The combination of rimonabant and leptin synergistically increased and decreased neuronal firing in the ventromedial and arcuate nuclei, respectively. Overall, these data demonstrate profound anti-obesity effects of combining cannabinoid type 1 receptor antagonists and leptin.
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Affiliation(s)
- Carine M Boustany-Kari
- Department of Cardiovascular, Metabolic and Endocrine Diseases, Pfizer Global Research and Development, Eastern Point Road, Groton, CT 06340, USA.
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13
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Abstract
INTRODUCTION Neuropeptides are known to modulate female receptivity. However, even though receptivity is a spinal reflex, the role of neuropeptides within the spinal cord remains to be elucidated. AIM The aims were to (i) investigate neuropeptides in the lumbosacral region; and (ii) determine how neuropeptides modulate glutamate release from stretch Ia fibers, touch sensation Abeta fibers and Adelta/C pain fibers. MAIN OUTCOME MEASURES Neuropeptide modulation of the lumbosacral dorsal-root ventral-root reflex in vitro. METHODS Spinal cords were removed from Sprague-Dawley rats in compliance with UK Home Office guidelines. Hemisected cords were superfused with aCSF and the dorsal root (L4-S1) was stimulated to evoke glutamate release. A biphasic reflex response was evoked from the opposite ventral root consisting of a monosynaptic (Ia fibers) and polysynaptic (Abeta, Adelta/C fibers) component. RESULTS The micro opioid receptor (MOR) agonist DAMGO inhibited the monosynaptic (EC(50) 0.02 +/- 0.02 nM) and polysynaptic area (EC(50) 125 +/- 167 nM) but not polysynaptic amplitude. Oxytocin and corticotrophin releasing factor (CRF) inhibited the monosynaptic amplitude (EC(50), 1.4 +/- 1.0 nM and EC(50) 4.3 +/- 3.5 nM, respectively), polysynaptic amplitude (EC(50) 18.2 +/- 28.0 nM and EC(50), 9.5 +/- 13.3 nM, respectively), and area (EC(50) 11.6 +/- 13.0 nM and EC(50), 2.8 +/- 3.3 nM, respectively); effects that were abolished by oxytocin and CRF(1) antagonists, L-368899 and 8w. Melanocortin agonists solely inhibited the monosynaptic component, which were blocked by the MC(3/4) receptor antagonist SHU9119. CONCLUSION These data suggest endogenous neuropeptides are released within the lumbosacral spinal cord. Melanocortin agonists, oxytocin, CRF, and DAMGO via MC(4), oxytocin, CRF(1), and MOR inhibit glutamate release but with differing effects on afferent fiber subtypes. Melanocortins, oxytocin, CRF, and DAMGO have the ability to modulate orgasm whereas oxytocin, CRF and DAMGO can increase pain threshold. Oxytocin and CRF may dampen touch sensation.
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Affiliation(s)
- Lesley A Wilson
- Pfizer Global Research & Development-Discovery Biology, Sandwich, Kent, UK
| | - Chris P Wayman
- Pfizer Global Research & Development-Discovery Biology, Sandwich, Kent, UK
| | - V Margaret Jackson
- Pfizer Global Research & Development-Discovery Biology, Sandwich, Kent, UK.
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14
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Aughton KL, Hamilton-Smith K, Gupta J, Morton JS, Wayman CP, Jackson VM. Pharmacological profiling of neuropeptides on rabbit vaginal wall and vaginal artery smooth muscle in vitro. Br J Pharmacol 2008; 155:236-43. [PMID: 18587425 DOI: 10.1038/bjp.2008.253] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Hypothalamic neuropeptides centrally modulate sexual arousal. However, the role of neuropeptides in peripheral arousal has been ignored. Vascular and non-vascular smooth muscle relaxation in the vagina is important for female sexual arousal. To date, in vitro studies have focused on vaginal strips with no studies on vaginal arteries. The aim of this study was to compare the effects of sexual hypothalamic neuropeptides on rabbit vaginal wall strips and arteries. EXPERIMENTAL APPROACH Tissue bath and wire myography techniques were used to measure isometric tension from strips and arteries, respectively. KEY RESULTS Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) relaxed both preparations, effects that were only antagonized by the VIP/PACAP antagonist VIP6-28 (10 nM) and the PAC(1) antagonist PACAP 6-38 (1 microM). The melanocortin agonist alpha-melanocortin-stimulating hormone (1 microM), but not bremelanotide (1 microM), also relaxed both preparations. Oxytocin and vasopressin contracted vaginal preparations, which could be antagonized by the V(1A) antagonist SR 49059. Neuropeptide Y (NPY) and the NPY Y(1) agonist Leu(31), Pro(34) NPY only contracted arteries, which was antagonized by the NPY Y(1) receptor antagonist BIBP 3226. Melanin-concentrating hormone (MCH; 1 microM) contracted arteries. CONCLUSION AND IMPLICATIONS Hypothalamic neuropeptides can exert contractile and relaxant effects on vaginal strips and arteries. NPY Y(1), V(1A), MCH(1) antagonists as well as VIP/PAC(1) agonists may have therapeutic potential in both central and peripheral female sexual arousal. Differences in effect of neuropeptides between preparations raise the question of which preparation is important for female sexual arousal.
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Affiliation(s)
- K L Aughton
- Discovery Biology, Pfizer Global Research & Development, Sandwich, UK
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15
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Morton JS, Jackson VM, Daly CJ, McGrath JC. Endothelium Dependent Relaxation in Rabbit Genital Resistance Arteries is Predominantly Mediated by Endothelial-Derived Hyperpolarizing Factor in Females and Nitric Oxide in Males. J Urol 2007; 177:786-91. [PMID: 17222682 DOI: 10.1016/j.juro.2006.09.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2005] [Indexed: 11/29/2022]
Abstract
PURPOSE In nongenital arteries a sex difference has been postulated in the dominant endothelium-derived relaxant factor(s), eg nitric oxide, prostacyclin or endothelial-derived hyperpolarizing factor. Knowledge of endothelium-derived relaxant factor mechanisms in genital tissues could influence the development of novel treatments for sexual dysfunction. We compared nitric oxide and endothelial-derived hyperpolarizing factor contributions to acetylcholine induced relaxation in the genital arteries of the 2 sexes. MATERIALS AND METHODS Male dorsal and cavernous penile arteries, and female extravaginal and intravaginal arteries from New Zealand White rabbits were studied. Acetylcholine concentration-vasodilator response curves were constructed in the presence of the nitric oxide synthase inhibitor Nomega-nitro-L-arginine methyl ester, K(+) channel blockers (apamin and charybdotoxin) or a combination. Indomethacin was present throughout to exclude prostacyclins. RESULTS Extravaginal artery relaxation was predominantly endothelial-derived hyperpolarizing factor induced. Apamin plus charybdotoxin decreased maximal relaxations from a mean +/- SEM of 77% +/- 4% to 23% +/- 3% in 6 preparations (p <0.01). However, nitric oxide and endothelial-derived hyperpolarizing factor contributed to overall function. Dorsal artery relaxation was largely nitric oxide induced. Nomega-nitro-L-arginine methyl ester decreased maximal relaxations from 90% +/- 3% to 41% +/- 9% (p <0.001) with no endothelial-derived hyperpolarizing factor involvement (p >0.05). In cavernous and intravaginal arteries nitric oxide and endothelial-derived hyperpolarizing factor contributed to acetylcholine induced relaxation, while nitric oxide predominated. Blocking nitric oxide synthase or K(+) channels indicated that myogenic tone and constitutive activity of endothelium-derived relaxant factors were present. Vasodilator nerve mediated responses were influenced by each with the former more effective. CONCLUSIONS Vaginal inflow arteries showed a dominance of endothelial-derived hyperpolarizing factor, contrasting with nitric oxide in penile arteries. Penile arteries followed the trend that endothelial-derived hyperpolarizing factor involvement increased with decreasing vessel caliber, while the reverse was demonstrated in female arteries.
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16
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Abstract
BACKGROUND AND PURPOSE Maintained penile erection depends on the absence of alpha-adrenoceptor (alpha-AR) activation and so can be facilitated by alpha-blockers. This study seeks the alpha(1)-AR subtypes involved in order to inform the pro-erectile consequences of subtype selective blockade. EXPERIMENTAL APPROACH Wire myography was used with dorsal (nutritional supply) and cavernous (erectile inflow) penile arteries; standard alpha-AR-selective agonists and antagonists were employed to classify responses. KEY RESULTS In both penile arteries noradrenaline (NA) and phenylephrine (PE, alpha(1)-AR agonist) caused concentration-dependent contractions. Sensitivity to NA was increased by NA uptake blockers, cocaine (3 microM) and corticosterone (30 microM). PE responses were antagonised by phentolamine (non-selective alpha-AR: dorsal pK(B) 8.00, cavernous 8.33), prazosin (non-subtype-selective alpha(1)-AR: dorsal 8.60, cavernous 8.41) and RS100329 (alpha(1A)-AR selective: dorsal 9.03, cavernous 8.80) but not by BMY7378 (alpha(1D)-AR selective: no effect at 1-100 nM) or Rec15/2615 (alpha(1B)-AR selective: no effect at 1-100 nM). Schild analysis was straightforward in cavernous artery, indicating that PE activates only alpha(1A)-AR. In dorsal artery Schild slopes were low, though alpha(1A)-AR was still indicated. Analysis using UK 14,304 and rauwolscine indicated an alpha(2)-AR component in dorsal artery that may account for low slopes to alpha(1)-AR antagonists. CONCLUSIONS AND IMPLICATIONS Penile arteries have a predominant, functional alpha(1A)-AR population with little evidence of other alpha(1)-AR subtypes. Dorsal arteries (nutritional supply) also have alpha(2)-ARs. Thus, alpha-AR blockers with affinity for alpha(1A)-AR or alpha(2)-AR would potentially have pro-erectile properties; the combination of these perhaps being most effective. This should inform the design of drugs to assist/avoid penile erection.
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Affiliation(s)
- J S Morton
- Autonomic Physiology Unit, Institute of Biomedical and Life Sciences, West Medical Building, University of Glasgow, Glasgow, UK
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17
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Jackson VM, Trout SJ, Cunnane TC. Regional variation in electrically-evoked contractions of rabbit isolated pulmonary artery. Br J Pharmacol 2002; 137:488-96. [PMID: 12359630 PMCID: PMC1573507 DOI: 10.1038/sj.bjp.0704863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2002] [Accepted: 06/27/2002] [Indexed: 11/10/2022] Open
Abstract
1. Electrically-evoked contractions in different regions of the rabbit isolated pulmonary artery have been investigated using stimulation parameters generally assumed to stimulate nerves selectively. 2. In extrapulmonary artery, trains of stimuli (10 Hz; pulse width 0.1 ms) evoked monophasic contractions. In contrast, a biphasic contraction was evoked in the intrapulmonary artery consisting of an initial fast component followed by a secondary very long-lasting component. 3. The contraction in the extrapulmonary artery was prazosin-sensitive (1 micro M) whereas that in the intrapulmonary artery was prazosin-resistant. 4. alpha,beta-Methylene ATP (1 micro M), atropine (1 micro M), losartan (1 micro M), BIBO3304 (1 nM) or nifedipine (1 micro M) had no effect on the biphasic contraction of the intrapulmonary artery. Bretylium (2 micro M) abolished the contraction of extrapulmonary artery but only partially inhibited the initial component in the intra region with no effect on the second component. 5. Tetrodotoxin (0.3-1 micro M), abolished the contraction of extrapulmonary artery but only partially reduced the electrically-evoked contraction of intrapulmonary artery. 6. Removal of the endothelium and application of sulphisoxazole (0.6-22 micro M) had no effect. 7. Varying the resting tone on the arteries, or applying gadolinium, had no effect on contractions. 8. Using confocal microscopy and calcium imaging, reproducible whole cell calcium transients were evoked in individual smooth muscle cells in intact preparations but only when direct muscle stimulation was used (pulse width of 5-10 ms). No detectable changes in calcium were elicited when brief pulse widths were used (0.1-2 ms). 9. Together, these data suggest that noradrenaline is the neurotransmitter inducing contraction in extrapulmonary artery. Noradrenaline and sympathetic nerves appear to play a less important role in the intrapulmonary artery. The tetrodoxin-resistant component is not mediated by ATP, NPY, acetylcholine, angiotensins, ET-1, stretch-activation or Ca(2+) influx through L-type Ca(2+) channels. Smooth muscle cells do not appear to be damaged by the stimulation protocol. The mechanism underlying the long lasting contraction of intrapulmonary artery evoked by brief electrical stimuli remains to be elucidated.
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Affiliation(s)
- V Margaret Jackson
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
| | - Stephen J Trout
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
| | - Tom C Cunnane
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, U.K
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Brain KL, Jackson VM, Trout SJ, Cunnane TC. Intermittent ATP release from nerve terminals elicits focal smooth muscle Ca2+ transients in mouse vas deferens. J Physiol 2002; 541:849-62. [PMID: 12068045 PMCID: PMC2290369 DOI: 10.1113/jphysiol.2002.019612] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A confocal Ca2+ imaging technique has been used to detect ATP release from individual sympathetic varicosities on the same nerve terminal branch. Varicose nerve terminals and smooth muscle cells in mouse vas deferens were loaded with the Ca2+ indicator Oregon Green 488 BAPTA-1. Field (nerve) stimulation evoked discrete, focal increases in [Ca2+] in smooth muscle cells adjacent to identified varicosities. These focal increases in [Ca2+] have been termed 'neuroeffector Ca2+ transients' (NCTs). NCTs were abolished by alpha,beta-methylene ATP (1 microM), but not by nifedipine (1 microM) or prazosin (100 nM), suggesting that NCTs are generated by Ca2+ influx through P2X receptors without a detectable contribution from L-type Ca2+ channels or alpha(1)-adrenoceptor-mediated pathways. Action potential-evoked ATP release was highly intermittent (mean probability 0.019 +/- 0.002; range 0.001-0.10) at 1 Hz stimulation, even though there was no failure of action potential propagation in the nerve terminals. Twenty-eight per cent of varicosities failed to release transmitter following more than 500 stimuli. Spontaneous ATP release was very infrequent (0.0014 Hz). No Ca2+ transient attributable to noradrenaline release was detected even in response to 5 Hz stimulation. There was evidence of local noradrenaline release as the alpha(2)-adrenoceptor antagonist yohimbine increased the probability of occurrence of NCTs by 55 +/- 21 % during trains of stimuli at 1 Hz. Frequency-dependent facilitation preferentially occurred at low probability release sites. The monitoring of NCTs now allows transmitter release to be detected simultaneously from each functional varicosity on an identified nerve terminal branch on an impulse-to-impulse basis.
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Affiliation(s)
- Keith L Brain
- University Department of Pharmacology, University of Oxford, Mansfield Road, UK. ..uk
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Abstract
Action potential-evoked calcium transients in varicosities in mouse vas deferens were monitored using laser scanning confocal microscopy. Their significance was examined by comparison with excitatory junction potentials (EJPs) and neurogenic contractions, both indirect measurements of transmitter release. Bretylium abolished EJPs, as well as the ATP and NA-mediated phases of contraction. However, bretylium revealed a prominent late component of contraction that was atropine-sensitive. Bretylium abolished calcium transients in 21%, enhanced in 16% and had no effect in 63% of varicosities examined. Pre-treatment with 6-OHDA reduced NA levels to below detectable levels but many strings of varicosities still responded to nerve impulses with 'normal' calcium transients. Varicosities in which calcium transients were abolished by these agents were sympathetic. The identity of those varicosities in which calcium transients were resistant to bretylium (sympathetic but no uptake-1 sites, parasympathetic, sensory) remains to be established.
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Affiliation(s)
| | - Tom C Cunnane
- University Department of Pharmacology, Mansfield Road, Oxford, OX1 3QT
- Author for correspondence:
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Brain KL, Trout SJ, Jackson VM, Dass N, Cunnane TC. Nicotine induces calcium spikes in single nerve terminal varicosities: a role for intracellular calcium stores. Neuroscience 2002; 106:395-403. [PMID: 11566509 DOI: 10.1016/s0306-4522(01)00280-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
While nicotine is known to act at neuronal nicotinic acetylcholine receptors (nAChRs) to facilitate neurotransmitter release, the mechanisms underlying this action are poorly understood. Some of its effects are known to be mediated by presynaptic receptors. In the mouse vas deferens nicotine (10-30 microM) transiently increased the force of neurogenic contraction by 135+/-25%, increased the amplitude of excitatory junction potentials by 74+/-6% and increased the frequency of spontaneous excitatory junction potentials in four out of six preparations. Confocal microscopy and the calcium indicator Oregon Green 488 BAPTA-1 dextran were used to measure calcium concentration changes in the nerve terminals. Nicotine did not affect the action potential-evoked calcium transient but instead triggered small, random fluctuations ("calcium spikes") in intra-varicosity calcium concentrations at an average frequency of 0.09+/-0.02 Hz. These were insensitive to tetrodotoxin at a concentration that blocked action-potential evoked calcium transients (300 nM). They were abolished by the nAChR blocker hexamethonium (100 microM) and by both ryanodine (100 microM) and caffeine (3 mM), agents that modify calcium release from intracellular stores. We propose a novel mechanism whereby nicotine's action at nAChRs triggers calcium-induced calcium release from a ryanodine-sensitive calcium store in nerve terminals. This primes neurotransmitter release mechanisms and enhances both spontaneous and action potential-evoked neurotransmitter release.
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Affiliation(s)
- K L Brain
- Department of Pharmacology, Mansfield Road, University of Oxford, Oxford OX1 3QT, UK
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Abstract
1. Action potential-evoked Ca(2+) transients in postganglionic sympathetic axon bundles in mouse vas deferens have been characterized using confocal microscopy and Ca(2+) imaging. 2. Axonal Ca(2+) transients were tetrodotoxin sensitive. The amplitude depended on both the frequency of stimulation and the number of stimuli in a train. 3. Removal of extracellular Ca(2+) abolished the Ca(2+) transient. Cd(2+)(100 microM) inhibited the Ca(2+) transient by 78 +/- 10 %. The N-type Ca(2+) channel blocker omega-conotoxin GVIA (0.1 microM) reduced the amplitude by -35 +/-4 %, whereas nifedipine (10 microM; L-type) and omega-conotoxin MVIIC (0.1 microM; P/Q type) were ineffective. 4. Caffeine (10 mM), ryanodine (10 microM), cyclopiazonic acid (30 microM) or CCCP (10 microM) had no detectable effects. 5. Blockade of large and small conductance Ca(2+)-dependent K+ channels with iberiotoxin (0.1 microM) and apamin (1 microM), respectively, or Ca(2+)-dependent Cl(-) channels by niflumic acid (100 microM) did not alter Ca(2+) transients. 6. In contrast, the non-specific K+ channel blockers tetraethylammonium (10 mM) and 4-aminopyridine (10 mM) markedly increased the amplitude of the Ca(2+) transient. Blockade of delayed rectifiers and A-like K+ channels, by tityustoxin-K (alpha) (0.1 microM) and pandinustoxin-K (alpha) (10 nM), respectively, also increased the Ca(2+) transient amplitude. 7. Thus, Ca(2+) transients are evoked by Na(+)-dependent action potentials in axons. These transients originate mainly from Ca(2+) entry through voltage-dependent Ca(2+) channels (80 % Cd(2+) sensitive of which 40 % was attributable to N-type). Twenty per cent of the Ca(2+) transient was not due to Ca(2+) entry through voltage-gated Ca(2+) channels. Intracellular stores and mitochondria were not involved in the generation of the transient. Ca(2+) transients are modulated by A-like K+ channels and delayed rectifiers (possibly K(V)1.2) but not by Ca(2+)-activated ion channels.
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Affiliation(s)
- V M Jackson
- Department of Pharmacology, Mansfield Road, Oxford OX1 3QT, UK
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Abstract
In 1969, Paton and Vizi described the inhibitory actions of noradrenaline on acetylcholine release from the innervation of the guinea-pig ileum longitudinal muscle. They concluded "that acetylcholine output by the nervous networks of the longitudinal strip is under the normal control of the sympathetic by a species of presynaptic inhibition mediated by <==> receptors". This work was carried out in the Pharmacology Department at Oxford University. Clearly, a period in the 'Dreaming Spires' of Oxford sufficiently inspired Sylvester to take up a life long career in scientific research. He has published more than 300 papers on a wide range of topics but clearly has a strong interest in neurotransmitter release mechanisms and recently, non-synaptic interactions between neurons. It seems fitting therefore to write a brief review on the continuing studies on neurotransmitter release mechanisms in sympathetic neurons in a volume honoring the now distinguished Professor Vizi.
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Ward SM, Brennan MF, Jackson VM, Sanders KM. Role of PI3-kinase in the development of interstitial cells and pacemaking in murine gastrointestinal smooth muscle. J Physiol 1999; 516 ( Pt 3):835-46. [PMID: 10200429 PMCID: PMC2269307 DOI: 10.1111/j.1469-7793.1999.0835u.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
1. Development of the pacemaker system in the small intestine depends upon signalling via tyrosine kinase (Kit) receptors. The downstream pathways initiated by Kit in interstitial cells of Cajal (ICC) have not been investigated. Wortmannin and 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY 294002), inhibitors of phosphatidylinositol 3'-kinase (PI3-kinase), were used to test the involvement of this pathway in the development and maintenance of ICC and electrical rhythmicity in the murine small intestine. 2. ICC and electrical slow waves were present in the murine jejunum at birth. ICC and electrical rhythmicity continued to develop in neonates such that adult activity was recorded after 1 week. Development of ICC and rhythmicity were maintained in organ culture. 3. Wortmannin or LY 294002 inhibited the development of slow waves and blocked rhythmicity within 2-4 days. Loss of slow waves was preceded by disappearance of Kit-positive cells from the myenteric (IC-MY) and deep muscular plexus (IC-DMP) regions. Wortmannin or LY 294002 had no acute effect on slow waves. 4. Muscles from older animals (day 10-day 30) developed resistance to wortmannin treatment, but when the exposure to wortmannin was increased to 35 days, damage to ICC networks and electrical dysrhythmias were observed. 5. PI3-kinase appears to be a critical downstream signalling element linking Kit receptors to ICC development and maintenance of phenotype. ICC are more sensitive to Kit or PI3-kinase blockade at birth, but the importance of the PI3-kinase signalling in the maintenance of ICC persists into adulthood. Interference with PI3-kinase signalling in immature or adult animals could result in disruption of ICC and gastrointestinal dysrhythmias.
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Affiliation(s)
- S M Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Jackson VM, Dorman SM, Tennant LK, Chen WW. Effects of teaching specific guidelines for alcohol consumption on alcohol knowledge and behavioral intent of college students. Health Educ 1989; 20:51-4, 62. [PMID: 2516516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Abstract
The course of twin pregnancy is most amenable to positive intervention during the antepartal period. However, once a laboring woman arrives on the labor floor, there is still opportunity to influence outcome. The management of multiple gestation is best accomplished through use of a multidisciplinary team. Intrapartal events are handled with greater confidence when each member of the team is aware not only of his or her specific role, but also of all the tasks that need to be accomplished. Rehearsal prior to the delivery and communication during the delivery are essential. Each team member can positively affect the outcome in twin delivery through the use of unique skills. The preceding review of the literature regarding multiple gestation during labor portrays the dilemmas and controversies surrounding management. It is incumbent on all maternity staff to become acquainted with the issues and acquire the skills necessary to render safe care. Every complication of labor and delivery, including preterm labor, uterine dysfunction, abnormal presentation, prolapse of the umbilical cord, premature separation of the placenta, and immediate postpartum hemorrhage, occurs with greater frequency with multiple gestation. Therefore, the conduct of labor and delivery with twins is an excellent challenge to the skills of the team that provides care for the patient and her fetuses.
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DeVore NE, Jackson VM, Piening SL. Torch infections. Am J Nurs 1983; 83:1660-5. [PMID: 6316788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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