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Al Kury LT. Modulatory Effect of Medicinal Plants and Their Active Constituents on ATP-Sensitive Potassium Channels (KATP) in Diabetes. Pharmaceuticals (Basel) 2023; 16:ph16040523. [PMID: 37111281 PMCID: PMC10142548 DOI: 10.3390/ph16040523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/24/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Hyperglycemia, which is a chronic metabolic condition caused by either a defect in insulin secretion or insulin resistance, is a hallmark of diabetes mellitus (DM). Sustained hyperglycemia leads to the onset and development of many health complications. Despite the number of available antidiabetic medications on the market, there is still a need for novel treatment agents with increased efficacy and fewer adverse effects. Many medicinal plants offer a rich supply of bioactive compounds that have remarkable pharmacological effects with less toxicity and side effects. According to published evidence, natural antidiabetic substances influence pancreatic β-cell development and proliferation, inhibit pancreatic β-cell death, and directly increase insulin output. Pancreatic ATP-sensitive potassium channels play an essential role in coupling glucose metabolism to the secretion of insulin. Although much of the literature is available on the antidiabetic effects of medicinal plants, very limited studies discuss their direct action on pancreatic KATP. The aim of this review is to focus on the modulatory effects of antidiabetic medicinal plants and their active constituents on pancreatic KATP. The KATP channel should be regarded as a key therapeutic milestone in the treatment of diabetes. Therefore, continuous research into the interaction of medicinal plants with the KATP channel is crucial.
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Affiliation(s)
- Lina T Al Kury
- Department of Health Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi 144534, United Arab Emirates
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Lodato M, Plaisance V, Pawlowski V, Kwapich M, Barras A, Buissart E, Dalle S, Szunerits S, Vicogne J, Boukherroub R, Abderrahmani A. Venom Peptides, Polyphenols and Alkaloids: Are They the Next Antidiabetics That Will Preserve β-Cell Mass and Function in Type 2 Diabetes? Cells 2023; 12:cells12060940. [PMID: 36980281 PMCID: PMC10047094 DOI: 10.3390/cells12060940] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/09/2023] [Accepted: 03/17/2023] [Indexed: 03/22/2023] Open
Abstract
Improvement of insulin secretion by pancreatic β-cells and preservation of their mass are the current challenges that future antidiabetic drugs should meet for achieving efficient and long-term glycemic control in patients with type 2 diabetes (T2D). The successful development of glucagon-like peptide 1 (GLP-1) analogues, derived from the saliva of a lizard from the Helodermatidae family, has provided the proof of concept that antidiabetic drugs directly targeting pancreatic β-cells can emerge from venomous animals. The literature reporting on the antidiabetic effects of medicinal plants suggests that they contain some promising active substances such as polyphenols and alkaloids, which could be active as insulin secretagogues and β-cell protectors. In this review, we discuss the potential of several polyphenols, alkaloids and venom peptides from snake, frogs, scorpions and cone snails. These molecules could contribute to the development of new efficient antidiabetic medicines targeting β-cells, which would tackle the progression of the disease.
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Affiliation(s)
- Michele Lodato
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Plaisance
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Valérie Pawlowski
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Maxime Kwapich
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
- Service de Diabétologie et d’Endocrinologie, CH Dunkerque, 59385 Dunkirk, France
| | - Alexandre Barras
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Emeline Buissart
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Stéphane Dalle
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Sabine Szunerits
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Jérôme Vicogne
- University Lille, CNRS, Inserm, CHU Lille, Institut Pasteur de Lille, U1019-UMR 9017-CIIL-Center for Infection and Immunity of Lille, F-59000 Lille, France
| | - Rabah Boukherroub
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
| | - Amar Abderrahmani
- University Lille, CNRS, Centrale Lille, University Polytechnique Hauts-de-France, UMR 8520, IEMN, F-59000 Lille, France
- Correspondence: ; Tel.: +33-362531704
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Danysz W, Dekundy A, Scheschonka A, Riederer P. Amantadine: reappraisal of the timeless diamond-target updates and novel therapeutic potentials. J Neural Transm (Vienna) 2021; 128:127-169. [PMID: 33624170 PMCID: PMC7901515 DOI: 10.1007/s00702-021-02306-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/13/2021] [Indexed: 12/30/2022]
Abstract
The aim of the current review was to provide a new, in-depth insight into possible pharmacological targets of amantadine to pave the way to extending its therapeutic use to further indications beyond Parkinson's disease symptoms and viral infections. Considering amantadine's affinities in vitro and the expected concentration at targets at therapeutic doses in humans, the following primary targets seem to be most plausible: aromatic amino acids decarboxylase, glial-cell derived neurotrophic factor, sigma-1 receptors, phosphodiesterases, and nicotinic receptors. Further three targets could play a role to a lesser extent: NMDA receptors, 5-HT3 receptors, and potassium channels. Based on published clinical studies, traumatic brain injury, fatigue [e.g., in multiple sclerosis (MS)], and chorea in Huntington's disease should be regarded potential, encouraging indications. Preclinical investigations suggest amantadine's therapeutic potential in several further indications such as: depression, recovery after spinal cord injury, neuroprotection in MS, and cutaneous pain. Query in the database http://www.clinicaltrials.gov reveals research interest in several further indications: cancer, autism, cocaine abuse, MS, diabetes, attention deficit-hyperactivity disorder, obesity, and schizophrenia.
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Affiliation(s)
- Wojciech Danysz
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Andrzej Dekundy
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Astrid Scheschonka
- Merz Pharmaceuticals GmbH., Eckenheimer Landstraße 100, 60318, Frankfurt am Main, Germany
| | - Peter Riederer
- Clinic and Policlinic for Psychiatry, Psychosomatics and Psychotherapy, University Hospital Würzburg, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Department Psychiatry, University of Southern Denmark Odense, Vinslows Vey 18, 5000, Odense, Denmark.
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4
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Effects of amantadine on corneal endothelium. Exp Eye Res 2019; 181:208-212. [DOI: 10.1016/j.exer.2019.02.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 01/18/2019] [Accepted: 02/12/2019] [Indexed: 11/21/2022]
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Real J, Miranda C, Olofsson CS, Smith PA. Lipophilicity predicts the ability of nonsulphonylurea drugs to block pancreatic beta-cell K ATP channels and stimulate insulin secretion; statins as a test case. Endocrinol Diabetes Metab 2018; 1:e00017. [PMID: 30815553 PMCID: PMC6354820 DOI: 10.1002/edm2.17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 01/18/2018] [Accepted: 02/18/2018] [Indexed: 12/26/2022] Open
Abstract
AIMS KATP ion channels play a key role in glucose-stimulated insulin secretion. However, many drugs block KATP as "off targets" leading to hyperinsulinaemia and hypoglycaemia. As such drugs are often lipophilic, the aim was to examine the relationship between drug lipophilicity (P) and IC 50 for KATP block and explore if the IC 50's of statins could be predicted from their lipophilicity and whether this would allow one to forecast their acute action on insulin secretion. MATERIALS AND METHODS A meta-analysis of 26 lipophilic, nonsulphonylurea, blockers of KATP was performed. From this, the IC 50's for pravastatin and simvastatin were predicted and then tested experimentally by exploring their effects on KATP channel activity via patch-clamp measurement, calcium imaging and insulin secretion in murine beta cells and islets. RESULTS Nonsulphonylurea drugs inhibited KATP channels with a Log IC 50 linearly related to their logP. Simvastatin blocked KATP with an IC 50 of 25 nmol/L, a value independent of cytosolic factors, and within the range predicted by its lipophilicity (21-690 nmol/L). 10 μmol/L pravastatin, predicted IC 50 0.2-12 mmol/L, was without effect on the KATP channel. At 10-fold therapeutic levels, 100 nmol/L simvastatin depolarized the beta-cell membrane potential and stimulated Ca2+ influx but did not affect insulin secretion; the latter could be explained by serum binding. CONCLUSIONS The logP of a drug can aid prediction for its ability to block beta-cell KATP ion channels. However, although the IC 50 for the block of KATP by simvastatin was predicted, the difference between this and therapeutic levels, as well as serum sequestration, explains why hypoglycaemia is unlikely to be observed with acute use of this statin.
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Affiliation(s)
- Joana Real
- Department of Physiology/Metabolic PhysiologyInstitute of Neuroscience and PhysiologyGöteborgSweden
| | - Caroline Miranda
- Department of Physiology/Metabolic PhysiologyInstitute of Neuroscience and PhysiologyGöteborgSweden
| | - Charlotta S. Olofsson
- Department of Physiology/Metabolic PhysiologyInstitute of Neuroscience and PhysiologyGöteborgSweden
| | - Paul A. Smith
- School of Life Sciences University of NottinghamNottinghamUK
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Wiedemann M, Gurrola-Díaz CM, Vargas-Guerrero B, Wink M, García-López PM, Düfer M. Lupanine Improves Glucose Homeostasis by Influencing KATP Channels and Insulin Gene Expression. Molecules 2015; 20:19085-100. [PMID: 26492234 PMCID: PMC6332548 DOI: 10.3390/molecules201019085] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 09/22/2015] [Accepted: 10/13/2015] [Indexed: 11/26/2022] Open
Abstract
The glucose-lowering effects of lupin seeds involve the combined action of several components. The present study investigates the influence of one of the main quinolizidine alkaloids, lupanine, on pancreatic beta cells and in an animal model of type-2 diabetes mellitus. In vitro studies were performed with insulin-secreting INS-1E cells or islets of C57BL/6 mice. In the in vivo experiments, hyperglycemia was induced in rats by injecting streptozotocin (65 mg/kg body weight). In the presence of 15 mmol/L glucose, insulin secretion was significantly elevated by 0.5 mmol/L lupanine, whereas the alkaloid did not stimulate insulin release with lower glucose concentrations. In islets treated with l-arginine, the potentiating effect of lupanine already occurred at 8 mmol/L glucose. Lupanine increased the expression of the Ins-1 gene. The potentiating effect on secretion was correlated to membrane depolarization and an increase in the frequency of Ca(2+) action potentials. Determination of the current through ATP-dependent K⁺ channels (KATP channels) revealed that lupanine directly inhibited the channel. The effect was dose-dependent but, even with a high lupanine concentration of 1 mmol/L or after a prolonged exposure time (12 h), the KATP channel block was incomplete. Oral administration of lupanine did not induce hypoglycemia. By contrast, lupanine improved glycemic control in response to an oral glucose tolerance test in streptozotocin-diabetic rats. In summary, lupanine acts as a positive modulator of insulin release obviously without a risk for hypoglycemic episodes.
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Affiliation(s)
- Mats Wiedemann
- Dept. of Pharmaceutical and Medicinal Chemistry, Münster University, Corrensstraße 48, 48149 Münster, Germany.
| | - Carmen M Gurrola-Díaz
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, 44340 Guadalajara, Jalisco, Mexico.
| | - Belinda Vargas-Guerrero
- Departamento de Biología Molecular y Genómica, Centro Universitario de Ciencias de la Salud, Universidad de Guadalajara, 44340 Guadalajara, Jalisco, Mexico.
| | - Michael Wink
- Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg 69120, Germany.
| | - Pedro M García-López
- Departamento de Botánica y Zoología, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, 45110 Guadalajara, Jalisco, Mexico.
| | - Martina Düfer
- Dept. of Pharmaceutical and Medicinal Chemistry, Münster University, Corrensstraße 48, 48149 Münster, Germany.
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7
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Marquard J, Otter S, Welters A, Stirban A, Fischer A, Eglinger J, Herebian D, Kletke O, Klemen MS, Stožer A, Wnendt S, Piemonti L, Köhler M, Ferrer J, Thorens B, Schliess F, Rupnik MS, Heise T, Berggren PO, Klöcker N, Meissner T, Mayatepek E, Eberhard D, Kragl M, Lammert E. Characterization of pancreatic NMDA receptors as possible drug targets for diabetes treatment. Nat Med 2015; 21:363-72. [PMID: 25774850 DOI: 10.1038/nm.3822] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/10/2015] [Indexed: 12/14/2022]
Abstract
In the nervous system, NMDA receptors (NMDARs) participate in neurotransmission and modulate the viability of neurons. In contrast, little is known about the role of NMDARs in pancreatic islets and the insulin-secreting beta cells whose functional impairment contributes to diabetes mellitus. Here we found that inhibition of NMDARs in mouse and human islets enhanced their glucose-stimulated insulin secretion (GSIS) and survival of islet cells. Further, NMDAR inhibition prolonged the amount of time that glucose-stimulated beta cells spent in a depolarized state with high cytosolic Ca(2+) concentrations. We also noticed that, in vivo, the NMDAR antagonist dextromethorphan (DXM) enhanced glucose tolerance in mice, and that in vitro dextrorphan, the main metabolite of DXM, amplified the stimulatory effect of exendin-4 on GSIS. In a mouse model of type 2 diabetes mellitus (T2DM), long-term treatment with DXM improved islet insulin content, islet cell mass and blood glucose control. Further, in a small clinical trial we found that individuals with T2DM treated with DXM showed enhanced serum insulin concentrations and glucose tolerance. Our data highlight the possibility that antagonists of NMDARs may provide a useful adjunct treatment for diabetes.
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Affiliation(s)
- Jan Marquard
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Düsseldorf, Germany
| | - Silke Otter
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany. [3] German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
| | - Alena Welters
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Düsseldorf, Germany. [3] Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany. [4] German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
| | - Alin Stirban
- Profil Institute for Metabolic Research, Neuss, Germany
| | | | - Jan Eglinger
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany. [3] German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
| | - Diran Herebian
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Düsseldorf, Germany
| | - Olaf Kletke
- Institute of Neuro- and Sensory Physiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- 1] Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia. [2] Center for Open Innovations and Research, University of Maribor, Maribor, Slovenia
| | | | - Lorenzo Piemonti
- Diabetes Research Institute, Istituto di Ricovero e Cura a Carattere Scientifico, San Raffaele Scientific Institute, Milano, Italy
| | - Martin Köhler
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Jorge Ferrer
- 1] Department of Medicine, Imperial College London, London, UK. [2] Genomic Programming of Beta-Cells Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | | | - Marjan Slak Rupnik
- 1] Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia. [2] Center for Open Innovations and Research, University of Maribor, Maribor, Slovenia. [3] Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Tim Heise
- Profil Institute for Metabolic Research, Neuss, Germany
| | - Per-Olof Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Nikolaj Klöcker
- Institute of Neuro- and Sensory Physiology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Thomas Meissner
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Düsseldorf, Germany
| | - Ertan Mayatepek
- Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital Düsseldorf, Düsseldorf, Germany
| | - Daniel Eberhard
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany
| | - Martin Kragl
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
| | - Eckhard Lammert
- 1] Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany. [2] Institute for Beta Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany. [3] German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
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Chatelain FC, Gazzarrini S, Fujiwara Y, Arrigoni C, Domigan C, Ferrara G, Pantoja C, Thiel G, Moroni A, Minor DL. Selection of inhibitor-resistant viral potassium channels identifies a selectivity filter site that affects barium and amantadine block. PLoS One 2009; 4:e7496. [PMID: 19834614 PMCID: PMC2759520 DOI: 10.1371/journal.pone.0007496] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 09/23/2009] [Indexed: 12/02/2022] Open
Abstract
Background Understanding the interactions between ion channels and blockers remains an important goal that has implications for delineating the basic mechanisms of ion channel function and for the discovery and development of ion channel directed drugs. Methodology/Principal Findings We used genetic selection methods to probe the interaction of two ion channel blockers, barium and amantadine, with the miniature viral potassium channel Kcv. Selection for Kcv mutants that were resistant to either blocker identified a mutant bearing multiple changes that was resistant to both. Implementation of a PCR shuffling and backcrossing procedure uncovered that the blocker resistance could be attributed to a single change, T63S, at a position that is likely to form the binding site for the inner ion in the selectivity filter (site 4). A combination of electrophysiological and biochemical assays revealed a distinct difference in the ability of the mutant channel to interact with the blockers. Studies of the analogous mutation in the mammalian inward rectifier Kir2.1 show that the T→S mutation affects barium block as well as the stability of the conductive state. Comparison of the effects of similar barium resistant mutations in Kcv and Kir2.1 shows that neighboring amino acids in the Kcv selectivity filter affect blocker binding. Conclusions/Significance The data support the idea that permeant ions have an integral role in stabilizing potassium channel structure, suggest that both barium and amantadine act at a similar site, and demonstrate how genetic selections can be used to map blocker binding sites and reveal mechanistic features.
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Affiliation(s)
- Franck C. Chatelain
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Sabrina Gazzarrini
- Dipartimento di Biologia e Istituto di Biofisica del Consiglio Nazionale delle Ricerche, Università degli Studi di Milano, Milan, Italy
| | - Yuichiro Fujiwara
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Cristina Arrigoni
- Dipartimento di Biologia e Istituto di Biofisica del Consiglio Nazionale delle Ricerche, Università degli Studi di Milano, Milan, Italy
| | - Courtney Domigan
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
| | - Giuseppina Ferrara
- Dipartimento di Biologia e Istituto di Biofisica del Consiglio Nazionale delle Ricerche, Università degli Studi di Milano, Milan, Italy
| | - Carlos Pantoja
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, United States of America
| | - Gerhard Thiel
- Technische Universität Darmstadt, Institute für Botanik, Darmstadt, Germany
| | - Anna Moroni
- Dipartimento di Biologia e Istituto di Biofisica del Consiglio Nazionale delle Ricerche, Università degli Studi di Milano, Milan, Italy
| | - Daniel L. Minor
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California, United States of America
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, California, United States of America
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, California, United States of America
- Department of California Institute for Quantitative Biomedical Research, University of California San Francisco, San Francisco, California, United States of America
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- * E-mail:
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9
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Syeda R, Holden MA, Hwang WL, Bayley H. Screening Blockers Against a Potassium Channel with a Droplet Interface Bilayer Array. J Am Chem Soc 2008; 130:15543-8. [DOI: 10.1021/ja804968g] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ruhma Syeda
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K
| | - Matthew A. Holden
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K
| | - William L. Hwang
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K
| | - Hagan Bayley
- Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K
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10
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Bobkiewicz-Kozłowska T, Dworacka M, Kuczyński S, Abramczyk M, Kolanoś R, Wysocka W, Garcia Lopez PM, Winiarska H. Hypoglycaemic effect of quinolizidine alkaloids — lupanine and 2-thionosparteine on non-diabetic and streptozotocin-induced diabetic rats. Eur J Pharmacol 2007; 565:240-4. [PMID: 17379208 DOI: 10.1016/j.ejphar.2007.02.032] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Revised: 02/13/2007] [Accepted: 02/15/2007] [Indexed: 11/20/2022]
Abstract
The hypoglycaemic effects of two quinolizidine alkaloids: lupanine and 2-thionosparteine were examined in non-diabetic and in streptozotocin-induced diabetic rats. The model of experimental diabetes can be considered to be related to diabetes mellitus type 2 with regards to the impairment of beta-cells' secretory function. A single intraperitoneal injection of 2-thionosparteine at a dose of 8.6 mg/kg lowered the blood glucose levels in diabetic rats at 90 and 120 min after administration and showed similar hypoglycaemic effects to glibenclamide and sparteine, which were used as reference substances. In contrast to glibenclamide, 2-thionosparteine did not result in a significant increase in plasma insulin levels in diabetic rats; an increase was only observed in the non-diabetic group. It was found that lupanine did not exert hypoglycaemic potency in diabetic and in non-diabetic animals and did not significantly increase plasma insulin concentration independent of the group examined. From this study we can state that 2-thionosparteine, but not lupanine, is confirmed to be a possible plasma glucose lowering agent. It is possible that 2-thionosparteine-dependent decrease in blood glucose level is not the only result of this drug's related insulin secretion.
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Affiliation(s)
- Teresa Bobkiewicz-Kozłowska
- Department of Pharmacology, Poznan University of Medical Sciences, ul. Rokietnicka 5a, 60-806, Poznań, Poland
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11
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Chen J, Cassar SC, Zhang D, Gopalakrishnan M. A novel potassium channel encoded by Ectocarpus siliculosus virus. Biochem Biophys Res Commun 2005; 326:887-93. [PMID: 15607752 DOI: 10.1016/j.bbrc.2004.11.125] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Indexed: 10/26/2022]
Abstract
Kcv, the first identified viral potassium channel encoded by the green algae Paramecium bursaria chlorella virus (PBCV-1), conducted K(+) selective currents when expressed in heterologous systems. This K(+) channel was proposed to be important for PBCV-1 infection and replication. In the present study, we identified and functionally characterized a novel K(+) channel Kesv, encoded by Ectocarpus siliculosus virus that infects filamentous marine brown algae. Kesv encodes a protein of 124 amino acids and is 21.8% identical and 37.1% homologous to Kcv. Membrane topology programs predicted that Kesv consists of three transmembrane domains. When expressed in Xenopus oocytes, Kesv induced largely instantaneous, K(+) selective currents that were sensitive to block by Ba(2+) and amantadine. Thus, Kesv along with Kcv, constitutes an emerging family of viral potassium channels, which may play important roles in the life cycle of viruses.
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Affiliation(s)
- Jun Chen
- Neuroscience Research, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064-6125, USA.
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12
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Mehmel M, Rothermel M, Meckel T, Van Etten JL, Moroni A, Thiel G. Possible function for virus encoded K+ channel Kcv in the replication of chlorella virus PBCV-1. FEBS Lett 2003; 552:7-11. [PMID: 12972144 DOI: 10.1016/s0014-5793(03)00776-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The K+ channel Kcv is encoded by the chlorella virus PBCV-1. There is evidence that this channel plays an essential role in the replication of the virus, because both PBCV-1 plaque formation and Kcv channel activity in Xenopus oocytes have similar sensitivities to inhibitors. Here we report circumstantial evidence that the Kcv channel is important during virus infection. Recordings of membrane voltage in the host cells Chlorella NC64A reveal a membrane depolarization within the first few minutes of infection. This depolarization displays the same sensitivity to cations as Kcv conductance; depolarization also requires the intact membrane of the virion. Together these data are consistent with the idea that the virus carries functional K+ channels in the virion and inserts them into the host cell plasma membrane during infection.
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Affiliation(s)
- Mario Mehmel
- Membrane Biophysics, Botany Institute, Darmstadt University of Technology, Schnittspahnstrasse 3, 64287 Darmstadt, Germany
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13
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Interference of alkaloids with neuroreceptors and ion channels. BIOACTIVE NATURAL PRODUCTS (PART B) 2000. [DOI: 10.1016/s1572-5995(00)80004-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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14
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Lamb RA, Pinto LH. Do Vpu and Vpr of human immunodeficiency virus type 1 and NB of influenza B virus have ion channel activities in the viral life cycles? Virology 1997; 229:1-11. [PMID: 9123850 DOI: 10.1006/viro.1997.8451] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- R A Lamb
- Howard Hughes Medical Institute, Northwestern University, Evanston, Illinois 60208-3500, USA.
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15
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Kakkar R, Raju RV, Rajput AH, Sharma RK. Amantadine: an antiparkinsonian agent inhibits bovine brain 60 kDa calmodulin-dependent cyclic nucleotide phosphodiesterase isozyme. Brain Res 1997; 749:290-4. [PMID: 9138729 DOI: 10.1016/s0006-8993(96)01318-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effect of amantadine (an antiparkinsonian agent) on calmodulin-dependent cyclic nucleotide phosphodiesterase isozymes was investigated. Amantadine inhibited bovine brain 60 kDa calmodulin-dependent cyclic nucleotide phosphodiesterase but not the bovine brain 63 kDa, heart and lung calmodulin-dependent cyclic nucleotide phosphodiesterase isozymes. The inhibition of bovine brain 60 kDa calmodulin-dependent cyclic nucleotide phosphodiesterase was overcome by increasing the concentration of calmodulin. This suggests that amantadine may be an antagonist of calmodulin or act specifically and reversibly on the action of calmodulin. The bovine brain 60 kDa calmodulin-dependent cyclic nucleotide phosphodiesterase isozyme is predominantly expressed in the brain and its inhibition may result in increased intracellular levels of cyclic AMP (cAMP). The increased intracellular levels of cAMP have a protective role for dopaminergic neurons. The present findings suggest that amantadine may be a valuable tool to investigate the physiological role of 60 kDa calmodulin-dependent cyclic nucleotide phosphodiesterase isozyme in the progression of Parkinson's disease and gives a new insight into the action of this drug.
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Affiliation(s)
- R Kakkar
- Department of Pathology, Saskatoon Cancer Centre, University of Saskatchewan, Canada
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16
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Fujita T, Seto Y, Kondo N, Kato R. Studies on the N-[(trans-4-isopropylcyclohexyl)-carbonyl]-D-phenylalanin e (A-4166)receptor in HIT T-15 cells. Displacement of [3H]glibenclamide. Biochem Pharmacol 1996; 52:407-11. [PMID: 8687494 DOI: 10.1016/0006-2952(96)00242-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A-4166 is a new type of oral hypoglycemic agent that does not contain a sulfonylurea moiety. To clarify the mechanism of insulin secretion by A-4166, a specific receptor for A-4166 was investigated in a hamster pancreatic beta cell line (HIT T-15), using [3H]A-4166 or [3H]glibenclamide as a ligand. The saturation binding of [3H]A-4166 to HIT cell membranes was not observed up to 10 microM. In the displacement study, unlabeled A-4166 inhibited [3H]A-4166 binding to HIT cell membranes, but glibenclamide did not. On the other hand, A-4166 inhibited [3H]glibenclamide binding to the sulfonylurea receptor (Ki = 248 nM). A-4166 inhibited 86Rb efflux from HIT cells (IC50 = 350 nM). The EC50 for insulin secretion by A-4166 was 20 microM in HIT cells when they were incubated for 30 min in Krebs-Ringer bicarbonate buffer containing 16 mM HEPES supplemented with 5 mg/mL BSA in the absence of glucose. These data demonstrate the possibility of the presence of two kinds of binding sites for A-4166: one of them is the sulfonylurea receptor, and the other might be a binding site specific for A-4166.
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Affiliation(s)
- T Fujita
- Pharmaceutical Institute, Keio University School of Medicine, Tokyo, Japan
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17
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Kakei M, Nakazaki M, Kamisaki T, Nagayama I, Fukamachi Y, Tanaka H. Inhibition of the ATP-sensitive potassium channel by class I antiarrhythmic agent, cibenzoline, in rat pancreatic beta-cells. Br J Pharmacol 1993; 109:1226-31. [PMID: 8401933 PMCID: PMC2175729 DOI: 10.1111/j.1476-5381.1993.tb13753.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
1. Cibenzoline, a class I antiarrhythmic agent, was investigated for its effect on the ATP-sensitive K+ channel of pancreatic beta-cells by the patch clamp technique. 2. In perforated patch clamp experiments, cibenzoline depolarized the membrane of single beta-cells and thereafter, caused firing of action potentials in the presence of 2.8 mM glucose. 3. Cibenzoline inhibited the activity of the ATP-sensitive K+ channel in cell-attached recordings in the presence of 2.8 mM glucose and evoked repetitive fluctuations of the baseline current, apparently reflecting the action potentials of the beta-cell. 4. In whole-cell clamp experiments, time-independent outward current was induced by depleting cytoplasmic ATP with 0.1 mM ATP and 0.1 mM ADP in the solution contained in the pipette. The outward current was inhibited by cibenzoline in a dose-dependent manner in the concentration range of 1 microM to 100 microM and half maximum inhibition occurred at 1.5 microM. 5. Cibenzoline blocked substantially the ATP-sensitive K+ channel current when applied at the inner side of the membrane in isolated inside-out membrane patches. 6. It is concluded that cibenzoline blocks the ATP-sensitive K+ channel of pancreatic beta-cells and, thereby, stimulates insulin secretion at sub-stimulatory levels of glucose.
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Affiliation(s)
- M Kakei
- First Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Japan
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Gopalakrishnan M, Janis RA, Triggle DJ. ATP-sensitive K+ channels: Pharmacologic properties, regulation, and therapeutic potential. Drug Dev Res 1993. [DOI: 10.1002/ddr.430280202] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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19
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Duff KC, Ashley RH. The transmembrane domain of influenza A M2 protein forms amantadine-sensitive proton channels in planar lipid bilayers. Virology 1992; 190:485-9. [PMID: 1382343 DOI: 10.1016/0042-6822(92)91239-q] [Citation(s) in RCA: 198] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In a direct test of the hypothesis that the M2 coat protein of influenza A can function as a proton translocator, we incorporated a synthetic peptide containing its putative transmembrane domain into voltage-clamped planar lipid bilayers. We observed single proton-selective ion channels with a conductance of approximately 10 pS at a pH of 2.3, consistent with the association of several monomers around a central water-filled pore. The channels were reversibly blocked by the anti-influenza drug amantadine. These experiments imply a central role for M2 protein in virus replication and assembly and may explain the mechanism of action of amantadine. Analogous proteins may have a similar function in other viruses, and these may be susceptible to similar antiviral agents.
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Affiliation(s)
- K C Duff
- Department of Biochemistry, University of Edinburgh, U.K
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Abstract
Ionic and electrical events play a central role in the stimulus-secretion coupling of the pancreatic B cell. Potassium permeability is critically involved in the regulation of B cell membrane potential and insulin secretion. In the absence of glucose, membrane potential remains stable, around -65 mV. This resting potential is mainly determined by the high potassium conductance of the membrane. The ATP generated by glucose metabolism in B cells blocks the K+(ATP) channels controlling resting membrane potential. Thus, glucose metabolism leads to closure of the ATP-dependent potassium channels; the resulting decrease in K+ permeability induces depolarization and opening of voltage-activated Ca-channels. The subsequent increase in Ca2+ influx raises the cytoplasmic concentration of free Ca2+, which in turn triggers exocytosis of secretory granules. Other types of K+ channels have also been identified in the B cell, such as voltage- and Ca(2+)-dependent K+ channels, which are not a target for the action of glucose, but may play a role in the repolarization of spikes. The modulation of insulin release by some hormones and neurotransmitters involves, among other mechanisms, an interference with the plasma membrane K+ conductance. Thus, galanine, somatostatin and adrenaline, which inhibit insulin release, increase K+ conductance by a G protein-dependent mechanism; both peptides were reported to open ATP-sensitive K+ channels in insulin-secreting cell line RINm5F. It was also observed that extracellular purine nucleotides could interfere with K+ channels. Among the various drugs interfering with insulin secretion, sulfonylureas, such as tolbutamide and glibenclamide, directly inhibit ATP-dependent K+ channels in the B cell membrane and thereby initiate insulin release. In contrast, potassium channel openers such as diazoxide, antagonize the effects of glucose by increasing K+ permeability of the B cell membrane. Furthermore, other classes of drugs have recently been shown to interact with K+ (ATP) channels. Thus, K+ channels of the pancreatic B cell, particularly ATP-dependent ones, play a crucial role in the electrophysiology of insulin secretion; they are an important target for pharmacological agents designed to modulate this secretion.
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Affiliation(s)
- P Petit
- Laboratoire de Pharmacologie, URA 599 du CNRS, Faculté de Médecine, Montpellier, France
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