1
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Blažević T, Ciotu CI, Gold-Binder M, Heiss EH, Fischer MJM, Dirsch VM. Cultured rat aortic vascular smooth muscle cells do not express a functional TRPV1. PLoS One 2023; 18:e0281191. [PMID: 36787302 PMCID: PMC9928102 DOI: 10.1371/journal.pone.0281191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 01/17/2023] [Indexed: 02/15/2023] Open
Abstract
We showed previously that capsaicin, an active compound of chili peppers, can inhibit platelet-derived growth factor-induced proliferation in primary rat vascular smooth muscle cells (VSMCs). The inhibition of BrdU incorporation by capsaicin in these cells was revoked by BCTC, which might be explained by a role of TRPV1 in VSMCs proliferation. To further pursue the hypothesis of a TRPV1-dependent effect of capsaicin, we investigated TRPV1 expression and function. Commercially available antibodies against two different TRPV1 epitopes (N-terminus and C-terminus) were rendered invalid in detecting TRPV1, as shown: i) in western blot experiments using control lysates of TRPV1-expressing (PC-12 and hTRPV1 transfected HEK293T) and TRPV1-downregulated (CRISPR/Cas gene edited A10) cells, and ii) by substantial differences in staining patterns between the applied antibodies using fluorescence confocal microscopy. The TRPV1 agonists capsaicin, resiniferatoxin, piperine and evodiamine did not increase intracellular calcium levels in primary VSMCs and in A10 cells. Using RT qPCR, we could detect a rather low TRPV1 expression in VSMCs at the mRNA level (Cp value around 30), after validating the primer pair in NGF-stimulated PC-12 cells. We conclude that rat vascular smooth muscle cells do not possess canonical TRPV1 channel activity, which could explain the observed antiproliferative effect of capsaicin.
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Affiliation(s)
- Tina Blažević
- Department of Pharmaceutical Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
- * E-mail:
| | - Cosmin I. Ciotu
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Markus Gold-Binder
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Elke H. Heiss
- Department of Pharmaceutical Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
| | - Michael J. M. Fischer
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Verena M. Dirsch
- Department of Pharmaceutical Sciences, Faculty of Life Sciences, University of Vienna, Vienna, Austria
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2
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Zarban AA, Chaudhry H, de Sousa Valente J, Argunhan F, Ghanim H, Brain SD. Elucidating the Ability of CGRP to Modulate Microvascular Events in Mouse Skin. Int J Mol Sci 2022; 23:12246. [PMID: 36293102 PMCID: PMC9602655 DOI: 10.3390/ijms232012246] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/28/2022] [Accepted: 10/06/2022] [Indexed: 11/29/2022] Open
Abstract
Oedema formation and polymorphonuclear leukocyte (neutrophil) accumulation are involved in both acute and chronic inflammation. Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide that is released from stimulated sensory nerves. CGRP is a potent vasodilator neuropeptide, especially when administered to the cutaneous microvasculature, with a long duration of action. Here, we have investigated the ability of vasodilator amounts of CGRP to modulate oedema formation and neutrophil accumulation induced in the cutaneous microvasculature of the mouse. To learn more about the mechanism of action of endogenous CGRP, we have investigated the response to the inflammatory stimulants tumour necrosis factor alpha (TNFα) and carrageenan in three different murine models: a model where sensory nerves were depleted by resiniferatoxin (RTX); a pharmacological method to investigate the effect of a selective CGRP receptor antagonist; and a genetic approach using wildtype (WT) and αCGRP knockout (KO) mice. Our results show that exogenous CGRP potentiates oedema formation induced by substance P (SP) and TNFα. This is further supported by our findings from sensory nerve-depleted mice (in the absence of all neuropeptides), which indicated that sensory nerves are involved in mediating the oedema formation and neutrophil accumulation induced by TNFα, and also carrageenan in cutaneous microvasculature. Furthermore, endogenous CGRP was shown to contribute to this inflammatory response as carrageenan-induced oedema formation is attenuated in WT mice treated with the CGRP receptor antagonist, and in αCGRPKO mice. It is therefore concluded that CGRP can contribute to inflammation by promoting oedema formation in skin, but this response is dependent on the pro-inflammatory stimulus and circumstance.
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Affiliation(s)
- Ali A. Zarban
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
- Department of Pharmacology and Toxicology, College of Pharmacy, Jazan University, Jazan 45142, Saudi Arabia
| | - Hiba Chaudhry
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
| | - João de Sousa Valente
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
| | - Fulye Argunhan
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
| | - Hala Ghanim
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
| | - Susan D. Brain
- Section of Vascular Biology and Inflammation, School of Cardiovascular and Metabolic Medicine & Sciences, BHF Centre of Research Excellence, Franklin-Wilkins Building, Waterloo Campus, King’s College London, London SE1 9NH, UK
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3
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Non-Canonical Cannabinoid Receptors with Distinct Binding and Signaling Properties in Prostate and Other Cancer Cell Types Mediate Cell Death. Int J Mol Sci 2022; 23:ijms23063049. [PMID: 35328467 PMCID: PMC8954350 DOI: 10.3390/ijms23063049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/04/2022] [Accepted: 03/05/2022] [Indexed: 02/01/2023] Open
Abstract
Cannabinoids exert anti-cancer actions; however, the underlying cytotoxic mechanisms and the cannabinoid receptors (CBRs) involved remain unclear. In this study, CBRs were characterized in several cancer cell lines. Radioligand binding screens surprisingly revealed specific binding only for the non-selective cannabinoid [3H]WIN-55,212-2, and not [3H]CP-55,940, indicating that the expressed CBRs exhibit atypical binding properties. Furthermore, [3H]WIN-55,212-2 bound to a single site in all cancer cells with high affinity and varying densities. CBR characteristics were next compared between human prostate cancer cell lines expressing low (PC-3) and high (DU-145) CBR density. Although mRNA for canonical CBRs was detected in both cell lines, only 5 out of 15 compounds with known high affinity for canonical CBRs displaced [3H]WIN-55,212-2 binding. Functional assays further established that CBRs in prostate cancer cells exhibit distinct signaling properties relative to canonical Gi/Go-coupled CBRs. Prostate cancer cells chronically exposed to both CBR agonists and antagonists/inverse agonists produced receptor downregulation, inconsistent with actions at canonical CBRs. Treatment of DU-145 cells with CBR ligands increased LDH-release, decreased ATP-dependent cell viability, and produced mitochondrial membrane potential depolarization. In summary, several cancer cell lines express CBRs with binding and signaling profiles dissimilar to canonical CBRs. Drugs selectively targeting these atypical CBRs might exhibit improved anti-cancer properties.
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4
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Liviero F, Campisi M, Mason P, Pavanello S. Transient Receptor Potential Vanilloid Subtype 1: Potential Role in Infection, Susceptibility, Symptoms and Treatment of COVID-19. Front Med (Lausanne) 2021; 8:753819. [PMID: 34805220 PMCID: PMC8599155 DOI: 10.3389/fmed.2021.753819] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/08/2021] [Indexed: 12/20/2022] Open
Abstract
The battle against the new coronavirus that continues to kill millions of people will be still long. Novel strategies are demanded to control infection, mitigate symptoms and treatment of COVID-19. This is even more imperative given the long sequels that the disease has on the health of the infected. The discovery that S protein includes two ankyrin binding motifs (S-ARBMs) and that the transient receptor potential vanilloid subtype 1 (TRPV-1) cation channels contain these ankyrin repeat domains (TRPs-ARDs) suggest that TRPV-1, the most studied member of the TRPV channel family, can play a role in binding SARS-CoV-2. This hypothesis is strengthened by studies showing that other respiratory viruses bind the TRPV-1 on sensory nerves and epithelial cells in the airways. Furthermore, the pathophysiology in COVID-19 patients is similar to the effects generated by TRPV-1 stimulation. Lastly, treatment with agonists that down-regulate or inactivate TRPV-1 can have a beneficial action on impaired lung functions and clearance of infection. In this review, we explore the role of the TRPV-1 channel in the infection, susceptibility, pathogenesis, and treatment of COVID-19, with the aim of looking at novel strategies to control infection and mitigate symptoms, and trying to translate this knowledge into new preventive and therapeutic interventions.
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Affiliation(s)
| | | | | | - Sofia Pavanello
- Occupational Medicine, Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University Hospital of Padua, Padova, Italy
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5
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Heat-dependent opening of TRPV1 in the presence of capsaicin. Nat Struct Mol Biol 2021; 28:554-563. [PMID: 34239123 PMCID: PMC8335751 DOI: 10.1038/s41594-021-00616-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023]
Abstract
Transient receptor potential vanilloid member 1 (TRPV1) is a Ca2+-permeable cation channel that serves as the primary heat and capsaicin sensor in humans. Using cryo-EM, we have determined the structures of apo and capsaicin-bound full-length rat TRPV1 reconstituted into lipid nanodiscs over a range of temperatures. This has allowed us to visualize the noxious heat-induced opening of TRPV1 in the presence of capsaicin. Notably, noxious heat-dependent TRPV1 opening comprises stepwise conformational transitions. Global conformational changes across multiple subdomains of TRPV1 are followed by the rearrangement of the outer pore, leading to gate opening. Solvent-accessible surface area analyses and functional studies suggest that a subset of residues form an interaction network that is directly involved in heat sensing. Our study provides a glimpse of the molecular principles underlying noxious physical and chemical stimuli sensing by TRPV1, which can be extended to other thermal sensing ion channels.
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6
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Bousquet J, Czarlewski W, Zuberbier T, Mullol J, Blain H, Cristol JP, De La Torre R, Pizarro Lozano N, Le Moing V, Bedbrook A, Agache I, Akdis CA, Canonica GW, Cruz AA, Fiocchi A, Fonseca JA, Fonseca S, Gemicioğlu B, Haahtela T, Iaccarino G, Ivancevich JC, Jutel M, Klimek L, Kraxner H, Kuna P, Larenas-Linnemann DE, Martineau A, Melén E, Okamoto Y, Papadopoulos NG, Pfaar O, Regateiro FS, Reynes J, Rolland Y, Rouadi PW, Samolinski B, Sheikh A, Toppila-Salmi S, Valiulis A, Choi HJ, Kim HJ, Anto JM. Potential Interplay between Nrf2, TRPA1, and TRPV1 in Nutrients for the Control of COVID-19. Int Arch Allergy Immunol 2021; 182:324-338. [PMID: 33567446 PMCID: PMC8018185 DOI: 10.1159/000514204] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 12/15/2020] [Indexed: 12/16/2022] Open
Abstract
In this article, we propose that differences in COVID-19 morbidity may be associated with transient receptor potential ankyrin 1 (TRPA1) and/or transient receptor potential vanilloid 1 (TRPV1) activation as well as desensitization. TRPA1 and TRPV1 induce inflammation and play a key role in the physiology of almost all organs. They may augment sensory or vagal nerve discharges to evoke pain and several symptoms of COVID-19, including cough, nasal obstruction, vomiting, diarrhea, and, at least partly, sudden and severe loss of smell and taste. TRPA1 can be activated by reactive oxygen species and may therefore be up-regulated in COVID-19. TRPA1 and TRPV1 channels can be activated by pungent compounds including many nuclear factor (erythroid-derived 2) (Nrf2)-interacting foods leading to channel desensitization. Interactions between Nrf2-associated nutrients and TRPA1/TRPV1 may be partly responsible for the severity of some of the COVID-19 symptoms. The regulation by Nrf2 of TRPA1/TRPV1 is still unclear, but suggested from very limited clinical evidence. In COVID-19, it is proposed that rapid desensitization of TRAP1/TRPV1 by some ingredients in foods could reduce symptom severity and provide new therapeutic strategies.
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Affiliation(s)
- Jean Bousquet
- Department of Dermatology and Allergy, Comprehensive Allergy Center, Charité, and Berlin Institute of Health, Comprehensive Allergy Center, Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin, Germany, .,University Hospital and MACVIA France, Montpellier, France,
| | | | - Torsten Zuberbier
- Department of Dermatology and Allergy, Comprehensive Allergy Center, Charité, and Berlin Institute of Health, Comprehensive Allergy Center, Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Joaquim Mullol
- Rhinology Unit & Smell Clinic, ENT Department, Hospital Clinic - Clinical & Experimental Respiratory Immunoallergy, IDIBAPS, CIBERES, Universitat de Barcelona, Barcelona, Spain
| | - Hubert Blain
- Department of Geriatrics, Montpellier University Hospital, Montpellier, France
| | - Jean-Paul Cristol
- Laboratoire de Biochimie et Hormonologie, PhyMedExp, Université de Montpellier, INSERM, CNRS, CHU de, Montpellier, France
| | - Rafael De La Torre
- CIBER Fisiopatologia de la Obesidad y Nutrición (CIBEROBN), Madrid, Spain.,IMIM (Hospital del Mar Research Institute), Barcelona, Spain.,Departament de Ciències Experimentals i de la Salut Toxicologia, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | | | - Anna Bedbrook
- University Hospital and MACVIA France, Montpellier, France.,MASK-air, Montpellier, France
| | - Ioana Agache
- Faculty of Medicine, Transylvania University, Brasov, Romania
| | - Cezmi A Akdis
- Christine Kühne - Center for Allergy Research and Education (CK-CARE), Swiss Institute of Allergy and Asthma Research (SIAF), University of Zurich, Zurich, Switzerland
| | - G Walter Canonica
- Personalized Medicine, Asthma and Allergy, Humanitas Clinical and Research Center IRCCS and Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy
| | - Alvaro A Cruz
- Fundação ProAR, Federal University of Bahia and GARD/WHO Planning Group, Salvador, Brazil
| | - Alessandro Fiocchi
- Division of Allergy, The Bambino Gesù Children's Research Hospital IRCCS, Rome, Italy
| | - Joao A Fonseca
- CINTESIS, Center for Research in Health Technologies and Information Systems, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,MEDIDA, Lda, Porto, Portugal
| | - Susana Fonseca
- GreenUPorto - Sustainable Agrifood Production Research Centre, DGAOT, Faculty of Sciences, University of Porto, Vila do Conde, Portugal
| | - Bilun Gemicioğlu
- Department of Pulmonary Diseases, Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine, Istanbul, Turkey
| | - Tari Haahtela
- Skin and Allergy Hospital, Helsinki University Hospital, and University of Helsinki, Helsinki, Finland
| | - Guido Iaccarino
- Interdepartmental Center of Research on Hypertension and Related Conditions CIRIAPA, Federico II University, Napoli, Italy
| | | | - Marek Jutel
- Department of Clinical Immunology, Wrocław Medical University and ALL-MED Medical Research Institute, Wrocław, Poland
| | - Ludger Klimek
- Center for Rhinology and Allergology, Wiesbaden, Germany
| | - Helga Kraxner
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - Piotr Kuna
- Division of Internal Medicine, Asthma and Allergy, Barlicki University Hospital, Medical University of Lodz, Lodz, Poland
| | - Désirée E Larenas-Linnemann
- Center of Excellence in Asthma and Allergy, Médica Sur Clinical Foundation and Hospital, Mexico City, Mexico
| | - Adrian Martineau
- Institute for Population Health Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Erik Melén
- Institute of Environmental Medicine, Karolinska Institutet and Sachs' Children's Hospital, Stockholm, Sweden
| | - Yoshitaka Okamoto
- Department of Otorhinolaryngology, Chiba University Hospital, Chiba, Japan
| | - Nikolaos G Papadopoulos
- Division of Infection, Immunity & Respiratory Medicine, Royal Manchester Children's Hospital, University of Manchester, Manchester, United Kingdom.,Allergy Department, 2nd Pediatric Clinic, Athens General Children's Hospital "P&A Kyriakou," University of Athens, Athens, Greece
| | - Oliver Pfaar
- Section of Rhinology and Allergy, Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Marburg, Philipps-Universität Marburg, Marburg, Germany
| | - Frederico S Regateiro
- Allergy and Clinical Immunology Unit, Centro Hospitalar e Universitário de Coimbra, Faculty of Medicine, Institute of Immunology, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, ICBR - Institute for Clinical and Biomedical Research, CIBB, University of Coimbra, Coimbra, Portugal
| | - Jacques Reynes
- Maladies Infectieuses et Tropicales, CHU, Montpellier, France
| | | | - Philip W Rouadi
- Department of Otolaryngology-Head and Neck Surgery, Eye and Ear University Hospital, Beirut, Lebanon
| | - Boleslaw Samolinski
- Department of Prevention of Environmental Hazards and Allergology, Medical University of Warsaw, Warsaw, Poland
| | - Aziz Sheikh
- Usher Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Sanna Toppila-Salmi
- Skin and Allergy Hospital, Helsinki University Hospital, and University of Helsinki, Helsinki, Finland
| | - Arunas Valiulis
- Vilnius University Faculty of Medicine, Institute of Clinical Medicine & Institute of Health Sciences, Vilnius, Lithuania
| | - Hak-Jong Choi
- Research and Development Division, Microbiology and Functionality Research Group, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Hyun Ju Kim
- Strategy and Planning Division, SME Service Department, World Institute of Kimchi, Gwangju, Republic of Korea
| | - Josep M Anto
- IMIM (Hospital del Mar Research Institute), Barcelona, Spain.,Departament de Ciències Experimentals i de la Salut Toxicologia, Universitat Pompeu Fabra (UPF), Barcelona, Spain.,CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain.,ISGlobAL, Barcelona, Centre for Research in Environmental Epidemiology, Barcelona, Spain
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7
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Pharmacological Activity of Eriodictyol: The Major Natural Polyphenolic Flavanone. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:6681352. [PMID: 33414838 PMCID: PMC7752289 DOI: 10.1155/2020/6681352] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 12/01/2020] [Accepted: 12/02/2020] [Indexed: 01/17/2023]
Abstract
Eriodictyol is a flavonoid that belongs to a subclass of flavanones and is widespread in citrus fruits, vegetables, and medicinally important plants. Eriodictyol has been anticipated to explain the method of its activity via multiple cellular signaling cascades. Eriodictyol is an effective natural drug source to maintain higher health standards due to its excellent therapeutic roles in neuroprotection, cardioprotective activity, hepatoprotective activity, antidiabetes and obesity, and skin protection and having highly analgesic, antioxidant, and anti-inflammatory effects, antipyretic and antinociceptive actions, antitumor activity, and much more. This review aims to highlight the modes of action of eriodictyol against various diseases via multiple cellular signaling pathways.
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8
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Abstract
The transient receptor potential vanilloid-1 (TRPV1) is a non-specific cation channel known for its sensitivity to pungent vanilloid compound (i.e. capsaicin) and noxious stimuli, including heat, low pH or inflammatory mediators. TRPV1 is found in the somatosensory system, particularly primary afferent neurons that respond to damaging or potentially damaging stimuli (nociceptors). Stimulation of TRPV1 evokes a burning sensation, reflecting a central role of the channel in pain. Pharmacological and genetic studies have validated TRPV1 as a therapeutic target in several preclinical models of chronic pain, including cancer, neuropathic, postoperative and musculoskeletal pain. While antagonists of TRPV1 were found to be a valuable addition to the pain therapeutic toolbox, their clinical use has been limited by detrimental side effects, such as hyperthermia. In contrast, capsaicin induces a prolonged defunctionalisation of nociceptors and thus opened the door to the development of a new class of therapeutics with long-lasting pain-relieving effects. Here we review the list of TRPV1 agonists undergoing clinical trials for chronic pain management, and discuss new indications, formulations or combination therapies being explored for capsaicin. While the analgesic pharmacopeia for chronic pain patients is ancient and poorly effective, modern TRPV1-targeted drugs could rapidly become available as the next generation of analgesics for a broad spectrum of pain conditions.
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Affiliation(s)
- Mircea Iftinca
- Department of Physiology and Pharmacology, Inflammation Research Network-Snyder Institute for Chronic Diseases and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, T2N 4N1, Canada
| | - Manon Defaye
- Department of Physiology and Pharmacology, Inflammation Research Network-Snyder Institute for Chronic Diseases and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, T2N 4N1, Canada
| | - Christophe Altier
- Department of Physiology and Pharmacology, Inflammation Research Network-Snyder Institute for Chronic Diseases and Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Dr NW, Calgary, Alberta, T2N 4N1, Canada.
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9
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Pelleg A, Schulman ES, Barnes PJ. Extracellular Adenosine 5'-Triphosphate in Obstructive Airway Diseases. Chest 2016; 150:908-915. [PMID: 27568579 DOI: 10.1016/j.chest.2016.06.045] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 06/15/2016] [Accepted: 06/16/2016] [Indexed: 02/06/2023] Open
Abstract
In recent years, numerous studies have generated data supporting the hypothesis that extracellular adenosine 5'-triphosphate (ATP) plays a major role in obstructive airway diseases. Studies in animal models and human subjects have shown that increased amounts of extracellular ATP are found in the lungs of patients with COPD and asthma and that ATP has effects on multiple cell types in the lungs, resulting in increased inflammation, induction of bronchoconstriction, and cough. These effects of ATP are mediated by cell surface P2 purinergic receptors and involve other endogenous inflammatory agents. Recent clinical trials reported promising treatment with P2X3R antagonists for the alleviation of chronic cough. The purpose of this review was to describe these studies and outline some of the remaining questions, as well as the potential clinical implications, associated with the pharmacologic manipulation of ATP signaling in the lungs.
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Affiliation(s)
- Amir Pelleg
- College of Medicine, Department of Medicine, Drexel University, Philadelphia, PA.
| | - Edward S Schulman
- College of Medicine, Department of Medicine, Drexel University, Philadelphia, PA
| | - Peter J Barnes
- Airway Disease Section, National Heart and Lung Institute, Imperial College, London, UK
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10
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Zhang F, Hanson SM, Jara-Oseguera A, Krepkiy D, Bae C, Pearce LV, Blumberg PM, Newstead S, Swartz KJ. Engineering vanilloid-sensitivity into the rat TRPV2 channel. eLife 2016; 5:e16409. [PMID: 27177419 PMCID: PMC4907692 DOI: 10.7554/elife.16409] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Accepted: 05/12/2016] [Indexed: 01/08/2023] Open
Abstract
The TRPV1 channel is a detector of noxious stimuli, including heat, acidosis, vanilloid compounds and lipids. The gating mechanisms of the related TRPV2 channel are poorly understood because selective high affinity ligands are not available, and the threshold for heat activation is extremely high (>50°C). Cryo-EM structures of TRPV1 and TRPV2 reveal that they adopt similar structures, and identify a putative vanilloid binding pocket near the internal side of TRPV1. Here we use biochemical and electrophysiological approaches to investigate the resiniferatoxin(RTx) binding site in TRPV1 and to explore the functional relationships between TRPV1 and TRPV2. Collectively, our results support the interaction of vanilloids with the proposed RTx binding pocket, and demonstrate an allosteric influence of a tarantula toxin on vanilloid binding. Moreover, we show that sensitivity to RTx can be engineered into TRPV2, demonstrating that the gating and permeation properties of this channel are similar to TRPV1.
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Affiliation(s)
- Feng Zhang
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Sonya M Hanson
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Andres Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Dmitriy Krepkiy
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Chanhyung Bae
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Larry V Pearce
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - Peter M Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, United States
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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11
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Mickle AD, Shepherd AJ, Mohapatra DP. Sensory TRP channels: the key transducers of nociception and pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:73-118. [PMID: 25744671 DOI: 10.1016/bs.pmbts.2015.01.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peripheral detection of nociceptive and painful stimuli by sensory neurons involves a complex repertoire of molecular detectors and/or transducers on distinct subsets of nerve fibers. The majority of such molecular detectors/transducers belong to the transient receptor potential (TRP) family of cation channels, which comprise both specific receptors for distinct nociceptive stimuli, as well as for multiple stimuli. This chapter discusses the classification, distribution, and functional properties of individual TRP channel types that have been implicated in various nociceptive and/or painful conditions.
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Affiliation(s)
- Aaron D Mickle
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrew J Shepherd
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Durga P Mohapatra
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesia, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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12
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An Introduction to Pain Pathways and Pain “Targets”. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:1-30. [DOI: 10.1016/bs.pmbts.2015.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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13
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Veldhuis NA, Poole DP, Grace M, McIntyre P, Bunnett NW. The G Protein–Coupled Receptor–Transient Receptor Potential Channel Axis: Molecular Insights for Targeting Disorders of Sensation and Inflammation. Pharmacol Rev 2014; 67:36-73. [DOI: 10.1124/pr.114.009555] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Abstract
Temperature-sensitive transient receptor potential (TRP) ion channels are members of the large tetrameric cation channels superfamily but are considered to be uniquely sensitive to heat, which has been presumed to be due to the existence of an unidentified temperature-sensing domain. Here we report that the homologous voltage-gated potassium (Kv) channels also exhibit high temperature sensitivity comparable to that of TRPV1, which is detectable under specific conditions when the voltage sensor is functionally decoupled from the activation gate through either intrinsic mechanisms or mutations. Interestingly, mutations could tune Shaker channel to be either heat-activated or heat-deactivated. Therefore, high temperature sensitivity is intrinsic to both TRP and Kv channels. Our findings suggest important physiological roles of heat-induced variation in Kv channel activities. Mechanistically our findings indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain; instead, non-obligatory allosteric gating permits the intrinsic heat sensitivity to drive channel activation, allowing temperature-sensitive TRP channels to function as polymodal nociceptors. DOI:http://dx.doi.org/10.7554/eLife.03255.001 If you touch something too hot, it can cause you pain and damage your skin. Sensing the heat given off by an object or the temperature of the environment is possible, at least in part, because of proteins called temperature-sensitive TRP ion channels. These proteins are found in the cell membranes of nerve endings that are underneath the skin; and they open in response to heat, allowing ions to flow into the nerve cell. This in turn triggers a nerve impulse that is sent to our central nervous system and is perceived as heat and/or pain. The ability to sense heat was thought to be unique to these TRP ion channels, and it was believed that these ion channels contained an as-yet unidentified temperature-sensing domain. However, Yang and Zheng now report that similar ion channels, which open in response to changes in the voltage that exists across a cell's membrane, are also sensitive to changes in temperature. The temperature response of these ‘voltage-gated channels’ had largely eluded the attention of researchers in the past. This is because parts of the ion channel—which act like a ‘voltage sensor’ and only shift when the membrane voltage changes—normally keep the channel closed and directly open the channel when they move. Like all other proteins, ion channels are made from smaller building blocks called amino acids; and by changing some of the amino acids in the voltage-gated channel Yang and Zheng could decouple these normally linked actions. The changes to the channel meant that it did not immediately open when the voltage sensor moved; and decreasing the concentration of calcium ions inside the cell had the same effect as changing these amino acids. Both approaches revealed that, after a change in membrane voltage caused the voltage sensor to move, the ion channel remained closed until a high temperature caused it to open. Yang and Zheng revealed that the response of the modified voltage-gated channel to temperature was comparable to that of a typical heat-sensitive TRP ion channel. Further experiments showed that replacing some of the amino acids in the voltage-gated potassium ion channel with different amino acids could cause the channel to be either opened or closed by heat. The findings of Yang and Zheng indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain. Instead, as these TRP ion channels do not require other parts of the protein to move in order to open the channel, they can be activated by their own inherent sensitivity to heat. DOI:http://dx.doi.org/10.7554/eLife.03255.002
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Affiliation(s)
- Fan Yang
- Department of Physiology and Membrane Biology, University of California, Davis School of Medicine, Davis, United States
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California, Davis School of Medicine, Davis, United States
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Lim KS, Lee H, Kim SE, Ha TH, Ann J, Son K, Choi S, Sun W, Pearce LV, DeAndrea-Lazarus IA, Blumberg PM, Lee J. The carbonate analogues of 5'-halogenated resiniferatoxin as TRPV1 ligands. Eur J Med Chem 2013; 68:233-43. [PMID: 23981530 DOI: 10.1016/j.ejmech.2013.07.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Revised: 07/04/2013] [Accepted: 07/12/2013] [Indexed: 11/28/2022]
Abstract
A series of carbonate analogues of 5'-halogenated RTX have been investigated in order to examine the effect of the carbonate group as a linker and the role of halogens in the reversal of activity from agonism to antagonism for rat and human TRPV1 heterologously expressed in Chinese hamster ovary cells. The carbonate analogues showed similar activities to the corresponding RTX derivatives in rat TRPV1 but lower potency in human TRPV1. 5-Halogenation converted the agonists to partial agonists or full antagonists and the extent of antagonism reflected the order of I>Br>Cl>F, with a somewhat greater extent of antagonism for the derivatives of the 4-amino RTX surrogates compared to the corresponding derivatives of RTX itself. The carbonate analogues of I-RTX (60) and 5-bromo-4-amino-RTX (66) were potent and full antagonists with Ki(ant)=2.23 and 2.46 nM, respectively, for rat TRPV1, which were ca. 5-fold more potent than I-RTX (2) under our conditions. The conformational analysis of the I-RTX-carbonate (60) indicated that its bent conformation was similar to that of I-RTX, consistent with compound 60 and I-RTX showing comparable potent antagonism.
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Affiliation(s)
- Kwang Su Lim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
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16
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Abraham TS, Chen ML, Ma SX. TRPV1 expression in acupuncture points: response to electroacupuncture stimulation. J Chem Neuroanat 2011; 41:129-36. [PMID: 21256210 PMCID: PMC3117662 DOI: 10.1016/j.jchemneu.2011.01.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Revised: 12/16/2010] [Accepted: 01/03/2011] [Indexed: 01/23/2023]
Abstract
The present study was to examine the distribution of transient receptor potential vanilloid type-1 (TRPV1) receptor immunoreactivity in the acupuncture points (acupoint), and determine the influences of electroacupuncture (EA) stimulation on TRPV1 expression. EA stimulation of BL 40 was conducted in two sessions of 20 min separated by an 80 min interval in anesthetized rats. Sections of skin containing BL 40, and its non-meridian control were examined by immunolabeling with antibodies directed against TRPV1. Without EA, the number of subepidermal nerve fibers expressing TRPV1 was higher in the acupoint than in non-acupoint control skin (p<0.01). The subepidermal nerve fibers showed the co-localization of TRPV1 with peripherine, a marker for the C-fibers and A-δ fibers. The expression of TRPV1 in nerve fibers is significantly increased by EA stimulation in acupoints (p<0.01). However the upregulation in the non acupoint meridian and the non-meridian control skin was short of statistical significance. Double immunostaining of TRPV1 and neuronal nitric oxide synthase (nNOS) revealed their co-localization in both the subepidermal nerve fibers and in the dermal connective tissue cells. These results show that a high expression of TRPV1 endowed with nNOS in subepidermal nerve fibers exists in the acupoints and the expression is increased by EA. We conclude that the higher expression of TRPV1 in the subepidermal nerve fibers and its upregulation after EA stimulation may play a key role in mediating the transduction of EA signals to the CNS, and its expression in the subepidermal connective tissue cells may play a role in conducting the local effect of the EA.
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Affiliation(s)
- Therese S Abraham
- Department of Obstetrics and Gynecology, David Geffen School of Medicine at University of California at Los Angeles, Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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17
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Abstract
The transient receptor potential (TRP) multigene superfamily encodes integral membrane proteins that function as ion channels. Members of this family are conserved in yeast, invertebrates and vertebrates. The TRP family is subdivided into seven subfamilies: TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPP (polycystin), TRPML (mucolipin), TRPA (ankyrin) and TRPN (NOMPC-like); the latter is found only in invertebrates and fish. TRP ion channels are widely expressed in many different tissues and cell types, where they are involved in diverse physiological processes, such as sensation of different stimuli or ion homeostasis. Most TRPs are non-selective cation channels, only few are highly Ca2+ selective, some are even permeable for highly hydrated Mg2+ ions. This channel family shows a variety of gating mechanisms, with modes of activation ranging from ligand binding, voltage and changes in temperature to covalent modifications of nucleophilic residues. Activated TRP channels cause depolarization of the cellular membrane, which in turn activates voltage-dependent ion channels, resulting in a change of intracellular Ca2+ concentration; they serve as gatekeeper for transcellular transport of several cations (such as Ca2+ and Mg2+), and are required for the function of intracellular organelles (such as endosomes and lysosomes). Because of their function as intracellular Ca2+ release channels, they have an important regulatory role in cellular organelles. Mutations in several TRP genes have been implicated in diverse pathological states, including neurodegenerative disorders, skeletal dysplasia, kidney disorders and pain, and ongoing research may help find new therapies for treatments of related diseases.
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Affiliation(s)
- Bernd Nilius
- Department of Molecular Cell Biology, Laboratory of Ion Channel Research, Campus Gasthuisberg, KU Leuven, Herestraat 49, B-3000 Leuven, Belgium
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18
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Eriodictyol: A flavonoid antagonist of the TRPV1 receptor with antioxidant activity. Biochem Pharmacol 2011; 81:544-51. [DOI: 10.1016/j.bcp.2010.11.004] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 10/26/2010] [Accepted: 11/05/2010] [Indexed: 11/19/2022]
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19
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Okun A, DeFelice M, Eyde N, Ren J, Mercado R, King T, Porreca F. Transient inflammation-induced ongoing pain is driven by TRPV1 sensitive afferents. Mol Pain 2011; 7:7. [PMID: 21241462 PMCID: PMC3031241 DOI: 10.1186/1744-8069-7-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 01/17/2011] [Indexed: 12/13/2022] Open
Abstract
Background Neuropathic pain is a chronic disease resulting from dysfunction within the "pain matrix". The basolateral amygdala (BLA) can modulate cortical functions and interactions between this structure and the medial prefrontal cortex (mPFC) are important for integrating emotionally salient information. In this study, we have investigated the involvement of the transient receptor potential vanilloid type 1 (TRPV1) and the catabolic enzyme fatty acid amide hydrolase (FAAH) in the morphofunctional changes occurring in the pre-limbic/infra-limbic (PL/IL) cortex in neuropathic rats. Results The effect of N-arachidonoyl-serotonin (AA-5-HT), a hybrid FAAH inhibitor and TPRV1 channel antagonist, was tested on nociceptive behaviour associated with neuropathic pain as well as on some phenotypic changes occurring on PL/IL cortex pyramidal neurons. Those neurons were identified as belonging to the BLA-mPFC pathway by electrical stimulation of the BLA followed by hind-paw pressoceptive stimulus application. Changes in their spontaneous and evoked activity were studied in sham or spared nerve injury (SNI) rats before or after repeated treatment with AA-5-HT. Consistently with the SNI-induced changes in PL/IL cortex neurons which underwent profound phenotypic reorganization, suggesting a profound imbalance between excitatory and inhibitory responses in the mPFC neurons, we found an increase in extracellular glutamate levels, as well as the up-regulation of FAAH and TRPV1 in the PL/IL cortex of SNI rats. Daily treatment with AA-5-HT restored cortical neuronal activity, normalizing the electrophysiological changes associated with the peripheral injury of the sciatic nerve. Finally, a single acute intra-PL/IL cortex microinjection of AA-5-HT transiently decreased allodynia more effectively than URB597 or I-RTX, a selective FAAH inhibitor or a TRPV1 blocker, respectively. Conclusion These data suggest a possible involvement of endovanilloids in the cortical plastic changes associated with peripheral nerve injury and indicate that therapies able to normalize endovanilloid transmission may prove useful in ameliorating the symptoms and central sequelae associated with neuropathic pain.
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Affiliation(s)
- Alec Okun
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724, USA
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20
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Lim KS, Kang DW, Kim YS, Kim MS, Park SG, Choi S, Pearce LV, Blumberg PM, Lee J. Receptor activity and conformational analysis of 5'-halogenated resiniferatoxin analogs as TRPV1 ligands. Bioorg Med Chem Lett 2011; 21:299-302. [PMID: 21111618 PMCID: PMC3420360 DOI: 10.1016/j.bmcl.2010.11.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 11/01/2010] [Indexed: 10/18/2022]
Abstract
A series of 5'-halogenated resiniferatoxin analogs have been investigated in order to examine the effect of halogenation in the A-region on their binding and the functional pattern of agonism/antagonism for rat TRPV1 heterologously expressed in Chinese hamster ovary cells. Halogenation at the 5-position in the A-region of RTX and of 4-amino RTX shifted the agonism of parent compounds toward antagonism. The extent of antagonism was greater as the size of the halogen increased (I > Br > Cl > F) while the binding affinities were similar, as previously observed for our potent agonists. In this series, 5-bromo-4-amino RTX (39) showed very potent antagonism with K(i) (ant) = 2.81 nM, which was thus 4.5-fold more potent than 5'-iodo RTX, previously reported as a potent TRPV1 antagonist. Molecular modeling analyses with selected agonists and the corresponding halogenated antagonists revealed a striking conformational difference. The 3-methoxy of the A-region in the agonists remained free to interact with the receptor whereas in the case of the antagonists, the compounds assumed a bent conformation, permitting the 3-methoxy to instead form an internal hydrogen bond with the C4-hydroxyl of the diterpene.
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Affiliation(s)
- Kwang Su Lim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Dong Wook Kang
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Yong Soo Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Myeong Seop Kim
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
| | - Seul-Gi Park
- College of Pharmacy, Division of Life & Pharmaceutical Sciences, and National Core Research Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea
| | - Sun Choi
- College of Pharmacy, Division of Life & Pharmaceutical Sciences, and National Core Research Center for Cell Signaling & Drug Discovery Research, Ewha Womans University, Seoul 120-750, Korea
| | - Larry V. Pearce
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Peter M. Blumberg
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Jeewoo Lee
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul 151-742, Korea
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Pungency of TRPV1 agonists is directly correlated with kinetics of receptor activation and lipophilicity. Eur J Pharmacol 2010; 641:114-22. [DOI: 10.1016/j.ejphar.2010.05.029] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 04/19/2010] [Accepted: 05/23/2010] [Indexed: 12/11/2022]
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22
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Qiao LY, Grider JR. Colitis elicits differential changes in the expression levels of receptor tyrosine kinase TrkA and TrkB in colonic afferent neurons: a possible involvement of axonal transport. Pain 2010; 151:117-127. [PMID: 20638179 DOI: 10.1016/j.pain.2010.06.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Revised: 06/17/2010] [Accepted: 06/25/2010] [Indexed: 12/22/2022]
Abstract
The role of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in colitis-induced hypersensitivity has been suggested. NGF and BDNF facilitate cellular physiology through binding to receptor tyrosine kinase TrkA and TrkB, respectively. The present study by examining the mRNA and/or protein levels of TrkA and TrkB in the distal colon and in colonic primary afferent neurons in the dorsal root ganglia (DRG) during colitis demonstrated that colitis elicited location-specific changes in the mRNA and protein levels of TrkA and TrkB in colonic primary sensory pathways. In colitis both the TrkA and TrkB protein levels were increased in the L1 and S1 DRGs in a time-dependent manner; however, the level of TrkB mRNA but not TrkA mRNA was increased in these DRGs. Further experiments showed that colitis facilitated a retrograde transport of TrkA protein toward and an anterograde transport of TrkA mRNA away from the DRG, which may contribute to the increased TrkA mRNA level in the distal colon during colitis. Colitis also increased the level of NGF mRNA but not BDNF mRNA in the distal colon. Double staining showed that the expression of TrkA but not TrkB was increased in the specifically labeled colonic afferent neurons in the L1 and S1 DRGs during colitis; this increase in TrkA level was attenuated by pretreatment with resiniferatoxin. These results suggested that colitis-induced primary afferent activation involved retrograde transport of TrkA but not TrkB from the distal colon to primary afferent neurons in DRG.
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Affiliation(s)
- Li-Ya Qiao
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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23
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Bartness TJ, Shrestha YB, Vaughan CH, Schwartz GJ, Song CK. Sensory and sympathetic nervous system control of white adipose tissue lipolysis. Mol Cell Endocrinol 2010; 318:34-43. [PMID: 19747957 PMCID: PMC2826518 DOI: 10.1016/j.mce.2009.08.031] [Citation(s) in RCA: 212] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 08/25/2009] [Accepted: 08/26/2009] [Indexed: 12/14/2022]
Abstract
Circulating factors are typically invoked to explain bidirectional communication between the CNS and white adipose tissue (WAT). Thus, initiation of lipolysis has been relegated primarily to adrenal medullary secreted catecholamines and the inhibition of lipolysis primarily to pancreatic insulin, whereas signals of body fat levels to the brain have been ascribed to adipokines such as leptin. By contrast, evidence is given for bidirectional communication between brain and WAT occurring via the sympathetic nervous system (SNS) and sensory innervation of this tissue. Using retrograde transneuronal viral tract tracers, the SNS outflow from brain to WAT has been defined. Functionally, sympathetic denervation of WAT blocks lipolysis to a variety of lipolytic stimuli. Using anterograde transneuronal viral tract tracers, the sensory input from WAT to brain has been defined. Functionally, these WAT sensory nerves respond electrophysiologically to increases in WAT SNS drive suggesting a possible neural negative feedback loop to regulate lipolysis.
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Affiliation(s)
- Timothy J Bartness
- Department of Biology and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302-4010, USA.
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Crouzin N, de Jesus Ferreira MC, Cohen-Solal C, Barbanel G, Guiramand J, Vignes M. Neuroprotection induced by vitamin E against oxidative stress in hippocampal neurons: Involvement of TRPV1 channels. Mol Nutr Food Res 2010; 54:496-505. [DOI: 10.1002/mnfr.200900188] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Jara-Oseguera A, Simon SA, Rosenbaum T. TRPV1: on the road to pain relief. Curr Mol Pharmacol 2010; 1:255-69. [PMID: 20021438 DOI: 10.2174/1874467210801030255] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Historically, drug research targeted to pain treatment has focused on trying to prevent the propagation of action potentials in the periphery from reaching the brain rather than pinpointing the molecular basis underlying the initial detection of the nociceptive stimulus: the receptor itself. This has now changed, given that many receptors of nociceptive stimuli have been identified and/or cloned. Transient Receptor Potential (TRP) channels have been implicated in several physiological processes such as mechanical, chemical and thermal stimuli detection. Ten years after the cloning of TRPV1, compelling data has been gathered on the role of this channel in inflammatory and neuropathic states. TRPV1 activation in nociceptive neurons, where it is normally expressed, triggers the release of neuropeptides and transmitters resulting in the generation of action potentials that will be sent to higher CNS areas where they will often be perceived as pain. Its activation also will evoke the peripheral release of pro-inflammatory compounds that may sensitize other neurons to physical, thermal or chemical stimuli. For these reasons as well as because its continuous activation causes analgesia, TRPV1 has become a viable drug target for clinical use in the management of pain. This review will provide a general picture of the physiological and pathophysiological roles of the TRPV1 channel and of its structural, pharmacological and biophysical properties. Finally, it will provide the reader with an overall view of the status of the discovery of potential therapeutic agents for the management of chronic and neuropathic pain.
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Affiliation(s)
- Andrés Jara-Oseguera
- Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
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Effect of lipid raft disruption on TRPV1 receptor activation of trigeminal sensory neurons and transfected cell line. Eur J Pharmacol 2009; 628:67-74. [PMID: 19958765 DOI: 10.1016/j.ejphar.2009.11.052] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 11/17/2009] [Accepted: 11/24/2009] [Indexed: 01/17/2023]
Abstract
The transient receptor potential vanilloid 1 (TRPV1) is a noxious heat-sensitive, chemonociceptive cation channel which is expressed in primary sensory neurons of polymodal nociceptors. The present study is devoted to analyse the role of lipid raft constituents in calcium influx evoked by various TRPV1 agonists on sensory neurons and on rTRPV1-transfected CHO cell line. Depletion of cholesterol by methyl beta-cyclodextrin (MCD, 1-10mM) diminished the percent of the calcium uptake response of cultured trigeminal neurons to capsaicin (100nM) or resiniferatoxin (RTX, 3nM). In contrast, in TRPV1-transfected cells the inhibition was observed only when capsaicin or N-oleoyldopamine (OLDA, 10microM) was applied, but not when RTX, anandamide (AEA, 10microM) or pH 5.5 was used for gating. The magnitude of Ca(2+)-transients evoked by capsaicin (330nM) was also inhibited in both cell types. Treatment of rTRPV1-expressing cells with sphinomyelinase inhibited the capsaicin-evoked (45)Ca-uptake leaving the RTX-induced response unchanged. On the other hand, in trigeminal neurons the effect of both compounds was inhibited by sphingomyelinase treatment. Inhibition of ganglioside biosynthesis by d-threo-1-Phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP, 10-20microM) or myriocyn (5-50nM) diminished similarly capsaicin- or RTX-evoked calcium uptake in both cultured trigeminal neurons and rTRPV1-expressing cells. The present study revealed that depletion of different constituents of lipid raft inhibited gating the TRPV1 cation channel by various vanilloid and non-vanilloid agents. Evidence for a supporting role of cholesterol, sphingomyelin and gangliosides were obtained both in native and TRPV1-transfected cells. Differential modulation of responses to capsaicin and RTX was often observed.
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Abstract
Three sensory systems, olfaction, taste, and somatosensation, are dedicated to the detection of chemicals in the environment. Trigeminal somatosensory neurons enable us to detect a wide range of environmental stimuli, including pressure, temperature, and chemical irritants, within the oral and nasal mucosa. Natural plant-derived irritants have served as powerful pharmacological tools for identifying receptors underlying somatosensation. This is illustrated by the use of capsaicin, menthol, and wasabi to identify the heat-sensitive ion channel TRPV1, the cold-sensitive ion channel TRPM8, and the irritant receptor TRPA1, respectively. In addition to TRP channels, members of the two-pore potassium channel family have also been implicated in trigeminal chemosensation. KCNK18 was recently identified as a target for hydroxy-alpha-sanshool, the tingling and numbing compound produced in Schezuan peppers and other members of the Xanthoxylum genus. The role of these channels in trigeminal thermosensation and pain will be discussed.
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Affiliation(s)
- Kristin A Gerhold
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720-3200, USA
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28
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Potenzieri C, Brink TS, Simone DA. Excitation of cutaneous C nociceptors by intraplantar administration of anandamide. Brain Res 2009; 1268:38-47. [PMID: 19285051 DOI: 10.1016/j.brainres.2009.02.061] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 02/16/2009] [Accepted: 02/17/2009] [Indexed: 11/20/2022]
Abstract
Anandamide has been characterized as both an endocannabinoid and endovanilloid. Consistent with its actions as an endovanilloid, previous studies have demonstrated that anandamide can excite primary sensory neurons in vitro via transient receptor potential vanilloid type one (TRPV1) receptors. In the present study, we sought to determine if anandamide excited cutaneous C nociceptors in vivo and if this excitation correlated with nocifensive behaviors. Using teased-fiber electrophysiological methods in the rat, C nociceptors isolated from the tibial nerve with receptive fields (RFs) on the plantar surface of the hindpaw were studied. Injection of anandamide into the RF dose-dependently excited nociceptors at doses of 10 and 100 microg. The TRPV1 receptor antagonists, capsazepine or SB 366791, were applied to the RF to determine if excitation by anandamide was mediated through TRPV1 receptors. Intraplantar injection of either capsazepine (10 microg) or SB 366791 (3 microg) attenuated the excitation produced by 100 microg anandamide. We also determined whether excitation of C nociceptors by anandamide was associated with nocifensive behaviors. Intraplantar injection of 100 microg anandamide produced nocifensive behaviors that were attenuated by pre-treatment with either capsazepine or SB 366791. Furthermore, we determined if intraplantar injection of anandamide altered withdrawal responses to radiant heat. Neither intraplantar injection of anandamide nor vehicle produced antinociception or hyperalgesia to radiant heat. Our results indicate that anandamide excited cutaneous C nociceptors and produced nocifensive behaviors via activation of TRPV1 receptors.
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Affiliation(s)
- Carl Potenzieri
- Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, MN, USA; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Thaddeus S Brink
- Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Donald A Simone
- Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, MN, USA; Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, USA.
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Choi HK, Choi S, Lee Y, Kang DW, Ryu H, Maeng HJ, Chung SJ, Pavlyukovets VA, Pearce LV, Toth A, Tran R, Wang Y, Morgan MA, Blumberg PM, Lee J. Non-vanillyl resiniferatoxin analogues as potent and metabolically stable transient receptor potential vanilloid 1 agonists. Bioorg Med Chem 2008; 17:690-8. [PMID: 19135377 DOI: 10.1016/j.bmc.2008.11.085] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2008] [Revised: 11/20/2008] [Accepted: 11/20/2008] [Indexed: 01/08/2023]
Abstract
A series of non-vanillyl resiniferatoxin analogues, having 4-methylsulfonylaminophenyl and fluorophenyl moieties as vanillyl surrogates, have been investigated as ligands for rat TRPV1 heterologously expressed in Chinese hamster ovary cells. Although lacking the metabolically problematic 4-hydroxy substituent on the A-region phenyl ring, the compounds retained substantial agonist potency. Indeed, the 3-methoxy-4-methylsulfonylaminophenyl analog (1) was modestly (2.5-fold) more potent than RTX, with an EC(50)=0.106 nM. Further, it resembled RTX in its kinetics and pattern of stimulation of the levels of intracellular calcium in individual cells, as revealed by imaging. Compound 1 displayed modestly enhanced in vitro stability in rat liver microsomes and in plasma, suggesting that it might be a pharmacokinetically more favorable surrogate of resiniferatoxin. Molecular modeling analyses with selected analogues provide evidence that the conformational differences could affect their binding affinities, especially for the ester versus amide at the B-region.
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Affiliation(s)
- Hyun-Kyung Choi
- Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Shinlim-Dong, Kwanak-Ku, Seoul 151-742, South Korea
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30
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Marincsák R, Tóth BI, Czifra G, Szabó T, Kovács L, Bíró T. The Analgesic Drug, Tramadol, Acts as an Agonist of the Transient Receptor Potential Vanilloid-1. Anesth Analg 2008; 106:1890-6. [DOI: 10.1213/ane.0b013e318172fefc] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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31
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Fezza F, Oddi S, Di Tommaso M, De Simone C, Rapino C, Pasquariello N, Dainese E, Finazzi-Agrò A, Maccarrone M. Characterization of biotin-anandamide, a novel tool for the visualization of anandamide accumulation. J Lipid Res 2008; 49:1216-23. [PMID: 18316795 DOI: 10.1194/jlr.m700486-jlr200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Anandamide (N-arachidonoylethanolamide; AEA) acts as an endogenous agonist of both cannabinoid and vanilloid receptors. During the last two decades, its metabolic pathways and biological activity have been investigated extensively and relatively well characterized. In contrast, at present, the effective nature and mechanism of AEA transport remain controversial and still unsolved issues. Here, we report the characterization of a biotinylated analog of AEA (b-AEA) that has the same lipophilicity of the parent compound. In addition, by means of biochemical assays and fluorescence microscopy, we show that b-AEA is accumulated inside the cells in a way superimposable on that of AEA. Conversely, b-AEA does not interact or interfere with the other components of the endocannabinoid system, such as type-1 and type-2 cannabinoid receptors, vanilloid receptor, AEA synthetase (N-acylphosphatidylethanolamine-hydrolyzing phospholipase D), or AEA hydrolase (fatty acid amide hydrolase). Together, our data suggest that b-AEA could be a very useful probe for visualizing the accumulation and intracellular distribution of this endocannabinoid.
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Affiliation(s)
- Filomena Fezza
- European Center for Brain Research/Istituto di Ricovero e Cura a Carattere Scientifico S. Lucia Foundation, Rome, Italy
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32
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Chung KF. Effective antitussives for the cough patient: an unmet need. Pulm Pharmacol Ther 2006; 20:438-45. [PMID: 17161637 DOI: 10.1016/j.pupt.2006.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Accepted: 10/26/2006] [Indexed: 02/07/2023]
Abstract
Chronic cough is a prevalent symptom in the community but it is likely that only a small fraction of chronic coughers seek medical attention. Chronic cough can be controlled by addressing the 'cause' of the cough, but not all cough is controlled using this approach; an 'idiopathic' cough or cough of unknown aetiology is becoming more well-recognized. In these patients and in those whose cough has not responded to treatment of the cause(s), there is a lack of efficacious antitussive therapies ('non-specific' antitussives). Even in those whose cough is controlled by treatment of the cause, an efficacious antitussive for symptomatic relief would be useful for breakthrough symptoms. It is necessary to address the mechanisms underlying chronic cough, particularly the process of sensitization, both peripherally and centrally, that is the basis of chronic cough; such a process may persist even in the absence of the initiating event that first induced the cough. Currently-available antitussives in both acute and chronic cough are not very effective. Novel targets that may result in effective antitussives have been identified and with the development of clinical tools to measure cough accurately and reliably (e.g. cough counts and cough-specific quality-of-life questionnaires) and the evoked cough response (e.g. citric acid or capsaicin challenges), clinical trials should be performed. The chronic cough population is clinically heterogeneous but is characterized by an enhanced cough reflex; this should be the target population for study. Patients with chronic cough are in desperate need of effective antitussives that can be used either on demand or on a long-term basis.
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Affiliation(s)
- K F Chung
- National Heart and Lung Institute, Imperial College London and Royal Brompton and Harefield NHS Trust, London SW3, UK.
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33
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BARBERO R, BADINO P, CUNIBERTI B, MIOLO A, ODORE R, DI MARZO V, RE G. G02 Identification of functional TRPV1 vanilloid receptor in MCF-7 cells. J Vet Pharmacol Ther 2006. [DOI: 10.1111/j.1365-2885.2006.00765_3.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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34
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Barbero R, Badino P, Cuniberti B, Miolo A, Odore R, Girardi C, Re G. Identification of the VR-1 Vanilloid Receptor in Cell Cultures. Vet Res Commun 2006. [DOI: 10.1007/s11259-006-0060-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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35
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Kim S, Kang C, Shin CY, Hwang SW, Yang YD, Shim WS, Park MY, Kim E, Kim M, Kim BM, Cho H, Shin Y, Oh U. TRPV1 recapitulates native capsaicin receptor in sensory neurons in association with Fas-associated factor 1. J Neurosci 2006; 26:2403-12. [PMID: 16510717 PMCID: PMC6793661 DOI: 10.1523/jneurosci.4691-05.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
TRPV1, a cloned capsaicin receptor, is a molecular sensor for detecting adverse stimuli and a key element for inflammatory nociception and represents biophysical properties of native channel. However, there seems to be a marked difference between TRPV1 and native capsaicin receptors in the pharmacological response profiles to vanilloids or acid. One plausible explanation for this overt discrepancy is the presence of regulatory proteins associated with TRPV1. Here, we identify Fas-associated factor 1 (FAF1) as a regulatory factor, which is coexpressed with and binds to TRPV1 in sensory neurons. When expressed heterologously, FAF1 reduces the responses of TRPV1 to capsaicin, acid, and heat, to the pharmacological level of native capsaicin receptor in sensory neurons. Furthermore, silencing FAF1 by RNA interference augments capsaicin-sensitive current in native sensory neurons. We therefore conclude that FAF1 forms an integral component of the vanilloid receptor complex and that it constitutively modulates the sensitivity of TRPV1 to various noxious stimuli in sensory neurons.
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MESH Headings
- Acids/pharmacology
- Adaptor Proteins, Signal Transducing/metabolism
- Analysis of Variance
- Animals
- Animals, Newborn
- Apoptosis Regulatory Proteins
- Biotinylation/methods
- Blotting, Western/methods
- Blotting, Western/statistics & numerical data
- Capsaicin/pharmacology
- Cells, Cultured
- Cloning, Molecular/methods
- Dose-Response Relationship, Drug
- Electric Stimulation/methods
- Ganglia, Spinal/cytology
- Gene Expression Regulation/drug effects
- Humans
- Immunohistochemistry/methods
- Immunoprecipitation/methods
- Membrane Potentials/drug effects
- Membrane Potentials/radiation effects
- Mutation
- Neurons, Afferent/drug effects
- Neurons, Afferent/physiology
- Patch-Clamp Techniques/methods
- Protein Structure, Tertiary/physiology
- RNA, Small Interfering/pharmacology
- Radioligand Assay/methods
- Rats
- Reverse Transcriptase Polymerase Chain Reaction/methods
- TRPV Cation Channels/physiology
- Temperature
- Transfection/methods
- Ubiquitin/metabolism
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36
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Elmes SJR, Millns PJ, Smart D, Kendall DA, Chapman V. Evidence for biological effects of exogenous LPA on rat primary afferent and spinal cord neurons. Brain Res 2006; 1022:205-13. [PMID: 15353230 DOI: 10.1016/j.brainres.2004.07.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2004] [Indexed: 10/26/2022]
Abstract
There is growing behavioural evidence that the phospholipid growth factor lysophosphatidic acid (LPA) modulates nociceptive responses in vivo. The present study investigated further the effects of LPA on peripheral nociceptive processing. Effects of intraplantar injection of LPA on ongoing and peripheral mechanically evoked responses of spinal neurons were studied in vivo. In addition, LPA-evoked responses of adult rat dorsal root ganglion (DRG) neurons were studied with calcium imaging. To determine whether LPA may also act at the level of the spinal cord, LPA receptor G-protein coupling in lumbar spinal cord sections was studied with in vitro autoradiography of guanylyl 5'-[g-[(35)S]thio]triphosphate ([(35)S]GTPgammaS) binding. Intraplantar injection of LPA (5 microg/5 microl) significantly increased the duration (P<0.001) and frequency of spinal neuronal firing (P<0.01), compared to vehicle. Intraplantar injection of LPA (1 microg/5 microl) did not significantly alter innocuous and noxious mechanically evoked responses of spinal neurons, but a higher dose of LPA (5 microg) significantly (P<0.05) attenuated mechanically evoked responses of spinal neurons. Calcium imaging studies demonstrated that LPA (0.001-3 microM) increases intracellular calcium concentration in adult DRG neurons, suggesting that LPA can produce direct effects on. Incubation of spinal cord sections with LPA (1 microM) significantly (P<0.001) increased [(35)S]GTPgammaS binding in the superficial laminae of the dorsal horn of the spinal cord, suggesting that LPA may also have biological effects at this level. These data provide further evidence that exogenous LPA can modulate nociceptive processing and suggest that this may be mediated by a direct effect on primary afferent nociceptors.
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Affiliation(s)
- Steven J R Elmes
- Institute of Neuroscience, School of Biomedical Sciences, E Floor, Medical School, Queen's Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom.
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37
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Gram DX, Hansen AJ, Deacon CF, Brand CL, Ribel U, Wilken M, Carr RD, Svendsen O, Ahrén B. Sensory nerve desensitization by resiniferatoxin improves glucose tolerance and increases insulin secretion in Zucker Diabetic Fatty rats and is associated with reduced plasma activity of dipeptidyl peptidase IV. Eur J Pharmacol 2005; 509:211-7. [PMID: 15733558 DOI: 10.1016/j.ejphar.2004.12.039] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 12/17/2004] [Accepted: 12/24/2004] [Indexed: 11/21/2022]
Abstract
Sensory nerve desensitization by capsaicin has been shown to improve the diabetic condition in Zucker Diabetic Fatty rats. However, administration of capsaicin to adult rats is associated with an increased mortality. Therefore, in this experiment, we examined the influence of resiniferatoxin, a tolerable analogue of capsaicin suitable for in vivo use, on the diabetic condition of Zucker Diabetic Fatty rats. A single subcutaneous injection of resiniferatoxin (0.01 mg/kg) to these rats was tolerable, with no mortality. When administered to early diabetic rats at 15 weeks of age, the further deterioration of glucose homeostasis was prevented by resiniferatoxin. Further, when administered to overtly diabetic rats at 19 weeks of age, resiniferatoxin markedly improved glucose tolerance at two weeks after administration and this was accompanied by an increased insulin response to oral glucose as well as a reduction in the plasma levels of dipeptidyl peptidase IV. Therefore, resiniferatoxin is a safe alternative to capsaicin for further investigations of the role of the sensory nerves in experimental diabetes.
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Affiliation(s)
- Dorte X Gram
- Research and Development, Novo Nordisk A/S, Måløv, Denmark.
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38
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Kimball ES, Wallace NH, Schneider CR, D'Andrea MR, Hornby PJ. Vanilloid receptor 1 antagonists attenuate disease severity in dextran sulphate sodium-induced colitis in mice. Neurogastroenterol Motil 2004; 16:811-8. [PMID: 15601431 DOI: 10.1111/j.1365-2982.2004.00549.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Neurogenic mechanisms have been implicated in the induction of inflammatory bowel disease (IBD). Vanilloid receptor type 1 (TRPV1) has been visualized on nerve terminals of intrinsic and extrinsic afferent neurones innervating the gastrointestinal tract and local administration of a TRPV1 antagonist, capsazepine, reduces the severity of dextran sulphate sodium (DSS)-induced colitis in rats (Gut 2003; 52: 713-9(1)). Our aim was to test whether systemically or orally administered TRPV1 antagonists attenuate experimental colitis induced by 5% DSS in Balb/c mice. Intraperitoneal capsazepine (2.5 mg kg(-1), bid), significantly reduced the overall macroscopic damage severity compared with vehicle-treated animals (80% inhibition, P < 0.05); however, there was no effect on myeloperoxidase (MPO) levels. An experimental TRPV1 antagonist given orally was tested against DSS-induced colitis, and shown to reverse the macroscopic damage score at doses of 0.5 and 5.0 mg kg(-1). Epithelial damage assessed microscopically was significantly reduced. MPO levels were attenuated by approximately 50%, and diarrhoea scores were reduced by as much as 70%. These results suggest that pharmacological modulation of TRPV1 attenuates indices of experimental colitis in mice, and that development of orally active TRPV1 antagonists might have therapeutic potential for the treatment of IBD.
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Affiliation(s)
- E S Kimball
- Drug Discovery Division, Johnson and Johnson Pharmaceutical Research and Development, PA 19477, USA.
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39
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Herst PM, Tan AS, Scarlett DJG, Berridge MV. Cell surface oxygen consumption by mitochondrial gene knockout cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2004; 1656:79-87. [PMID: 15178469 DOI: 10.1016/j.bbabio.2004.01.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Revised: 01/29/2004] [Accepted: 01/30/2004] [Indexed: 11/18/2022]
Abstract
Mitochondrial gene knockout (rho(0)) cells that depend on glycolysis for their energy requirements show an increased ability to reduce cell-impermeable tetrazolium dyes by electron transport across the plasma membrane. In this report, we show for the first time, that oxygen functions as a terminal electron acceptor for trans-plasma membrane electron transport (tPMET) in HL60rho(0) cells, and that this cell surface oxygen consumption is associated with oxygen-dependent cell growth in the absence of mitochondrial electron transport function. Non-mitochondrial oxygen consumption by HL60rho(0) cells was extensively inhibited by extracellular NADH and NADPH, but not by NAD(+), localizing this process at the cell surface. Mitochondrial electron transport inhibitors and the uncoupler, FCCP, did not affect oxygen consumption by HL60rho(0) cells. Inhibitors of glucose uptake and glycolysis, the ubiquinone redox cycle inhibitors, capsaicin and resiniferatoxin, the flavin centre inhibitor, diphenyleneiodonium, and the NQO1 inhibitor, dicoumarol, all inhibited oxygen consumption by HL60rho(0) cells. Similarities in inhibition profiles between non-mitochondrial oxygen consumption and reduction of the cell-impermeable tetrazolium dye, WST-1, suggest that both systems may share a common tPMET pathway. This is supported by the finding that terminal electron acceptors from both pathways compete for electrons from intracellular NADH.
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Affiliation(s)
- Patries M Herst
- Department of Radiation Therapy, Wellington School of Medicine and Health Sciences, University of Otago, PO Box 7343, Wellington, New Zealand
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40
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Nilius B, Vriens J, Prenen J, Droogmans G, Voets T. TRPV4 calcium entry channel: a paradigm for gating diversity. Am J Physiol Cell Physiol 2004; 286:C195-205. [PMID: 14707014 DOI: 10.1152/ajpcell.00365.2003] [Citation(s) in RCA: 353] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The vanilloid receptor-1 (VR1, now TRPV1) was the founding member of a subgroup of cation channels within the TRP family. The TRPV subgroup contains six mammalian members, which all function as Ca2+ entry channels gated by a variety of physical and chemical stimuli. TRPV4, which displays 45% sequence identity with TRPV1, is characterized by a surprising gating promiscuity: it is activated by hypotonic cell swelling, heat, synthetic 4alpha-phorbols, and several endogenous substances including arachidonic acid (AA), the endocannabinoids anandamide and 2-AG, and cytochrome P-450 metabolites of AA, such as epoxyeicosatrienoic acids. This review summarizes data on TRPV4 as a paradigm of gating diversity in this subfamily of Ca2+ entry channels.
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Affiliation(s)
- Bernd Nilius
- Laboratorium voor Fysiologie, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium.
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41
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Caudle RM, Karai L, Mena N, Cooper BY, Mannes AJ, Perez FM, Iadarola MJ, Olah Z. Resiniferatoxin-induced loss of plasma membrane in vanilloid receptor expressing cells. Neurotoxicology 2004; 24:895-908. [PMID: 14637384 DOI: 10.1016/s0161-813x(03)00146-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Resiniferatoxin (RTX), a potent analog of capsaicin, was evaluated electrophysiologically in dorsal root ganglion (DRG) cells and cell lines ectopically expressing the vanilloid receptor type 1 (VR1) to determine if cell phenotype influenced RTXs neurotoxic properties. Furthermore, capsaicin and heat activation of VR1 were evaluated in these cells to determine if cellular damage was unique to RTX activation of the receptors. RTX application to DRG cells identified as type 1, 2 or 5, cell types known to express VR1, induced large inward currents. RTX did not induce currents in DRG cells that do not express the receptor (type 4 cells). In cell lines ectopically expressing VR1, RTX-induced similar currents. RTX produced no effect in non-transfected cells. After exposure to RTX both DRG cells and transfected cells failed to respond to subsequent applications of the agonist. In addition, whole cell capacitance was reduced up to 70%. The decrease in capacitance was associated with the loss of plasma membrane, as determined by confocal microscopy. Cell phenotype, other than VR1 expression, did not influence the response to RTX. Interestingly, capsaicin and heat activation of vanilloid receptors also decreased cell capacitance, but the loss of membrane was not as great as with RTX and responses to these stimuli were not lost after the initial exposure. The loss of cell membrane required elevated intracellular levels of Ca2+. From these data it was concluded that the loss of cell membrane was dependent on the presence of both VR1 and intracellular Ca2+ accumulation, but not on cell phenotype.
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Affiliation(s)
- Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry and the University of Florida McKnight Brain Institute, 1600 Archer Road, P.O. Box 100416, Gainesville, FL 32610, USA.
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42
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Shin CY, Shin J, Kim BM, Wang MH, Jang JH, Surh YJ, Oh U. Essential role of mitochondrial permeability transition in vanilloid receptor 1-dependent cell death of sensory neurons. Mol Cell Neurosci 2004; 24:57-68. [PMID: 14550768 DOI: 10.1016/s1044-7431(03)00121-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Capsaicin causes pain by activating VR1, a cloned capsaicin receptor, in sensory neurons. After the initial excitatory responses, capsaicin produces prolonged analgesia, presumably because of the neurotoxic effect that leads to the death of sensory neurons. However, the mechanism underlying capsaicin-induced cell death of sensory neurons is not known. Here we report that capsaicin induces cell death in VR1-expressing sensory neurons and VR1-transfected human embryonic kidney cells. Cell death of sensory neurons induced by capsaicin is accompanied by DNA fragmentation, TUNEL staining, and shrinkage of the nucleus in a caspase-dependent manner, indicating the apoptotic nature of the cell death. Mitochondrial permeability transition is likely to be a major component of capsaicin-induced cell death because bonkrekic acid and cyclosporin A, inhibitors of mitochondrial permeability transition, block this cell death. These results imply that capsaicin induces mitochondrial dysfunction in VR1-expressing cells, leading to apoptotic cell death, which is a well-known neurotoxic effect of capsaicin.
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MESH Headings
- Animals
- Animals, Newborn
- Apoptosis/drug effects
- Apoptosis/physiology
- Capsaicin/toxicity
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/physiology
- Cells, Cultured
- Cyclosporine/pharmacology
- DNA Fragmentation/drug effects
- DNA Fragmentation/physiology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/physiopathology
- Humans
- Intracellular Membranes/drug effects
- Intracellular Membranes/physiology
- Mitochondria/drug effects
- Mitochondria/metabolism
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Neurotoxins/toxicity
- Pain/chemically induced
- Pain/metabolism
- Pain/physiopathology
- Permeability/drug effects
- Rats
- Receptors, Drug/drug effects
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Transfection
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Affiliation(s)
- Chan Young Shin
- The Sensory Research Center, National Creative Research Initiatives, Seoul National University, College of Pharmacy, Kwanak-Gu, Shinlim 9-dong, Seoul 151-742, South Korea
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43
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Enhanced evoked excitatory transmitter release in experimental neuropathy requires descending facilitation. J Neurosci 2003. [PMID: 12967999 DOI: 10.1523/jneurosci.23-23-08370.2003] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nerve injury-induced afferent discharge is thought to elicit spinal sensitization and consequent abnormal pain. Experimental neuropathic pain, however, also depends on central changes, including descending facilitation arising from the rostral ventromedial medulla (RVM) and upregulation of spinal dynorphin. A possible intersection of these influences at the spinal level was explored by measuring evoked, excitatory transmitter release in tissues taken from nerve-injured animals with or without previous manipulation of descending modulatory systems. Spinal nerve ligation (SNL) produced expected tactile and thermal hyperesthesias. Capsaicin-evoked calcitonin gene-related peptide (CGRP) release was markedly enhanced in lumbar spinal tissue from SNL rats when compared with sham-operated controls. Enhanced, evoked CGRP release from SNL rats was blocked by anti-dynorphin A(1-13) antiserum; this treatment did not alter evoked release in tissues from sham-operated rats. Dorsolateral funiculus lesion (DLF) or destruction of RVM neurons expressing mu-opioid receptors with dermorphin-saporin, blocked tactile and thermal hypersensitivity, as well as SNL-induced upregulation of spinal dynorphin. Spinal tissues from these DLF-lesioned or dermorphin-saporin-treated SNL rats did not exhibit enhanced capsaicin-evoked CGRP-IR release. These data demonstrate exaggerated release of excitatory transmitter from primary afferents after injury to peripheral nerves, supporting the likely importance of increased afferent input as a driving force of neuropathic pain. The data also show that modulatory influences of descending facilitation are required for enhanced evoked transmitter release after nerve injury. Thus, convergence of descending modulation, spinal plasticity, and afferent drive in the nerve-injured state reveals a mechanism by which some aspects of nerve injury-induced hyperesthesias may occur.
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44
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Gardell LR, Vanderah TW, Gardell SE, Wang R, Ossipov MH, Lai J, Porreca F. Enhanced evoked excitatory transmitter release in experimental neuropathy requires descending facilitation. J Neurosci 2003; 23:8370-9. [PMID: 12967999 PMCID: PMC6740686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023] Open
Abstract
Nerve injury-induced afferent discharge is thought to elicit spinal sensitization and consequent abnormal pain. Experimental neuropathic pain, however, also depends on central changes, including descending facilitation arising from the rostral ventromedial medulla (RVM) and upregulation of spinal dynorphin. A possible intersection of these influences at the spinal level was explored by measuring evoked, excitatory transmitter release in tissues taken from nerve-injured animals with or without previous manipulation of descending modulatory systems. Spinal nerve ligation (SNL) produced expected tactile and thermal hyperesthesias. Capsaicin-evoked calcitonin gene-related peptide (CGRP) release was markedly enhanced in lumbar spinal tissue from SNL rats when compared with sham-operated controls. Enhanced, evoked CGRP release from SNL rats was blocked by anti-dynorphin A(1-13) antiserum; this treatment did not alter evoked release in tissues from sham-operated rats. Dorsolateral funiculus lesion (DLF) or destruction of RVM neurons expressing mu-opioid receptors with dermorphin-saporin, blocked tactile and thermal hypersensitivity, as well as SNL-induced upregulation of spinal dynorphin. Spinal tissues from these DLF-lesioned or dermorphin-saporin-treated SNL rats did not exhibit enhanced capsaicin-evoked CGRP-IR release. These data demonstrate exaggerated release of excitatory transmitter from primary afferents after injury to peripheral nerves, supporting the likely importance of increased afferent input as a driving force of neuropathic pain. The data also show that modulatory influences of descending facilitation are required for enhanced evoked transmitter release after nerve injury. Thus, convergence of descending modulation, spinal plasticity, and afferent drive in the nerve-injured state reveals a mechanism by which some aspects of nerve injury-induced hyperesthesias may occur.
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Affiliation(s)
- L R Gardell
- Department of Pharmacology, University of Arizona, Tucson, Arizona 85724, USA
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45
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Wang Y, Toth A, Tran R, Szabo T, Welter JD, Blumberg PM, Lee J, Kang SU, Lim JO, Lee J. High-affinity partial agonists of the vanilloid receptor. Mol Pharmacol 2003; 64:325-33. [PMID: 12869637 DOI: 10.1124/mol.64.2.325] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The vanilloid receptor VR1 is a polymodal nociceptor sensitive to capsaicin, protons, and heat. Because VR1 represents an attractive therapeutic target for conditions ranging from long-term pain to bladder hyperreflexia, we and other groups have sought to develop novel ligands with enhanced potencies and novel pharmacological properties. Here, we characterize two compounds, N-[2-(3,4-dimethylbenzyl)-3-(pivaloyloxy)propyl]-N'-[4-(methylsulfonylamino)benzyl]thiourea (JYL827) and N-(4-tert-butylbenzyl)-N'-[3-methoxy-4-(methylsulfonylamino)benzyl]thiourea (JYL1511), that function as partial agonists for rat VR1 heterologously expressed in Chinese hamster ovary cells. Both compounds showed substantially enhanced potency, inhibiting [3H] resiniferatoxin binding with Ki values of 29.3 +/- 7.6 and 50.4 +/- 16.5 nM, respectively, compared with 1810 +/- 270 nM for capsaicin. The compounds showed different extents of partial agonism, 6.8 +/- 0.7% and 17.4 +/- 0.6%, respectively, and the expected corresponding degrees of partial antagonism (93.9 +/- 0.9 and 84.1 +/- 3.2%, respectively). Their IC50 values for antagonism of 45Ca2+ uptake in response to capsaicin were 67.3 +/- 24.9 nM and 3.4 +/- 0.5 nM, respectively. Protons, temperature, and protein kinase C all function as coactivators/modulators of rVR1. All enhanced the extent of partial agonism of JYL827 and JYL1511. Thus, at pH 5.5, for example, the extents of partial agonism increased to 54.9 +/- 2.5% and to 90.7 +/- 1.7%, respectively, relative to the response elicited by 300 nM capsaicin. The extents of partial antagonism decreased correspondingly. Compounds such as JYL827 and JYL1511 now permit exploration of the potential utility of partial agonists of rVR1 in animal models. Our results emphasize, moreover, the strong dependence of such partial agonists on other modulators of rVR1 and predict that their biological behavior will depend strongly on biological context.
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Affiliation(s)
- Yun Wang
- National Cancer Institute, Building 37, Room 4048, 37 Convent Drive MSC 4255, Bethesda, MD 20892-4255, USA
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46
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Qiao LY, Vizzard MA. Up-regulation of phosphorylated CREB but not c-Jun in bladder afferent neurons in dorsal root ganglia after cystitis. J Comp Neurol 2003; 469:262-74. [PMID: 14694538 DOI: 10.1002/cne.11009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We examined the changes of two transcription factors, CREB and c-Jun, in dorsal root ganglia (DRG) after acute (8 or 48 hours) or chronic (10 days) cyclophosphamide (CYP)-induced cystitis. Results showed an increase in the number of p-CREB-immunoreactive (-IR) cells in the L1 and L2 DRG (5-7-fold; P < or = 0.05) as well as L6 and S1 DRG (2-4-fold; P < or = 0.05) after acute and chronic cystitis. The number of p-CREB-IR cells in the L4-L5 DRG was not altered with cystitis. The number of c-Jun-IR cells increased in the L1-L2 DRG (L1: 10-fold; L2: 8-fold; P < or = 0.05) only with chronic cystitis, although it increased in the L6-S1 DRG with CYP-induced cystitis of acute (2-3-fold; P < or = 0.05) and chronic (6-10-fold; P < or = 0.05) duration. After CYP treatment, the percentage of bladder afferent cells expressing p-CREB immunoreactivity (3-7-fold; P < or = 0.05) increased in L1, L2, L6, and S1 DRG. The increase occurred 8 hours post-CYP injection and was maintained with chronic cystitis. There were few c-Jun-IR cells in the bladder afferent population. These results demonstrate that CYP induces p-CREB and c-Jun expression in DRG in a time-dependent manner. However, c-Jun expression is not associated with bladder afferent neurons. Resiniferatoxin reduced CYP-induced up-regulation of p-CREB in DRG, suggesting that cystitis can reveal an altered CREB phosphorylation that may be mediated by capsaicin-sensitive bladder afferents. Colocalization of p-CREB and Trk receptor(s) showed that a subpopulation of p-CREB-IR cells expressed p-Trk with cystitis. These results suggest that up-regulation of p-CREB may be mediated by a neurotrophin/Trk signaling pathway.
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Affiliation(s)
- Li-Ya Qiao
- Department of Neurology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
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47
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Khan GM, Chen SR, Pan HL. Role of primary afferent nerves in allodynia caused by diabetic neuropathy in rats. Neuroscience 2002; 114:291-9. [PMID: 12204199 DOI: 10.1016/s0306-4522(02)00372-x] [Citation(s) in RCA: 181] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Both myelinated and unmyelinated afferents are implicated in transmitting diabetic neuropathic pain. Although unmyelinated afferents are generally considered to play a significant role in diabetic neuropathic pain, pathological changes in diabetic neuropathy occur mostly in myelinated A-fibers. In the present study, we first examined the role of capsaicin-sensitive C-fibers in the development of allodynia induced by diabetic neuropathy. We then studied the functional changes of afferent nerves pertinent to diabetic neuropathic pain. Diabetes was induced in rats by i.p. streptozotocin. To deplete capsaicin-sensitive C-fibers, rats were treated with i.p. resiniferatoxin (300 microg/kg). Mechanical and thermal sensitivities were measured using von Frey filaments and a radiant heat stimulus. Single-unit activity of afferents was recorded from the tibial nerve. Tactile allodynia, but not thermal hyperalgesia, developed in diabetic rats. Resiniferatoxin treatment did not alter significantly the degree and time course of allodynia. Post-treatment with resiniferatoxin also failed to attenuate allodynia in diabetic rats. The electrophysiological recordings revealed ectopic discharges and a higher spontaneous activity mainly in Adelta- and Abeta-fiber afferents in diabetic rats regardless of resiniferatoxin treatment. Furthermore, these afferent fibers had a lower threshold for activation and augmented responses to mechanical stimuli. Thus, our study suggests that capsaicin-sensitive C-fiber afferents are not required in the development of allodynia in this rat model of diabetes. Our electrophysiological data provide substantial new evidence that the abnormal sensory input from Adelta- and Abeta-fiber afferents may play an important role in diabetic neuropathic pain.
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MESH Headings
- Afferent Pathways/drug effects
- Afferent Pathways/pathology
- Afferent Pathways/physiopathology
- Animals
- Diabetes Mellitus, Experimental/complications
- Diabetes Mellitus, Experimental/physiopathology
- Diabetic Neuropathies/pathology
- Diabetic Neuropathies/physiopathology
- Disease Models, Animal
- Diterpenes/pharmacology
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/pathology
- Ganglia, Spinal/physiopathology
- Hyperalgesia/pathology
- Hyperalgesia/physiopathology
- Male
- Microscopy, Electron
- Nerve Fibers, Myelinated/drug effects
- Nerve Fibers, Myelinated/pathology
- Nerve Fibers, Myelinated/physiology
- Nerve Fibers, Unmyelinated/drug effects
- Nerve Fibers, Unmyelinated/pathology
- Nerve Fibers, Unmyelinated/physiology
- Neurons, Afferent/drug effects
- Neurons, Afferent/pathology
- Neurons, Afferent/physiology
- Nociceptors/drug effects
- Nociceptors/physiopathology
- Pain Threshold/drug effects
- Pain Threshold/physiology
- Physical Stimulation
- Rats
- Rats, Sprague-Dawley
- Reaction Time/drug effects
- Reaction Time/physiology
- Tibial Nerve/pathology
- Tibial Nerve/physiology
- Tibial Nerve/ultrastructure
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Affiliation(s)
- G M Khan
- Department of Anesthesiology H187, Penn State University College of Medicine, 500 University Drive, Hershey, PA 17033, USA
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48
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Fukuoka T, Tokunaga A, Tachibana T, Dai Y, Yamanaka H, Noguchi K. VR1, but not P2X(3), increases in the spared L4 DRG in rats with L5 spinal nerve ligation. Pain 2002; 99:111-20. [PMID: 12237189 DOI: 10.1016/s0304-3959(02)00067-2] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated the expression of two candidate transducers of noxious stimuli in peripheral tissues, the vanilloid receptor subtype 1 (VR1) and the P2X(3), a subunit of the ionotropic P2X receptor for ATP, in spared L4 DRG neurons following L5 spinal nerve ligation, a neuropathic pain model. VR1 mRNA expression increased in the small- and medium-sized DRG neurons from the first to 28th day after injury, and this up-regulation corresponded well with the development and maintenance of thermal hyperalgesia of the hind paw. The increase in VR1-immunoreactive (ir) neurons was confirmed at the third day after surgery. In contrast, there was no change in expression of P2X(3) mRNA over 4 weeks after ligation, or in the percentage of P2X(3)-ir neurons observed 3 days after surgery. Our data suggests that increased VR1 in the spared L4 DRG may contribute to the exaggerated heat response observed in this neuropathic pain model. Taken together with the previous reports that P2X(3) expression increases in the spared DRG neurons in other neuropathic pain models, there appears to be differences in the phenotypic changes and pathomechanisms of the various neuropathic pain models.
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MESH Headings
- Animals
- Disease Models, Animal
- Ganglia, Spinal/cytology
- Ganglia, Spinal/physiology
- Gene Expression/physiology
- Hindlimb
- Hyperalgesia/metabolism
- Hyperalgesia/physiopathology
- Ligation
- Lumbar Vertebrae
- Male
- Neuralgia/metabolism
- Neuralgia/physiopathology
- Neurons, Afferent/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Drug/genetics
- Receptors, Drug/metabolism
- Receptors, Purinergic P2/genetics
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X3
- Spinal Nerves/cytology
- Spinal Nerves/physiology
- TRPV Cation Channels
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Affiliation(s)
- Tetsuo Fukuoka
- Department of Anatomy & Neuroscience, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
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Tóth A, Kedei N, Szabó T, Wang Y, Blumberg PM. Thapsigargin binds to and inhibits the cloned vanilloid receptor-1. Biochem Biophys Res Commun 2002; 293:777-82. [PMID: 12054538 DOI: 10.1016/s0006-291x(02)00293-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigated the effect of thapsigargin, a well-known sarcoplasmic reticulum ATPase (SERCA) inhibitor, on the non-specific Ca2+ channel vanilloid receptor-1 (VR1) in CHO-VR1 cells. We found that thapsigargin inhibited the VR-1 mediated (45)Ca2+ uptake of CHO-VR1 cells (IC50=6.4+/-1.9 microM) and the [3H]RTX binding to VR1 (IC50=4.0+/-1.3 microM). Further analysis revealed that thapsigargin is a mixed-type inhibitor, suggesting both direct and indirect interactions between thapsigargin and the capsaicin binding site of VR1. Thapsigargin alone transiently elevated the [Ca2+]i in CHO-VR1 cells (EC50=44 nM). However, 45Ca2+ uptake was not detected after thapsigargin treatment, indicating that the emptying of the thapsigargin sensitive intracellular pools of Ca2+ was responsible for the elevated [Ca2+]i level rather than the activation of VR-1. We conclude that thapsigargin represents a new prototype of a VR1 inhibitor and that caution should be exercised in interpreting the effects of thapsigargin, especially when it is used in the micromolar range to inhibit SERCA activity.
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Affiliation(s)
- Attila Tóth
- Molecular Mechanisms of Tumor Promotion Section, Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institutes of Health, Building 37, Room 3A01, 37 Convent Drive, MSC 4255, Bethesda, MD 20892, USA
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50
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McIntyre P, McLatchie LM, Chambers A, Phillips E, Clarke M, Savidge J, Toms C, Peacock M, Shah K, Winter J, Weerasakera N, Webb M, Rang HP, Bevan S, James IF. Pharmacological differences between the human and rat vanilloid receptor 1 (VR1). Br J Pharmacol 2001; 132:1084-94. [PMID: 11226139 PMCID: PMC1572656 DOI: 10.1038/sj.bjp.0703918] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Vanilloid receptors (VR1) were cloned from human and rat dorsal root ganglion libraries and expressed in Xenopus oocytes or Chinese Hamster Ovary (CHO) cells. Both rat and human VR1 formed ligand gated channels that were activated by capsaicin with similar EC(50) values. Capsaicin had a lower potency on both channels, when measured electrophysiologically in oocytes compared to CHO cells (oocytes: rat=1.90+/-0.20 microM; human=1.90+/-0.30 microM: CHO cells: rat=0.20+/-0.06 microM; human=0.19+/-0.08 microM). In CHO cell lines co-expressing either rat or human VR1 and the calcium sensitive, luminescent protein, aequorin, the EC(50) values for capsaicin-induced responses were similar in both cell lines (rat=0.35+/-0.06 microM, human=0.53+/-0.03 microM). The threshold for activation by acidic solutions was lower for human VR1 channels than that for rat VR1 (EC(50) pH 5.49+/-0.04 and pH 5.78+/-0.09, respectively). The threshold for heat activation was identical (42 degrees C) for rat and human VR1. PPAHV was an agonist at rat VR1 (EC(50) between 3 and 10 microM) but was virtually inactive at the human VR1 (EC(50)>10 microM). Capsazepine and ruthenium red were both more potent at blocking the capsaicin response of human VR1 than rat VR1. Capsazepine blocked the human but not the rat VR1 response to low pH. Capsazepine was also more effective at inhibiting the noxious heat response of human than of rat VR1.
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Affiliation(s)
- P McIntyre
- Novartis Institute for Medical Sciences, 5 Gower Place, London WC1E 6BN, UK.
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