201
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Stavermann M, Buddrus K, St John JA, Ekberg JA, Nilius B, Deitmer JW, Lohr C. Temperature-dependent calcium-induced calcium release via InsP3 receptors in mouse olfactory ensheathing glial cells. Cell Calcium 2012; 52:113-23. [DOI: 10.1016/j.ceca.2012.04.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 03/22/2012] [Accepted: 04/24/2012] [Indexed: 02/07/2023]
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202
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El-Arabi AM, Salazar CS, Schmidt JJ. Ion channel drug potency assay with an artificial bilayer chip. LAB ON A CHIP 2012; 12:2409-2413. [PMID: 22549308 DOI: 10.1039/c2lc40087a] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The potency of pharmaceutical compounds acting on ion channels can be determined through measurements of ion channel conductance as a function of compound concentration. We have developed an artificial lipid bilayer chip for simple, fast, and high-yield measurement of ion channel conductance with simultaneous solution perfusion. Here we show the application of this chip to the measurement of the mammalian cold and menthol receptor TRPM8. Ensemble measurements of TRPM8 as a function of concentration of menthol and 2-aminoethoxydiphenyl borate (2-APB) enabled efficient determination of menthol's EC(50) (111.8 μM ± 2.4 μM) and 2-APB's IC(50) (4.9 μM ± 0.2 μM) in agreement with published values. This validation, coupled with the compatibility of this platform with automation and parallelization, indicates significant potential for large-scale pharmaceutical ion channel screening.
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Affiliation(s)
- Ahmad M El-Arabi
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
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203
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Johar P, Grover V, Topp R, Behm DG. A comparison of topical menthol to ice on pain, evoked tetanic and voluntary force during delayed onset muscle soreness. Int J Sports Phys Ther 2012; 7:314-322. [PMID: 22666646 PMCID: PMC3362986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023] Open
Abstract
PURPOSE/BACKGROUND Pain can adversely affect muscle functioning by inhibiting muscle contractions. Delayed onset muscle soreness was used as a tool to ascertain whether a topical menthol-based analgesic or ice was more effective at reducing pain and permitting greater muscular voluntary and evoked force. METHODS Sixteen subjects were randomized to receive either a topical gel containing 3.5% menthol or topical application of ice to the non-dominant elbow flexors two days following the performance of an exercise designed to induce muscle soreness. Two days later, DOMS discomfort was treated with a menthol based analgesic or ice. Maximum voluntary contractions and evoked tetanic contractions of the non-dominant elbow flexors were measured at baseline prior to inducing muscle soreness (T1), two days following inducing DOMS after 20 (T2), 25 (T3) and 35 (T4) minutes of either menthol gel or ice therapy. Pain perception using a 10-point visual analog scale was also measured at these four data collection points. Treatment analysis included a 2 way repeated measures ANOVA (2 × 4). RESULTS Delayed onset muscle soreness decreased (p = 0.04) voluntary force 17.1% at T2 with no treatment effect. Tetanic force was 116.9% higher (p<0.05) with the topical analgesic than ice. Pain perception at T2 was significantly (p=0.02) less with the topical analgesic versus ice. CONCLUSIONS Compared to ice, the topical menthol-based analgesic decreased perceived discomfort to a greater extent and permitted greater tetanic forces to be produced. LEVEL OF EVIDENCE Level 2b.
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Affiliation(s)
- Pramod Johar
- Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Varun Grover
- Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | | | - David G. Behm
- Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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204
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Yudin Y, Rohacs T. Regulation of TRPM8 channel activity. Mol Cell Endocrinol 2012; 353:68-74. [PMID: 22061619 PMCID: PMC3295897 DOI: 10.1016/j.mce.2011.10.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 11/28/2022]
Abstract
Transient Receptor Potential Melastatin 8 (TRPM8) is a Ca(2+) permeable non-selective cation channel directly activated by cold temperatures and chemical agonists such as menthol. It is a well established sensor of environmental cold temperatures, found in peripheral sensory neurons, where its activation evokes depolarization and action potentials. The activity of TRPM8 is regulated by a number of cellular signaling pathways, most notably by phosphoinositides and the activation of phospholipase C. This review will summarize current knowledge on the physiological and pathophysiological roles of TRPM8 and its regulation by various intracellular messenger molecules and signaling pathways.
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Affiliation(s)
- Yevgen Yudin
- Department of Pharmacology and Physiology, UMDNJ - New Jersey Medical School, Newark, NJ 07103, USA
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205
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Bharate SS, Bharate SB. Modulation of thermoreceptor TRPM8 by cooling compounds. ACS Chem Neurosci 2012; 3:248-67. [PMID: 22860192 PMCID: PMC3369806 DOI: 10.1021/cn300006u] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 02/13/2012] [Indexed: 02/06/2023] Open
Abstract
ThermoTRPs, a subset of the Transient Receptor Potential (TRP) family of cation channels, have been implicated in sensing temperature. TRPM8 and TRPA1 are both activated by cooling. TRPM8 is activated by innocuous cooling (<30 °C) and contributes to sensing unpleasant cold stimuli or mediating the effects of cold analgesia and is a receptor for menthol and icilin (mint-derived and synthetic cooling compounds, respectively). TRPA1 (Ankyrin family) is activated by noxious cold (<17 °C), icilin, and a variety of pungent compounds. Extensive amount of medicinal chemistry efforts have been published mainly in the form of patent literature on various classes of cooling compounds by various pharmaceutical companies; however, no prior comprehensive review has been published. When expressed in heterologous expression systems, such as Xenopus oocytes or mammalian cell lines, TRPM8 mediated currents are activated by a number of cooling compounds in addition to menthol and icilin. These include synthetic p-menthane carboxamides along with other class of compounds such as aliphatic/alicyclic alcohols/esters/amides, sulphones/sulphoxides/sulphonamides, heterocyclics, keto-enamines/lactams, and phosphine oxides. In the present review, the medicinal chemistry of various cooling compounds as activators of thermoTRPM8 channel will be discussed according to their chemical classes. The potential of these compounds to emerge as therapeutic agents is also discussed.
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Affiliation(s)
- Sonali S. Bharate
- Department of Pharmaceutics, P.E. Society’s Modern
College of Pharmacy for Ladies, Dehu-Alandi Road, Moshi,
Pune, India
| | - Sandip B. Bharate
- Medicinal
Chemistry Division, Indian Institute of Integrative Medicine
(CSIR), Canal
Road, Jammu-180001, India
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206
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Ishii S, Kurokawa A, Kishi M, Yamagami K, Okada S, Ishimaru Y, Misaka T. The response of PKD1L3/PKD2L1 to acid stimuli is inhibited by capsaicin and its pungent analogs. FEBS J 2012; 279:1857-70. [PMID: 22420714 PMCID: PMC3492849 DOI: 10.1111/j.1742-4658.2012.08566.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Polycystic kidney disease (PKD) 2L1 protein is a member of the transient receptor potential (TRP) ion channel family. In circumvallate and foliate papillae, PKD2L1 is coexpressed with PKD1L3. PKD2L1 and PKD1L3 interact through their transmembrane domain and the resulting heteromer PKD1L3/PKD2L1 owns a unique channel property called 'off-responses' to acid stimulation, although PKD2L1 does not own this property by itself. To define the pharmacological properties of the PKD1L3/PKD2L1 channel, we developed a new method to effectively evaluate channel activity using human embryonic kidney 293T cells in which the channel was heterologously expressed. This method was applied to screen substances that potentially regulate it. We found that capsaicin and its analogs, which are TRPV1 agonists, inhibited the response to acid stimuli and that the capsaicin inhibition was reversible with an IC(50) of 32.5 μm. Capsaicin and its analogs are thus useful tools for physiological analysis of PKD1L3/PKD2L1 function.
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Affiliation(s)
- Sho Ishii
- Central Research Institute, Mizkan Group Co., Handa, Aichi, Japan
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207
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Guimarães AG, Quintans JSS, Quintans-Júnior LJ. Monoterpenes with Analgesic Activity-A Systematic Review. Phytother Res 2012; 27:1-15. [DOI: 10.1002/ptr.4686] [Citation(s) in RCA: 192] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 03/03/2012] [Accepted: 03/07/2012] [Indexed: 11/06/2022]
Affiliation(s)
- Adriana G. Guimarães
- Departamento de Fisiologia; Universidade Federal de Sergipe (DFS/UFS); São Cristóvão SE Brazil
| | - Jullyana S. S. Quintans
- Departamento de Fisiologia; Universidade Federal de Sergipe (DFS/UFS); São Cristóvão SE Brazil
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208
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Klasen K, Hollatz D, Zielke S, Gisselmann G, Hatt H, Wetzel CH. The TRPM8 ion channel comprises direct Gq protein-activating capacity. Pflugers Arch 2012; 463:779-97. [PMID: 22460725 DOI: 10.1007/s00424-012-1098-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 03/12/2012] [Accepted: 03/14/2012] [Indexed: 11/29/2022]
Abstract
The transient receptor potential (TRP) family of ion channels comprises receptors that are activated by a vast variety of physical as well as chemical stimuli. TRP channels interact in a complex manner with several intracellular signaling cascades, both up- and downstream of receptor activation. Investigating cascades stimulated downstream of the cold and menthol receptor TRPM8, we found evidence for both, functional and structural interaction of TRPM8 with Gαq. We demonstrated menthol-evoked increase in intracellular Ca(2+) under extracellular Ca(2+)-free conditions, which was blocked by the PLC inhibitors U73122 or edelfosine. This metabotropic Ca(2+) signal could be observed also in cells expressing a channel-dead (i.e. non-conducting) or a chloride-conducting TRPM8 pore mutant. However, this intracellular metabotropic Ca(2+) signal could not be detected in Gαq deficient cells or in the presence of dominant-negative GαqX. Evidence for a close spatial proximity necessary for physical interaction of TRPM8 and Gαq was provided by acceptor bleaching experiments demonstrating FRET between TRPM8-CFP and Gαq-YFP. A Gαq-YFP mobility assay (FRAP) revealed a restricted diffusion of Gαq-YFP under conditions when TRPM8 is immobilized in the plasma membrane. Moreover, a menthol-induced and TRPM8-mediated G protein activation could be demonstrated by FRET experiments monitoring the dissociation of Gαq-YFP from a Gβ/Gγ-CFP complex, and by the exchange of radioactive [(35)S]GTPγS for GDP. Our observations lead to a view that extends the operational range of the TRPM8 receptor from its function as a pure ion channel to a molecular switch with additional metabotropic capacity.
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Affiliation(s)
- Katharina Klasen
- Lehrstuhl für Zellphysiologie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44780 Bochum, Germany
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209
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Matthews JM, Qin N, Colburn RW, Dax SL, Hawkins M, McNally JJ, Reany L, Youngman MA, Baker J, Hutchinson T, Liu Y, Lubin ML, Neeper M, Brandt MR, Stone DJ, Flores CM. The design and synthesis of novel, phosphonate-containing transient receptor potential melastatin 8 (TRPM8) antagonists. Bioorg Med Chem Lett 2012; 22:2922-6. [PMID: 22421018 DOI: 10.1016/j.bmcl.2012.02.060] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 02/16/2012] [Accepted: 02/17/2012] [Indexed: 11/17/2022]
Abstract
A series of benzothiophene-based phosphonates was synthesized and many analogs within the series were shown to be potent antagonists of the TRPM8 channel. The compounds were obtained as a racemic mixture in 5 synthetic steps, and were tested for TRPM8 antagonist activity in a recombinant, canine TRPM8-expressing cell line using a fluorometric imaging plate reader (FLIPR) assay. Structure-activity relationships were developed initially by modification of the core structure and subsequently by variation of the aromatic substituents and the phosphonate ester. Compound 9l was administered intraperitoneally to rats and demonstrated engagement of the TRPM8 target in both prevention and reversal-modes in an icilin-induced 'wet-dog' shake model.
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Affiliation(s)
- Jay M Matthews
- Janssen Pharmaceuticals, Spring House, PA 19477-0776, United States.
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210
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Liu S, Chen JF. Strategies for therapeutic hypometabothermia. JOURNAL OF EXPERIMENTAL STROKE & TRANSLATIONAL MEDICINE 2012; 5:31-42. [PMID: 24179563 PMCID: PMC3811165 DOI: 10.6030/1939-067x-5.1.31] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Although therapeutic hypothermia and metabolic suppression have shown robust neuroprotection in experimental brain ischemia, systemic complications have limited their use in treating acute stroke patients. The core temperature and basic metabolic rate are tightly regulated and maintained in a very stable level in mammals. Simply lowering body temperature or metabolic rate is actually a brutal therapy that may cause more systemic as well as regional problems other than providing protection. These problems are commonly seen in hypothermia and barbiturate coma. The main innovative concept of this review is to propose thermogenically optimal and synergistic reduction of core temperature and metabolic rate in therapeutic hypometabothermia using novel and clinically practical approaches. When metabolism and body temperature are reduced in a systematically synergistic manner, the outcome will be maximal protection and safe recovery, which happen in natural process, such as in hibernation, daily torpor and estivation.
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Affiliation(s)
- Shimin Liu
- Department of Neurology, Boston University School of Medicine, Boston, USA
| | - Jiang-Fan Chen
- Department of Neurology, Boston University School of Medicine, Boston, USA
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211
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Benko R, Illényi L, Kelemen D, Papp R, Papp A, Bartho L. Use and limitations of three TRPV-1 receptor antagonists on smooth muscles of animals and man: A vote for BCTC. Eur J Pharmacol 2012; 674:44-50. [DOI: 10.1016/j.ejphar.2011.10.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 10/03/2011] [Accepted: 10/11/2011] [Indexed: 10/16/2022]
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212
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Gaudioso C, Hao J, Martin-Eauclaire MF, Gabriac M, Delmas P. Menthol pain relief through cumulative inactivation of voltage-gated sodium channels. Pain 2011; 153:473-484. [PMID: 22172548 DOI: 10.1016/j.pain.2011.11.014] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 09/19/2011] [Accepted: 11/14/2011] [Indexed: 01/02/2023]
Abstract
Menthol is a natural compound of plant origin known to produce cool sensation via the activation of the TRPM8 channel. It is also frequently part of topical analgesic drugs available in a pharmacy, although its mechanism of action is still unknown. Compelling evidence indicates that voltage-gated Na(+) channels are critical for experiencing pain sensation. We tested the hypothesis that menthol may block voltage-gated Na(+) channels in dorsal root ganglion (DRG) neurons. By use of a patch clamp, we evaluated the effects of menthol application on tetrodotoxin (TTX)-resistant Nav1.8 and Nav1.9 channel subtypes in DRG neurons, and on TTX-sensitive Na(+) channels in immortalized DRG neuron-derived F11 cells. The results indicate that menthol inhibits Na(+) channels in a concentration-, voltage-, and frequency-dependent manner. Menthol promoted fast and slow inactivation states, causing use-dependent depression of Na(+) channel activity. In current clamp recordings, menthol inhibited firing at high-frequency stimulation with minimal effects on normal neuronal activity. We found that low concentrations of menthol cause analgesia in mice, relieving pain produced by a Na(+) channel-targeting toxin. We conclude that menthol is a state-selective blocker of Nav1.8, Nav1.9, and TTX-sensitive Na(+) channels, indicating a role for Na(+) channel blockade in the efficacy of menthol as topical analgesic compound.
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Affiliation(s)
- Christelle Gaudioso
- Centre de Recherche en Neurobiologie et Neurophysiologie de Marseille, Aix-Marseille Université, UMR 6231, CNRS, CS80011, Bd Pierre Dramard, 13344 Marseille Cedex 15, France
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213
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Fernández JA, Skryma R, Bidaux G, Magleby KL, Scholfield CN, McGeown JG, Prevarskaya N, Zholos AV. Short isoforms of the cold receptor TRPM8 inhibit channel gating by mimicking heat action rather than chemical inhibitors. J Biol Chem 2011; 287:2963-70. [PMID: 22128172 DOI: 10.1074/jbc.m111.272823] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transient receptor potential (TRP) channels couple various environmental factors to changes in membrane potential, calcium influx, and cell signaling. They also integrate multiple stimuli through their typically polymodal activation. Thus, although the TRPM8 channel has been extensively investigated as the major neuronal cold sensor, it is also regulated by various chemicals, as well as by several short channel isoforms. Mechanistic understanding of such complex regulation is facilitated by quantitative single-channel analysis. We have recently proposed a single-channel mechanism of TRPM8 regulation by voltage and temperature. Using this gating mechanism, we now investigate TRPM8 inhibition in cell-attached patches using HEK293 cells expressing TRPM8 alone or coexpressed with its short sM8-6 isoform. This is compared with inhibition by the chemicals N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide (BCTC) and clotrimazole or by elevated temperature. We found that within the seven-state single-channel gating mechanism, inhibition of TRPM8 by short sM8-6 isoforms closely resembles inhibition by increased temperature. In contrast, inhibition by BCTC and that by clotrimazole share a different set of common features.
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Affiliation(s)
- José A Fernández
- Center for Vision and Vascular Science, Queen's University Belfast, BT12 6BA Belfast, United Kingdom.
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214
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Behavioral Testing of the Effects of Thermosensitive TRP Channel Agonists on Touch, Temperature, and Pain Sensations. NEUROPHYSIOLOGY+ 2011. [DOI: 10.1007/s11062-011-9222-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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215
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Knowlton WM, Daniels RL, Palkar R, McCoy DD, McKemy DD. Pharmacological blockade of TRPM8 ion channels alters cold and cold pain responses in mice. PLoS One 2011; 6:e25894. [PMID: 21984952 PMCID: PMC3184174 DOI: 10.1371/journal.pone.0025894] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/12/2011] [Indexed: 12/21/2022] Open
Abstract
TRPM8 (Transient Receptor Potential Melastatin-8) is a cold- and menthol-gated ion channel necessary for the detection of cold temperatures in the mammalian peripheral nervous system. Functioning TRPM8 channels are required for behavioral responses to innocuous cool, noxious cold, injury-evoked cold hypersensitivity, cooling-mediated analgesia, and thermoregulation. Because of these various roles, the ability to pharmacologically manipulate TRPM8 function to alter the excitability of cold-sensing neurons may have broad impact clinically. Here we examined a novel compound, PBMC (1-phenylethyl-4-(benzyloxy)-3-methoxybenzyl(2-aminoethyl)carbamate) which robustly and selectively inhibited TRPM8 channels in vitro with sub-nanomolar affinity, as determined by calcium microfluorimetry and electrophysiology. The actions of PBMC were selective for TRPM8, with no functional effects observed for the sensory ion channels TRPV1 and TRPA1. PBMC altered TRPM8 gating by shifting the voltage-dependence of menthol-evoked currents towards positive membrane potentials. When administered systemically to mice, PBMC treatment produced a dose-dependent hypothermia in wildtype animals while TRPM8-knockout mice remained unaffected. This hypothermic response was reduced at lower doses, whereas responses to evaporative cooling were still significantly attenuated. Lastly, systemic PBMC also diminished cold hypersensitivity in inflammatory and nerve-injury pain models, but was ineffective against oxaliplatin-induced neuropathic cold hypersensitivity, despite our findings that TRPM8 is required for the cold-related symptoms of this pathology. Thus PBMC is an attractive compound that serves as a template for the formulation of highly specific and potent TRPM8 antagonists that will have utility both in vitro and in vivo.
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Affiliation(s)
- Wendy M. Knowlton
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
| | - Richard L. Daniels
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
| | - Radhika Palkar
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
| | - Daniel D. McCoy
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
| | - David D. McKemy
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, California, United States of America
- Neuroscience Graduate Program, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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216
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Willis DN, Liu B, Ha MA, Jordt SE, Morris JB. Menthol attenuates respiratory irritation responses to multiple cigarette smoke irritants. FASEB J 2011; 25:4434-44. [PMID: 21903934 DOI: 10.1096/fj.11-188383] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Menthol, the cooling agent in peppermint, is added to almost all commercially available cigarettes. Menthol stimulates olfactory sensations, and interacts with transient receptor potential melastatin 8 (TRPM8) ion channels in cold-sensitive sensory neurons, and transient receptor potential ankyrin 1 (TRPA1), an irritant-sensing channel. It is highly controversial whether menthol in cigarette smoke exerts pharmacological actions affecting smoking behavior. Using plethysmography, we investigated the effects of menthol on the respiratory sensory irritation response in mice elicited by smoke irritants (acrolein, acetic acid, and cyclohexanone). Menthol, at a concentration (16 ppm) lower than in smoke of mentholated cigarettes, immediately abolished the irritation response to acrolein, an agonist of TRPA1, as did eucalyptol (460 ppm), another TRPM8 agonist. Menthol's effects were reversed by a TRPM8 antagonist, AMTB. Menthol's effects were not specific to acrolein, as menthol also attenuated irritation responses to acetic acid, and cyclohexanone, an agonist of the capsaicin receptor, TRPV1. Menthol was efficiently absorbed in the respiratory tract, reaching local concentrations sufficient for activation of sensory TRP channels. These experiments demonstrate that menthol and eucalyptol, through activation of TRPM8, act as potent counterirritants against a broad spectrum of smoke constituents. Through suppression of respiratory irritation, menthol may facilitate smoke inhalation and promote nicotine addiction and smoking-related morbidities.
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Affiliation(s)
- Daniel N Willis
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
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217
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Topp R, Winchester LJ, Schilero J, Jacks D. Effect of topical menthol on ipsilateral and contralateral superficial blood flow following a bout of maximum voluntary muscle contraction. Int J Sports Phys Ther 2011; 6:83-91. [PMID: 21713232 PMCID: PMC3109898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
Abstract
PURPOSE/BACKGROUND Various doses of topical menthol are commonly applied prior to, during, and after exercise to relieve pain although there is limited empirical evidence examining the physiological effects of this treatment. The purpose of this study was to examine the effects of two different doses of menthol (3.5% and 10%) on blood flow and arterial diameter before and after an acute bout of three isokinetic maximum voluntary muscular contraction (MVMC) of the quadriceps and hamstrings. METHODS Blood flow and arterial diameter of the right and left popliteal arteries were measured with an ultrasound Doppler prior to and after subjects completed 1 set of 3 MVMC isokinetic knee extension/flexion exercises. Immediately following this exercise one of three different treatment conditions was randomly applied to the right thigh only; 3.5% menthol gel, 10% menthol wipe, or a control condition. Five minutes following the treatment application blood flow through both right and left popliteal arteries was reassessed. This procedure was completed once per week until each of the 16 subjects was exposed to each treatment condition. RESULTS Repeated measures ANOVA with post hoc analysis indicated that both menthol dosages resulted in significant decreases in popliteal blood flow on the right (-19.60 to -8.39%) and left sides (-14.72 to -5.4%) while the control condition demonstrated an increase in blood flow bilaterally (+26.40 to +15.19%) as a result of the MVMC exercise. The right popliteal arterial diameter was also significantly reduced as a result of both menthol dosages (-5.73 to -6.73%) and increased under the control condition (+6.67%). CONCLUSION These results indicate that topical menthol has a rapid effect on reducing ipsilateral and contralateral arterial blood flow as well as ipsilateral arterial diameter. LEVELS OF EVIDENCE 2a.
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Affiliation(s)
- Robert Topp
- Professor, School of Nursing University of Louisiville Louisville, KY, 40292
| | - Lee J. Winchester
- Graduate Student, Department of Health and Sports Science University of Louisiville Louisville, KY, 40292
| | - Jessica Schilero
- Graduate Student, Department of Health and Sports Science University of Louisiville Louisville, KY, 40292
| | - Dean Jacks
- Assistant Professor Department of Health and Sports Science University of Louisiville Louisville, KY, 40292
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218
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Perception of specific trigeminal chemosensory agonists. Neuroscience 2011; 189:377-83. [PMID: 21575683 DOI: 10.1016/j.neuroscience.2011.04.065] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 04/29/2011] [Accepted: 04/29/2011] [Indexed: 11/21/2022]
Abstract
The intranasal trigeminal system is a third chemical sense in addition to olfaction and gustation. As opposed to smell and taste, we still lack knowledge on the relationship between receptor binding and perception for the trigeminal system. We therefore investigated the sensitivity of the intranasal trigeminal system towards agonists of the trigeminal receptors TRPM8 and TRPA1 by assessing subjects' ability to identify which nostril has been stimulated in a monorhinal stimulation design. We summed the number of correct identifications resulting in a lateralization score. Stimuli were menthol (activating TRPM8 receptors), eucalyptol (TRPM8), mustard oil (TRPA1) and two mixtures thereof (menthol/eucalyptol and menthol/mustard oil). In addition, we examined the relationship between intensity and lateralization scores and investigated whether intensity evaluation and lateralization scores of the mixtures show additive effects. All stimuli were correctly lateralized significantly above chance. Across subjects the lateralization scores for single compounds activating the same receptor showed a stronger correlation than stimuli activating different receptors. Although single compounds were isointense, the mixture of menthol and eucalyptol (activating only TRPM8) was perceived as weaker and was lateralized less accurately than the mixture of menthol and mustard oil (activating both TRPM8 and TRPA1) suggesting suppression effects in the former mixture. In conclusion, sensitivity of different subpopulations of trigeminal sensory neurons seems to be related, but only to a certain degree. The large coherence in sensitivity between various intranasal trigeminal stimuli suggests that measuring sensitivity to one single trigeminal chemical stimulus may be sufficient to generally assess the trigeminal system's chemosensitivity. Further, for stimuli activating the same receptor a mixture suppression effect appears to occur similar to that observed in the other chemosensory systems.
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219
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Klein AH, Iodi Carstens M, McCluskey TS, Blancher G, Simons CT, Slack JP, Furrer S, Carstens E. Novel menthol-derived cooling compounds activate primary and second-order trigeminal sensory neurons and modulate lingual thermosensitivity. Chem Senses 2011; 36:649-58. [PMID: 21511802 DOI: 10.1093/chemse/bjr029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We presently investigated 2 novel menthol derivatives GIV1 and GIV2, which exhibit strong cooling effects. In previous human psychophysical studies, GIV1 delivered in a toothpaste medium elicited a cooling sensation that was longer lasting compared with GIV2 and menthol carboxamide (WS-3). In the current study, we investigated the molecular and cellular effects of these cooling agents. In calcium flux studies of TRPM8 expressed in HEK cells, both GIV1 and GIV2 were approximately 40- to 200-fold more potent than menthol and WS-3. GIV1 and GIV2 also activated TRPA1 but at levels that were 400 times greater than those required for TRPM8 activation. In calcium imaging studies, subpopulations of cultured rat trigeminal ganglion and dorsal root ganglion cells responded to GIV1 and/or GIV2; the majority of these were also activated by menthol and some were additionally activated by the TRPA1 agonist cinnamaldehyde and/or the TRPV1 agonist capsaicin. We also made in vivo single-unit recordings from cold-sensitive neurons in rat trigeminal subnucleus caudalis (Vc). GIV 1 and GIV2 directly excited some Vc neurons, GIV1 significantly enhanced their responses to cooling, and both GIV1 and GIV2 reduced responses to noxious heat. These novel cooling compounds provide additional molecular tools to investigate the neural processes of cold sensation.
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Affiliation(s)
- Amanda H Klein
- Department of Neurobiology, Physiology and Behavior, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA
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220
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Zakharian E, Thyagarajan B, French R, Pavlov E, Rohacs T. Inorganic Polyphosphate Modulates TRPM8 Channels. Inorg Chem 2011. [DOI: 10.1201/b12873-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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221
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Cysteine-rich secretory protein 4 is an inhibitor of transient receptor potential M8 with a role in establishing sperm function. Proc Natl Acad Sci U S A 2011; 108:7034-9. [PMID: 21482758 DOI: 10.1073/pnas.1015935108] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The cysteine-rich secretory proteins (CRISPs) are a group of four proteins in the mouse that are expressed abundantly in the male reproductive tract, and to a lesser extent in other tissues. Analysis of reptile CRISPs and mouse CRISP2 has shown that CRISPs can regulate cellular homeostasis via ion channels. With the exception of the ability of CRISP2 to regulate ryanodine receptors, the in vivo targets of mammalian CRISPs function are unknown. In this study, we have characterized the ion channel regulatory activity of epididymal CRISP4 using electrophysiology, cell assays, and mouse models. Through patch-clamping of testicular sperm, the CRISP4 CRISP domain was shown to inhibit the transient receptor potential (TRP) ion channel TRPM8. These data were confirmed using a stably transfected CHO cell line. TRPM8 is a major cold receptor in the body, but is found in other tissues, including the testis and on the tail and head of mouse and human sperm. Functional assays using sperm from wild-type mice showed that TRPM8 activation significantly reduced the number of sperm undergoing the progesterone-induced acrosome reaction following capacitation, and that this response was reversed by the coaddition of CRISP4. In accordance, sperm from Crisp4 null mice had a compromised ability to undergo to the progesterone-induced acrosome reaction. Collectively, these data identify CRISP4 as an endogenous regulator of TRPM8 with a role in normal sperm function.
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222
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Kupisz K, Trebacz K. Effect of cold and menthol on membrane potential in plants. PHYSIOLOGIA PLANTARUM 2011; 141:352-360. [PMID: 21214882 DOI: 10.1111/j.1399-3054.2011.01446.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In animals, cooling substances such as menthol are perceived as cold sensation because they bind to the same receptor TRPM8 (transient receptor potential melastatin) that activates upon temperature drops. We investigated the effect of menthol on the plant membrane potential to search for analogies between animal and plant perception systems. The study was conducted on the liverwort Conocephalum conicum- a non-vascular plant generating action potentials (APs) in response to different stimuli including cold. (+)Menthol, (-)menthol and (+/-)menthol induced one or more APs, depending on the concentration. In contrast to animal reactions to menthol, threshold concentrations of these isomers were the same (1 mM). The presence of menthol in medium shortened cold-induced APs, whereas low temperature prolonged the repolarization phase of AP evoked by menthol. Cells of C. conicum with anion and potassium channels blocked by anthracene-9-carboxylic acid (A9C) and tetraethylammonium chloride (TEACl) generate short spike-like voltage transients (VTs) in response to cold and light stimulation. Membrane potential changes evoked by menthol in A9C- and TEACl-treated plants differed significantly from VTs - lasted much longer and frequently occurred in series. 5 mM LaCl(3) , 1 mM EGTA (ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid) (0 Ca(2+) ) but not 0.2 mM verapamil blocked the putative calcium component of AP induced by menthol. Similar inhibitory effect was observed after the application of proton pump inhibitors: 0.05 mM N,N-dicyclohexylcarbodiimide (DCCD), 0.05 mM diethylstilbestrol (DES) or 0.01 mM carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP). Our results indicate that cold and menthol act independently, activating different membrane transporters in C. conicum cells.
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Affiliation(s)
- Kamila Kupisz
- Department of Biophysics, Institute of Biology, Maria Curie-Skłodowska University, 20-033 Lublin, Poland
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223
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Holzer P. Transient receptor potential (TRP) channels as drug targets for diseases of the digestive system. Pharmacol Ther 2011; 131:142-70. [PMID: 21420431 PMCID: PMC3107431 DOI: 10.1016/j.pharmthera.2011.03.006] [Citation(s) in RCA: 172] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 03/01/2011] [Indexed: 12/12/2022]
Abstract
Approximately 20 of the 30 mammalian transient receptor potential (TRP) channel subunits are expressed by specific neurons and cells within the alimentary canal. They subserve important roles in taste, chemesthesis, mechanosensation, pain and hyperalgesia and contribute to the regulation of gastrointestinal motility, absorptive and secretory processes, blood flow, and mucosal homeostasis. In a cellular perspective, TRP channels operate either as primary detectors of chemical and physical stimuli, as secondary transducers of ionotropic or metabotropic receptors, or as ion transport channels. The polymodal sensory function of TRPA1, TRPM5, TRPM8, TRPP2, TRPV1, TRPV3 and TRPV4 enables the digestive system to survey its physical and chemical environment, which is relevant to all processes of digestion. TRPV5 and TRPV6 as well as TRPM6 and TRPM7 contribute to the absorption of Ca²⁺ and Mg²⁺, respectively. TRPM7 participates in intestinal pacemaker activity, and TRPC4 transduces muscarinic acetylcholine receptor activation to smooth muscle contraction. Changes in TRP channel expression or function are associated with a variety of diseases/disorders of the digestive system, notably gastro-esophageal reflux disease, inflammatory bowel disease, pain and hyperalgesia in heartburn, functional dyspepsia and irritable bowel syndrome, cholera, hypomagnesemia with secondary hypocalcemia, infantile hypertrophic pyloric stenosis, esophageal, gastrointestinal and pancreatic cancer, and polycystic liver disease. These implications identify TRP channels as promising drug targets for the management of a number of gastrointestinal pathologies. As a result, major efforts are put into the development of selective TRP channel agonists and antagonists and the assessment of their therapeutic potential.
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Affiliation(s)
- Peter Holzer
- Research Unit of Translational Neurogastroenterology, Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, A-8010 Graz, Austria.
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224
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Martínez-López P, Treviño CL, de la Vega-Beltrán JL, De Blas G, Monroy E, Beltrán C, Orta G, Gibbs GM, O'Bryan MK, Darszon A. TRPM8 in mouse sperm detects temperature changes and may influence the acrosome reaction. J Cell Physiol 2011; 226:1620-31. [DOI: 10.1002/jcp.22493] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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225
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McCoy DD, Knowlton WM, McKemy DD. Scraping through the ice: uncovering the role of TRPM8 in cold transduction. Am J Physiol Regul Integr Comp Physiol 2011; 300:R1278-87. [PMID: 21411765 DOI: 10.1152/ajpregu.00631.2010] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The proper detection of environmental temperatures is essential for the optimal growth and survival of organisms of all shapes and phyla, yet only recently have the molecular mechanisms for temperature sensing been elucidated. The discovery of temperature-sensitive ion channels of the transient receptor potential (TRP) superfamily has been pivotal in explaining how temperatures are sensed in vivo, and here we will focus on the lone member of this cohort, TRPM8, which has been unequivocally shown to be cold sensitive. TRPM8 is expressed in somatosensory neurons that innervate peripheral tissues such as the skin and oral cavity, and recent genetic evidence has shown it to be the principal transducer of cool and cold stimuli. It is remarkable that this one channel, unlike other thermosensitive TRP channels, is associated with both innocuous and noxious temperature transduction, as well as cold hypersensitivity during injury and, paradoxically, cold-mediated analgesia. With ongoing research, the field is getting closer to answering a number of fundamental questions regarding this channel, including the cellular mechanisms of TRPM8 modulation, the molecular context of TRPM8 expression, as well as the full extent of the role of TRPM8 in cold signaling in vivo. These findings will further our understanding of basic thermotransduction and sensory coding, and may have important implications for treatments for acute and chronic pain.
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Affiliation(s)
- Daniel D McCoy
- Neurobiology, University of Southern California, Los Angeles, California 90089, USA
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226
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Gasperini RJ, Hou X, Parkington H, Coleman H, Klaver DW, Vincent AJ, Foa LC, Small DH. TRPM8 and Nav1.8 sodium channels are required for transthyretin-induced calcium influx in growth cones of small-diameter TrkA-positive sensory neurons. Mol Neurodegener 2011; 6:19. [PMID: 21375738 PMCID: PMC3058062 DOI: 10.1186/1750-1326-6-19] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 03/04/2011] [Indexed: 11/21/2022] Open
Abstract
Background Familial amyloidotic polyneuropathy (FAP) is a peripheral neuropathy caused by the extracellular accumulation and deposition of insoluble transthyretin (TTR) aggregates. However the molecular mechanism that underlies TTR toxicity in peripheral nerves is unclear. Previous studies have suggested that amyloidogenic proteins can aggregate into oligomers which disrupt intracellular calcium homeostasis by increasing the permeability of the plasma membrane to extracellular calcium. The aim of the present study was to examine the effect of TTR on calcium influx in dorsal root ganglion neurons. Results Levels of intracellular cytosolic calcium were monitored in dorsal root ganglion (DRG) neurons isolated from embryonic rats using the calcium-sensitive fluorescent indicator Fluo4. An amyloidogenic mutant form of TTR, L55P, induced calcium influx into the growth cones of DRG neurons, whereas wild-type TTR had no significant effect. Atomic force microscopy and dynamic light scattering studies confirmed that the L55P TTR contained oligomeric species of TTR. The effect of L55P TTR was decreased by blockers of voltage-gated calcium channels (VGCC), as well as by blockers of Nav1.8 voltage-gated sodium channels and transient receptor potential M8 (TRPM8) channels. siRNA knockdown of TRPM8 channels using three different TRPM8 siRNAs strongly inhibited calcium influx in DRG growth cones. Conclusions These data suggest that activation of TRPM8 channels triggers the activation of Nav1.8 channels which leads to calcium influx through VGCC. We suggest that TTR-induced calcium influx into DRG neurons may contribute to the pathophysiology of FAP. Furthermore, we speculate that similar mechanisms may mediate the toxic effects of other amyloidogenic proteins such as the β-amyloid protein of Alzheimer's disease.
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Affiliation(s)
- Robert J Gasperini
- Menzies Research Institute, University of Tasmania, Tasmania, 7001, Australia.
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227
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Icilin induces G1 arrest through activating JNK and p38 kinase in a TRPM8-independent manner. Biochem Biophys Res Commun 2011; 406:30-5. [DOI: 10.1016/j.bbrc.2011.01.094] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 01/26/2011] [Indexed: 11/18/2022]
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228
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Kim SH, Bae HC, Park EJ, Lee CR, Kim BJ, Lee S, Park HH, Kim SJ, So I, Kim TW, Jeon JH. Geraniol inhibits prostate cancer growth by targeting cell cycle and apoptosis pathways. Biochem Biophys Res Commun 2011; 407:129-34. [PMID: 21371438 DOI: 10.1016/j.bbrc.2011.02.124] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 02/24/2011] [Indexed: 01/08/2023]
Abstract
The progression of prostate cancer is associated with escape from cell cycle arrest and apoptosis under androgen-depleted conditions. Here, we found that geraniol, a naturally occurring monoterpene, induces cell cycle arrest and apoptosis in cultured cells and tumor grafted mice using PC-3 prostate cancer cells. Geraniol modulated the expression of various cell cycle regulators and Bcl-2 family proteins in PC-3 cells in vitro and in vivo. Furthermore, we showed that the combination of sub-optimal doses of geraniol and docetaxel noticeably suppresses prostate cancer growth in cultured cells and tumor xenograft mice. Therefore, our findings provide insight into unraveling the mechanisms underlying escape from cell cycle arrest and apoptosis and developing therapeutic strategies against prostate cancer.
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Affiliation(s)
- Su-Hwa Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
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229
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Andersson KE, Gratzke C, Hedlund P. The role of the transient receptor potential (TRP) superfamily of cation-selective channels in the management of the overactive bladder. BJU Int 2011; 106:1114-27. [PMID: 21156013 DOI: 10.1111/j.1464-410x.2010.09650.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
• The pathophysiology of lower urinary tract symptoms (LUTS), detrusor overactivity (DO), and the overactive bladder (OAB) syndrome is multifactorial and remains poorly understood. • The transient receptor potential (TRP) channel superfamily has been shown to be involved in nociception and mechanosensory transduction in various organ systems, and studies of the LUT have indicated that several TRP channels, including TRPV1, TRPV2, TRPV4, TRPM8, and TRPA1, are expressed in the bladder, and may act as sensors of stretch and/or chemical irritation. • However, the roles of these individual channels for normal LUT function and in LUTS/DO/OAB, have not been established. • TRPV1 is the channel best investigated. It is widely distributed in LUT structures, but despite extensive information on morphology and function in animal models, the role of this channel in normal human bladder function is still controversial. Conversely, its role in the pathophysiology and treatment of particularly neurogenic DO is well established. • TRPV1 is co-expressed with TRPA1, and TRPA1 is known to be present on capsaicin-sensitive primary sensory neurones. Activation of this channel can induce DO in animal models. • TRPV4 is a Ca(2+)-permeable stretch-activated cation channel, involved in stretch-induced ATP release, and TRPV4-deficient mice exhibit abnormal frequencies of voiding and non-voiding contractions in cystometric experiments. • TRPM8 is a cool receptor expressed in the urothelium and suburothelial sensory fibres. It has been implicated in the bladder-cooling reflex and in idiopathic DO. • The occurrence of other members of the TRP superfamily in the LUT has been reported, but information on their effects on LUT functions is scarce. There seem to be several links between activation of different members of the TRP superfamily and LUTS/DO/OAB, and further exploration of the involvement of these channels in LUT function, normally and in dysfunction, may be rewarding.
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Affiliation(s)
- Karl-Erik Andersson
- Institute for Regenerative Medicine, Wake Forest University School of Medicine, Winston Salem, NC 27157, USA.
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230
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Klein AH, Sawyer CM, Zanotto KL, Ivanov MA, Cheung S, Carstens MI, Furrer S, Simons CT, Slack JP, Carstens E. A tingling sanshool derivative excites primary sensory neurons and elicits nocifensive behavior in rats. J Neurophysiol 2011; 105:1701-10. [PMID: 21273322 DOI: 10.1152/jn.00922.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Szechuan peppers contain hydroxy-α-sanshool that imparts desirable tingling, cooling, and numbing sensations. Hydroxy-α-sanshool activates a subset of sensory dorsal root ganglion (DRG) neurons by inhibiting two-pore potassium channels. We presently investigated if a tingle-evoking sanshool analog, isobutylalkenyl amide (IBA), excites rat DRG neurons and, if so, if these neurons are also activated by agonists of TRPM8, TRPA1, and/or TRPV1. Thirty-four percent of DRG neurons tested responded to IBA, with 29% of them also responding to menthol, 29% to cinnamic aldehyde, 66% to capsaicin, and subsets responding to two or more transient receptor potential (TRP) agonists. IBA-responsive cells had similar size distributions regardless of whether they responded to capsaicin or not; cells only responsive to IBA were larger. Responses to repeated application of IBA at a 5-min interstimulus interval exhibited self-desensitization (tachyphylaxis). Capsaicin did not cross-desensitize responses to IBA to any greater extent than the tachyphylaxis observed with repeated IBA applications. These findings are consistent with psychophysical observations that IBA elicits tingle sensation accompanied by pungency and cooling, with self-desensitization but little cross-desensitization by capsaicin. Intraplantar injection of IBA elicited nocifensive responses (paw licking, shaking-flinching, and guarding) in a dose-related manner similar to the effects of intraplantar capsaicin and serotonin. IBA had no effect on thermal sensitivity but enhanced mechanical sensitivity at the highest dose tested. These observations suggest that IBA elicits an unfamiliar aversive sensation that is expressed behaviorally by the limited response repertoire available to the animal.
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Affiliation(s)
- Amanda H Klein
- University of California, Davis, Department of Neurobiology, Physiology and Behavior, 1 Shields Ave., Davis, CA 95616, USA
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231
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Viana F. Chemosensory properties of the trigeminal system. ACS Chem Neurosci 2011; 2:38-50. [PMID: 22778855 PMCID: PMC3369707 DOI: 10.1021/cn100102c] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 12/14/2010] [Indexed: 11/28/2022] Open
Abstract
The capacity of cutaneous, including trigeminal endings, to detect chemicals is known as chemesthesis or cutaneous chemosensation. This sensory function involves the activation of nociceptor and thermoreceptor endings and has a protective or defensive function, as many of these substances are irritants or poisonous. However, humans have also developed a liking for the distinct sharpness or pungency of many foods, beverages, and spices following activation of the same sensory afferents. Our understanding of the cellular and molecular mechanisms of chemosensation in the trigeminal system has experienced enormous progress in the past decade, following the cloning and functional characterization of several ion channels activated by physical and chemical stimuli. This brief review attempts to summarize our current knowledge in this field, including a functional description of various sensory channels, especially TRP channels, involved in trigeminal chemosensitivy. Finally, some of these new findings are discussed in the context of the pathophysiology of trigeminal chemosensation, including pain, pruritus, migraine, cough, airway inflammation, and ophthalmic diseases.
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Affiliation(s)
- Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550, San Juan de Alicante, Spain.
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232
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Abstract
Natural product ligands have contributed significantly to the deorphanisation of TRP ion channels. Furthermore, natural product ligands continue to provide valuable leads for the identification of ligands acting at "orphan" TRP channels. Additional naturally occurring modulators at TRP channels can be expected to be discovered in future, aiding in our understanding of not only their pharmacology and physiology, but also the therapeutic potential of this fascinating family of ion channels.
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233
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Liu Y, Qin N. TRPM8 in health and disease: cold sensing and beyond. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:185-208. [PMID: 21290296 DOI: 10.1007/978-94-007-0265-3_10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review focuses on TRPM8, one of the approximately 30 members of the diverse family of transient receptor potential (TRP) ion channels. Initially identified from the prostate, TRPM8 has been studied more extensively in the sensory system and is best established as a major transducer of environmental cold temperatures. An increasing body of evidence suggests that it may also be an important player in various chronic conditions, such as inflammatory/neuropathic pain and prostate cancer. Small molecule compounds that selectively modulate TRPM8 are beginning to emerge and will be critically valuable for better understanding the role of this channel in both physiological and pathological states, on which the prospects of TRPM8 as a viable therapeutic target rest.
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Affiliation(s)
- Yi Liu
- Johnson & Johnson Pharmaceutical Research and Development, LLC, San Diego, CA 92121, USA.
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234
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Harteneck C, Klose C, Krautwurst D. Synthetic modulators of TRP channel activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 704:87-106. [PMID: 21290290 DOI: 10.1007/978-94-007-0265-3_4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
In humans, 27 TRP channels from 6 related families contribute to a broad spectrum of cellular functions, such as thermo-, pressure-, volume-, pain- and chemosensation. Pain and inflammation-inducing compounds represent potent plant and animal defense mechanisms explaining the great variety of the naturally occurring, TRPV1-, TRPM8-, and TRPA1-activating ligands. The discovery of the first vanilloid receptor (TRPV1) and its involvement in nociception triggered the euphoria and the hope in novel therapeutic strategies treating pain, and this clear-cut indication inspired the development of TRPV1-selective ligands. On the other hand the nescience in the physiological role and putative clinical indication hampered the development of a selective drug in the case of the other TRP channels. Therefore, currently only a handful of mostly un-selective blocker is available to target TRP channels. Nevertheless, there is an ongoing quest for new, natural or synthetic ligands and modulators. In this chapter, we will give an overview on available broad-range blocker, as well as first TRP channel-selective compounds.
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Affiliation(s)
- Christian Harteneck
- Institute for Pharmacology and Toxicology, Interfaculty Center of Pharmacogenomics and Pharmaceutical Research (ICEPHA), Eberhard-Karls-University, Tübingen, Germany.
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235
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Sunesen M, Jacobsen RB. Study of TRP Channels by Automated Patch Clamp Systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 704:107-23. [DOI: 10.1007/978-94-007-0265-3_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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236
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5-Benzyloxytryptamine as an antagonist of TRPM8. Bioorg Med Chem Lett 2010; 20:7076-9. [DOI: 10.1016/j.bmcl.2010.09.099] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 11/22/2022]
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237
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Gijsen HJM, Berthelot D, Zaja M, Brône B, Geuens I, Mercken M. Analogues of morphanthridine and the tear gas dibenz[b,f][1,4]oxazepine (CR) as extremely potent activators of the human transient receptor potential ankyrin 1 (TRPA1) channel. J Med Chem 2010; 53:7011-20. [PMID: 20806939 DOI: 10.1021/jm100477n] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The TRPA1 channel can be considered as a key biological sensor to irritant chemicals. In this paper, the discovery of 11H-dibenz[b,e]azepines (morphanthridines) and dibenz[b,f][1,4]oxazepines is described as extremely potent agonists of the TRPA1 receptor. This has led to the discovery that most of the known tear gases are potent TRPA1 activators. The synthesis and biological activity of a number of substituted morphanthridines and dibenz[b,f][1,4]oxazepines have given insight into the SAR around this class of TRPA1 agonists, with EC(50) values ranging from 1 μM to 0.1 nM. Compounds 6 and 32 can be considered as the most potent TRPA1 agonists known to date, with 6 now being used successfully as a screening tool in the discovery of TRPA1 antagonists. The use of ligands such as 6 and 32 as pharmacological tools may contribute to the basic knowledge of the TRPA1 channel and advance the development of TRPA1 antagonists as potential treatment for conditions involving TRPA1 activation, including asthma and pain.
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Affiliation(s)
- Harrie J M Gijsen
- Medicinal Chemistry Department, Johnson & Johnson Pharmaceutical Research & Development, Turnhoutseweg 30, 2340 Beerse, Belgium.
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Klein AH, Carstens MI, Zanotto KL, Sawyer CM, Ivanov M, Cheung S, Carstens E. Self- and cross-desensitization of oral irritation by menthol and cinnamaldehyde (CA) via peripheral interactions at trigeminal sensory neurons. Chem Senses 2010; 36:199-208. [PMID: 21059698 DOI: 10.1093/chemse/bjq115] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Menthol and cinnamaldehyde (CA) are plant-derived spices commonly used in oral hygiene products, chewing gum, and many other applications. However, little is known regarding their sensory interactions in the oral cavity. We used a human psychophysics approach to investigate the temporal dynamics of oral irritation elicited by sequential application of menthol and/or CA, and ratiometric calcium imaging methods to investigate activation of rat trigeminal ganglion (TG) cells by these agents. Irritancy decreased significantly with sequential oral application of menthol and CA (self-desensitization). Menthol cross-desensitized irritation elicited by CA, and vice versa, over a time course of at least 60 min. Seventeen and 19% of TG cells were activated by menthol and CA, respectively, with ∼50% responding to both. TG cells exhibited significant self-desensitization to menthol applied at a 5, but not 10, min interval. They also exhibited significant self-desensitization to CA at 400 but not 200 μM. Menthol cross-desensitized TG cell responses to CA. CA at a concentration of 400 but not 200 μM also cross-desensitized menthol-evoked responses. The results support the argument that the perceived reductions in oral irritancy and cross-interactions between menthol and CA and menthol observed (at least at short interstimulus intervals) can be largely accounted for by the properties of trigeminal sensory neurons innervating the tongue.
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Affiliation(s)
- Amanda H Klein
- Department of Neurobiology, Physiology & Behavior, University of California Davis, 1 Shields Avenue, Davis, California 95616, USA
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239
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Pharmacological and functional properties of TRPM8 channels in prostate tumor cells. Pflugers Arch 2010; 461:99-114. [PMID: 21052713 DOI: 10.1007/s00424-010-0895-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 10/09/2010] [Accepted: 10/11/2010] [Indexed: 10/18/2022]
Abstract
Prostate cancer (PC) is a major health problem in adult males. TRPM8, a cationic TRP channel activated by cooling and menthol is upregulated in PC. However, the precise role of TRPM8 in PC is still unclear. Some studies hypothesized that TRPM8-mediated transmembrane Ca(2+) fluxes play a key role in cellular proliferation of PC cells. In contrast, other findings suggest that high TRPM8 levels may reduce the metastatic potential of PC cells. A detailed understanding of the response of TRPM8 channels to pharmacological modulators of their activity is relevant when considering potential therapies, targeting this ion channel to treat PC. We characterized the pharmacological and functional properties of native TRPM8 channels in four human prostate cell lines, PNT1A, LNCaP, DU145, and PC3, commonly used as experimental models of PC. PNT1A is a non-tumoral prostate cell line while the other three correspond to different stages of PC. Here, we show that cold- and agonist-evoked [Ca(2+)](i) responses in PC cells are much less sensitive to well-characterized agonists (menthol and icilin) and antagonists (BCTC, clotrimazole, and DD01050) of TRPM8 channels, compared to TRPM8 channels in other tissues, suggesting a different molecular composition and/or spatial organization. In addition, the forced overexpression of human TRPM8 facilitated the trafficking of TRPM8 channels residing in the endoplasmic reticulum to the plasma membrane, leading to a marked potentiation in the efficacy of the different blockers. These results predict that blockers of canonical TRPM8 channels may be less effective in halting proliferation of PC cells than expected.
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240
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Cho Y, Jang Y, Yang YD, Lee CH, Lee Y, Oh U. TRPM8 mediates cold and menthol allergies associated with mast cell activation. Cell Calcium 2010; 48:202-8. [PMID: 20934218 DOI: 10.1016/j.ceca.2010.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 09/02/2010] [Indexed: 11/19/2022]
Abstract
Exposure to low temperatures often causes allergic responses or urticaria. Similarly, menthol, a common food additive is also known to cause urticaria, asthma, and rhinitis. However, despite the obvious clinical implications, the molecular mechanisms responsible for inducing allergic responses to low temperatures and menthol have not been determined. Because a non-selective cation channel, transient receptor potential subtype M8 (TRPM8) is activated by cold and menthol, we hypothesized that this channel mediates cold- and menthol-induced histamine release in mast cells. Here, we report that TRPM8 is expressed in the basophilic leukemia mast cell line, RBL-2H3, and that exposure to menthol or low temperatures induced Ca(2+) influx in RBL-2H3 cells, which was reversed by a TRPM8 blocker. Furthermore, menthol, a TRPM8 agonist, induced the dose-dependent release of histamine from RBL-2H3 cells. When TRPM8 transcripts were reduced by siRNA (small interfering RNA), menthol- and cold-induced Ca(2+) influx and histamine release were significantly reduced. In addition, subcutaneous injection of menthol evoked scratching, a typical histamine-induced response which was reversed by a TRPM8 blocker. Thus, our findings indicate that TRPM8 mediates the menthol- and cold-induced allergic responses of mast cells, and suggest that TRPM8 antagonists be viewed as potential treatments for cold- and menthol-induced allergies.
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Affiliation(s)
- Yeongyo Cho
- Sensory Research Center, College of Pharmacy, Seoul National University, Seoul 151-742, Republic of Korea
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241
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Hirata Y, Oku Y. TRP channels are involved in mediating hypercapnic Ca2+ responses in rat glia-rich medullary cultures independent of extracellular pH. Cell Calcium 2010; 48:124-32. [PMID: 20728216 DOI: 10.1016/j.ceca.2010.07.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 07/06/2010] [Accepted: 07/24/2010] [Indexed: 10/19/2022]
Abstract
The medulla contains central chemosensitive cells important for the maintenance of blood gas and pH homeostasis. To identify the intrinsic chemosensitive cells, we measured responses of intracellular Ca(2+) ([Ca(2+)](i)) and H(+) ([H(+)](i)), and membrane potential of rat primary-cultured medullary cells to 6-s exposure to acidosis. The cells showed transient [Ca(2+)](i) increases to extracellular pH 6.8, which was inhibited by the specific ASIC1a blocker (psalmotoxin-1), but did not respond to pH 7.1 in the HEPES-buffered solution. Isocapnic acidosis induced no changes in [Ca(2+)](i), whereas hypercapnic acidosis induced a remarkable Ca(2+) response and an increase in membrane potential in the HCO(3)(-)-buffered solution (pH 7.1). In glia-rich cultures, intracellular acidification preceded the hypercapnic acidosis-induced Ca(2+) response, and acetazolamide, a carbonic anhydrase inhibitor suppressed these responses. Transient receptor potential (TRP) channel broad-spectrum blockers Ni(2+) and ruthenium red, and a TRPV1- and TRPM8-specific blocker N-(4-tertiarybutylphenyl)-4-(3-chloropyridin-2-yl)-tetrahydropyrazine-1(2H)-carbox-amide attenuated the hypercapnic acidosis-induced Ca(2+) response. Subpopulations of cells that exhibited the hypercapnic acidosis-induced Ca(2+) response also responded to the application of capsaicin (TRPV1 agonist) and menthol (TRPM8 agonist). These results suggest that the TRP channel family partially mediates the fast hypercapnic acidosis-induced Ca(2+) response via changes in [H(+)](i) and is a candidate of central chemosensing proteins.
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Affiliation(s)
- Yutaka Hirata
- Department of Physiology, Hyogo College of Medicine, Mukogawa-cho, Nishinomiya, Japan
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242
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Vriens J, Nilius B, Vennekens R. Herbal compounds and toxins modulating TRP channels. Curr Neuropharmacol 2010; 6:79-96. [PMID: 19305789 PMCID: PMC2645550 DOI: 10.2174/157015908783769644] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 07/19/2007] [Accepted: 08/15/2007] [Indexed: 01/13/2023] Open
Abstract
Although the benefits are sometimes obvious, traditional or herbal medicine is regarded with skepticism, because the mechanism through which plant compounds exert their powers are largely elusive. Recent studies have shown however that many of these plant compounds interact with specific ion channels and thereby modulate the sensing mechanism of the human body. Especially members of the Transient Receptor Potential (TRP) channels have drawn large attention lately as the receptors for plant-derived compounds such as capsaicin and menthol. TRP channels constitute a large and diverse family of channel proteins that can serve as versatile sensors that allow individual cells and entire organisms to detect changes in their environment. For this family, a striking number of empirical views have turned into mechanism-based actions of natural compounds. In this review we will give an overview of herbal compounds and toxins, which modulate TRP channels.
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Affiliation(s)
- Joris Vriens
- Laboratory of Ion Channel Research, Department of Mol. Cell Biology, Division of Physiology, Campus Gasthuisberg, KU Leuven, Herestraat 49, B-3000 LEUVEN, Belgium
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243
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Story GM. The emerging role of TRP channels in mechanisms of temperature and pain sensation. Curr Neuropharmacol 2010; 4:183-96. [PMID: 18615141 DOI: 10.2174/157015906778019482] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/17/2006] [Indexed: 01/13/2023] Open
Abstract
Pain is universal and vital to survival. It is an essential component of our sense of touch; together, touch and pain have evolved to enable our awareness of the intricacies of our environment and to warn us of danger and possible injury. There is a clear link between temperature sensation and pain-painful temperature sensations occur acutely and are a hallmark of inflammatory and chronic pain disorders of the nervous system. Mounting evidence suggests a subset of Transient Receptor Potential (TRP) ion channels activated by temperature (thermoTRPs) are important molecular players in acute, inflammatory and chronic pain states. Varying degrees of heat activate four of these channels (TRPV1-4), while cooling temperatures ranging from pleasant to painful activate two distantly related thermoTRP channels (TRPM8 and TRPA1). ThermoTRP channels are also chemosensitive, being activated and or modulated by plant-derived small molecules and endogenous inflammatory mediators. All thermoTRPs are expressed in tissues essential to cutaneous thermal and pain sensation. This review examines the contribution of thermoTRP channels to our understanding of temperature and pain transduction at the molecular level.
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Affiliation(s)
- Gina M Story
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, Campus Box 8054, St. Louis, MO 63110, USA.
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244
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Batista PA, Werner MFDP, Oliveira EC, Burgos L, Pereira P, Brum LFDS, Story GM, Santos ARS. The antinociceptive effect of (-)-linalool in models of chronic inflammatory and neuropathic hypersensitivity in mice. THE JOURNAL OF PAIN 2010; 11:1222-9. [PMID: 20452289 DOI: 10.1016/j.jpain.2010.02.022] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2009] [Revised: 02/11/2010] [Accepted: 02/26/2010] [Indexed: 11/25/2022]
Abstract
UNLABELLED We used multiple pain models to investigate the effects of (-)-linalool, a monoterpene alcohol present in the essential oil of plants, on chronic inflammatory and neuropathic hypersensitivity in adult Swiss mice. Inflammatory or neuropathic hypersensitivity was induced by intraplantar (i.pl.) injection of complete Freund's adjuvant (CFA) or partial sciatic nerve ligation (PSNL), respectively. Twenty-four hours after CFA injection, we used Von Frey filaments and acetone-evoked cooling to evaluate tactile and thermal hypersensitivity, respectively. A single i.p. injection of (-)-linalool (50 or 200 mg/kg) administered 30 minutes before testing reduced CFA-induced mechanical hypersensitivity. Similarly, (-)-linalool reduced acetone-evoked hypersensitivity up to 4 hours after treatment. Compared with vehicle, (-)-linalool produced a marked reduction in CFA-induced paw edema. (-)-Linalool also reduced mechanical hypersensitivity induced by PSNL 7 days after injury. Multiple (-)-linalool treatments given chronically (twice a day for 10 days; 50 mg/kg, i.p.) significantly reduced mechanical hypersensitivity induced by CFA and PSNL. This multidose strategy did not cause tolerance. We also reasoned that (-)-linalool might reduce nociceptive behavior in response to direct administration of inflammatory mediators. Therefore, we injected the cytokines IL-1β (.1 pg/site) and TNF-α (1 pg/site) intrathecally. (-)-Linalool inhibited the biting response induced by IL-1β and TNF-α. PERSPECTIVE The article adds information about antinociceptive properties of (-)-linalool in chronic inflammatory and neuropathic hypersensitivity. It also indicates that (-)-linalool might be potentially interesting in the development of new clinically relevant drugs for the management of persistent pain.
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Affiliation(s)
- Patricia Aparecida Batista
- Department of Pharmacology, Center of Biological Science, Federal University of Santa Catarina, Florianopolis, SC, Brazil
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245
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Frasnelli J, La Buissonnière Ariza V, Collignon O, Lepore F. Localisation of unilateral nasal stimuli across sensory systems. Neurosci Lett 2010; 478:102-6. [PMID: 20451578 DOI: 10.1016/j.neulet.2010.04.074] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/28/2010] [Accepted: 04/29/2010] [Indexed: 11/19/2022]
Abstract
Odor stimuli presented to one nostril can only be localised if they additionally activate the trigeminal nerve's chemosensitive fibers. In this study we aimed to investigate characteristics in the localisation of unilateral trigeminal, olfactory and somatosensory nasal stimuli. We compared the ability of healthy young subjects to localise monorhinally presented (a) pure olfactory stimuli (phenyl ethyl alcohol), (b) mixed olfactory trigeminal stimuli (eucalyptol), and (c) somatosensory stimuli (air puffs). As expected, subjects could localise the air puffs and eucalyptol, but could not phenyl ethyl alcohol. Interestingly, we observed a significant correlation between localisation performance for eucalyptol and phenyl ethyl alcohol but not between the ability to localise somatosensory and trigeminal or olfactory stimuli. These observations show that on a behavioural level, the trigeminal chemosensory system is more intimately connected to the olfactory system than to the somatosensory system despite the fact that anatomically its information is conveyed via same nerve as the latter. Furthermore, they show that the trigeminal chemosensory system should therefore be considered a self-confined contributor to chemosensory perception.
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246
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Klein AH, Sawyer CM, Carstens MI, Tsagareli MG, Tsiklauri N, Carstens E. Topical application of L-menthol induces heat analgesia, mechanical allodynia, and a biphasic effect on cold sensitivity in rats. Behav Brain Res 2010; 212:179-86. [PMID: 20398704 DOI: 10.1016/j.bbr.2010.04.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/03/2010] [Accepted: 04/07/2010] [Indexed: 10/19/2022]
Abstract
Menthol is used in analgesic balms and also in foods and oral hygiene products for its fresh cooling sensation. Menthol enhances cooling by interacting with the cold-sensitive thermoTRP channel TRPM8, but its effect on pain is less well understood. We presently used behavioral methods to investigate effects of topical menthol on thermal (hot and cold) pain and innocuous cold and mechanical sensitivity in rats. Menthol dose-dependently increased the latency for noxious heat-evoked withdrawal of the treated hindpaw with a weak mirror-image effect, indicating antinociception. Menthol at the highest concentration (40%) reduced mechanical withdrawal thresholds, with no effect at lower concentrations. Menthol had a biphasic effect on cold avoidance. At high concentrations (10% and 40%) menthol reduced avoidance of colder temperatures (15 degrees C and 20 degrees C) compared to 30 degrees C, while at lower concentrations (0.01-1%) menthol enhanced cold avoidance. In a -5 degrees C cold plate test, 40% menthol significantly increased the nocifensive response latency (cold hypoalgesia) while lower concentrations were not different from vehicle controls. These results are generally consistent with neurophysiological and human psychophysical data and support TRPM8 as a potential peripheral target of pain modulation.
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Affiliation(s)
- Amanda H Klein
- Section of Neurobiology, Physiology and Behavior, University of California, 1 Shields Ave., Davis, CA 95616, USA
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247
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Idris AI, Landao-Bassonga E, Ralston SH. The TRPV1 ion channel antagonist capsazepine inhibits osteoclast and osteoblast differentiation in vitro and ovariectomy induced bone loss in vivo. Bone 2010; 46:1089-99. [PMID: 20096813 DOI: 10.1016/j.bone.2010.01.368] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 12/21/2009] [Accepted: 01/11/2010] [Indexed: 12/31/2022]
Abstract
The vanilloid type 1 ion channel (TRPV1) is known to play an important role in the regulation of pain and inflammation. Pharmacological ligands of TRPV1 regulate human osteoclast formation in vitro, but the effects of these agents on osteoblast function have not been studied and their effects on bone loss in vivo are unknown. Here we examined the effects of the TRPV1 ion channel antagonist capsazepine on mouse osteoclast and osteoblast differentiation in vitro and ovariectomy induced bone loss in vivo. Capsazepine inhibited osteoclast formation and bone resorption in a dose dependent manner in bone marrow-osteoblast co-cultures and RANKL generated osteoclast cultures, whereas the TRPV1 agonist capsaicin enhanced RANKL and M-CSF stimulated osteoclast formation. Capsazepine also suppressed RANKL induced IkappaB and ERK1/2 phosphorylation and caused apoptosis of mature osteoclasts and also inhibited alkaline phosphatase activity and bone nodule formation in calvarial osteoblast cultures. Studies in vivo showed that capsazepine (1mg/kg/day) inhibited ovariectomy induced bone loss in mice and histomorphometric analysis showed inhibitory effects on indices of bone resorption and bone formation. We conclude that pharmacological blockade of TRPV1 ion channels by capsazepine inhibits osteoclastic bone resorption and protects against ovariectomy induced bone loss in mice, but also inhibits osteoblast activity and bone formation.
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Affiliation(s)
- Aymen I Idris
- Bone Research Group, Institute of Genetic and Molecular Medicine, Molecular Medicine Centre, University of Edinburgh, General Western Hospital, Edinburgh, EH4 2XU, UK.
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248
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Zholos A. Pharmacology of transient receptor potential melastatin channels in the vasculature. Br J Pharmacol 2010; 159:1559-71. [PMID: 20233227 DOI: 10.1111/j.1476-5381.2010.00649.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Mammalian transient receptor potential melastatin (TRPM) non-selective cation channels, the largest TRP subfamily, are widely expressed in excitable and non-excitable cells where they perform diverse functions ranging from detection of cold, taste, osmolarity, redox state and pH to control of Mg(2+) homeostasis and cell proliferation or death. Recently, TRPM gene expression has been identified in vascular smooth muscles with dominance of the TRPM8 channel. There has been in parallel considerable progress in decoding the functional roles of several TRPMs in the vasculature. This research on native cells is aided by the knowledge of the activation mechanisms and pharmacological properties of heterologously expressed TRPM subtypes. This paper summarizes the present state of knowledge of vascular TRPM channels and outlines several anticipated directions of future research in this area.
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Affiliation(s)
- Alexander Zholos
- Centre for Vision and Vascular Science, Queen's University of Belfast, UK.
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249
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Development and Validation of a Secondary Screening Assay for TRPM8 Antagonists Using QPatch HT. Assay Drug Dev Technol 2010; 8:63-72. [DOI: 10.1089/adt.2009.0214] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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250
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Kizawa K, Kitahara T, Horii A, Maekawa C, Kuramasu T, Kawashima T, Nishiike S, Doi K, Inohara H. Behavioral assessment and identification of a molecular marker in a salicylate-induced tinnitus in rats. Neuroscience 2010; 165:1323-32. [DOI: 10.1016/j.neuroscience.2009.11.048] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 11/19/2009] [Accepted: 11/19/2009] [Indexed: 11/30/2022]
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