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Romanova J, Rydlovskaya A, Mochalov S, Proskurina O, Gorokh Y, Nebolsin V. The Effect of Anti-Chemokine Oral Drug XC8 on Cough Triggered by The Agonists of TRPA1 But Not TRPV1 Channels in Guinea Pigs. Pulm Ther 2022; 8:105-122. [PMID: 35133638 PMCID: PMC8824739 DOI: 10.1007/s41030-022-00183-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 01/14/2022] [Indexed: 01/09/2023] Open
Abstract
Introduction Chronic cough heavily affects patients’ quality of life, and there are no effective licensed therapies available. Cough is a complication of severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) infection, asthma, and other diseases. Patients with various diseases have a different profile of tussive responses to diverse cough triggers, thereby suggesting sundry mechanisms of neuronal dysfunctions. Previously, we demonstrated that the small molecule drug XC8 shows a clinical anti-asthmatic effect. The objective of the present study was to investigate the effect of XC8 on cough. Methods We studied the antitussive effect of XC8 on cough induced by agonists activating human transient receptor potential (TRP) cation channels TRPA1 or TRPV1 in guinea pigs. We checked the agonistic/antagonistic activity of XC8 on the human cation channels TRPA1, TRPV1, TRPM8, P2X purinoceptor 2 (P2X2), and human acid sensing ion channel 3 (hASIC3) in Fluorescent Imaging Plate Reader (FLIPR) assay. Results XC8 demonstrated clear antitussive activity and dose-dependently inhibited cough in guinea pigs induced by citric acid alone (up to 67.1%) or in combination with IFN-γ (up to 76.4%). XC8 suppressed cough reflexes induced by the repeated inhalation of citric acid (up to 80%) or by cinnamaldehyde (up to 60%). No activity of XC8 against cough evoked by capsaicin was revealed. No direct agonistic/antagonistic activity of XC8 on human TRPA1, TRPV1, TRPM8, P2X2, or hASIC3 was detected. Conclusions XC8 acts against cough evoked by the activation of TRPA1 (citric acid/cinnamaldehyde) but not TRPV1 (capsaicin) channels. XC8 inhibits the cough reflex and suppresses the cough potentiation by IFN-γ. XC8 might be of significant therapeutic value for patients suffering from chronic cough associated with inflammation.
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Affiliation(s)
- Julia Romanova
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation.
| | - Anastasia Rydlovskaya
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation
| | - Stepan Mochalov
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation
| | - Oxana Proskurina
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation
| | - Yulia Gorokh
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation
| | - Vladimir Nebolsin
- Pharmenterprises LLC, 42 Bolshoj Blvd., Building 1, office 771, 772, Skolkovo Innovation Centre, Moscow, 121205, Russian Federation
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Al-Kandery ASA, Rao MS, El-Hashim AZ. Prostaglandin E 2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 channels. Respir Res 2021; 22:296. [PMID: 34794450 PMCID: PMC8603488 DOI: 10.1186/s12931-021-01889-4] [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: 07/30/2021] [Accepted: 11/05/2021] [Indexed: 11/29/2022] Open
Abstract
Background Cough hypersensitivity is a major characteristic feature associated with several types of cough, including chronic cough, but its underlying mechanisms remain to be fully understood. Inflammatory mediators, such as prostaglandin E2 (PGE2), have been implicated in both peripheral induction and sensitization of the cough reflex. In this study, using a conscious guinea pig model of cough, we investigated whether PGE2 can sensitize the cough reflex via central actions and, if so, via which mechanisms. Methods All drugs were administered by intracerebroventricular (i.c.v.) route and whole-body plethysmograph set-up was used for both induction, using aerosolized citric acid (0.2 M), and recording of cough. Immunohistochemistry was performed to confirm the expression of NaV 1.8 channels in the nucleus tractus solitarius (nTS). Results We show that both PGE2 and the non-selective EP1/EP3 agonist, sulprostone, dose-dependently enhanced the citric acid-induced cough (P ≤ 0.001, P ≤ 0.01, respectively). Pretreatment with the EP1 antagonist, ONO-8130, did not affect the sulprostone-induced cough sensitization, whilst the EP3 antagonist, L-798,106, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, treatment with either the EP2 agonist, butaprost or the EP4 agonist, L-902,688, had no effect on cough sensitization. Additionally, pretreatment with either the TRPV1 antagonist, JNJ-17203212 or the TRPA1 antagonist, HC-030031, alone or in combination, nor with the NaV 1.1, 1.2, 1.3, 1.4, 1.6 and 1.7 channel blocker, tetrodotoxin, had any effect on the cough. In contrast, pretreatment with the NaV 1.8 antagonist, A-803467, dose-dependently inhibited this effect (P ≤ 0.05). Furthermore, NaV 1.8 channels were shown to be expressed in the nTS. Conclusion Collectively, our findings show that PGE2 sensitizes the cough reflex centrally via EP3 receptor-dependent activation of NaV 1.8 but independently of TRPV1,TRPA1 and TTX-sensitive sodium channel activation. These results indicate that PGE2 plays an important role in central sensitization of the cough reflex and suggest that central EP3 receptors and/or NaVv 1.8 channels may represent novel antitussive molecular targets. Graphical Abstract ![]()
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Affiliation(s)
- Al-Shaimaa A Al-Kandery
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Ahmed Z El-Hashim
- Department of Pharmacology & Therapeutics, Faculty of Pharmacy, Kuwait University, Kuwait City, Kuwait.
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Gu Q, Lee LY. TRP channels in airway sensory nerves. Neurosci Lett 2021; 748:135719. [PMID: 33587987 PMCID: PMC7988689 DOI: 10.1016/j.neulet.2021.135719] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 02/01/2021] [Accepted: 02/03/2021] [Indexed: 12/12/2022]
Abstract
Transient Receptor Potential (TRP) channels expressed in specific subsets of airway sensory nerves function as transducers and integrators of a diverse range of sensory inputs including chemical, mechanical and thermal signals. These TRP sensors can detect inhaled irritants as well as endogenously released chemical substances. They play an important role in generating the afferent activity carried by these sensory nerves and regulating the centrally mediated pulmonary defense reflexes. Increasing evidence reported in recent investigations has revealed important involvements of several TRP channels (TRPA1, TRPV1, TRPV4 and TRPM8) in the manifestation of various symptoms and pathogenesis of certain acute and chronic airway diseases. This mini-review focuses primarily on these recent findings of the responses of these TRP sensors to the biological stresses emerging under the pathophysiological conditions of the lung and airways.
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Affiliation(s)
- Qihai Gu
- Department of Biomedical Sciences, Mercer University School of Medicine, 1501 Mercer University Drive, Macon, GA, 31207, USA.
| | - Lu-Yuan Lee
- Department of Physiology, University of Kentucky Medical Center, 800 Rose Street, Lexington, KY, 40536-0298, USA.
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Ni F, Ogura T, Lin W. Electronic Cigarette Liquid Constituents Induce Nasal and Tracheal Sensory Irritation in Mice in Regionally Dependent Fashion. Nicotine Tob Res 2021; 22:S35-S44. [PMID: 33320249 PMCID: PMC7737480 DOI: 10.1093/ntr/ntaa174] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 10/01/2020] [Indexed: 02/05/2023]
Abstract
INTRODUCTION Electronic cigarettes (e-cigs) are currently used by millions of adults and adolescents worldwide. Major respiratory symptoms, such as coughing reported by e-cig users, including patients with e-cig, or vaping, product use-associated lung injury (EVALI), indicate e-cig constituent-induced sensory irritation. However, e-cig constituent-induced nociceptive activity in nasal and tracheal respiratory epithelia (RE) and neuronal activation in the trigeminal ganglia and brainstem nuclei, which receive airway chemosensory inputs have not been examined and compared. Comparisons of physiological responses between freebase nicotine and nicotine salts are also missing. AIMS AND METHODS Event-related potential (ERP) was recorded electrophysiologically to assess mouse nasal and tracheal RE chemosensory responses to various flavorings, nicotine, including freebase and nicotine salts, e-liquid mixtures, and tussigenic stimuli. Also, mice were subjected to inhalation exposure to aerosol of a vanilla-flavored e-liquid or air (control), and the activated-trigeminal nociceptive neurons and brainstem neurons were examined using immunohistochemistry. RESULTS Individual constituents and mixtures of e-liquids, capsaicin, and citric and acetic acids evoked significantly larger ERP in the nose than in the trachea with the exception of menthol. ERP responses to freebase nicotine were significantly larger than protonated nicotine. Four nicotine salts (benzoate, lactate, levulinate, and salicylate) induced similar responses. Compared with air-exposed mice, e-liquid aerosol-exposed mice showed a significant increase in numbers of activated trigeminal nociceptive neurons and brainstem neurons in the spinal trigeminal nucleus, paratrigeminal nucleus, and nucleus tractus solitarius. CONCLUSIONS E-liquid constituents region-dependently stimulate airway nociceptive chemosensory systems, and freebase nicotine is more potent than protonated nicotine. IMPLICATIONS Neural abnormalities have been implicated in the development of nasal and respiratory illnesses. The higher sensitivity of the nasal nociceptive chemosensory system to nicotine and flavorings may indicate a health risk for e-liquid aerosol-induced upper airway illnesses via neurogenic alteration and warrants further investigation.
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Affiliation(s)
- Fenge Ni
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD
| | - Tatsuya Ogura
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD
| | - Weihong Lin
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD
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Chang RYK, Kwok PCL, Ghassabian S, Brannan JD, Koskela HO, Chan H. Cough as an adverse effect on inhalation pharmaceutical products. Br J Pharmacol 2020; 177:4096-4112. [PMID: 32668011 PMCID: PMC7443471 DOI: 10.1111/bph.15197] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 01/06/2023] Open
Abstract
Cough is an adverse effect that may hinder the delivery of drugs into the lungs. Chemical or mechanical stimulants activate the transient receptor potential in some airway afferent nerves (C-fibres or A-fibres) to trigger cough. Types of inhaler device and drug, dose, excipients and formulation characteristics, including pH, tonicity, aerosol output and particle size may trigger cough by stimulating the cough receptors. Release of inflammatory mediators may increase the sensitivity of the cough receptors to stimulants. The cough-provoking effect of aerosols is enhanced by bronchoconstriction in diseased airways and reduces drug deposition in the target pulmonary regions. In this article, we review the factors by which inhalation products may cause cough.
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Affiliation(s)
- Rachel Yoon Kyung Chang
- Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneyCamperdownNSWAustralia
| | - Philip Chi Lip Kwok
- Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneyCamperdownNSWAustralia
| | - Sussan Ghassabian
- Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneyCamperdownNSWAustralia
| | - John D. Brannan
- Department of Respiratory and Sleep MedicineJohn Hunter HospitalNewcastleNSWAustralia
| | - Heikki O. Koskela
- Unit for Medicine and Clinical Research, Pulmonary DivisionKuopio University HospitalKuopioFinland
- School of Medicine, Faculty of Health SciencesUniversity of Eastern FinlandKuopioFinland
| | - Hak‐Kim Chan
- Advanced Drug Delivery Group, Sydney Pharmacy School, Faculty of Medicine and HealthThe University of SydneyCamperdownNSWAustralia
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Al-Shamlan F, El-Hashim AZ. Bradykinin sensitizes the cough reflex via a B 2 receptor dependent activation of TRPV1 and TRPA1 channels through metabolites of cyclooxygenase and 12-lipoxygenase. Respir Res 2019; 20:110. [PMID: 31170972 PMCID: PMC6551914 DOI: 10.1186/s12931-019-1060-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/28/2019] [Indexed: 01/10/2023] Open
Abstract
Background Inhaled bradykinin (BK) has been reported to both sensitize and induce cough but whether BK can centrally sensitize the cough reflex is not fully established. In this study, using a conscious guinea-pig model of cough, we investigated the role of BK in the central sensitization of the cough reflex and in airway obstruction. Methods Drugs were administered, to guinea pigs, by the intracerebroventricular (i.c.v.) route. Aerosolized citric acid (0.2 M) was used to induce cough in a whole-body plethysmograph box, following i.c.v. infusion of drugs. An automated analyser recorded both cough and airway obstruction simultaneously. Results BK, administered by the i.c.v. route, dose-dependently enhanced the citric acid-induced cough and airway obstruction. This effect was inhibited following i.c.v. pretreatment with a B2 receptor antagonist, TRPV1 and TRPA1 channels antagonists and cyclooxygenase (COX) and 12-lipoxygenase (12-LOX) inhibitors. Furthermore, co-administration of submaximal doses of the TRPV1 and TRPA1 antagonists or the COX and 12-LOX inhibitors resulted in a greater inhibition of both cough reflex and airway obstruction. Conclusions Our findings show that central BK administration sensitizes cough and enhances airway obstruction via a B2 receptor/TRPV1 and/or TRPA1 channels which are coupled via metabolites of COX and/or 12-LOX enzymes. In addition, combined blockade of TRPV1 and TRPA1 or COX and 12-LOX resulted in a greater inhibitory effect of both cough and airway obstruction. These results indicate that central B2 receptors, TRPV1/TRPA1 channels and COX/12-LOX enzymes may represent potential therapeutic targets for the treatment of cough hypersensitivity. Graphical abstract ![]()
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Affiliation(s)
- Fajer Al-Shamlan
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, P.O. BOX 24923, 13110, Safat, Kuwait
| | - Ahmed Z El-Hashim
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, P.O. BOX 24923, 13110, Safat, Kuwait.
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Hofmann ME, Andresen MC. Vanilloids selectively sensitize thermal glutamate release from TRPV1 expressing solitary tract afferents. Neuropharmacology 2015; 101:401-11. [PMID: 26471418 DOI: 10.1016/j.neuropharm.2015.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/11/2015] [Accepted: 10/07/2015] [Indexed: 01/09/2023]
Abstract
Vanilloids, high temperature, and low pH activate the transient receptor potential vanilloid type 1 (TRPV1) receptor. In spinal dorsal root ganglia, co-activation of one of these gating sites on TRPV1 sensitized receptor gating by other modes. Here in rat brainstem slices, we examined glutamate synaptic transmission in nucleus of the solitary tract (NTS) neurons where most cranial primary afferents express TRPV1, but TRPV1 sensitization is unknown. Electrical shocks to the solitary tract (ST) evoked EPSCs (ST-EPSCs). Activation of TRPV1 with capsaicin (100 nM) increased spontaneous EPSCs (sEPSCs) but inhibited ST-EPSCs. High concentrations of the ultra-potent vanilloid resiniferatoxin (RTX, 1 nM) similarly increased sEPSC rates but blocked ST-EPSCs. Lowering the RTX concentration to 150 pM modestly increased the frequency of the sEPSCs without causing failures in the evoked ST-EPSCs. The sEPSC rate increased with raising bath temperature to 36 °C. Such thermal responses were larger in 150 pM RTX, while the ST-EPSCs remained unaffected. Vanilloid sensitization of thermal responses persisted in TTX but was blocked by the TRPV1 antagonist capsazepine. Our results demonstrate that multimodal activation of TRPV1 facilitates sEPSC responses in more than the arithmetic sum of the two activators, i.e. co-activation sensitizes TRPV1 control of spontaneous glutamate release. Since action potential evoked glutamate release is unaltered, the work provides evidence for cooperativity in gating TRPV1 plus a remarkable separation of calcium mechanisms governing the independent vesicle pools responsible for spontaneous and evoked release at primary afferents in the NTS.
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Affiliation(s)
- Mackenzie E Hofmann
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA.
| | - Michael C Andresen
- Department of Physiology & Pharmacology, Oregon Health & Science University, Portland, OR, USA
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Horváth G, Ács K. Essential oils in the treatment of respiratory tract diseases highlighting their role in bacterial infections and their anti-inflammatory action: a review. FLAVOUR FRAG J 2015; 30:331-341. [PMID: 32313366 PMCID: PMC7163989 DOI: 10.1002/ffj.3252] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 03/31/2015] [Accepted: 04/16/2015] [Indexed: 12/11/2022]
Abstract
The appearance of multidrug resistant bacteria and growing antibiotic resistance is leading to a continuous need for discovering new drugs and alternative treatments against infections. The investigation of the antibacterial effect of essential oils (EOs), which are commonly used nowadays in cosmetics, health care, traditional medicine and food industry, could be one of the promising solutions for this worldwide problem. EOs have a complex mode of action due to their multiple composition. Respiratory tract diseases (RTDs) associated with bacterial infection and inflammation affect a large number of people from every age group worldwide. Because of volatility, EOs can easily reach the upper and lower parts of the respiratory tract via inhalation. Moreover, due to their antimicrobial and anti-inflammatory potency, they offer an effective treatment in respiratory tract infections (RTIs). The purpose of this review is to describe the most frequently developing infections of the upper and lower respiratory tract and to show methods used for the determination of the antibacterial activity of EOs by gaseous contact. The mode of action of EOs on bacterial cells and their anti-inflammatory action are also discussed. Results coming from recently performed in vivo animal studies as well as human trials are also reported. Patents deal with the role of EOs and their volatile constituents in the treatment of RTIs are also introduced. On the whole, this review aimed at showing EOs as potential antimicrobials and as anti-inflammatory agents to alleviate symptoms and signs of RTDs including RTIs. Copyright © 2015 John Wiley & Sons, Ltd.
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Affiliation(s)
- Györgyi Horváth
- Department of PharmacognosyUniversity of PécsRókus street 27624PécsHungary
| | - Kamilla Ács
- Department of PharmacognosyUniversity of PécsRókus street 27624PécsHungary
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Bonvini SJ, Birrell MA, Smith JA, Belvisi MG. Targeting TRP channels for chronic cough: from bench to bedside. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:401-20. [PMID: 25572384 DOI: 10.1007/s00210-014-1082-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/16/2014] [Indexed: 12/24/2022]
Abstract
Cough is currently the most common reason for patients to visit a primary care physician in the UK, yet it remains an unmet medical need. Current therapies have limited efficacy or have potentially dangerous side effects. Under normal circumstances, cough is a protective reflex to clear the lungs of harmful particles; however, in disease, cough can become excessive, dramatically impacting patients' lives. In many cases, this condition is linked to inflammatory diseases such as asthma and chronic obstructive pulmonary disease (COPD), but can also be refractory to treatment and idiopathic in nature. Therefore, there is an urgent need to develop therapies, and targeting the sensory afferent arm of the reflex which initiates the cough reflex may uncover novel therapeutic targets. The cough reflex is initiated following activation of ion channels present on vagal sensory afferents. These ion channels include the transient receptor potential (TRP) family of cation-selective ion channels which act as cellular sensors and respond to changes in the external environment. Many direct activators of TRP channels, including arachidonic acid derivatives, a lowered airway pH, changes in temperature, and altered airway osmolarity are present in the diseased airway where responses to challenge agents which activate airway sensory nerve activity are known to be enhanced. Furthermore, the expression of some TRP channels is increased in airway disease. Together, this makes them promising targets for the treatment of chronic cough. This review will cover the current understanding of the role of the TRP family of ion channels in the activation of airway sensory nerves and cough, focusing on four members, transient receptor potential vanilloid (TRPV) 1, transient receptor potential ankyrin (TRPA) 1, TRPV4, and transient receptor potential melastatin (TRPM) 8 as these represent the channels where most information has been gathered with relevance to the airways. We will describe recent data and highlight the possible therapeutic utility of specific TRP channel antagonists as antitussives in the clinic.
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Affiliation(s)
- Sara J Bonvini
- Respiratory Pharmacology Group, Airway Disease Section, National Heart & Lung Institute, Imperial College, Exhibition Road, London, SW7 2AZ, UK
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Ryan NM, Gibson PG. Recent additions in the treatment of cough. J Thorac Dis 2014; 6:S739-47. [PMID: 25383209 DOI: 10.3978/j.issn.2072-1439.2014.03.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 03/04/2014] [Indexed: 11/14/2022]
Abstract
BACKGROUND Worldwide, cough is regarded as a challenging clinical problem due to its frequency and often limited therapeutic options. Chronic cough that remains refractory to usual medical treatment causes significant quality of life impairment in people with this problem. METHODS We have examined current evidence on recent additions in the treatment of cough, specifically treatment of refractory chronic cough with speech pathology and gabapentin. Relevant randomised control trials, reviews and case reports were identified through a PubMed and SCOPUS search of English-language literature referring to these concepts over the last eight years. SUMMARY Of the one hundred and two articles comprising this review the majority investigated the role of the transient receptor potential (TRP) receptors TRP Vanilloid 1 (TRPV1) and TRPA1 in cough and the potential of TRP antagonists as effective anti-tussives. However, these have only been tested in the laboratory and therefore their clinical effectiveness is unknown. Behavioural treatments such as speech pathology have gained momentum and this was evident in the increasing number of articles investigating its positive effect on cough. Investigation on the effectiveness of neuromodulating medications in the treatment of cough have been supported primarily through case series reports and prospective reviews however; their use (particularly gabapentin) has been significantly advanced through recently conducted randomised controlled trials. CONCLUSIONS Recent additions in the treatment of chronic cough have been significant as they consider cough to have a unifying diagnosis of cough hypersensitivity with or without the presence of a neuropathic basis. Primarily, effective treatments for chronic cough target these areas and include behavioural treatment such as speech pathology and pharmaceutical treatment with neuromodulating medications such as gabapentin.
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Affiliation(s)
- Nicole M Ryan
- 1 Priority Centre for Asthma and Respiratory Diseases, School of Medicine and Public Health, The University of Newcastle, NSW 2308, Australia ; 2 VIVA, Level 2 West Wing, Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
| | - Peter G Gibson
- 1 Priority Centre for Asthma and Respiratory Diseases, School of Medicine and Public Health, The University of Newcastle, NSW 2308, Australia ; 2 VIVA, Level 2 West Wing, Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
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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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Moscato G, Pala G, Cullinan P, Folletti I, Gerth van Wijk R, Pignatti P, Quirce S, Sastre J, Toskala E, Vandenplas O, Walusiak-Skorupa J, Malo JL. EAACI Position Paper on assessment of cough in the workplace. Allergy 2014; 69:292-304. [PMID: 24428394 DOI: 10.1111/all.12352] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2013] [Indexed: 12/13/2022]
Abstract
Cough is a nonspecific and relatively common symptom that can present difficulties in diagnosis and management, particularly when it is reported to be associated with the workplace. The present consensus document, prepared by a taskforce of the Interest Group on Occupational Allergy of the European Academy of Allergy and Clinical Immunology by means of a nonsystematic review of the current literature, is intended to provide a definition and classification of work-related chronic cough (WRCC) to assist the daily practice of physicians facing with this symptom. The review demonstrates that several upper and lower airway work-related diseases may present with chronic cough; hence, the possible link with the workplace should always be considered. Due to the broad spectrum of underlying diseases, a multidisciplinary approach is necessary to achieve a definite diagnosis. Nevertheless, more epidemiological studies are necessary to estimate the real prevalence and risk factors for WRCC, the role of exposure to environmental and occupational sensitizers and irritants in its pathogenesis and the interaction with both upper and lower airways. Finally, the best management option should be evaluated in order to achieve the best outcome without adverse social and financial consequences for the worker.
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Affiliation(s)
- G. Moscato
- Allergology and Immunology Unit; Fondazione ‘Salvatore Maugeri’; Institute of Care and Research; Scientific Institute of Pavia; Pavia Italy
| | - G. Pala
- Allergology and Immunology Unit; Fondazione ‘Salvatore Maugeri’; Institute of Care and Research; Scientific Institute of Pavia; Pavia Italy
| | - P. Cullinan
- Department of Occupational and Environmental Medicine; Imperial College; London UK
| | - I. Folletti
- Department of Clinical and Experimental Medicine; Occupational Allergy Unit; Terni Hospital; University of Perugia; Terni Italy
| | - R. Gerth van Wijk
- Section of Allergology; Department of Internal Medicine; Erasmus MC; Rotterdam the Netherlands
| | - P. Pignatti
- Allergology and Immunology Unit; Fondazione ‘Salvatore Maugeri’; Institute of Care and Research; Scientific Institute of Pavia; Pavia Italy
| | - S. Quirce
- Department of Allergy; Hospital La Paz Institute for Health Research (IdiPAZ), and CIBER de Enfermedades Respiratorias CIBERES; Madrid Spain
| | - J. Sastre
- Department of Allergy; Fundación Jiménez Díaz, and CIBER de Enfermedades Respiratorias CIBERES; Madrid Spain
| | - E. Toskala
- Department of Otolaryngology, Head and Neck Surgery; School of Medicine; Temple University; Philadelphia PA USA
| | - O. Vandenplas
- Department of Chest Medicine; Centre Hospitalier Universitaire de Mont-Godinne; Université Catholique de Louvain; Yvoir Belgium
| | - J. Walusiak-Skorupa
- Department of Occupational Diseases; Nofer Institute of Occupational Medicine; Lodz Poland
| | - J. L. Malo
- Department of Chest Medicine; Hôpital du Sacré-Coeur de Montréal; Université de Montréal; Montreal Canada
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Büch T, Schäfer E, Steinritz D, Dietrich A, Gudermann T. Chemosensory TRP Channels in the Respiratory Tract: Role in Toxic Lung Injury and Potential as “Sweet Spots” for Targeted Therapies. Rev Physiol Biochem Pharmacol 2013; 165:31-65. [DOI: 10.1007/112_2012_10] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Shen MY, Luo YL, Yang CH, Ruan T, Lai CJ. Hypersensitivity of lung vagal C fibers induced by acute intermittent hypoxia in rats: role of reactive oxygen species and TRPA1. Am J Physiol Regul Integr Comp Physiol 2012; 303:R1175-85. [PMID: 23076873 DOI: 10.1152/ajpregu.00227.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Obstructive sleep apnea, manifested by intermittent hypoxia and excess production of reactive oxygen species (ROS) in airways, is associated with hyperreactive airway diseases, but the mechanism remains unclear. Sensitization of lung vagal C fibers (LVCFs) contributes to the airway hypersensitivity. We investigated the mechanisms underlying the sensitization of LVCFs with acute intermittent hypoxia (AIH), by 10 episodes of exposure to 30 s of hypoxic air (0%, 5%, or 10% O(2)) followed by 30 s of room air in anesthetized, open-chest, and artificially ventilated rats. Reflex apneic response to intravenous capsaicin (an LVCF stimulant), as measured by phrenic nerve activity, was concentration dependently augmented by AIH. Similarly, reflex apneic response to intravenous α,β-methylene-ATP (another LVCF stimulant) was augmented by AIH (0% O(2)). The reflex apnea evoked by these two stimulants was abolished by bilateral vagotomy, which suggests the involvement of lung vagal afferents. The AIH-augmented apneic response to these two stimulants was prevented by pretreatment with dimethylthiourea (a hydroxyl radical scavenger), N-acetyl-l-cysteine (an antioxidant) and HC-030031 [a transient receptor potential ankyrin 1 (TRPA1) receptor antagonist]. Consistently, electrophysiological study revealed the afferent responses of LVCFs to capsaicin or α,β-methylene-ATP were augmented by AIH, and this sensitization of LVCFs was prevented by dimethylthiourea, N-acetyl-l-cysteine, and HC-030031. In contrast, AIH did not alter the afferent response of LVCFs to mechanical stimulation by lung hyperinflation. We concluded that AIH sensitizes LVCFs in rats, thus resulting in exaggerated airway reflexogenic responses to chemical stimulants, possibly by ROS action and activation of TRPA1 receptors.
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Affiliation(s)
- Mei-Ya Shen
- Department of Physiology, Tzu Chi University, Hualien, Taiwan
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15
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Abstract
This review dissects the complex human cough reflex and suggests hypotheses about the evolutionary basis for the reflex. A mechanosensory-induced cough reflex conveys through branches of myelinated Aδ nerve fibers is not chemically reactive (i.e., capsaicin, bradykinin); possibly, its evolution is to prevent the harmful effects of aspiration of gastric or particulate contents into the lungs. This became necessary as the larynx moves closer to the opening of the esophagus as human ancestors adapt phonation over olfaction beginning less than 10 million years ago. The second type of cough reflex, a chemosensory type, is carried by unmyelinated C fibers. Supposedly, its origin dates back when prehistoric humans began living in close proximity to each other and were at risk for infectious respiratory diseases or irritant-induced lung injury. The mechanism for the latter type of cough is analogous to induced pain after tissue injury; and, it is controlled by the identical transient receptor potential vanilloid cation channel (TRPV1). The airways do not normally manifest nociceptive pain from a stimulus but the only consistent response that capsaicin and lung inflammation provoke in healthy human airways is cough. TRPA1, another excitatory ion channel, has been referred to as the "irritant receptor" and its activation also induces cough. For both types of cough, the motor responses are identical and via coordinated, precisely-timed and sequential respiratory events orchestrated by complex neuromuscular networking of the diaphragm, chest and abdominal respiratory muscles, the glottis and parts of the brain.
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Affiliation(s)
- Stuart M Brooks
- Colleges of Public Health and Medicine, University of South Florida, Tampa, Florida.
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16
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Targeting peripheral afferent nerve terminals for cough and dyspnea. Curr Opin Pharmacol 2011; 11:254-64. [PMID: 21705272 DOI: 10.1016/j.coph.2011.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 05/13/2011] [Accepted: 05/24/2011] [Indexed: 01/01/2023]
Abstract
Chronic unproductive coughing and dyspnea are symptoms that severely diminish the quality of life in a substantial proportion of the population. There are presently few if any drugs that effectively treat these symptoms. Rational drug targets for cough and dyspnea have emerged over the recent years based on developments in our understanding of the innervation of the respiratory tract. These drug targets can be subcategorized into those that target the vagal afferent nerve endings, and those that target neural activity within the CNS. This review focuses on targets presumed to be in the peripheral terminals of afferent nerves within the airways. Conceptually, the activity of peripheral afferent nerves involved with unwanted urge-to-cough or dyspnea sensations can be inhibited by limiting the intensity of the stimulus, inhibiting the amplitude of the stimulus-induced generator potential, or inhibiting the transduction between the generator potential and action potential discharge and conduction. These mechanisms reveal many therapeutic strategies for anti-tussive and anti-dyspnea drug development with peripheral sites of action.
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17
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Investigation of the neural control of cough and cough suppression in humans using functional brain imaging. J Neurosci 2011; 31:2948-58. [PMID: 21414916 DOI: 10.1523/jneurosci.4597-10.2011] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Excessive coughing is one of the most common reasons for seeking medical advice, yet the available therapies for treating cough disorders are inadequate. Humans can voluntarily cough, choose to suppress their cough, and are acutely aware of an irritation that is present in their airways. This indicates a significant level of behavioral and conscious control over the basic cough reflex pathway. However, very little is known about the neural basis for higher brain regulation of coughing. The aim of the present study was to use functional brain imaging in healthy humans to describe the supramedullary control of cough and cough suppression. Our data show that the brain circuitry activated during coughing in response to capsaicin-evoked airways irritation is not simply a function of voluntarily initiated coughing and the perception of airways irritation. Rather, activations in several brain regions, including the posterior insula and posterior cingulate cortex, define the unique attributes of an evoked cough. Furthermore, the active suppression of irritant-evoked coughing is also associated with a unique pattern of brain activity, including an involvement of the anterior insula, anterior mid-cingulate cortex, and inferior frontal gyrus. These data demonstrate for the first time that evoked cough is not solely a brainstem-mediated reflex response to irritation of the airways, but rather requires active facilitation by cortical regions, and is further regulated by distinct higher order inhibitory processes.
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18
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Lee LY, Ni D, Hayes D, Lin RL. TRPV1 as a cough sensor and its temperature-sensitive properties. Pulm Pharmacol Ther 2011; 24:280-5. [PMID: 21215321 DOI: 10.1016/j.pupt.2010.12.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 12/15/2010] [Indexed: 12/24/2022]
Abstract
In the respiratory tract, TRPV1, a non-selective cation channel and a polymodal transducer, is expressed primarily in non-myelinated sensory nerves. A significant role of TRPV1 in eliciting the cough reflex has been extensively documented. Inhalation of capsaicin aerosol, a selective agonist of TRPV1, consistently and reproducibly evoked coughs in a dose-dependent manner in both healthy humans and in patients with airway inflammatory diseases. A number of endogenous inflammatory mediators known to upregulate the TRPV1 sensitivity, such as prostaglandin E(2) and bradykinin, also enhanced the cough sensitivity. Furthermore, a substantial increase of TRPV1-immunoreactive nerve profiles was found in the bronchial tissue of patients with chronic cough. In addition to the cough reflex, activation of TRPV1-expressing sensory nerves in the airways is also known to elicit reflex bronchoconstriction and mucus secretion mediated through cholinergic pathways. One of the physiological stimuli known to activate TRPV1 receptor directly is high temperature. Recent studies have demonstrated that increasing temperature within the normal physiological range significantly elevated the baseline activity and sensitivity of isolated rat vagal pulmonary sensory neurons, and the sensitizing effect of hyperthermia appeared to be mediated selectively through the TRPV1 channel. This temperature-sensitive property of TRPV1 may play an important role in regulating the physiological function of the TRPV1-expressing airway sensory nerves and the sensitivity of their reflex responses, such as cough and reflex bronchoconstriction.
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Affiliation(s)
- Lu-Yuan Lee
- Department of Physiology, University of Kentucky, 800 Rose Street, Lexington, KY 40536-0298, USA.
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19
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Birring SS. Controversies in the evaluation and management of chronic cough. Am J Respir Crit Care Med 2010; 183:708-15. [PMID: 21148722 DOI: 10.1164/rccm.201007-1017ci] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Chronic cough that cannot be explained after basic evaluation is a common reason for patients to be referred to respiratory outpatient clinics. Asthma, gastroesophageal reflux, and upper airway disorders frequently coexist with chronic cough. There is some controversy as to whether these conditions are causes or aggravants of cough. Heightened cough reflex sensitivity is an important feature in most patients. There is good evidence that it is reversible when associated with upper respiratory tract infection, angiotensin-converting enzyme inhibitor medications, and chronic cough associated with eosinophilic airway inflammation. In many patients, heightened cough reflex sensitivity is persistent and their cough is unexplained. There are few therapeutic options for patients with unexplained chronic cough. There is a pressing need to understand the genetic, molecular, and physiological basis of unexplained chronic cough and to develop novel antitussive drugs that down-regulate cough reflex sensitivity.
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Affiliation(s)
- Surinder S Birring
- King's College London, Division of Asthma, Allergy and Lung Biology, Denmark Hill, London SE5 9RS, UK.
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20
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Lin YS, Hsu CC, Bien MY, Hsu HC, Weng HT, Kou YR. Activations of TRPA1 and P2X receptors are important in ROS-mediated stimulation of capsaicin-sensitive lung vagal afferents by cigarette smoke in rats. J Appl Physiol (1985) 2010; 108:1293-303. [PMID: 20167675 DOI: 10.1152/japplphysiol.01048.2009] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Capsaicin-sensitive lung vagal afferents (CSLVAs) are important in detecting pulmonary reactive oxygen species (ROS). We investigated the mechanisms underlying the stimulation of CSLVAs by inhaled cigarette smoke (CS) in 216 anesthetized rats. In spontaneously breathing rats, CS evoked a CSLVA-mediated reflex bradypnea that was prevented by N-acetyl-L-cysteine (NAC; an antioxidant), HC-030031 [a transient receptor potential ankyrin 1 (TRPA1) receptor antagonist], and iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate (iso-PPADS; a P2X receptor antagonist). In paralyzed, artificially ventilated rats, CS evoked an increase in CSLVA fiber activity (DeltaFA) that was abolished by NAC and was attenuated by HC-030031, iso-PPADS, indomethacin (Indo; a cyclooxygenase inhibitor), and a combination of apyrase and adenosine deaminase (ADA) (ATP scavengers); the response to CS was reduced to 11.7+/-4.0%, 39.5+/-10.0%, 52.9+/-14.4%, 68.7+/-10.1%, and 47.2+/-12.9% of control, respectively. The suppressive effect on this afferent response was not improved by a combination of HC-030031 and Indo (DeltaFA=39.5+/-10.1% of control) compared with that induced by HC-030031 alone. In contrast, the suppressive effect was enhanced by a combination of HC-030031 and apyrase+ADA (DeltaFA=5.3+/-4.9% of control) or a combination of iso-PPADS and Indo (DeltaFA=23.3+/-7.7% of control) compared with that induced by HC-030031 alone or iso-PPADS alone. This afferent response was not altered by the vehicles for these drugs. These results suggest that activations of TRPA1 receptors by cyclooxygenase metabolites and P2X receptors by ATP are both necessary for the ROS-mediated stimulation of CSLVA fibers by CS in rats.
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Affiliation(s)
- You Shuei Lin
- Graduate Institute of Medical Sciences, Department of Physiology, School of Respiratory Therapy, College of Medicine, Taipei Medical University, and Neuroscience Research Center, Department of Respiratory Therapy, Taipei Medical University Hospital, Taipei, Taiwan
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21
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Hondoh A, Ishida Y, Ugawa S, Ueda T, Shibata Y, Yamada T, Shikano M, Murakami S, Shimada S. Distinct expression of cold receptors (TRPM8 and TRPA1) in the rat nodose-petrosal ganglion complex. Brain Res 2010; 1319:60-9. [PMID: 20079339 DOI: 10.1016/j.brainres.2010.01.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 01/06/2010] [Accepted: 01/06/2010] [Indexed: 01/06/2023]
Abstract
TRPM8 and TRPA1 are cold-activated transient receptor potential (TRP) cation channels. TRPM8 is activated by moderate cooling, while TRPA1 is activated by extreme, noxious cold temperatures. These cold receptors are expressed in different subpopulations of primary afferent neurons. TRPA1 is co-expressed in a subpopulation of somatosensory neurons expressing TRPV1, which is activated by heat. However, the distribution and co-expression of these channels in the nodose-petrosal ganglion complex, which contains the jugular (JG), petrosal (PG), and nodose ganglia (NG) (mainly involved in putative somatic, chemo- and somato-sensation, and somato and visceral sensation, respectively), remain unknown. Here, we conducted in situ hybridization analysis of the rat nodose-petrosal ganglion complex using specific riboprobes for TRPM8, TRPA1, and TRPV1 to compare the features of the cranial sensory ganglia. Hybridization signals for TRPA1 were diffusely observed throughout these ganglia, whereas TRPM8 transcripts were seen in the JG and PG but not in the NG. We retrogradely labeled cranial nerve X with Fast Blue (fluorescent dye) and found TRPM8 transcripts in the jugular-vagal ganglion but not the NG neurons. TRPA1 transcripts were not detected in TRPM8-expressing neurons but were present in the subpopulation of TRPV1-expressing visceral sensory neurons. Taken together, these findings support that in the vagal system the expression of cold-activated TRP channels differs between nodose- and jugular-ganglion neurons suggesting different mechanisms of cold-transduction and that the TRPA1 distribution is consistent with its proposed function as a cold-sensing receptor in the visceral system.
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Affiliation(s)
- Aki Hondoh
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Nagoya City University, Nagoya 467-8601, Japan.
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22
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Cough: The Emerging Role of the TRPA1 Channel. Lung 2009; 188 Suppl 1:S63-8. [PMID: 20091046 DOI: 10.1007/s00408-009-9201-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2009] [Accepted: 11/12/2009] [Indexed: 10/20/2022]
Abstract
Sneezing, cough, mucus secretion, and bronchoconstriction represent the main components of a coordinated and efficient reaction direct to expel or neutralize irritant agents from the respiratory system. A dense network of sensory nerves localized from the nose to the lower airways beneath the epithelium subserves this function. A variety of receptors and channels present in sensory nerve terminals by sensing irritant stimuli activate the system in emergence and initiate protective reflex responses, including cough. Previous and recent literature highlights the prominent role of some transient receptor potential (TRP) ion channels, and specifically the vanilloid 1 (TRPV1) and the ankyrin 1 (TRPA1) as sensors of airway irritation and initiators of the cough reflex.
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23
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Andrè E, Gatti R, Trevisani M, Preti D, Baraldi PG, Patacchini R, Geppetti P. Transient receptor potential ankyrin receptor 1 is a novel target for pro-tussive agents. Br J Pharmacol 2009; 158:1621-8. [PMID: 19845671 DOI: 10.1111/j.1476-5381.2009.00438.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The transient receptor potential ankyrin receptor 1 (TRPA1) is a cation channel, co-expressed with the pro-tussive transient receptor potential vanilloid type 1 (TRPV1) channel in primary sensory neurons. TRPA1 is activated by a series of irritant exogenous and endogenous alpha,beta-unsaturated aldehydes which seem to play a role in airway diseases. We investigated whether TRPA1 agonists provoke cough in guinea pigs and whether TRPA1 antagonists inhibit this response. EXPERIMENTAL APPROACH Animals were placed in a Perspex box, and cough sounds were recorded and counted by observers unaware of the treatment used. KEY RESULTS Inhalation of two selective TRPA1 agonists, allyl isothiocyanate and cinnamaldehyde, dose-dependently caused cough in control guinea pigs, but not in those with airway sensory nerves desensitized by capsaicin. Coughs elicited by TRPA1 agonists were reduced by non-selective (camphor and gentamicin) and selective (HC-030031) TRPA1 antagonists, whereas they were unaffected by the TRPV1 antagonist, capsazepine. Acrolein and crotonaldehyde, two alpha,beta-unsaturated aldehydes recently identified as TRPA1 stimulants and contained in cigarette smoke, air pollution or produced endogenously by oxidative stress, caused a remarkable tussive effect, a response that was selectively inhibited by HC-030031. Part of the cough response induced by cigarette smoke inhalation was inhibited by HC-030031, suggesting the involvement of TRPA1. CONCLUSIONS AND IMPLICATIONS A novel pro-tussive pathway involves the TRPA1 channel, expressed by capsaicin-sensitive airway sensory nerves and is activated by a series of exogenous (cigarette smoke) and endogenous irritants. These results suggest TRPA1 may be a novel target for anti-tussive medicines.
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Affiliation(s)
- E Andrè
- Centre of Excellence for the Study of Inflammation, University of Ferrara, Italy
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24
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Colsoul B, Nilius B, Vennekens R. On the putative role of transient receptor potential cation channels in asthma. Clin Exp Allergy 2009; 39:1456-66. [PMID: 19624522 DOI: 10.1111/j.1365-2222.2009.03315.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The mammalian transient receptor potential (TRP) superfamily consists of 28 mammalian TRP cation channels, which can be subdivided into six main subfamilies: the TRPC ('Canonical'), TRPV ('Vanilloid'), TRPM ('Melastatin'), TRPP ('Polycystin'), TRPML ('Mucolipin') and the TRPA ('Ankyrin') groups. Increasing evidence has accumulated during the previous few years that links TRP channels to the cause of several diseases or to critically influence and/or determine their progress. This review focuses on the possible role of TRP channels in the aetiology of asthmatic lung disease.
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Affiliation(s)
- B Colsoul
- Laboratory Ion Channel Research, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
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25
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Canning BJ. Central regulation of the cough reflex: therapeutic implications. Pulm Pharmacol Ther 2009; 22:75-81. [PMID: 19284972 DOI: 10.1016/j.pupt.2009.01.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2008] [Accepted: 01/08/2009] [Indexed: 01/12/2023]
Abstract
In many species including humans, antagonists of NMDA-type glutamate receptors such as dextromethorphan, when used at sufficient doses, have been found to be relatively safe and effective antitussives. Similarly, now in five different species (guinea pigs, rabbits, cats, dogs and pigs), neurokinin receptor antagonists have also proven to be safe and effective antitussive agents. Both of these classes of drugs act centrally to prevent cough. A brief review of what is known about the central encoding of cough is presented, as are the advantages of centrally acting antitussives. Also discussed are new insights into cough and NMDA receptor signaling that may lead to the development of more effective antitussive agents with limited side effects and broad application in treating cough associated with a variety of aetiologies.
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