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Flammer LJ, Ellis H, Rivers N, Caronia L, Ghidewon MY, Christensen CM, Jiang P, Breslin PAS, Tordoff MG. Topical application of a P2X2/P2X3 purine receptor inhibitor suppresses the bitter taste of medicines and other taste qualities. Br J Pharmacol 2024. [PMID: 38745397 DOI: 10.1111/bph.16411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 04/01/2024] [Accepted: 04/05/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND AND PURPOSE Many medications taste intensely bitter. The innate aversion to bitterness affects medical compliance, especially in children. There is a clear need to develop bitter blockers to suppress the bitterness of vital medications. Bitter taste is mediated by TAS2R receptors. Because different pharmaceutical compounds activate distinct sets of TAS2Rs, targeting specific receptors may only suppress bitterness for certain, but not all, bitter-tasting compounds. Alternative strategies are needed to identify universal bitter blockers that will improve the acceptance of every medication. Taste cells in the mouth transmit signals to afferent gustatory nerve fibres through the release of ATP, which activates the gustatory nerve-expressed purine receptors P2X2/P2X3. We hypothesized that blocking gustatory nerve transmission with P2X2/P2X3 inhibitors (e.g. 5-(5-iodo-4-methoxy-2-propan-2-ylphenoxy)pyrimidine-2,4-diamine [AF-353]) would reduce bitterness for all medications and bitter compounds. EXPERIMENTAL APPROACH Human sensory taste testing and mouse behavioural analyses were performed to determine if oral application of AF-353 blocks perception of bitter taste and other taste qualities but not non-gustatory oral sensations (e.g. tingle). KEY RESULTS Rinsing the mouth with AF-353 in humans or oral swabbing it in mice suppressed the bitter taste and avoidance behaviours of all compounds tested. We further showed that AF-353 suppressed other taste qualities (i.e. salt, sweet, sour and savoury) but had no effects on other oral or nasal sensations (e.g, astringency and oral tingle). CONCLUSION AND IMPLICATIONS This is the first time a universal, reversible taste blocker in humans has been reported. Topical application of P2X2/P2X3 inhibitor to suppress bitterness may improve medical compliance.
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Affiliation(s)
- Linda J Flammer
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Hillary Ellis
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Natasha Rivers
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Lauren Caronia
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Misgana Y Ghidewon
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Peihua Jiang
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
| | - Paul A S Breslin
- Monell Chemical Senses Center, Philadelphia, Pennsylvania, USA
- Department of Nutritional Sciences, Rutgers University, New Brunswick, New Jersey, USA
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Smith JA. The Therapeutic Landscape in Chronic Cough. Lung 2024; 202:5-16. [PMID: 38127133 PMCID: PMC10896934 DOI: 10.1007/s00408-023-00666-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 12/12/2023] [Indexed: 12/23/2023]
Abstract
In recent years, there has been a substantial increase in the development of antitussive therapies and the first new therapy, gefapixant has been licenced in Europe. This review describes current unlicenced treatments for chronic cough and details treatments currently in development for refractory chronic cough and cough in idiopathic pulmonary fibrosis, as well as compounds previously explored.
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Affiliation(s)
- Jaclyn A Smith
- Division of Immunology, Immunity to Infection and Respiratory Medicine, University of Manchester and Manchester Academic Health Science Centre, Wythenshawe Hospital, Southmoor Road, Manchester, M23 9LT, UK.
- Manchester University NHS Foundation Trust, Manchester, UK.
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Mishra S, Shelke V, Dagar N, Lech M, Gaikwad AB. Molecular insights into P2X signalling cascades in acute kidney injury. Purinergic Signal 2024:10.1007/s11302-024-09987-w. [PMID: 38246970 DOI: 10.1007/s11302-024-09987-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/18/2024] [Indexed: 01/23/2024] Open
Abstract
Acute kidney injury (AKI) is a critical health issue with high mortality and morbidity rates in hospitalized individuals. The complex pathophysiology and underlying health conditions further complicate AKI management. Growing evidence suggests the pivotal role of ion channels in AKI progression, through promoting tubular cell death and altering immune cell functions. Among these channels, P2X purinergic receptors emerge as key players in AKI pathophysiology. P2X receptors gated by adenosine triphosphate (ATP), exhibit increased extracellular levels of ATP during AKI episodes. More importantly, certain P2X receptor subtypes upon activation exacerbate the situation by promoting the release of extracellular ATP. While therapeutic investigations have primarily focused on P2X4 and P2X7 subtypes in the context of AKI, while understanding about other subtypes still remains limited. Whilst some P2X antagonists show promising results against different types of kidney diseases, their role in managing AKI remains unexplored. Henceforth, understanding the intricate interplay between P2X receptors and AKI is crucial for developing targeted interventions. This review elucidates the functional alterations of all P2X receptors during normal kidney function and AKI, offering insights into their involvement in AKI. Notably, we have highlighted the current knowledge of P2X receptor antagonists and the possibilities to use them against AKI in the future. Furthermore, the review delves into the pathways influenced by activated P2X receptors during AKI, presenting potential targets for future therapeutic interventions against this critical condition.
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Affiliation(s)
- Swati Mishra
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Pilani, Rajasthan, 333031, India
| | - Vishwadeep Shelke
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Pilani, Rajasthan, 333031, India
| | - Neha Dagar
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Pilani, Rajasthan, 333031, India
| | - Maciej Lech
- Division of Nephrology, Department of Medicine IV, LMU University Hospital, Ludwig Maximilians University Munich, 80336, Munich, Germany
| | - Anil Bhanudas Gaikwad
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani Campus, Pilani, Rajasthan, 333031, India.
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Clark G, Fitzgerald DA, Rubin BK. Cough medicines for children- time for a reality check. Paediatr Respir Rev 2023; 48:30-38. [PMID: 37718235 DOI: 10.1016/j.prrv.2023.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 08/15/2023] [Indexed: 09/19/2023]
Abstract
Cough medicines have been in use for over a century to treat the common and troublesome, but often helpful, symptoms of cough in children. They contain various combinations of "anti-tussive" drugs including opioids, antihistamines, herbal preparations, mucolytics, decongestants and expectorants. Whilst theoretically attractive for symptom relief when children are suffering, as time has passed these popular over the counter medicines have been shown to lack efficacy, delay more serious underlying diagnoses, and can cause complications and sometimes death. This has resulted in clinician concerns, a citizen petition to the American Food and Drug Association in 2007, some self-regulation from manufacturers and escalating restrictions on their use from regulatory agencies across the world over the last twenty years. This article will review the protective role of cough, juxtapose the conflicting treatment goals of suppressing a dry cough and promoting expectoration for a wet cough, consider the evidence basis for prescribing cough medicines in comparison to other more specific treatments such as for asthma [beta agonists] or infection [antibiotics], regulatory interventions, and conclude with the view that over counter cough medicines should not be used in children, especially young children.
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Affiliation(s)
- Gene Clark
- Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - Dominic A Fitzgerald
- Department of Respiratory Medicine, The Children's Hospital at Westmead, Sydney, NSW, Australia; Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, NSW, Australia
| | - Bruce K Rubin
- Virginia Commonwealth University School of Medicine, Richmond, VA, USA; The Children's Hospital of Richmond at VCU, Richmond, VA, USA.
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Zhang M, Morice AH. Unravelling vagal hypersensitivity in chronic cough: A distinct disease. J Physiol 2023. [PMID: 37642341 DOI: 10.1113/jp284641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/14/2023] [Indexed: 08/31/2023] Open
Abstract
Chronic cough (CC) is a common but poorly understood disease that has a negative impact on quality of life. For years, clinicians have been trying to find the underlying diagnosis and using existing disease models to describe the patients' illness. This presents a confusing picture of CC. Most patients with CC present with hypersensitivity of the cough reflex, which is characterised by laryngeal paraesthesia and an increased response to the tussive stimuli or an innocuous stimulus that would not trigger coughing in healthy people. Recently, it has been proposed that CC is a unique disease characterised by vagal hypersensitivity that projects to the central nervous system altering responsiveness. The evidence supports the hypothesis that CC is primarily a neurological disorder, consisting of different phenotypes.
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Affiliation(s)
- Mengru Zhang
- Department of Pulmonary and Critical Care Medicine, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Centre for Clinical Science, Respiratory Medicine, Hull York Medical School, University of Hull, Castle Hill Hospital, Cottingham, UK
| | - Alyn H Morice
- Centre for Clinical Science, Respiratory Medicine, Hull York Medical School, University of Hull, Castle Hill Hospital, Cottingham, UK
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Drake MG, McGarvey LP, Morice AH. From bench to bedside: The role of cough hypersensitivity in chronic cough. Clin Transl Med 2023; 13:e1343. [PMID: 37501282 PMCID: PMC10374883 DOI: 10.1002/ctm2.1343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 07/13/2023] [Accepted: 07/18/2023] [Indexed: 07/29/2023] Open
Abstract
BACKGROUND Chronic cough is a burdensome condition characterized by persistent cough lasting longer than 8 weeks. Chronic cough can significantly affect quality of life, physical function and productivity, with many people troubled with a cough that lasts for months or even years. People with chronic cough commonly report a persistent urge to cough with frequent bouts of coughing triggered by innocuous stimuli, which has led to the concept of cough hypersensitivity. MAIN BODY Both central and peripheral neural pathways regulate cough, and although mechanisms driving development of cough hypersensitivity are not fully known, sensitization of these neural pathways contributes to excessive cough triggering in cough hypersensitivity. Effective therapies that control chronic cough are currently lacking. Recent therapeutic development has focused on several ion channels and receptors involved in peripheral activation of cough (e.g., transient receptor potential channels, P2 × 3 receptors and voltage-gated sodium channels) or central cough processing (e.g., neurokinin-1 [NK-1] receptors and nicotinic acetylcholine receptors). CONCLUSION These targeted therapies provide novel insights into mechanisms underlying cough hypersensitivity and may offer new treatment options for people with chronic cough. In this review, we explore preclinical and clinical studies that have improved our understanding of the mechanisms responsible for chronic cough and discuss the most promising targeted approaches to date, including trials of P2 × 3-receptor antagonists and NK-1-receptor antagonists.
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Affiliation(s)
- Matthew G. Drake
- Division of Pulmonary and Critical Care Medicine, Department of MedicineOregon Health and Science UniversityPortlandOregonUSA
| | - Lorcan P. McGarvey
- Wellcome‐Wolfson Institute for Experimental Medicine, School of MedicineDentistry & Biomedical Science, Queen's University BelfastBelfastUnited Kingdom of Great Britain and Northern Ireland
| | - Alyn H. Morice
- Respiratory Research GroupHull York Medical SchoolUniversity of HullCottinghamUK
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