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Szallasi A. Resiniferatoxin: Nature's Precision Medicine to Silence TRPV1-Positive Afferents. Int J Mol Sci 2023; 24:15042. [PMID: 37894723 PMCID: PMC10606200 DOI: 10.3390/ijms242015042] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 09/27/2023] [Accepted: 10/07/2023] [Indexed: 10/29/2023] Open
Abstract
Resiniferatoxin (RTX) is an ultrapotent capsaicin analog with a unique spectrum of pharmacological actions. The therapeutic window of RTX is broad, allowing for the full desensitization of pain perception and neurogenic inflammation without causing unacceptable side effects. Intravesical RTX was shown to restore continence in a subset of patients with idiopathic and neurogenic detrusor overactivity. RTX can also ablate sensory neurons as a "molecular scalpel" to achieve permanent analgesia. This targeted (intrathecal or epidural) RTX therapy holds great promise in cancer pain management. Intra-articular RTX is undergoing clinical trials to treat moderate-to-severe knee pain in patients with osteoarthritis. Similar targeted approaches may be useful in the management of post-operative pain or pain associated with severe burn injuries. The current state of this field is reviewed, from preclinical studies through veterinary medicine to clinical trials.
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Affiliation(s)
- Arpad Szallasi
- Department of Pathology and Experimental Cancer Research, Semmelweis University, 1083 Budapest, Hungary
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Rinwa P, Calvo-Enrique L, Zhang MD, Nyengaard JR, Karlsson P, Ernfors P. Demise of nociceptive Schwann cells causes nerve retraction and pain hyperalgesia. Pain 2021; 162:1816-1827. [PMID: 33979318 PMCID: PMC8120683 DOI: 10.1097/j.pain.0000000000002169] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/11/2020] [Accepted: 11/18/2020] [Indexed: 12/14/2022]
Abstract
ABSTRACT Recent findings indicate that nociceptive nerves are not "free", but similar to touch and pressure sensitive nerves, terminate in an end-organ in mice. This sensory structure consists of the nociceptive nerves and specialized nociceptive Schwann cells forming a mesh-like organ in subepidermis with pain transduction initiated at both these cellular constituents. The intimate relation of nociceptive nerves with nociceptive Schwann cells in mice raises the question whether defects in nociceptive Schwann cells can by itself contribute to pain hyperalgesia, nerve retraction, and peripheral neuropathy. We therefore examined the existence of nociceptive Schwann cells in human skin and their possible contribution to neuropathy and pain hyperalgesia in mouse models. Similar to mouse, human skin contains SOX10+/S100B+/AQP1+ Schwann cells in the subepidermal border that have extensive processes, which are intimately associated with nociceptive nerves projecting into epidermis. The ablation of nociceptive Schwann cells in mice resulted in nerve retraction and mechanical, cold, and heat hyperalgesia. Conversely, ablating the nociceptive nerves led to a retraction of epidermal Schwann cell processes, changes in nociceptive Schwann cell soma morphology, heat analgesia, and mechanical hyperalgesia. Our results provide evidence for a nociceptive sensory end-organ in the human skin and using animal models highlight the interdependence of the nerve and the nociceptive Schwann cell. Finally, we show that demise of nociceptive Schwann cells is sufficient to cause neuropathic-like pain in the mouse.
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Affiliation(s)
- Puneet Rinwa
- Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Laura Calvo-Enrique
- Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Ming-Dong Zhang
- Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, Stockholm, Sweden
| | - Jens Randel Nyengaard
- Department of Clinical Medicine—Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University, Aarhus, Denmark
- Centre for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, Aarhus, Denmark
| | - Páll Karlsson
- Department of Clinical Medicine—Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Aarhus University, Aarhus, Denmark
- Danish Pain Research Center, Aarhus University, Aarhus, Denmark
| | - Patrik Ernfors
- Department of Medical Biochemistry and Biophysics, Division of Molecular Neurobiology, Karolinska Institutet, Stockholm, Sweden
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3
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Exploring Nonopioid Analgesic Agents for Intrathecal Use. Neuromodulation 2018. [DOI: 10.1016/b978-0-12-805353-9.00068-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Pecze L, Viskolcz B, Oláh Z. Molecular Surgery Concept from Bench to Bedside: A Focus on TRPV1+ Pain-Sensing Neurons. Front Physiol 2017. [PMID: 28626428 PMCID: PMC5455100 DOI: 10.3389/fphys.2017.00378] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
"Molecular neurosurgery" is emerging as a new medical concept, and is the combination of two partners: (i) a molecular neurosurgery agent, and (ii) the cognate receptor whose activation results in the selective elimination of a specific subset of neurons in which this receptor is endogenously expressed. In general, a molecular surgery agent is a selective and potent ligand, and the target is a specific cell type whose elimination is desired through the molecular surgery procedure. These target cells have the highest innate sensitivity to the molecular surgery agent usually due to the highest receptor density being in their plasma membrane. The interaction between the ligand and its receptor evokes an overactivity of the receptor. If the receptor is a ligand-activated non-selective cation channel, the overactivity of receptor leads to excess Ca2+ and Na+ influx into the cell and finally cell death. One of the best known examples of such an interaction is the effect of ultrapotent vanilloids on TRPV1-expressing pain-sensing neurons. One intrathecal resiniferatoxin (RTX) dose allows for the receptor-mediated removal of TRPV1+ neurons from the peripheral nervous system. The TRPV1 receptor-mediated ion influx induces necrotic processes, but only in pain-sensing neurons, and usually within an hour. Besides that, target-specific apoptotic processes are also induced. Thus, as a nano-surgery scalpel, RTX removes the neurons responsible for generating pain and inflammation from the peripheral nervous system providing an option in clinical management for the treatment of morphine-insensitive pain conditions. In the future, the molecular surgery concept can also be exploited in cancer research for selectively targeting the specific tumor cell.
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Affiliation(s)
- László Pecze
- Unit of Anatomy, Department of Medicine, University of FribourgFribourg, Switzerland
| | - Béla Viskolcz
- Institute of Chemistry, Faculty of Materials Science and Engineering, University of MiskolcMiskolc, Hungary
| | - Zoltán Oláh
- Institute of Chemistry, Faculty of Materials Science and Engineering, University of MiskolcMiskolc, Hungary.,Acheuron Ltd.Szeged, Hungary
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Chung MK, Campbell JN. Use of Capsaicin to Treat Pain: Mechanistic and Therapeutic Considerations. Pharmaceuticals (Basel) 2016; 9:ph9040066. [PMID: 27809268 PMCID: PMC5198041 DOI: 10.3390/ph9040066] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/25/2016] [Accepted: 10/27/2016] [Indexed: 12/31/2022] Open
Abstract
Capsaicin is the pungent ingredient of chili peppers and is approved as a topical treatment of neuropathic pain. The analgesia lasts for several months after a single treatment. Capsaicin selectively activates TRPV1, a Ca2+-permeable cationic ion channel that is enriched in the terminals of certain nociceptors. Activation is followed by a prolonged decreased response to noxious stimuli. Interest also exists in the use of injectable capsaicin as a treatment for focal pain conditions, such as arthritis and other musculoskeletal conditions. Recently injection of capsaicin showed therapeutic efficacy in patients with Morton’s neuroma, a painful foot condition associated with compression of one of the digital nerves. The relief of pain was associated with no change in tactile sensibility. Though injection evokes short term pain, the brief systemic exposure and potential to establish long term analgesia without other sensory changes creates an attractive clinical profile. Short-term and long-term effects arise from both functional and structural changes in nociceptive terminals. In this review, we discuss how local administration of capsaicin may induce ablation of nociceptive terminals and the clinical implications.
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Affiliation(s)
- Man-Kyo Chung
- Department of Neural and Pain Sciences, University of Maryland, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, Baltimore, MD 21201, USA.
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Fattori V, Hohmann MSN, Rossaneis AC, Pinho-Ribeiro FA, Verri WA. Capsaicin: Current Understanding of Its Mechanisms and Therapy of Pain and Other Pre-Clinical and Clinical Uses. Molecules 2016; 21:E844. [PMID: 27367653 PMCID: PMC6273101 DOI: 10.3390/molecules21070844] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 04/27/2016] [Indexed: 02/06/2023] Open
Abstract
In this review, we discuss the importance of capsaicin to the current understanding of neuronal modulation of pain and explore the mechanisms of capsaicin-induced pain. We will focus on the analgesic effects of capsaicin and its clinical applicability in treating pain. Furthermore, we will draw attention to the rationale for other clinical therapeutic uses and implications of capsaicin in diseases such as obesity, diabetes, cardiovascular conditions, cancer, airway diseases, itch, gastric, and urological disorders.
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Affiliation(s)
- Victor Fattori
- Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid KM480 PR445, Caixa Postal 10.011, 86057-970 Londrina, Paraná, Brazil.
| | - Miriam S N Hohmann
- Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid KM480 PR445, Caixa Postal 10.011, 86057-970 Londrina, Paraná, Brazil.
| | - Ana C Rossaneis
- Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid KM480 PR445, Caixa Postal 10.011, 86057-970 Londrina, Paraná, Brazil.
| | - Felipe A Pinho-Ribeiro
- Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid KM480 PR445, Caixa Postal 10.011, 86057-970 Londrina, Paraná, Brazil.
| | - Waldiceu A Verri
- Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid KM480 PR445, Caixa Postal 10.011, 86057-970 Londrina, Paraná, Brazil.
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7
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Abstract
Objectives:Resiniferatoxin, the most potent agonist of inflammatory pain/vanilloid receptor/cation channel (TRPV1) can be used for neuron subtype specific ablation of pain generating cells at the level of the peripheral nervous system by Ca2+-excytotoxicity. Molecular neurosurgery is an emerging technology either to alleviate severe pain in cancer or treat/prevent different local neuropathies. Our aim was determining sensory modalities that may be lost after resiniferatoxin treatment.Methods:Newborn or adult mice were treated with resiniferatoxin, then changes in chemical and heat sensitivity were correlated with alterations of the cell composition of sensory ganglions.Results:Only mice treated at adult age became less sensitive to heat stimuli, while both treatment groups lost sensitivity to specific vanilloid agonists of TRPV1 and, interestingly, to allyl-isothiocyanate, a selective agonist of TRPA1. Our in vivo and post mortem analytical results confirmed that TRPV1 and TRPA1 function together and resiniferatoxin-mediated neurosurgery removes both sensor moleculesDiscussion:In adult mice resiniferatoxin causes: i) desensitization to heat and ii) sensitization to cold. Cold hyperalgesia, an imbalance in thermosensation, might be conferred by a prominent cold receptor that is expressed in surviving resiniferatoxin-resistant sensory neurons and compensates for pain signals lost with TRPA1 and TRPV1 double positive cells in the peripheral nervous system.
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Intrathecal drug delivery for chronic pain management-scope, limitations and future. J Clin Monit Comput 2014; 29:241-9. [DOI: 10.1007/s10877-014-9607-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
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Abstract
The global burden of cancer pain is enormous and opioids, despite their side effects, remain the primary therapeutic approach. The cause of cancer pain is unknown. Mechanisms driving cancer pain differ from those mechanisms responsible for inflammatory and neuropathic pain. The prevailing hypothesis put forward to explain cancer pain posits that cancers generate and secrete mediators which sensitize and activate primary afferent nociceptors in the cancer microenvironment. Moreover, cancers induce neurochemical reorganization of the spinal cord, which contributes to spontaneous activity and enhanced responsiveness. The purpose of this review, which covers clinical and preclinical studies, is to highlight those peripheral and central mechanisms responsible for cancer pain. The challenges facing neuroscientists and clinicians studying and ultimately treating cancer pain are discussed.
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Affiliation(s)
- Brian L Schmidt
- Department of Oral Maxillofacial Surgery, New York University College of Dentistry, New York, NY, USA Department of Neuroscience & Physiology, New York University School of Medicine, New York, NY, USA Bluestone Center for Clinical Research, New York University, NY, USA
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Resiniferatoxin (RTX) causes a uniquely protracted musculoskeletal hyperalgesia in mice by activation of TRPV1 receptors. THE JOURNAL OF PAIN 2013; 14:1629-41. [PMID: 24188863 DOI: 10.1016/j.jpain.2013.07.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/26/2013] [Accepted: 07/30/2013] [Indexed: 11/20/2022]
Abstract
UNLABELLED Inactivation of transient receptor potential vanilloid-1 (TRPV1) receptors is one approach to analgesic drug development. However, TRPV1 receptors exert different effects on each modality of pain. Because muscle pain is clinically important, we compared the effect of TRPV1 ligands on musculoskeletal nociception to that on thermal and tactile nociception. Injected parenterally, capsaicin had no effect on von Frey fiber responses (tactile) but induced a transient hypothermia and hyperalgesia in both the tail flick (thermal) and grip force (musculoskeletal) assays, presumably by its agonistic action at TRPV1 sites. In contrast, resiniferatoxin (RTX) produced a chronic (>58 days) thermal antinociception, consistent with its reported ability to desensitize TRPV1 sites. In the same mice, RTX produced a transient hypothermia (7 hours) and a protracted (28-day) musculoskeletal hyperalgesia in spite of a 35.5% reduction in TRPV1 receptor immunoreactivity in muscle afferents. Once musculoskeletal hyperalgesia subsided, mice were tolerant to the hyperalgesic effects of either capsaicin or RTX whereas tolerance to hypothermia did not develop until after 3 injections. Musculoskeletal hyperalgesia was prevented but not reversed by SB-366791, a TRPV1 antagonist, indicating that TRPV1 receptors initiate but do not maintain hyperalgesia. Injected intrathecally, RTX produced only a brief musculoskeletal hyperalgesia (2 days), after which mice were tolerant to this effect. PERSPECTIVE The effect of TRPV1 receptors varies depending on modality and tissue type, such that RTX causes thermal antinociception, musculoskeletal hyperalgesia, and no effect on tactile nociception in healthy mice. Spinal TRPV1 receptors are a potential target for pain relief as they induce only a short musculoskeletal hyperalgesia followed by desensitization.
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Bishnoi M, Bosgraaf CA, Premkumar LS. Preservation of acute pain and efferent functions following intrathecal resiniferatoxin-induced analgesia in rats. THE JOURNAL OF PAIN 2011; 12:991-1003. [PMID: 21680254 DOI: 10.1016/j.jpain.2011.03.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 01/25/2011] [Accepted: 03/16/2011] [Indexed: 01/29/2023]
Abstract
UNLABELLED Resiniferatoxin (RTX) is a potent agonist of TRPV1, which possesses unique properties that can be utilized to treat certain modalities of pain. In the present study, systemic intraperitoneal (i.p.) administration of RTX resulted in a significant decrease in acute thermal pain sensitivity, whereas localized intrathecal (i.t.) administration had no effect on acute thermal pain sensitivity. Both i.p. and i.t. administration of RTX prevented TRPV1-induced nocifensive behavior and inflammatory thermal hypersensitivity. There were no alterations in mechanical sensitivity either by i.p. or i.t. administration of RTX. In spinal dorsal horn (L4-L6), TRPV1 and substance P immunoreactivity were abolished following i.p. and i.t. administration of RTX. In dorsal root ganglia (DRG), TRPV1 immunoreactivity was diminished following i.p. administration, but was unaffected following i.t. administration of RTX. Following i.p. administration, basal and evoked calcitonin gene-related peptide release were reduced both in the spinal cord and peripheral tissues. However, following i.t. administration, basal and evoked calcitonin gene-related peptide release were reduced in spinal cord (L4-L6), but were unaffected in peripheral tissues. Both i.p. and i.t. RTX administration lowered the body temperature acutely, but this effect reversed with time. Targeting TRPV1-expressing nerve terminals at the spinal cord can selectively abolish inflammatory thermal hypersensitivity without affecting acute thermal sensitivity and can preserve the efferent functions of DRG neurons at the peripheral nerve terminals. I.t. administration of RTX can be considered as a strategy for treating certain chronic and debilitating pain conditions. PERSPECTIVE Localized administration of RTX in spinal cord could be a useful strategy to treat chronic debilitating pain arising from certain conditions such as cancer and at the same time could maintain normal physiological peripheral efferent functions mediated by TRPV1.
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Affiliation(s)
- Mahendra Bishnoi
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois 62702, USA
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Lawson EF, Wallace MS. Current developments in intraspinal agents for cancer and noncancer pain. Curr Pain Headache Rep 2010; 14:8-16. [PMID: 20425209 PMCID: PMC2826634 DOI: 10.1007/s11916-009-0092-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Since the late 1980s, intrathecal (IT) analgesic therapy has improved, and implantable IT drug delivery devices have become increasingly sophisticated. Physicians and patients now have myriad more options for agents and their combination, as well as for refining their delivery. As recently as 2007, The Polyanalgesic Consensus Conference of expert panelists updated its algorithm for drug selection in IT polyanalgesia. We review this algorithm and the emerging therapy included. This article provides an update on newly approved as well as emerging IT agents and the advances in technology for their delivery.
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Affiliation(s)
- Erin F Lawson
- Division of Pain Medicine, Department of Anesthesiology, University of California, San Diego, La Jolla, CA 92037, USA.
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Premkumar LS, Sikand P. TRPV1: a target for next generation analgesics. Curr Neuropharmacol 2010; 6:151-63. [PMID: 19305794 PMCID: PMC2647151 DOI: 10.2174/157015908784533888] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 10/17/2007] [Accepted: 11/11/2007] [Indexed: 12/11/2022] Open
Abstract
Transient Receptor Potential Vanilloid 1 (TRPV1) is a Ca2+ permeant non-selective cation channel expressed in a subpopulation of primary afferent neurons. TRPV1 is activated by physical and chemical stimuli. It is critical for the detection of nociceptive and thermal inflammatory pain as revealed by the deletion of the TRPV1 gene. TRPV1 is distributed in the peripheral and central terminals of the sensory neurons and plays a role in initiating action potentials at the nerve terminals and modulating neurotransmitter release at the first sensory synapse, respectively. Distribution of TRPV1 in the nerve terminals innervating blood vessels and in parts of the CNS that are not subjected to temperature range that is required to activate TRPV1 suggests a role beyond a noxious thermal sensor. Presently, TRPV1 is being considered as a target for analgesics through evaluation of different antagonists. Here, we will discuss the distribution and the functions of TRPV1, potential use of its agonists and antagonists as analgesics and highlight the functions that are not related to nociceptive transmission that might lead to adverse effects.
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Affiliation(s)
- Louis S Premkumar
- Department of Pharmacology, Southern Illinois University School of Medicine Springfield, IL 62702, USA.
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Fujiuchi A, Toga T. Pharmacological effect of capsaicin on rat avoidance behaviours elicited by sine-wave electrical stimulation of different frequencies by Neurometer. J Pharm Pharmacol 2010; 60:467-71. [DOI: 10.1211/jpp.60.4.0009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Abstract
The Neurometer is a diagnostic device for measuring the perception and threshold of transcutaneous stimulation. It has been used in patients to selectively activate Aβ-, Aδ- and C-fibres in the primary afferents at different stimulus frequencies (2000, 250 and 5 Hz, respectively). In this study, we investigated use of the Neurometer to selectively activate nerves in conscious rats. The behavioural endpoint of paw withdrawal was used to measure the current threshold (CT). This behaviour was elicited by a lower stimulus current than other behaviours evoked by Neurometer stimulation and caused only mild stress in rats. Repeated topical application of capsaicin (four doses of 100 μg) or systemic administration of the capsaicin analogue resiniferatoxin (30 or 300 μg kg−1) increased the CT value for this behaviour at 5 Hz stimulation but not at 2000 Hz or 250 Hz. This change in CT at 5 Hz is probably due to C-fibre desensitization by the pharmacological treatments. The combination of 5 Hz sine-wave stimulation with a Neurometer and the observation of paw withdrawal behaviour make it possible to perform preclinical studies of C-fibres in animals as an alternative to the use of high- and low-rate heating of the paw.
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Affiliation(s)
- Akiyoshi Fujiuchi
- Discovery Biology Research, Nagoya Laboratories, Pfizer Global Research and Development, Pfizer Japan Inc., 5-2 Taketoyo, Aichi, 470-2393, Japan
| | - Tetsuo Toga
- Discovery Biology Research, Nagoya Laboratories, Pfizer Global Research and Development, Pfizer Japan Inc., 5-2 Taketoyo, Aichi, 470-2393, Japan
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15
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Jeffry JA, Yu SQ, Sikand P, Parihar A, Evans MS, Premkumar LS. Selective targeting of TRPV1 expressing sensory nerve terminals in the spinal cord for long lasting analgesia. PLoS One 2009; 4:e7021. [PMID: 19753113 PMCID: PMC2737142 DOI: 10.1371/journal.pone.0007021] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 08/10/2009] [Indexed: 11/18/2022] Open
Abstract
Chronic pain is a major clinical problem and opiates are often the only treatment, but they cause significant problems ranging from sedation to deadly respiratory depression. Resiniferatoxin (RTX), a potent agonist of Transient Receptor Potential Vanilloid 1 (TRPV1), causes a slow, sustained and irreversible activation of TRPV1 and increases the frequency of spontaneous excitatory postsynaptic currents, but causes significant depression of evoked EPSCs due to nerve terminal depolarization block. Intrathecal administration of RTX to rats in the short-term inhibits nociceptive synaptic transmission, and in the long-term causes a localized, selective ablation of TRPV1-expressing central sensory nerve terminals leading to long lasting analgesia in behavioral models. Since RTX actions are selective for central sensory nerve terminals, other efferent functions of dorsal root ganglion neurons can be preserved. Preventing nociceptive transmission at the level of the spinal cord can be a useful strategy to treat chronic, debilitating and intractable pain.
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Affiliation(s)
- Joseph A. Jeffry
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Shuang-Quan Yu
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Parul Sikand
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Arti Parihar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - M. Steven Evans
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
| | - Louis S. Premkumar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, United States of America
- * E-mail:
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16
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Intrathecal delivery of resiniferatoxin (RTX) reduces detrusor overactivity and spinal expression of TRPV1 in spinal cord injured animals. Exp Neurol 2008; 214:301-8. [DOI: 10.1016/j.expneurol.2008.08.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Revised: 08/20/2008] [Accepted: 08/22/2008] [Indexed: 12/29/2022]
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Neubert JK, Mannes AJ, Karai LJ, Jenkins AC, Zawatski L, Abu-Asab M, Iadarola MJ. Perineural resiniferatoxin selectively inhibits inflammatory hyperalgesia. Mol Pain 2008; 4:3. [PMID: 18199335 PMCID: PMC2242785 DOI: 10.1186/1744-8069-4-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Accepted: 01/16/2008] [Indexed: 11/26/2022] Open
Abstract
Resiniferatoxin (RTX) is an ultrapotent capsaicin analog that binds to the transient receptor potential channel, vanilloid subfamily member 1 (TRPV1). There is a large body of evidence supporting a role for TRPV1 in noxious-mediated and inflammatory hyperalgesic responses. In this study, we evaluated low, graded, doses of perineural RTX as a method for regional pain control. We hypothesized that this approach can provide long-term, but reversible, blockade of a portion of nociceptive afferent fibers within peripheral nerves when given at a site remote from the neuronal perikarya in the dorsal root ganglia. Following perineural RTX application to the sciatic nerve, we demonstrated a significant inhibition of inflammatory nociception that was dose- and time-dependent. At the same time, treated animals maintained normal proprioceptive sensations and motor control, and other nociceptive responses were largely unaffected. Using a range of mechanical and thermal algesic tests, we found that the most sensitive measure following perineural RTX administration was inhibition of inflammatory hyperalgesia. Recovery studies showed that physiologic sensory function could return as early as two weeks post-RTX treatment, however, immunohistochemical examination of the DRG revealed a partial, but significant reduction in the number of the TRPV1-positive neurons. We propose that this method could represent a beneficial treatment for a range of chronic pain problems, including neuropathic and inflammatory pain not responding to other therapies.
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Affiliation(s)
- John K Neubert
- College of Dentistry Department of Orthodontics, University of Florida, Gainesville, FL, USA.
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Raisinghani M, Pabbidi RM, Premkumar LS. Activation of transient receptor potential vanilloid 1 (TRPV1) by resiniferatoxin. J Physiol 2005; 567:771-86. [PMID: 16037081 PMCID: PMC1474234 DOI: 10.1113/jphysiol.2005.087874] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is a Ca(2+) permeable non-selective cation channel activated by physical and chemical stimuli. Resiniferatoxin (RTX), an ultrapotent agonist of TRPV1, is under investigation for treatment of urinary bladder hyper-reflexia and chronic pain conditions. Here, we have determined the characteristics of RTX-induced responses in cells expressing native and cloned rat TRPV1. Whole-cell currents increase with repeated application of submaximal concentrations of RTX until a maximal response is attained and do not deactivate even after prolonged washout. Interestingly, the rate of activation and block by capsazepine of RTX-induced currents are significantly slower than for capsaicin-induced currents. RTX-induced whole-cell currents are outwardly rectifying, but to a lesser extent than capsaicin-induced currents. RTX-induced single channel currents exhibit multiple conductance states and outward rectification. The open probability (P(o)) of RTX-induced currents is higher at all potentials as compared to capsaicin-induced currents, which showed a strong voltage-dependent decrease at negative potentials. Single-channel kinetic analyses reveal that open-time distribution of RTX-induced currents can be fitted with three exponential components at negative and positive potentials. The areas of distribution of the longer open time constants are significantly larger than capsaicin-induced currents. The closed-time distribution of RTX-induced currents can be fitted with three exponential components as compared to capsaicin-induced currents, which require four exponential components. Current-clamp experiments reveal that low concentrations of RTX caused a slow and sustained depolarization beyond threshold while generating few action potentials. Concentrations of capsaicin required for the same extent of depolarization generated a significantly greater number of action potentials. These properties of RTX may play a role in its clinical usefulness.
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Affiliation(s)
- Manish Raisinghani
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, 62702, USA
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Nagy I, Sántha P, Jancsó G, Urbán L. The role of the vanilloid (capsaicin) receptor (TRPV1) in physiology and pathology. Eur J Pharmacol 2005; 500:351-69. [PMID: 15464045 DOI: 10.1016/j.ejphar.2004.07.037] [Citation(s) in RCA: 198] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2004] [Indexed: 02/06/2023]
Abstract
The cloning of the vanilloid receptor 1 opened a floodgate for discoveries regarding the function of this complex molecule. It has been found that, in addition to heat, protons and vanilloids, this receptor also responds to various endogenous ligands. Furthermore, it has been also emerged that, through associations with other molecules, the vanilloid receptor 1 plays an important role in the integration of various stimuli and modulation of cellular excitability. Although, originally, the vanilloid receptor 1 was associated with nociceptive primary afferent fibres, it has been gradually revealed that it is broadly expressed in the brain, epidermis and visceral cells. The expression pattern of the vanilloid receptor 1 indicates that it could be involved in various physiological functions and in the pathomechanisms of diverse diseases. Here, we summarise the molecular, pharmacological and physiological characteristics, and putative functions, of the vanilloid receptor 1, and discuss the therapeutic potential of this molecule.
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Affiliation(s)
- István Nagy
- Department of Anaesthetics and Intensive Care, Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, United Kingdom.
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Borsook D, Edwards AD. Antineuropathic Effects of the Antibiotic Derivative Spicamycin KRN5500. PAIN MEDICINE 2004; 5:104-8. [PMID: 14996243 DOI: 10.1111/j.1526-4637.2004.04004.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Excellence in neuropathic pain management continues to challenge the ability of health care providers. Current medications are helpful but often create significant side effects or simply fail to provide adequate analgesia. We report here on a serendipitous finding of the successful attenuation of neuropathic pain in a patient with long-standing monoclonal gammopathy, Raynaud's disease, and neuropathic pain who received the trial chemotherapeutic agent KRN5500. This finding led to animal studies that have provided support for the possible use of KRN5500 in the treatment of neuropathic pain in humans as well as some insight into the possible mechanism(s) of action of this drug.
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Affiliation(s)
- David Borsook
- Center for Functional Pain Neuroimaging and Therapy Research, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
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Caudle RM, Karai L, Mena N, Cooper BY, Mannes AJ, Perez FM, Iadarola MJ, Olah Z. Resiniferatoxin-induced loss of plasma membrane in vanilloid receptor expressing cells. Neurotoxicology 2004; 24:895-908. [PMID: 14637384 DOI: 10.1016/s0161-813x(03)00146-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Resiniferatoxin (RTX), a potent analog of capsaicin, was evaluated electrophysiologically in dorsal root ganglion (DRG) cells and cell lines ectopically expressing the vanilloid receptor type 1 (VR1) to determine if cell phenotype influenced RTXs neurotoxic properties. Furthermore, capsaicin and heat activation of VR1 were evaluated in these cells to determine if cellular damage was unique to RTX activation of the receptors. RTX application to DRG cells identified as type 1, 2 or 5, cell types known to express VR1, induced large inward currents. RTX did not induce currents in DRG cells that do not express the receptor (type 4 cells). In cell lines ectopically expressing VR1, RTX-induced similar currents. RTX produced no effect in non-transfected cells. After exposure to RTX both DRG cells and transfected cells failed to respond to subsequent applications of the agonist. In addition, whole cell capacitance was reduced up to 70%. The decrease in capacitance was associated with the loss of plasma membrane, as determined by confocal microscopy. Cell phenotype, other than VR1 expression, did not influence the response to RTX. Interestingly, capsaicin and heat activation of vanilloid receptors also decreased cell capacitance, but the loss of membrane was not as great as with RTX and responses to these stimuli were not lost after the initial exposure. The loss of cell membrane required elevated intracellular levels of Ca2+. From these data it was concluded that the loss of cell membrane was dependent on the presence of both VR1 and intracellular Ca2+ accumulation, but not on cell phenotype.
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Affiliation(s)
- Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry and the University of Florida McKnight Brain Institute, 1600 Archer Road, P.O. Box 100416, Gainesville, FL 32610, USA.
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Abstract
Selective blockade of nociceptive pathways represents a mechanism-based approach that has attracted a large variety of pharmacological and molecular investigations. A potential site for selective intervention is the primary afferent nociceptive nerve terminal. Binding of resiniferatoxin (RTX) to the vanilloid-1 receptor (VR1) stimulates and then inactivates heat and vanilloid-responsive nerve endings involved in heat and inflammatory pain signaling which can progress to localized degeneration of the peripheral ending followed by regeneration. Application of RTX directly to peripheral nerve endings produces a long term, reversible attenuation of nociceptive transmission. Heat hyperalgesia and mechanical allodynia were assessed prior to injection of RTX into the hindpaw (baseline) and at acute (minutes-hours) and more chronic (days-weeks) times after injection. Acutely, an inverse dose-to-pain response (guarding, licking) for RTX (0.0625-2.0 microg) occurs, followed by selective attenuation of peripheral pain transmission. Thermal nociception was decreased in a concentration-dependent fashion and lasted up to 21 days, without impairing motor function. Administration of RTX blocked both inflammation-induced hyperalgesia and spinal c-Fos induction. The results demonstrate the efficacy and therapeutic potential of reversible, peripheral C-fiber 'inactivation' for intermediate duration pain control.
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Affiliation(s)
- John K Neubert
- Pain and Neurosensory Mechanisms Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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Szabo T, Biro T, Gonzalez AF, Palkovits M, Blumberg PM. Pharmacological characterization of vanilloid receptor located in the brain. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2002; 98:51-7. [PMID: 11834295 DOI: 10.1016/s0169-328x(01)00313-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Specific [3H]resiniferatoxin (RTX) binding detects the vanilloid receptor type I (VR1). In the present study we demonstrate specific, high-affinity, saturable [3H]RTX binding in various areas of monkey brain not known to be innervated by primary afferent neurons as well as in spinal cord and dorsal root ganglion neurons of the same origin. Detailed pharmacological characterization and comparison revealed no major difference in binding affinities between the peripheral and the central sites as measured by K(d)/K(i) values. In general, lower receptor density was measured in selected brain areas than in the periphery. Areas with higher receptor density were detected in the locus ceruleus, preoptic area, and medial basal hypothalamus of the brain. Both capsaicin and the competitive antagonist capsazepine inhibited the specific binding of [3H]RTX to membrane preparations of the dorsal horn of the spinal cord and dorsal root ganglia with K(i) values of 4.3+/-0.32 microM and 2.7+/-0.33 microM, respectively. Inhibition was observed in the central areas (hypothalamus) with K(i) values of 0.95+/-0.1 microM for capsaicin and 0.86+/-0.11 microM for capsazepine. Previous biological and pharmacological evidence suggested that vanilloid receptors were present in the brain. Our results demonstrate that the pharmacological properties of both the peripheral and central receptor sites display appropriate pharmacological similarity to represent the same receptor class. The modest differences in ligand affinities for the vanilloid receptor expressed in the brain nuclei and the dorsal root ganglion neurons may correspond to differences in sequence, modification or associated proteins.
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Affiliation(s)
- Tamas Szabo
- Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institute of Mental Health, Bldg. 37, Room 3A01, 37 Convent Drive, MSC 4255, Bethesda, MD 20892, USA
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Olah Z, Szabo T, Karai L, Hough C, Fields RD, Caudle RM, Blumberg PM, Iadarola MJ. Ligand-induced dynamic membrane changes and cell deletion conferred by vanilloid receptor 1. J Biol Chem 2001; 276:11021-30. [PMID: 11124944 DOI: 10.1074/jbc.m008392200] [Citation(s) in RCA: 188] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The real time dynamics of vanilloid-induced cytotoxicity and the specific deletion of nociceptive neurons expressing the wild-type vanilloid receptor (VR1) were investigated. VR1 was C-terminally tagged with either the 27-kDa enhanced green fluorescent protein (eGFP) or a 12-amino acid epsilon-epitope. Upon exposure to resiniferatoxin, VR1eGFP- or VR1epsilon-expressing cells exhibited pharmacological responses similar to those of cells expressing the untagged VR1. Within seconds of vanilloid exposure, the intracellular free calcium ([Ca(2+)](i)) was elevated in cells expressing VR1. A functional pool of VR1 also was localized to the endoplasmic reticulum that, in the absence of extracellular calcium, also was capable of releasing calcium upon agonist treatment. Confocal imaging disclosed that resiniferatoxin treatment induced vesiculation of the mitochondria and the endoplasmic reticulum ( approximately 1 min), nuclear membrane disruption (5-10 min), and cell lysis (1-2 h). Nociceptive primary sensory neurons endogenously express VR1, and resiniferatoxin treatment induced a sudden increase in [Ca(2+)](i) and mitochondrial disruption which was cell-selective, as glia and non-VR1-expressing neurons were unaffected. Early hallmarks of cytotoxicity were followed by specific deletion of VR1-expressing cells. These data demonstrate that vanilloids disrupt vital organelles within the cell body and, if administered to sensory ganglia, may be employed to rapidly and selectively delete nociceptive neurons.
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Affiliation(s)
- Z Olah
- Neuronal Gene Expression Unit, Pain and Neurosensory Mechanisms Branch, NIDCR, the Laboratory of Cellular Carcinogenesis and Tumor Promotion, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Chapter 3. Recent advances in development of novel analgesics. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 2000. [DOI: 10.1016/s0065-7743(00)35004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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