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Vijayakumar Sreelatha H, Palekkodan H, Fasaludeen A, K. Krishnan L, Abelson KSP. Refinement of the motorised laminectomy-assisted rat spinal cord injury model by analgesic treatment. PLoS One 2024; 19:e0294720. [PMID: 38227583 PMCID: PMC10790998 DOI: 10.1371/journal.pone.0294720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/06/2023] [Indexed: 01/18/2024] Open
Abstract
Usage and reporting of analgesia in animal models of spinal cord injury (SCI) have been sparse and requires proper attention. The majority of experimental SCI research uses rats as an animal model. This study aimed to probe into the effects of some commonly used regimens with NSAIDs and opioids on well-being of the rats as well as on the functional outcome of the model. This eight-week study used forty-two female Wistar rats (Crl: WI), randomly and equally divided into 6 treatment groups, viz. I) tramadol (5mg/kg) and buprenorphine (0.05mg/kg); II) carprofen (5mg/kg) and buprenorphine (0.05mg/kg); III) carprofen (5mg/kg); IV) meloxicam (1mg/kg) and buprenorphine (0.05mg/kg); V) meloxicam (1mg/kg); and VI) no analgesia (0.5 ml sterile saline). Buprenorphine was administered twice daily whereas other treatments were given once daily for five days post-operatively. Injections were given subcutaneously. All animals underwent dental burr-assisted laminectomy at the T10-T11 vertebra level. A custom-built calibrated spring-loaded 200 kilodynes force deliverer was used to induce severe SCI. Weekly body weight scores, Rat Grimace Scale (RGS), and dark-phase home cage activity were used as markers for well-being. Weekly Basso Beattie and Bresnahan (BBB) scores served as markers for functionality together with Novel Object Recognition test (NOR) at week 8 and terminal histopathology using area of vacuolisation and live neuronal count from the ventral horns of spinal cord. It was concluded that the usage of analgesia improved animal wellbeing while having no effects on the functional aspects of the animal model in comparison to the animals that received no analgesics.
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Affiliation(s)
- Harikrishnan Vijayakumar Sreelatha
- Department of Applied Biology, Division of Laboratory Animal Science, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hamza Palekkodan
- Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookot, Wayanad, Kerala, India
| | - Ansar Fasaludeen
- Department of Veterinary Pathology, College of Veterinary and Animal Sciences, Pookot, Wayanad, Kerala, India
| | - Lissy K. Krishnan
- Biological Research and Innovation Wing, Dr. Moopen’s Medical College, Wayanad, Kerala, India
| | - Klas S. P. Abelson
- Department of Experimental Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Bernatoniene J, Sciupokas A, Kopustinskiene DM, Petrikonis K. Novel Drug Targets and Emerging Pharmacotherapies in Neuropathic Pain. Pharmaceutics 2023; 15:1799. [PMID: 37513986 PMCID: PMC10384314 DOI: 10.3390/pharmaceutics15071799] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023] Open
Abstract
Neuropathic pain is a debilitating condition characterized by abnormal signaling within the nervous system, resulting in persistent and often intense sensations of pain. It can arise from various causes, including traumatic nerve injury, neuropathy, and certain diseases. We present an overview of current and emerging pharmacotherapies for neuropathic pain, focusing on novel drug targets and potential therapeutic agents. Current pharmacotherapies, including tricyclic antidepressants, gabapentinoids, and serotonin norepinephrine re-uptake inhibitors, are discussed, as are emerging treatments, such as ambroxol, cannabidiol, and N-acetyl-L-cysteine. Additionally, the article highlights the need for further research in this field to identify new targets and develop more effective and targeted therapies for neuropathic pain management.
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Affiliation(s)
- Jurga Bernatoniene
- Department of Drug Technology and Social Pharmacy, Faculty of Pharmacy, Medical Academy, Lithuanian University of Health Sciences, Sukileliu pr. 13, LT-50161 Kaunas, Lithuania
- Institute of Pharmaceutical Technologies, Faculty of Pharmacy, Medical Academy, Lithuanian University of Health Sciences, Sukileliu pr. 13, LT-50161 Kaunas, Lithuania
| | - Arunas Sciupokas
- Pain Clinic, Lithuanian University of Health Sciences Hospital Kauno Klinikos, Eivenių Str. 2, LT-50009 Kaunas, Lithuania
- Department of Neurology, Lithuanian University of Health Sciences, Eivenių Str. 2, LT-50009 Kaunas, Lithuania
| | - Dalia Marija Kopustinskiene
- Institute of Pharmaceutical Technologies, Faculty of Pharmacy, Medical Academy, Lithuanian University of Health Sciences, Sukileliu pr. 13, LT-50161 Kaunas, Lithuania
| | - Kestutis Petrikonis
- Department of Neurology, Lithuanian University of Health Sciences, Eivenių Str. 2, LT-50009 Kaunas, Lithuania
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Ambroxol for neuropathic pain: hiding in plain sight? Pain 2023; 164:3-13. [PMID: 35580314 DOI: 10.1097/j.pain.0000000000002693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/12/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary analgesic mechanism of action-blockade of voltage-gated sodium (Na v ) channels in sensory neurons. Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of chronic pain. In this review, we discuss the analgesic mechanisms of action of ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent pain and neuropathic pain symptoms, including trigeminal neuralgia, fibromyalgia, and complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.
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Fakhri S, Sabouri S, Kiani A, Farzaei MH, Rashidi K, Mohammadi-Farani A, Mohammadi-Noori E, Abbaszadeh F. Intrathecal administration of naringenin improves motor dysfunction and neuropathic pain following compression spinal cord injury in rats: relevance to its antioxidant and anti-inflammatory activities. Korean J Pain 2022; 35:291-302. [PMID: 35768984 PMCID: PMC9251389 DOI: 10.3344/kjp.2022.35.3.291] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/08/2022] [Accepted: 05/13/2022] [Indexed: 12/02/2022] Open
Abstract
Background Spinal cord injury (SCI) is one of the most debilitating disorders throughout the world, causing persistent sensory-motor dysfunction, with no effective treatment. Oxidative stress and inflammatory responses play key roles in the secondary phase of SCI. Naringenin (NAR) is a natural flavonoid with known anti-inflammatory and antioxidative properties. This study aims at evaluating the effects of intrathecal NAR administration on sensory-motor disability after SCI. Methods Animals underwent a severe compression injury using an aneurysm clip. About 30 minutes after surgery, NAR was injected intrathecally at the doses of 5, 10, and 15 mM in 20 µL volumes. For the assessment of neuropathic pain and locomotor function, acetone drop, hot plate, inclined plane, and Basso, Beattie, Bresnahan tests were carried out weekly till day 28 post-SCI. Effects of NAR on matrix metalloproteinase (MMP)-2 and MMP-9 activity was appraised by gelatin zymography. Also, histopathological analyses and serum levels of glutathione (GSH), catalase and nitrite were measured in different groups. Results NAR reduced neuropathic pain, improved locomotor function, and also attenuated SCI-induced weight loss weekly till day 28 post-SCI. Zymography analysis showed that NAR suppressed MMP-9 activity, whereas it increased that of MMP-2, indicating its anti-neuroinflammatory effects. Also, intrathecal NAR modified oxidative stress related markers GSH, catalase, and nitrite levels. Besides, the neuroprotective effect of NAR was corroborated through increased survival of sensory and motor neurons after SCI. Conclusions These results suggest intrathecal NAR as a promising candidate for medical therapeutics for SCI-induced sensory and motor dysfunction.
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Affiliation(s)
- Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Shahryar Sabouri
- Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Amir Kiani
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Mohammad Hosein Farzaei
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Khodabakhsh Rashidi
- Research Center of Oils and Fats, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ahmad Mohammadi-Farani
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Ehsan Mohammadi-Noori
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran.,Medical Biology Research Center, Health Technology Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Fatemeh Abbaszadeh
- Department of Neuroscience, Faculty of Advanced Technologies in Medical Sciences, Iran University of Medical Sciences, Tehran, Iran.,Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Sałat K, Furgała-Wojas A, Sałat R. The Microglial Activation Inhibitor Minocycline, Used Alone and in Combination with Duloxetine, Attenuates Pain Caused by Oxaliplatin in Mice. Molecules 2021; 26:molecules26123577. [PMID: 34208184 PMCID: PMC8230860 DOI: 10.3390/molecules26123577] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/05/2021] [Accepted: 06/07/2021] [Indexed: 11/26/2022] Open
Abstract
The antitumor drug, oxaliplatin, induces neuropathic pain, which is resistant to available analgesics, and novel mechanism-based therapies are being evaluated for this debilitating condition. Since activated microglia, impaired serotonergic and noradrenergic neurotransmission and overexpressed sodium channels are implicated in oxaliplatin-induced pain, this in vivo study assessed the effect of minocycline, a microglial activation inhibitor used alone or in combination with ambroxol, a sodium channel blocker, or duloxetine, a serotonin and noradrenaline reuptake inhibitor, on oxaliplatin-induced tactile allodynia and cold hyperalgesia. To induce neuropathic pain, a single dose (10 mg/kg) of intraperitoneal oxaliplatin was used. The mechanical and cold pain thresholds were assessed using mouse von Frey and cold plate tests, respectively. On the day of oxaliplatin administration, only duloxetine (30 mg/kg) and minocycline (100 mg/kg) used alone attenuated both tactile allodynia and cold hyperalgesia 1 h and 6 h after administration. Minocycline (50 mg/kg), duloxetine (10 mg/kg) and combined minocycline + duloxetine influenced only tactile allodynia. Seven days after oxaliplatin, tactile allodynia (but not cold hyperalgesia) was attenuated by minocycline (100 mg/kg), duloxetine (30 mg/kg) and combined minocycline and duloxetine. These results indicate a potential usefulness of minocycline used alone or combination with duloxetine in the treatment of oxaliplatin-induced pain.
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Affiliation(s)
- Kinga Sałat
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland;
- Correspondence: ; Tel./Fax: +48-12-62-05-554
| | - Anna Furgała-Wojas
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland;
| | - Robert Sałat
- Faculty of Electrical and Computer Engineering, Cracow University of Technology, 24 Warszawska St., 31-155 Krakow, Poland;
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Fakhri S, Abbaszadeh F, Jorjani M. On the therapeutic targets and pharmacological treatments for pain relief following spinal cord injury: A mechanistic review. Biomed Pharmacother 2021; 139:111563. [PMID: 33873146 DOI: 10.1016/j.biopha.2021.111563] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal cord injury (SCI) is globally considered as one of the most debilitating disorders, which interferes with daily activities and life of the affected patients. Despite many developments in related recognizing and treating procedures, post-SCI neuropathic pain (NP) is still a clinical challenge for clinicians with no distinct treatments. Accordingly, a comprehensive search was conducted in PubMed, Medline, Scopus, Web of Science, and national database (SID and Irandoc). The relevant articles regarding signaling pathways, therapeutic targets and pharmacotherapy of post-SCI pain were also reviewed. Data were collected with no time limitation until November 2020. The present study provides the findings on molecular mechanisms and therapeutic targets, as well as developing the critical signaling pathways to introduce novel neuroprotective treatments of post-SCI pain. From the pathophysiological mechanistic point of view, post-SCI inflammation activates the innate immune system, in which the immune cells elicit secondary injuries. So, targeting the critical signaling pathways for pain management in the SCI population has significant importance in providing new treatments. Indeed, several receptors, ion channels, excitatory neurotransmitters, enzymes, and key signaling pathways could be used as therapeutic targets, with a pivotal role of n-methyl-D-aspartate, gamma-aminobutyric acid, and inflammatory mediators. The current review focuses on conventional therapies, as well as crucial signaling pathways and promising therapeutic targets for post-SCI pain to provide new insights into the clinical treatment of post-SCI pain. The need to develop innovative delivery systems to treat SCI is also considered.
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Affiliation(s)
- Sajad Fakhri
- Pharmaceutical Sciences Research Center, Health Institute, Kermanshah University of Medical Sciences, Kermanshah, Iran
| | - Fatemeh Abbaszadeh
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences (IUMS), Tehran, Iran
| | - Masoumeh Jorjani
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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7
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Schneider R, Leven P, Glowka T, Kuzmanov I, Lysson M, Schneiker B, Miesen A, Baqi Y, Spanier C, Grants I, Mazzotta E, Villalobos‐Hernandez E, Kalff JC, Müller CE, Christofi FL, Wehner S. A novel P2X2-dependent purinergic mechanism of enteric gliosis in intestinal inflammation. EMBO Mol Med 2021; 13:e12724. [PMID: 33332729 PMCID: PMC7799361 DOI: 10.15252/emmm.202012724] [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: 05/19/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 12/19/2022] Open
Abstract
Enteric glial cells (EGC) modulate motility, maintain gut homeostasis, and contribute to neuroinflammation in intestinal diseases and motility disorders. Damage induces a reactive glial phenotype known as "gliosis", but the molecular identity of the inducing mechanism and triggers of "enteric gliosis" are poorly understood. We tested the hypothesis that surgical trauma during intestinal surgery triggers ATP release that drives enteric gliosis and inflammation leading to impaired motility in postoperative ileus (POI). ATP activation of a p38-dependent MAPK pathway triggers cytokine release and a gliosis phenotype in murine (and human) EGCs. Receptor antagonism and genetic depletion studies revealed P2X2 as the relevant ATP receptor and pharmacological screenings identified ambroxol as a novel P2X2 antagonist. Ambroxol prevented ATP-induced enteric gliosis, inflammation, and protected against dysmotility, while abrogating enteric gliosis in human intestine exposed to surgical trauma. We identified a novel pathogenic P2X2-dependent pathway of ATP-induced enteric gliosis, inflammation and dysmotility in humans and mice. Interventions that block enteric glial P2X2 receptors during trauma may represent a novel therapy in treating POI and immune-driven intestinal motility disorders.
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Affiliation(s)
| | | | - Tim Glowka
- Department of SurgeryUniversity of BonnBonnGermany
| | | | | | | | - Anna Miesen
- Department of SurgeryUniversity of BonnBonnGermany
| | - Younis Baqi
- Faculty of ScienceDepartment of ChemistrySultan Qaboos UniversityMuscatOman
- Pharmaceutical InstitutePharmaceutical & Medical ChemistryUniversity of BonnBonnGermany
| | - Claudia Spanier
- Pharmaceutical InstitutePharmaceutical & Medical ChemistryUniversity of BonnBonnGermany
| | - Iveta Grants
- Department of AnesthesiologyWexner Medical CenterThe Ohio State UniversityColumbusOHUSA
| | - Elvio Mazzotta
- Department of AnesthesiologyWexner Medical CenterThe Ohio State UniversityColumbusOHUSA
| | | | - Jörg C Kalff
- Department of SurgeryUniversity of BonnBonnGermany
| | - Christa E Müller
- Pharmaceutical InstitutePharmaceutical & Medical ChemistryUniversity of BonnBonnGermany
| | - Fedias L Christofi
- Department of AnesthesiologyWexner Medical CenterThe Ohio State UniversityColumbusOHUSA
| | - Sven Wehner
- Department of SurgeryUniversity of BonnBonnGermany
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Furgała-Wojas A, Kowalska M, Nowaczyk A, Fijałkowski Ł, Sałat K. Comparison of Bromhexine and its Active Metabolite - Ambroxol as Potential Analgesics Reducing Oxaliplatin-induced Neuropathic Pain - Pharmacodynamic and Molecular Docking Studies. Curr Drug Metab 2020; 21:548-561. [PMID: 32651960 DOI: 10.2174/1389200221666200711155632] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/30/2020] [Accepted: 05/21/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Painful peripheral neuropathy is a dose-limiting adverse effect of the antitumor drug oxaliplatin. The main symptoms of neuropathy: tactile allodynia and cold hyperalgesia, appear in more than 80% of patients on oxaliplatin therapy and are due to the overexpression of neuronal sodium channels (Navs) and neuroinflammation. OBJECTIVE This study assessed antiallodynic and antihyperalgesic properties of two repurposed drugs with antiinflammatory and Nav-blocking properties (bromhexine and its pharmacologically active metabolite - ambroxol) in a mouse model of neuropathic pain induced by oxaliplatin. Using molecular docking techniques, we predicted targets implicated in the observed in vivo activity of bromhexine. METHODS Oxaliplatin (a single intraperitoneal dose of 10 mg/kg) induced tactile allodynia and cold hyperalgesia in CD-1 mice and the effectiveness of single-dose or repeated-dose bromhexine and ambroxol to attenuate pain hypersensitivity was assessed in von Frey and cold plate tests. Additionally, Veber analysis and molecular docking experiments of bromhexine on mouse (m) and human (h) Nav1.6-1.9 were carried out. RESULTS At the corresponding doses, ambroxol was more effective than bromhexine as an antiallodynic agent. However, at the dose of 150 mg/kg, ambroxol induced motor impairments in mice. Repeated-dose bromhexine and ambroxol partially attenuated the development of late-phase tactile allodynia in oxaliplatin-treated mice. Only 7-day administration of bromhexine attenuated the development of late-phase cold hyperalgesia. Bromhexine was predicted to be a strong inhibitor of mNav1.6, mNav1.7, mNav1.9, and hNav1.7-hNav1.9. CONCLUSION The conversion of bromhexine to other than ambroxol active metabolites should be considered when interpreting some of its in vivo effects. Nav-blocking properties of bromhexine (and previously also predicted for ambroxol) might underlie its ability to attenuate pain caused by oxaliplatin.
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Affiliation(s)
- Anna Furgała-Wojas
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland
| | - Magdalena Kowalska
- Department of Organic Chemistry, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland
| | - Alicja Nowaczyk
- Department of Organic Chemistry, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland
| | - Łukasz Fijałkowski
- Department of Organic Chemistry, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, 2 dr. A. Jurasza St., 85-094, Bydgoszcz, Poland
| | - Kinga Sałat
- Department of Pharmacodynamics, Chair of Pharmacodynamics, Jagiellonian University Medical College, 9 Medyczna St., 30-688 Krakow, Poland
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9
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Alsaloum M, Higerd GP, Effraim PR, Waxman SG. Status of peripheral sodium channel blockers for non-addictive pain treatment. Nat Rev Neurol 2020; 16:689-705. [PMID: 33110213 DOI: 10.1038/s41582-020-00415-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/10/2020] [Indexed: 12/15/2022]
Abstract
The effective and safe treatment of pain is an unmet health-care need. Current medications used for pain management are often only partially effective, carry dose-limiting adverse effects and are potentially addictive, highlighting the need for improved therapeutic agents. Most common pain conditions originate in the periphery, where dorsal root ganglion and trigeminal ganglion neurons feed pain information into the CNS. Voltage-gated sodium (NaV) channels drive neuronal excitability and three subtypes - NaV1.7, NaV1.8 and NaV1.9 - are preferentially expressed in the peripheral nervous system, suggesting that their inhibition might treat pain while avoiding central and cardiac adverse effects. Genetic and functional studies of human pain disorders have identified NaV1.7, NaV1.8 and NaV1.9 as mediators of pain and validated them as targets for pain treatment. Consequently, multiple NaV1.7-specific and NaV1.8-specific blockers have undergone clinical trials, with others in preclinical development, and the targeting of NaV1.9, although hampered by technical constraints, might also be moving ahead. In this Review, we summarize the clinical and preclinical literature describing compounds that target peripheral NaV channels and discuss the challenges and future prospects for the field. Although the potential of peripheral NaV channel inhibition for the treatment of pain has yet to be realized, this remains a promising strategy to achieve non-addictive analgesia for multiple pain conditions.
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Affiliation(s)
- Matthew Alsaloum
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Yale Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, USA.,Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT, USA
| | - Grant P Higerd
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA.,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Yale Medical Scientist Training Program, Yale School of Medicine, New Haven, CT, USA
| | - Philip R Effraim
- Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA.,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.,Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Stephen G Waxman
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA. .,Center for Neuroscience & Regeneration Research, Yale University, West Haven, CT, USA. .,Center for Rehabilitation Research, VA Connecticut Healthcare System, West Haven, CT, USA.
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10
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Sham surgeries for central and peripheral neural injuries persistently enhance pain-avoidance behavior as revealed by an operant conflict test. Pain 2020; 160:2440-2455. [PMID: 31323014 DOI: 10.1097/j.pain.0000000000001642] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Studies using rodent models of neuropathic pain use sham surgery control procedures that cause deep tissue damage. Sham surgeries would thus be expected to induce potentially long-lasting postsurgical pain, but little evidence for such pain has been reported. Operant tests of voluntary behavior can reveal negative motivational and cognitive aspects of pain that may provide sensitive tools for detecting pain-related alterations. In a previously described operant mechanical conflict test involving lengthy familiarization and training, rodents freely choose to either escape from a brightly lit chamber by crossing sharp probes or refuse to cross. Here, we describe a brief (2-day) mechanical conflict protocol that exploits rats' innate exploratory response to a novel environment to detect persistently enhanced pain-avoidance behavior after sham surgeries for 2 neural injury models: thoracic spinal cord injury and chronic constriction injury of the sciatic nerve. Pitting the combined motivations to avoid the bright light and to explore the novel device against pain from crossing noxious probes disclosed a conflicting, hyperalgesia-related reluctance to repeatedly cross the probes after injury. Rats receiving standard sham surgeries demonstrated enhanced pain-like avoidance behavior compared with naive controls, and this behavior was similar to that of corresponding chronic constriction injury or spinal cord injury rats weeks or months after injury. In the case of sham surgery for spinal cord injury, video analysis of voluntary exploratory behavior directed at the probes revealed enhanced forepaw withdrawal responses. These findings have important implications for preclinical investigations into behavioral alterations and physiological mechanisms associated with postsurgical and neuropathic pain.
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11
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Sex Difference in Trigeminal Neuropathic Pain Response to Exercise: Role of Oxidative Stress. Pain Res Manag 2020; 2020:3939757. [PMID: 32676135 PMCID: PMC7341438 DOI: 10.1155/2020/3939757] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 05/17/2020] [Accepted: 06/08/2020] [Indexed: 11/17/2022]
Abstract
Aim Orofacial chronic neuropathic pain commonly occurs following trigeminal nerve injuries. We investigated whether swimming exercise can reduce trigeminal neuropathic pain through improving antioxidant capacity. Materials and Methods Twenty-eight Wistar rats of either sex and 180–220 grams were divided into 4 groups as sham, neuropathy, neuropathy + single bout exercise, and neuropathy + 2 weeks of exercise. Trigeminal neuropathy was carried out through chronic constriction injury (CCI) of infraorbital nerve. Protocols of exercise were included a single bout session (45 minutes) and a 2-week (45 minutes/day/6 days a week) swimming exercise. Mechanical allodynia was detected using Von Frey filaments. The activity of the serum antioxidant enzymes glutathione peroxidase and superoxides dismutase was assayed using ELISA kits. Results We found that CCI significantly reduced facial pain threshold in both sexes (P < 0.05). Both swimming exercise protocols significantly reduced mechanical allodynia in female rats compared to the sham group; however, only 2 weeks of exercise were significantly effective in male rats. The activity of antioxidant enzyme glutathione peroxidase significantly (P < 0.05) decreased following CCI in female rats against that in the sham group and 2-week exercise significantly (P < 0.05) increased it toward the control level. The levels of glutathione peroxidase in male rats and superoxidase dismutase in both sexes were not significantly different compared to their sham groups. Conclusion Swimming exercise alleviates trigeminal neuropathic pain in both sexes. Oxidative stress as a possible mechanism was involved in the effect of exercise on female rat trigeminal neuropathy.
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Le-Niculescu H, Roseberry K, Levey DF, Rogers J, Kosary K, Prabha S, Jones T, Judd S, McCormick MA, Wessel AR, Williams A, Phalen PL, Mamdani F, Sequeira A, Kurian SM, Niculescu AB. Towards precision medicine for stress disorders: diagnostic biomarkers and targeted drugs. Mol Psychiatry 2020; 25:918-938. [PMID: 30862937 PMCID: PMC7192849 DOI: 10.1038/s41380-019-0370-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 01/14/2019] [Accepted: 01/23/2019] [Indexed: 01/09/2023]
Abstract
The biological fingerprint of environmental adversity may be key to understanding health and disease, as it encompasses the damage induced as well as the compensatory reactions of the organism. Metabolic and hormonal changes may be an informative but incomplete window into the underlying biology. We endeavored to identify objective blood gene expression biomarkers for psychological stress, a subjective sensation with biological roots. To quantify the stress perception at a particular moment in time, we used a simple visual analog scale for life stress in psychiatric patients, a high-risk group. Then, using a stepwise discovery, prioritization, validation, and testing in independent cohort design, we were successful in identifying gene expression biomarkers that were predictive of high-stress states and of future psychiatric hospitalizations related to stress, more so when personalized by gender and diagnosis. One of the top biomarkers that survived discovery, prioritization, validation, and testing was FKBP5, a well-known gene involved in stress response, which serves as a de facto reassuring positive control. We also compared our biomarker findings with telomere length (TL), another well-established biological marker of psychological stress and show that newly identified predictive biomarkers such as NUB1, APOL3, MAD1L1, or NKTR are comparable or better state or trait predictors of stress than TL or FKBP5. Over half of the top predictive biomarkers for stress also had prior evidence of involvement in suicide, and the majority of them had evidence in other psychiatric disorders, providing a molecular underpinning for the effects of stress in those disorders. Some of the biomarkers are targets of existing drugs, of potential utility in patient stratification, and pharmacogenomics approaches. Based on our studies and analyses, the biomarkers with the best overall convergent functional evidence (CFE) for involvement in stress were FKBP5, DDX6, B2M, LAIR1, RTN4, and NUB1. Moreover, the biomarker gene expression signatures yielded leads for possible new drug candidates and natural compounds upon bioinformatics drug repurposing analyses, such as calcium folinate and betulin. Our work may lead to improved diagnosis and treatment for stress disorders such as PTSD, that result in decreased quality of life and adverse outcomes, including addictions, violence, and suicide.
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Affiliation(s)
- H Le-Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - K Roseberry
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - D F Levey
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - J Rogers
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - K Kosary
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - S Prabha
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - T Jones
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - S Judd
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - M A McCormick
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A R Wessel
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A Williams
- Indianapolis VA Medical Center, Indianapolis, IN, USA
| | - P L Phalen
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - F Mamdani
- Department of Psychiatry and Human Behavior, UC Irvine, Irvine, CA, USA
| | - A Sequeira
- Department of Psychiatry and Human Behavior, UC Irvine, Irvine, CA, USA
| | - S M Kurian
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - A B Niculescu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indianapolis VA Medical Center, Indianapolis, IN, USA.
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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Barut EN, Engin S, Barut B, Kaya C, Kerimoglu G, Ozel A, Kadioglu M. Uroprotective effect of ambroxol in cyclophosphamide-induced cystitis in mice. Int Urol Nephrol 2019; 51:803-810. [DOI: 10.1007/s11255-019-02128-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 03/11/2019] [Indexed: 12/25/2022]
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Kern KU, Schwickert-Nieswandt M, Maihöfner C, Gaul C. Topical Ambroxol 20% for the Treatment of Classical Trigeminal Neuralgia - A New Option? Initial Clinical Case Observations. Headache 2019; 59:418-429. [PMID: 30653673 DOI: 10.1111/head.13475] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Trigeminal neuralgia is difficult to treat and shows upregulation of sodium channels. The expectorant ambroxol acts as a strong local anesthetic, about 40 times stronger than lidocaine. It preferentially inhibits the channel subtype Nav 1.8, expressed especially in nociceptive C-fibers. It seemed reasonable to try ambroxol for the treatment with neuropathic facial pain unresponsive to other standard options. MATERIAL AND METHODS Medical records of patients suffering from classical trigeminal neuralgia (n = 5) and successful pain reduction following topical ambroxol 20% cream in addition to standard treatment are reported. RESULTS All patients reported pain attacks with pain intensity between 4 and 10 NRS (numeric pain scale). In all cases they could be triggered, 3 patients reported additional spontaneous pain. Attacks were reduced in all 5 patients. Pain reduction achieved following ambroxol 20% cream was 2-8 points (NRS) earliest within 15-30 minutes and lasted for 4-6 hours mostly. This was reproducible in all cases; in one case pain was eliminated after 1 week. No patient reported side effects or skin changes; oral medication was reduced in 2 patients. CONCLUSION For the first time, a clinically significant pain relief following topical ambroxol 20% cream in patients with trigeminal neuralgia is reported. In view of the positive side effect profile, topical ambroxol for patients with such a highly impaired quality of life should be investigated further as a matter of urgency.
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Affiliation(s)
- Kai-Uwe Kern
- Institute for Pain Medicine/Pain Practice Wiesbaden, Wiesbaden, Germany
| | | | | | - Charly Gaul
- Migraine and Headache Clinic, Königstein, Germany
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Fakhri S, Dargahi L, Abbaszadeh F, Jorjani M. Effects of astaxanthin on sensory-motor function in a compression model of spinal cord injury: Involvement of ERK and AKT signalling pathway. Eur J Pain 2018; 23:750-764. [PMID: 30427581 DOI: 10.1002/ejp.1342] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 10/04/2018] [Accepted: 11/08/2018] [Indexed: 12/28/2022]
Abstract
BACKGROUND Spinal cord injury (SCI) causes continuous neurological deficits and major sensory-motor impairments. There is no effective treatment to enhance sensory-motor function following SCI. Thus, it is crucial to develop novel therapeutics for this particular patient population. Astaxanthin (AST) is a strong antioxidant, anti-inflammatory and anti-apoptotic agent. In the present study, it was tested in a severe compression SCI model with emphasis on sensory-motor outcomes, signalling pathway, along with other complications. METHODS A severe SCI was induced by compression of the rat thoracic spinal cord with an aneurysm clip and treatment with AST or the vehicle was carried out, 30 min after injury. Behavioural tests including open field, von Frey, hot plate and BBB were performed weekly to 28 days post-injury. Rats were assigned to measure blood glucose, weight and auricle temperature. Western blot and histological analysis also were performed at the same time points. RESULTS AST decreased mechanical and thermal pain and also improved motor function performance, reduced blood glucose and auricle temperature increases and attenuated weight loss in SCI rats. Western blot analysis showed decreased activation of ERK1/2 and increased activation of AKT following AST treatment. The histology results revealed that AST considerably preserved myelinated white matter and the number of motor neurons following SCI. CONCLUSION Taken together, the beneficial effects of AST to improve sensory-motor outcomes, attenuate pathological tissue damage and modulate ERK and AKT signalling pathways following SCI, suggest it as a strong therapeutic agent towards clinical applications. SIGNIFICANCE Spinal cord injury (SCI) impairs sensory-motor function and causes complications, which astaxanthin (AST) has the potential to be used as a treatment for. The present study investigates the effects of AST in a compression model of SCI with emphasis on sensory-motor outcomes alongside other complications, histopathological damage and also related signalling pathways.
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Affiliation(s)
- Sajad Fakhri
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Abbaszadeh
- Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Masoumeh Jorjani
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Neurobiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Maihöfner C, Schneider S, Bialas P, Gockel H, Beer KG, Bartels M, Kern KU. Successful treatment of complex regional pain syndrome with topical ambroxol: a case series. Pain Manag 2018; 8:427-436. [PMID: 30394190 DOI: 10.2217/pmt-2018-0048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
AIM The secretolytic drug ambroxol may be useful for the treatment of neuropathic pain due to its multiple modes of action. We hypothesized that ambroxol may be a treatment option for complex regional pain syndrome (CRPS). METHODS Additional to standard therapy, eight CRPS-patients with symptoms of less than 12 months were treated with topical 20% ambroxol cream. Clinical courses were assessed using detailed anamnesis and clinical examination. RESULTS Following treatment we found a reduction of spontaneous pain (6 patients), pain on movement (6 patients), edema (seven patients), allodynia (six patients), hyperalgesia (seven patients), reduction of skin reddening (four patients), improvement of motor dysfunction (six patients) and improvement of skin temperature (four patients). CONCLUSION Topical treatment with ambroxol cream may ameliorate symptoms of CRPS.
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Affiliation(s)
- Christian Maihöfner
- Department of Neurology, General Hospital Fürth, Jakob-Henle-Straße 1, 90766 Fürth, Germany
| | | | - Patric Bialas
- Saarland University Medical Center & Medical Faculty of Saarland University; Homburg (Saar), Germany
| | - Helmut Gockel
- Center for Pain Medicine/Pain Practice Vilsbiburg, Germany
| | | | - Max Bartels
- Department of Neurology, General Hospital Fürth, Jakob-Henle-Straße 1, 90766 Fürth, Germany
| | - Kai-Uwe Kern
- Institute for Pain Medicine/Pain Practice Wiesbaden, Germany
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Mishra A, Chandravanshi LP, Trigun SK, Krishnamurthy S. Ambroxol modulates 6-Hydroxydopamine-induced temporal reduction in Glucocerebrosidase (GCase) enzymatic activity and Parkinson's disease symptoms. Biochem Pharmacol 2018; 155:479-493. [PMID: 30040928 DOI: 10.1016/j.bcp.2018.07.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 07/20/2018] [Indexed: 12/26/2022]
Abstract
Reduced glucocerebrosidase (GCase) enzymatic activity is found in sporadic cases of Parkinson's disease making GCase a serious risk factor for PD. GCase gene mutations constitute a major risk factor in early-onset PD but only account for 5-10% cases. Having enough evidence for construct and face validity, 6-OHDA-induced hemiparkinson's model may be useful to assess the GCase-targeting drugs in order to have new leads for treatment of PD. Ambroxol (AMB) is reported to increase GCase activity in different brain-regions. Therefore, we investigated anti-PD like effects of AMB as well as GCase activity in striatal and nigral tissues of rats in hemiparkinson's model. AMB was given a dose of 400 mg/kg per oral twice daily and SEL used as positive control was given in the dose of 10 mg/kg per oral daily from D-4 to D-27 after 6-OHDA administration. 6-OHDA reduced GCase activity in striatal and in a progressive manner in nigral tissues. AMB and SEL attenuated 6-OHDA-induced motor impairments, dopamine (DA) depletion and GCase deficiency. AMB and SEL also ameliorated 6-OHDA-induced mitochondrial dysfunction in terms of MTT reduction, α-synuclein pathology, loss of nigral cells, and intrinsic pathway of apoptosis by modulating cytochrome-C, caspase-9, and caspase-3 expressions. The results suggest that AMB attenuated 6-OHDA-induced GCase deficiency and PD symptoms. Therefore, the regenerative effects of AMB in dopamine toxicity may be due to its effects on GCase activity and mitochondrial function. Results indicate that SEL also has regenerative effect in the 6-OHDA model. Thus, GCase enzymatic activity is likely to be involved in the development of PD symptoms, and 6-OHDA-induced hemiparkinson's model may be used to evaluate compounds targeting GCase activity for management of PD symptoms.
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Affiliation(s)
- Akanksha Mishra
- Neurotherapeutics Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, U.P., India
| | - Lalit Pratap Chandravanshi
- Biochemistry Section, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, U.P., India
| | - Surendra Kumar Trigun
- Biochemistry Section, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi 221005, U.P., India
| | - Sairam Krishnamurthy
- Neurotherapeutics Laboratory, Department of Pharmaceutical Engineering & Technology, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005, U.P., India.
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18
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Dugan E, Sagen J. A novel affective-motivational-based Overground System for detecting spinal cord injury-associated thermal and mechanical hypersensitivity in rats. Eur J Pain 2018; 22:1628-1640. [DOI: 10.1002/ejp.1245] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2018] [Indexed: 12/17/2022]
Affiliation(s)
- E.A. Dugan
- University of Miami; Miller School of Medicine; Miami USA
| | - J. Sagen
- University of Miami; Miller School of Medicine; Miami USA
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Sałat K, Gryzło B, Kulig K. Experimental Drugs for Neuropathic Pain. Curr Neuropharmacol 2018; 16:1193-1209. [PMID: 29745335 PMCID: PMC6187752 DOI: 10.2174/1570159x16666180510151241] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 02/02/2018] [Accepted: 05/07/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Neuropathic pain (NP) is an important public health problem and despite recent progress in the understanding, diagnosis, pathophysiological mechanisms and the treatment of NP, many patients remain refractory to pharmacotherapy. OBJECTIVE Currently used drugs have limited efficacy and dose-limiting adverse effects, and thus there is a substantial need for further development of novel medications for its treatment. Alternatively, drugs approved for use in diseases other than NP can be applied as experimental for NP conditions. This paper covers advances in the field of NP treatment. RESULTS The prime focus of this paper is on drugs with well-established pharmacological activity whose current therapeutic applications are distinct from NP. These drugs could be a potential novel treatment of NP. Data from preclinical studies and clinical trials on these experimental drugs are presented. The development of advanced methods of genomics enabled to propose new targets for drugs which could be effective in the NP treatment. CONCLUSION Experimental drugs for NP can be a treatment option which should be tailor-made for each individual on the basis of pain features, previous therapies, associated clinical conditions, recurrence of pain, adverse effects, contraindications and patients' preferences. At present, there are only some agents which may have potential as novel treatments. Increasing knowledge about mechanisms underlying NP, mechanisms of drug action, as well as available data from preclinical and clinical studies make botulinum toxin A, minocycline, ambroxol, statins and PPAR agonists (ATx086001) promising potential future treatment options.
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Affiliation(s)
- Kinga Sałat
- Address correspondence to this author at the Faculty of Pharmacy,
Jagiellonian University, 9 Medyczna St., 30-688 Kraków, Poland; Tel: + 48 12 6205 555; Fax: + 48 12 6205 554; E-mail:
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Abstract
Fibromyalgia appears to present in subgroups with regard to biological pain induction, with primarily inflammatory, neuropathic/neurodegenerative, sympathetic, oxidative, nitrosative, or muscular factors and/or central sensitization. Recent research has also discussed glial activation or interrupted dopaminergic neurotransmission, as well as increased skin mast cells and mitochondrial dysfunction. Therapy is difficult, and the treatment options used so far mostly just have the potential to address only one of these aspects. As ambroxol addresses all of them in a single substance and furthermore also reduces visceral hypersensitivity, in fibromyalgia existing as irritable bowel syndrome or chronic bladder pain, it should be systematically investigated for this purpose. Encouraged by first clinical observations of two working groups using topical or oral ambroxol for fibromyalgia treatments, the present paper outlines the scientific argument for this approach by looking at each of the aforementioned aspects of this complex disease and summarizes putative modes of action of ambroxol. Nevertheless, at this point the evidence basis for ambroxol is not strong enough for clinical recommendation.
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Affiliation(s)
- Kai-Uwe Kern
- Institute of Pain Medicine/Pain Practice, Wiesbaden, Germany
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21
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Ambroxol for fibromyalgia: one group pretest-posttest open-label pilot study. Clin Rheumatol 2017; 36:1879-1884. [DOI: 10.1007/s10067-017-3664-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 04/19/2017] [Accepted: 04/25/2017] [Indexed: 12/24/2022]
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Abstract
Purpose of Review Topical therapeutic approaches in localized neuropathic pain (LNP) syndromes are increasingly used by both specialists and general practitioners, with a potentially promising effect on pain reduction. In this narrative review, we describe the available compounds for topical use in LNP syndromes and address their potential efficacy according to the literature. Recent Findings Local anaesthetics (e.g., lidocaine, bupivacaine and mepivacaine), as well as general anaesthetic agents (e.g., ketamine), muscle relaxants (e.g., baclofen), capsaicin, anti-inflammatory drugs (e.g., diclofenac), salicylates, antidepressants (e.g., amitriptyline and doxepin), α2 adrenergic agents (e.g., clonidine), or even a combination of them have been tested in various applications for the treatment of LNP. Few of them have reached a sufficient level of evidence to support systematic use as treatment options. Summary Relatively few systemic side effects or drug–drug interactions and satisfactory efficacy seem to be the benefits of topical treatments. More well-organized and tailored studies are necessary for the further conceptualization of topical treatments for LNP.
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Affiliation(s)
- Roberto Casale
- Department of High Technology Rehabilitation & Pain Rehabilitation Unit, Habilita Care and Research Hospitals, Via Bologna 1-24040, Zingonia di Ciserano (BG), Italy.
| | - Z Symeonidou
- Department of High Technology Rehabilitation & Pain Rehabilitation Unit, Habilita Care and Research Hospitals, Via Bologna 1-24040, Zingonia di Ciserano (BG), Italy.,Department of Physical and Rehabilitation Medicine, General Hospital of Attica "KAT", Athens, Greece
| | - M Bartolo
- Department of Rehabilitation, Neurorehabilitation Unit, Habilita, Zingonia di Ciserano (BG), Italy
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Kern KU, Weiser T. Topical ambroxol for the treatment of neuropathic pain. An initial clinical observation. Schmerz 2017; 29 Suppl 3:S89-96. [PMID: 26589711 PMCID: PMC4701773 DOI: 10.1007/s00482-015-0060-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Neuropathic pain is difficult to treat, and the available options are often inadequate. The expectorant ambroxol also acts as a strong local anaesthetic and blocks sodium channels about 40 times more potently than lidocaine. It preferentially inhibits the channel subtype Nav 1.8, which is expressed especially in nociceptive C-fibres. In view of the low toxicity of ambroxol, it seemed reasonable to try using it for the treatment of neuropathic pain that failed to respond to other standard options. MATERIAL AND METHODS The medical records of seven patients with severe neuropathic pain and pain reduction following topical ambroxol treatment are reported retrospectively. As standard therapies had not proved sufficient, a topical ambroxol 20% cream was repeatedly applied by the patients in the area of neuropathic pain. RESULTS The reasons for neuropathic pain were postherpetic neuralgia (2 ×), mononeuropathy multiplex, phantom pain, deafferentation pain, postoperative neuralgia and foot neuropathy of unknown origin. The individual mean pain intensity reported was between 4 and 6/10 (NRS), maximum pain at 6-10/10 (NRS). The pain reduction achieved individually following ambroxol cream was 2-8 points (NRS) within 5-30 min and lasted for 3-8 h. Pain attacks were reduced in all five patients presenting with this problem. Four patients with no improvement after lidocaine 5% and one patient with no response to capsaicin 8% nevertheless experienced a pain reduction with topical ambroxol. No patient reported any side effects or skin changes during a treatment that has since been continued for up to 4 years. CONCLUSION Ambroxol acts as a strong local anaesthetic and preferentially inhibits the nociceptively relevant sodium channel subtype Nav 1.8. For the first time, we report below on a relevant pain relief following topical ambroxol 20% cream in patients with neuropathic pain. In view of the positive side effect profile, the clinical benefit in patients with pain should be investigated further.
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Affiliation(s)
- K-U Kern
- Institut für Schmerzmedizin/Schmerzpraxis Wiesbaden, Sonnenberger Str. 68, 65193, Wiesbaden, Germany.
| | - T Weiser
- Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim, Germany
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Kern KU, Weiser T. [Topical ambroxol for the treatment of neuropathic pain: A first clinical observation. German version]. Schmerz 2017; 29:632-40. [PMID: 26597641 DOI: 10.1007/s00482-015-0065-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Neuropathic pain is difficult to treat and available options are frequently not sufficient. The expectorant ambroxol also works as a strong local anesthetic and blocks sodium channels about 40 times more potently than lidocaine. Ambroxol preferentially inhibits the channel subtype Nav 1.8, which is expressed particularly in nociceptive C fibers. Due to the low toxicity, topical ambroxol seemed to represent a reasonable therapeutic attempt for treatment of neuropathic pain resistant to other standard options. MATERIALS AND METHODS Medical records of 7 patients with severe neuropathic pain, in whom many attempts at treatment with approved substances were not sufficient or possible, are reported retrospectively. Patients were then treated with topical ambroxol 20% cream applied in the area of neuropathic pain. RESULTS Causes of neuropathic pain were postherpetic neuralgia (2-×), mononeuropathy multiplex, phantom pain, deafferentation pain, postoperative neuralgia and an unclear allodynia of the foot. Mean pain intensity was reported as 4-6/10 on a numeric rating scale (NRS) and maximum pain intensity as 6-10/10. Pain reduction following ambroxol cream was 2-8 points (NRS) within 15-30 min and lasted 3-8 h. Pain attacks were reduced in all 5 patients presenting this problem. Topical ambroxol achieved pain reduction in 4 patients with no improvement after lidocaine 5% and 1 patient with no response to capsaicin 8%. No adverse events or skin changes have been observed, and the longest treatment duration is currently 4 years. CONCLUSION Ambroxol acts as a strong local anesthetic and preferentially inhibits the nociceptive-relevant sodium channel subtype Nav 1.8. For the first time, we report relevant pain reduction following topical Ambroxol 20% cream in patients with neuropathic pain. Regarding the advantageous profile with rare side effects, the clinical benefit for pain patients should be further investigated.
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Affiliation(s)
- K-U Kern
- Institut für Schmerzmedizin / Schmerzpraxis Wiesbaden, Wiesbaden, Deutschland. .,Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim am Rhein, Deutschland.
| | - T Weiser
- Boehringer Ingelheim Pharma GmbH & Co. KG, Ingelheim am Rhein, Deutschland
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25
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Xu YQ, Jin SJ, Liu N, Li YX, Zheng J, Ma L, Du J, Zhou R, Zhao CJ, Niu Y, Sun T, Yu JQ. Aloperine attenuated neuropathic pain induced by chronic constriction injury via anti-oxidation activity and suppression of the nuclear factor kappa B pathway. Biochem Biophys Res Commun 2014; 451:568-73. [DOI: 10.1016/j.bbrc.2014.08.025] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/05/2014] [Indexed: 01/02/2023]
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Belkouch M, Dansereau MA, Tétreault P, Biet M, Beaudet N, Dumaine R, Chraibi A, Mélik-Parsadaniantz S, Sarret P. Functional up-regulation of Nav1.8 sodium channel in Aβ afferent fibers subjected to chronic peripheral inflammation. J Neuroinflammation 2014; 11:45. [PMID: 24606981 PMCID: PMC4007624 DOI: 10.1186/1742-2094-11-45] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 02/21/2014] [Indexed: 02/05/2023] Open
Abstract
Background Functional alterations in the properties of Aβ afferent fibers may account for the increased pain sensitivity observed under peripheral chronic inflammation. Among the voltage-gated sodium channels involved in the pathophysiology of pain, Nav1.8 has been shown to participate in the peripheral sensitization of nociceptors. However, to date, there is no evidence for a role of Nav1.8 in controlling Aβ-fiber excitability following persistent inflammation. Methods Distribution and expression of Nav1.8 in dorsal root ganglia and sciatic nerves were qualitatively or quantitatively assessed by immunohistochemical staining and by real time-polymerase chain reaction at different time points following complete Freund’s adjuvant (CFA) administration. Using a whole-cell patch-clamp configuration, we further determined both total INa and TTX-R Nav1.8 currents in large-soma dorsal root ganglia (DRG) neurons isolated from sham or CFA-treated rats. Finally, we analyzed the effects of ambroxol, a Nav1.8-preferring blocker on the electrophysiological properties of Nav1.8 currents and on the mechanical sensitivity and inflammation of the hind paw in CFA-treated rats. Results Our findings revealed that Nav1.8 is up-regulated in NF200-positive large sensory neurons and is subsequently anterogradely transported from the DRG cell bodies along the axons toward the periphery after CFA-induced inflammation. We also demonstrated that both total INa and Nav1.8 peak current densities are enhanced in inflamed large myelinated Aβ-fiber neurons. Persistent inflammation leading to nociception also induced time-dependent changes in Aβ-fiber neuron excitability by shifting the voltage-dependent activation of Nav1.8 in the hyperpolarizing direction, thus decreasing the current threshold for triggering action potentials. Finally, we found that ambroxol significantly reduces the potentiation of Nav1.8 currents in Aβ-fiber neurons observed following intraplantar CFA injection and concomitantly blocks CFA-induced mechanical allodynia, suggesting that Nav1.8 regulation in Aβ-fibers contributes to inflammatory pain. Conclusions Collectively, these findings support a key role for Nav1.8 in controlling the excitability of Aβ-fibers and its potential contribution to the development of mechanical allodynia under persistent inflammation.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Philippe Sarret
- Department of Physiology and Biophysics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, 3001, 12th Avenue North, Sherbrooke, Quebec J1H 5N4, Canada.
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Kanno H, Pressman Y, Moody A, Berg R, Muir EM, Rogers JH, Ozawa H, Itoi E, Pearse DD, Bunge MB. Combination of engineered Schwann cell grafts to secrete neurotrophin and chondroitinase promotes axonal regeneration and locomotion after spinal cord injury. J Neurosci 2014; 34:1838-55. [PMID: 24478364 PMCID: PMC3905147 DOI: 10.1523/jneurosci.2661-13.2014] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 11/14/2013] [Accepted: 12/19/2013] [Indexed: 11/21/2022] Open
Abstract
Transplantation of Schwann cells (SCs) is a promising therapeutic strategy for spinal cord repair. SCs introduced into lesions support axon regeneration, but because these axons do not exit the transplant, additional approaches with SCs are needed. Here, we transplanted SCs genetically modified to secrete a bifunctional neurotrophin (D15A) and chondroitinase ABC (ChABC) into a subacute contusion injury in rats. We examined the effects of these modifications on graft volume, SC number, degradation of chondroitin sulfate proteoglycans (CSPGs), astrogliosis, SC myelination of axons, propriospinal and supraspinal axon numbers, locomotor outcome (BBB scoring, CatWalk gait analysis), and mechanical and thermal sensitivity on the hind paws. D15A secreted from transplanted SCs increased graft volume and SC number and myelinated axon number. SCs secreting ChABC significantly decreased CSPGs, led to some egress of SCs from the graft, and increased propriospinal and 5-HT-positive axons in the graft. SCs secreting both D15A and ChABC yielded the best responses: (1) the largest number of SC myelinated axons, (2) more propriospinal axons in the graft and host tissue around and caudal to it, (3) more corticospinal axons closer to the graft and around and caudal to it, (4) more brainstem neurons projecting caudal to the transplant, (5) increased 5-HT-positive axons in the graft and caudal to it, (6) significant improvement in aspects of locomotion, and (7) improvement in mechanical and thermal allodynia. This is the first evidence that the combination of SC transplants engineered to secrete neurotrophin and chondroitinase further improves axonal regeneration and locomotor and sensory function.
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Affiliation(s)
- Haruo Kanno
- Miami Project to Cure Paralysis
- Department of Orthopaedic Surgery, Tohoku University School of Medicine, Sendai, Japan, 9808574
| | | | | | | | - Elizabeth M. Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, United Kingdom, and
| | - John H. Rogers
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, United Kingdom, and
| | - Hiroshi Ozawa
- Department of Orthopaedic Surgery, Tohoku University School of Medicine, Sendai, Japan, 9808574
| | - Eiji Itoi
- Department of Orthopaedic Surgery, Tohoku University School of Medicine, Sendai, Japan, 9808574
| | - Damien D. Pearse
- Miami Project to Cure Paralysis
- Department of Neurological Surgery
- Neuroscience Program
- Interdisciplinary Stem Cell Institute, and
| | - Mary Bartlett Bunge
- Miami Project to Cure Paralysis
- Department of Neurological Surgery
- Neuroscience Program
- Interdisciplinary Stem Cell Institute, and
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, Florida 33136
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Pilot study using ambroxol as a pharmacological chaperone in type 1 Gaucher disease. Blood Cells Mol Dis 2013; 50:134-7. [DOI: 10.1016/j.bcmd.2012.09.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 09/24/2012] [Indexed: 12/19/2022]
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Nardi A, Damann N, Hertrampf T, Kless A. Advances in targeting voltage-gated sodium channels with small molecules. ChemMedChem 2012; 7:1712-40. [PMID: 22945552 DOI: 10.1002/cmdc.201200298] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Revised: 07/30/2012] [Indexed: 12/19/2022]
Abstract
Blockade of voltage-gated sodium channels (VGSCs) has been used successfully in the clinic to enable control of pathological firing patterns that occur in conditions as diverse as chronic pain, epilepsy, and arrhythmias. Herein we review the state of the art in marketed sodium channel inhibitors, including a brief compendium of their binding sites and of the cellular and molecular biology of sodium channels. Despite the preferential action of this drug class toward over-excited cells, which significantly limits potential undesired side effects on other cells, the need to develop a second generation of sodium channel inhibitors to overcome their critical clinical shortcomings is apparent. Current approaches in drug discovery to deliver novel and truly innovative sodium channel inhibitors is next presented by surveying the most recent medicinal chemistry breakthroughs in the field of small molecules and developments in automated patch-clamp platforms. Various strategies aimed at identifying small molecules that target either particular isoforms of sodium channels involved in specific diseases or anomalous sodium channel currents, irrespective of the isoform by which they have been generated, are critically discussed and revised.
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Affiliation(s)
- Antonio Nardi
- Global Drug Discovery, Department of Medicinal Chemistry, Grünenthal, Zieglerstrasse 6, 52078 Aachen, Germany.
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Hama A, Sagen J. Combination Drug Therapy for Pain following Chronic Spinal Cord Injury. PAIN RESEARCH AND TREATMENT 2012; 2012:840486. [PMID: 22550581 PMCID: PMC3324948 DOI: 10.1155/2012/840486] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 01/06/2012] [Indexed: 12/15/2022]
Abstract
A number of mechanisms have been elucidated that maintain neuropathic pain due to spinal cord injury (SCI). While target-based therapeutics are being developed based on elucidation of these mechanisms, treatment for neuropathic SCI pain has not been entirely satisfactory due in part to the significant convergence of neurological and inflammatory processes that maintain the neuropathic pain state. Thus, a combination drug treatment strategy, wherein several pain-related mechanism are simultaneously engaged, could be more efficacious than treatment against individual mechanisms alone. Also, by engaging several targets at once, it may be possible to reduce the doses of the individual drugs, thereby minimizing the potential for adverse side effects. Positive preclinical and clinical studies have demonstrated improved efficacy of combination drug treatment over single drug treatment in neuropathic pain of peripheral origin, and perhaps such combinations could be utilized for neuropathic SCI pain. At the same time, there are mechanisms that distinguish SCI from peripheral neuropathic pain, so novel combination therapies will be needed.
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Affiliation(s)
- Aldric Hama
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, 1095 SW 14th Terrace, Miami, FL 33136, USA
| | - Jacqueline Sagen
- The Miami Project to Cure Paralysis, Miller School of Medicine, University of Miami, 1095 SW 14th Terrace, Miami, FL 33136, USA
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Gwak YS, Hulsebosch CE. Neuronal hyperexcitability: a substrate for central neuropathic pain after spinal cord injury. Curr Pain Headache Rep 2012; 15:215-22. [PMID: 21387163 DOI: 10.1007/s11916-011-0186-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neuronal hyperexcitability produces enhanced pain transmission in the spinal dorsal horn after spinal cord injury (SCI). Spontaneous and evoked neuronal excitability normally are well controlled by neural circuits. However, SCI produces maladaptive synaptic circuits in the spinal dorsal horn that result in neuronal hyperexcitability. After SCI, activated primary afferent neurons produce enhanced release of glutamate, neuropeptides, adenosine triphosphate, and proinflammatory cytokines, which are known to be major components for pain transmission in the spinal dorsal horn. Enhanced neurochemical events contribute to neuronal hyperexcitability, and neuroanatomical changes also contribute to maladaptive synaptic circuits and neuronal hyperexcitability. These neurochemical and neuroanatomical changes produce enhanced cellular signaling cascades that ensure persistently enhanced pain transmission. This review describes altered neurochemical and neuroanatomical contributions on neuronal hyperexcitability in the spinal dorsal horn, which serve as substrates for central neuropathic pain after SCI.
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Affiliation(s)
- Young Seob Gwak
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1043, USA
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Moon JY, Song S, Yoon SY, Roh DH, Kang SY, Park JH, Beitz AJ, Lee JH. The differential effect of intrathecal Nav1.8 blockers on the induction and maintenance of capsaicin- and peripheral ischemia-induced mechanical allodynia and thermal hyperalgesia. Anesth Analg 2011; 114:215-23. [PMID: 22127815 DOI: 10.1213/ane.0b013e318238002e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND It has been reported that the selective blockade of Nav1.8 sodium channels could be a possible target for the development of analgesics without unwanted side effects. However, the precise role of spinal Nav1.8 in the induction and maintenance of persistent pain, e.g., mechanical allodynia (MA) and thermal hyperalgesia (TH), is not clear. We designed this study to investigate whether spinal Nav1.8 contributes to capsaicin-induced and peripheral ischemia-induced MA and TH. METHODS The Nav1.8 blockers, A-803467 or ambroxol, were injected intrathecally either before or after intraplantar capsaicin injection. To evaluate capsaicin-induced neuronal activation in the spinal cord, we quantified the number of Fos-immunoreactive cells in the dorsal horn. In the thrombus-induced ischemic pain model, we determined the differential effect of A-803467 on the induction phase or maintenance phase of MA. RESULTS Intrathecal injection of A-803467 (10, 30, 100 nmol) or ambroxol (241, 724, 2410 nmol) before intraplantar injection of capsaicin dose dependently prevented the induction of both MA and TH. However, posttreatment with A-803467 (100 nmol) and ambroxol (2410 nmol) did not reduce the MA that had already developed, but did significantly suppress capsaicin-induced TH. Moreover, the capsaicin-induced increase of spinal Fos-immunoreactive cells was significantly diminished by pretreatment, but not posttreatment with Nav1.8 blockers. In thrombus-induced ischemic pain rats, repetitive treatments of A-803467 during the induction period also prevented the development of MA, whereas A-803467 treatments during the maintenance period were ineffective in preventing or reducing MA. CONCLUSIONS These results demonstrate that spinal activation of Nav1.8 mediates the early induction of MA, but not the maintenance of MA. However, both the induction and maintenance of TH are modulated by the intrathecal injection of Nav1.8 blockers. These findings suggest that early treatment with a Nav1.8 blocker can be an important factor in the clinical management of chronic MA associated with inflammatory and ischemic pain.
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Affiliation(s)
- Ji-Young Moon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, South Korea
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Theile JW, Cummins TR. Recent developments regarding voltage-gated sodium channel blockers for the treatment of inherited and acquired neuropathic pain syndromes. Front Pharmacol 2011; 2:54. [PMID: 22007172 PMCID: PMC3185237 DOI: 10.3389/fphar.2011.00054] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/12/2011] [Indexed: 12/19/2022] Open
Abstract
Chronic and neuropathic pain constitute significant health problems affecting millions of individuals each year. Pain sensations typically originate in sensory neurons of the peripheral nervous system which relay information to the central nervous system (CNS). Pathological pain sensations can arise as result of changes in excitability of these peripheral sensory neurons. Voltage-gated sodium channels are key determinants regulating action potential generation and propagation; thus, changes in sodium channel function can have profound effects on neuronal excitability and pain signaling. At present, most of the clinically available sodium channel blockers used to treat pain are non-selective across sodium channel isoforms and can contribute to cardio-toxicity, motor impairments, and CNS side effects. Numerous strides have been made over the last decade in an effort to develop more selective and efficacious sodium channel blockers to treat pain. The purpose of this review is to highlight some of the more recent developments put forth by research universities and pharmaceutical companies alike in the pursuit of developing more targeted sodium channel therapies for the treatment of a variety of neuropathic pain conditions.
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Affiliation(s)
- Jonathan W Theile
- Department of Pharmacology and Toxicology, Stark Neurosciences Research Institute, Indiana University School of Medicine Indianapolis, IN, USA
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Muthuraman A, Singh N. Attenuating effect of Acorus calamus extract in chronic constriction injury induced neuropathic pain in rats: an evidence of anti-oxidative, anti-inflammatory, neuroprotective and calcium inhibitory effects. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 11:24. [PMID: 21426568 PMCID: PMC3072356 DOI: 10.1186/1472-6882-11-24] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Accepted: 03/22/2011] [Indexed: 01/13/2023]
Abstract
Background Acorus calamus (family: Araceae), is an indigenous plant, traditionally it is used as an ingredient of various cocktail preparations and for the management of severe inflammatory disorders in Indian system of medicine. Present study investigated the attenuating role of Acorus calamus plant extract in chronic constriction injury (CCI) of sciatic nerve induced peripheral neuropathy in rats. Methods Hot plate, plantar, Randall Selitto, Von Frey Hair, pin prick, acetone drop, photoactometer and rota-rod tests were performed to assess degree of thermal, radiant, mechanical, chemical sensation, spontaneous motor activity and motor co-ordination changes respectively, at different time intervals i.e., day 0, 1, 3, 6, 9, 12, 15, 18 and 21. Tissue myeloperoxidase, superoxide anion and total calcium levels were determined after 21st day to assess biochemical alterations. Histopathological evaluations were also performed. Hydroalcoholic extract of Acorus calamus (HAE-AC, 100 and 200 mg/kg, p.o.) and pregabalin (10 mg/kg, p.o.) were administered from the day of surgery for 14 days. Results CCI of sciatic nerve significantly induced thermal, radiant, mechanical hyperalgesia and thermal, chemical, tactile allodynia, along with increase in the levels of superoxide anion, total calcium and myeloperoxidase activity. Moreover significant histological changes were also observed. HAE-AC attenuated CCI induced development of painful behavioural, biochemical and histological changes in a dose dependent manner similar to that of pregabalin serving as positive control. Conclusions Acorus calamus prevented CCI induced neuropathy which may be attributed to its multiple actions including anti-oxidative, anti-inflammatory, neuroprotective and calcium inhibitory actions.
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