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Cheng XL, Ruan YL, Dai JY, Fan HZ, Ling JY, Chen J, Lu WG, Gao XJ, Cao P. 8-shogaol derived from dietary ginger alleviated acute and inflammatory pain by targeting TRPV1. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2024; 128:155500. [PMID: 38484627 DOI: 10.1016/j.phymed.2024.155500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 01/24/2024] [Accepted: 02/26/2024] [Indexed: 05/01/2024]
Abstract
Ginger, a well-known spice plant, has been used widely in medicinal preparations for pain relief. However, little is known about its analgesic components and the underlying mechanism. Here, we ascertained, the efficacy of ginger ingredient 8-Shogaol (8S), on inflammatory pain and tolerance induced by morphine, and probed the role of TRPV1 in its analgesic action using genetic and electrophysiology approaches. Results showed that 8S effectively reduced nociceptive behaviors of mice elicited by chemical stimuli, noxious heat as well as inflammation, and antagonized morphine analgesic tolerance independent on opioid receptor function. Genetic deletion of TRPV1 significantly abolished 8S' analgesia action. Further calcium imaging and patch-clamp recording showed that 8S could specifically activate TRPV1 in TRPV1-expressing HEK293T cells and dorsal root ganglion (DRG) neurons. The increase of [Ca2+]i in DRG was primarily mediated through TRPV1. Mutational and computation studies revealed the key binding sites for the interactions between 8S and TRPV1 included Leu515, Leu670, Ile573, Phe587, Tyr511, and Phe591. Further studies showed that TRPV1 activation evoked by 8S resulted in channel desensitization both in vitro and in vivo, as may be attributed to TRPV1 degradation or TRPV1 withdrawal from the cell surface. Collectively, this work provides the first evidence for the attractive analgesia of 8S in inflammatory pain and morphine analgesic tolerance mediated by targeting pain-sensing TRPV1 channel. 8S from dietary ginger has potential as a candidate drug for the treatment of inflammatory pain.
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Affiliation(s)
- Xiao-Lan Cheng
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China; School of Integrated Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Yong-Lan Ruan
- Department of Neurology, Changzhou Hospital Affiliated to Nanjing University of Chinese Medicine, Changzhou, 213003, China
| | - Jing-Ya Dai
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China; Wanbei Health Vocational College, Suzhou, Anhui, 234000, China
| | - Hai-Zhen Fan
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China
| | - Jin-Ying Ling
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China
| | - Jiao Chen
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China
| | - Wu-Guang Lu
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China
| | - Xue-Jiao Gao
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China.
| | - Peng Cao
- Jiangsu Provincial Medical Innovation Center, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, 100 Hongshan Road, Nanjing 210028, China; The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, 100 Minjiang Road, Quzhou, Zhejiang 324000, China.
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2
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Chang X, Zhang H, Chen S. Neural circuits regulating visceral pain. Commun Biol 2024; 7:457. [PMID: 38615103 PMCID: PMC11016080 DOI: 10.1038/s42003-024-06148-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 04/05/2024] [Indexed: 04/15/2024] Open
Abstract
Visceral hypersensitivity, a common clinical manifestation of irritable bowel syndrome, may contribute to the development of chronic visceral pain, which is a major challenge for both patients and health providers. Neural circuits in the brain encode, store, and transfer pain information across brain regions. In this review, we focus on the anterior cingulate cortex and paraventricular nucleus of the hypothalamus to highlight the progress in identifying the neural circuits involved in visceral pain. We also discuss several neural circuit mechanisms and emphasize the importance of cross-species, multiangle approaches and the identification of specific neurons in determining the neural circuits that control visceral pain.
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Affiliation(s)
- Xiaoli Chang
- College of Acupuncture and Massage, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China.
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China.
| | - Haiyan Zhang
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Shaozong Chen
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, 250355, China.
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3
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Chen X, Gan Y, Au NPB, Ma CHE. Current understanding of the molecular mechanisms of chemotherapy-induced peripheral neuropathy. Front Mol Neurosci 2024; 17:1345811. [PMID: 38660386 PMCID: PMC11039947 DOI: 10.3389/fnmol.2024.1345811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is the most common off-target adverse effects caused by various chemotherapeutic agents, such as cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib. CIPN is characterized by a substantial loss of primary afferent sensory axonal fibers leading to sensory disturbances in patients. An estimated of 19-85% of patients developed CIPN during the course of chemotherapy. The lack of preventive measures and limited treatment options often require a dose reduction or even early termination of life-saving chemotherapy, impacting treatment efficacy and patient survival. In this Review, we summarized the current understanding on the pathogenesis of CIPN. One prominent change induced by chemotherapeutic agents involves the disruption of neuronal cytoskeletal architecture and axonal transport dynamics largely influenced by the interference of microtubule stability in peripheral neurons. Due to an ineffective blood-nerve barrier in our peripheral nervous system, exposure to some chemotherapeutic agents causes mitochondrial swelling in peripheral nerves, which lead to the opening of mitochondrial permeability transition pore and cytochrome c release resulting in degeneration of primary afferent sensory fibers. The exacerbated nociceptive signaling and pain transmission in CIPN patients is often linked the increased neuronal excitability largely due to the elevated expression of various ion channels in the dorsal root ganglion neurons. Another important contributing factor of CIPN is the neuroinflammation caused by an increased infiltration of immune cells and production of inflammatory cytokines. In the central nervous system, chemotherapeutic agents also induce neuronal hyperexcitability in the spinal dorsal horn and anterior cingulate cortex leading to the development of central sensitization that causes CIPN. Emerging evidence suggests that the change in the composition and diversity of gut microbiota (dysbiosis) could have direct impact on the development and progression of CIPN. Collectively, all these aspects contribute to the pathogenesis of CIPN. Recent advances in RNA-sequencing offer solid platform for in silico drug screening which enable the identification of novel therapeutic agents or repurpose existing drugs to alleviate CIPN, holding immense promises for enhancing the quality of life for cancer patients who undergo chemotherapy and improve their overall treatment outcomes.
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Affiliation(s)
- Xinyu Chen
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yumeng Gan
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Ngan Pan Bennett Au
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
- Institute of Life Sciences and Healthcare, University of Portsmouth, Portsmouth, United Kingdom
| | - Chi Him Eddie Ma
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
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Shehab S, Javed H, Johnson AM, Tariq S, Kumar CA, Emerald BS. Unveiling the mechanisms of neuropathic pain suppression: perineural resiniferatoxin targets Trpv1 and beyond. Front Neuroanat 2023; 17:1306180. [PMID: 38099210 PMCID: PMC10720729 DOI: 10.3389/fnana.2023.1306180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/10/2023] [Indexed: 12/17/2023] Open
Abstract
Neuropathic pain arises from damage or disorders affecting the somatosensory system. In rats, L5 nerve injury induces thermal and mechanical hypersensitivity/hyperalgesia. Recently, we demonstrated that applying resiniferatoxin (RTX) directly on uninjured L3 and L4 nerves alleviated thermal and mechanical hypersensitivity resulting from L5 nerve injury. Herein, using immunohistochemistry, Western blot, and qRT-PCR techniques, we reveal that perineural application of RTX (0.002%) on the L4 nerve substantially downregulated the expression of its receptor (Trpv1) and three different voltage-gated ion channels (Nav1.9, Kv4.3, and Cav2.2). These channels are found primarily in small-sized neurons and show significant colocalization with Trpv1 in the dorsal root ganglion (DRG). However, RTX treatment did not affect the expression of Kv1.1, Piezo2 (found in large-sized neurons without colocalization with Trpv1), and Kir4.1 (localized in satellite cells) in the ipsilateral DRGs. Furthermore, RTX application on L3 and L4 nerves reduced the activation of c-fos in the spinal neurons induced by heat stimulation. Subsequently, we investigated whether applying RTX to the L3 and L4 nerves 3 weeks before the L5 nerve injury could prevent the onset of neuropathic pain. Both 0.002 and 0.004% concentrations of RTX produced significant analgesic effects, while complete prevention of thermal and mechanical hypersensitivity required a concentration of 0.008%. Importantly, this preventive effect on neuropathic manifestations was not associated with nerve degeneration, as microscopic examination revealed no morphological changes. Overall, this study underscores the mechanisms and the significance of perineural RTX treatment applied to adjacent uninjured nerves in entirely preventing nerve injury-induced neuropathic pain in humans and animals.
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Affiliation(s)
- Safa Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
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Miękisiak G. Editorial for the Special Issue “Chronic Neuropathic Pain Therapy and Anaesthesia”. Medicina (B Aires) 2023; 59:medicina59040674. [PMID: 37109632 PMCID: PMC10145259 DOI: 10.3390/medicina59040674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Chronic neuropathic pain (CNP), a complex and debilitating condition arising from damage or dysfunction of the somatosensory nervous system, affects millions of people worldwide [...]
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Exploring the possible mechanism involved in the anti-nociceptive effect of β-sitosterol: modulation of oxidative stress, nitric oxide and IL-6. Inflammopharmacology 2023; 31:517-527. [PMID: 36574096 DOI: 10.1007/s10787-022-01122-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 11/25/2022] [Indexed: 12/28/2022]
Abstract
Β-sitosterol is a phytosterol, documented to possess various activities including protection against inflammation, diabetes and Alzheimer's disease. The current investigation was designed to explore the analgesic potential of β-sitosterol and the possible molecular mechanism involved in the observed effect. β-sitosterol was administered at varying doses of 10, 20, and 40 mg/kg before subjecting the mice to acetic acid and formalin challenges. The number of writhings in acetic acid and the number of flinchings and foot tappings were quantified in the formalin test. For mechanistic studies, substance P (cyclooxygenase-2 (COX-2) stimulator) and L-Nitro arginine methyl ester (L-NAME) (nitric oxide synthetases (NOS) inhibitor) and L-arginine (nitric oxide precursor) were administered before β-sitosterol treatment. β-sitosterol (10, 20, 40 mg/kg) treatment significantly reduced acetic acid-induced writhings and ameliorated the formalin-induced inflammatory phase dose-dependently. Whereas, 40 mg/kg dose of β-sitosterol abrogated the formalin-induced neurogenic phase. Substance-P abrogated the effect of β-sitosterol in both neurogenic and inflammatory phases. Whereas, L-arginine only abrogated the inflammatory phase. In biochemical analysis, β-sitosterol treatment reduced the level of interleukin-6 (IL-6), thiobarbituric acid reactive substances (TBARS) and increased the level of reduced glutathione (GSH). Furthermore, L-arginine and substance-P abrogated the GSH increasing and TBARS lowering effect of β-sitosterol (40 mg/kg). Overall, the current study delineated that β-sitosterol may induce an anti-nociceptive effect via inhibiting the IL-6, oxidative stress, cyclo-oxygenase and nitric oxide.
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7
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Goyal S, Goyal S, Goins AE, Alles SR. Plant-derived natural products targeting ion channels for pain. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 13:100128. [PMID: 37151956 PMCID: PMC10160805 DOI: 10.1016/j.ynpai.2023.100128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/27/2023] [Accepted: 04/11/2023] [Indexed: 05/09/2023]
Abstract
Chronic pain affects approximately one-fifth of people worldwide and reduces quality of life and in some cases, working ability. Ion channels expressed along nociceptive pathways affect neuronal excitability and as a result modulate pain experience. Several ion channels have been identified and investigated as potential targets for new medicines for the treatment of a variety of human diseases, including chronic pain. Voltage-gated channels Na+ and Ca2+ channels, K+ channels, transient receptor potential channels (TRP), purinergic (P2X) channels and acid-sensing ion channels (ASICs) are some examples of ion channels exhibiting altered function or expression in different chronic pain states. Pharmacological approaches are being developed to mitigate dysregulation of these channels as potential treatment options. Since natural compounds of plant origin exert promising biological and pharmacological properties and are believed to possess less adverse effects compared to synthetic drugs, they have been widely studied as treatments for chronic pain for their ability to alter the functional activity of ion channels. A literature review was conducted using Medline, Google Scholar and PubMed, resulted in listing 79 natural compounds/extracts that are reported to interact with ion channels as part of their analgesic mechanism of action. Most in vitro studies utilized electrophysiological techniques to study the effect of natural compounds on ion channels using primary cultures of dorsal root ganglia (DRG) neurons. In vivo studies concentrated on different pain models and were conducted mainly in mice and rats. Proceeding into clinical trials will require further study to develop new, potent and specific ion channel modulators of plant origin.
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Affiliation(s)
- Sachin Goyal
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
| | - Shivali Goyal
- School of Pharmacy, Abhilashi University, Chail Chowk, Mandi, HP 175045, India
| | - Aleyah E. Goins
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
| | - Sascha R.A. Alles
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
- Corresponding author.
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8
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Kaisis E, Thei LJ, Stephens GJ, Dallas ML. Protofibrillar Amyloid Beta Modulation of Recombinant hCaV2.2 (N-Type) Voltage-Gated Channels. Pharmaceuticals (Basel) 2022; 15:ph15121459. [PMID: 36558910 PMCID: PMC9783047 DOI: 10.3390/ph15121459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
Cav2.2 channels are key regulators of presynaptic Ca2+ influx and their dysfunction and/or aberrant regulation has been implicated in many disease states; however, the nature of their involvement in Alzheimer's disease (AD) is less clear. In this short communication, we show that recombinant hCav2.2/b1b/a2d1 channels are modulated by human synthetic AD-related protofibrillar amyloid beta Ab1-42 peptides. Structural studies revealed a time-dependent increase in protofibril length, with the majority of protofibrils less than 100 nm at 24 h, while at 48 h, the majority were longer than 100 nm. Cav2.2 modulation by Ab1-42 was different between a 'low' (100 nM) and 'high' (1 µM) concentration in terms of distinct effects on individual biophysical parameters. A concentration of 100 nM Ab1-42 caused no significant changes in the measured biophysical properties of Cav2.2 currents. In contrast, 1 µM Ab1-42 caused an inhibitory decrease in the current density (pA/pF) and maximum conductance (Gmax), and a depolarizing shift in the slope factor (k). These data highlight a differential modulation of Cav2.2 channels by the Ab1-42 peptide. Discrete changes in the presynaptic Ca2+ flux have been reported to occur at an early stage of AD; therefore, this study reveals a potential mechanistic link between amyloid accumulation and Cav2.2 channel modulation.
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9
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Zheng Q, Dong X, Green DP, Dong X. Peripheral mechanisms of chronic pain. MEDICAL REVIEW 2022; 2:251-270. [PMID: 36067122 PMCID: PMC9381002 DOI: 10.1515/mr-2022-0013] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 06/13/2022] [Indexed: 11/15/2022]
Abstract
Abstract
Acutely, pain serves to protect us from potentially harmful stimuli, however damage to the somatosensory system can cause maladaptive changes in neurons leading to chronic pain. Although acute pain is fairly well controlled, chronic pain remains difficult to treat. Chronic pain is primarily a neuropathic condition, but studies examining the mechanisms underlying chronic pain are now looking beyond afferent nerve lesions and exploring new receptor targets, immune cells, and the role of the autonomic nervous system in contributing chronic pain conditions. The studies outlined in this review reveal how chronic pain is not only confined to alterations in the nervous system and presents findings on new treatment targets and for this debilitating disease.
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Affiliation(s)
- Qin Zheng
- Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Xintong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Dustin P. Green
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Howard Hughes Medical Institute, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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10
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Systemic, Intrathecal, and Intracerebroventricular Antihyperalgesic Effects of the Calcium Channel Blocker CTK 01512–2 Toxin in Persistent Pain Models. Mol Neurobiol 2022; 59:4436-4452. [DOI: 10.1007/s12035-022-02864-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 04/28/2022] [Indexed: 11/25/2022]
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11
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Mirabelli E, Elkabes S. Neuropathic Pain in Multiple Sclerosis and Its Animal Models: Focus on Mechanisms, Knowledge Gaps and Future Directions. Front Neurol 2022; 12:793745. [PMID: 34975739 PMCID: PMC8716468 DOI: 10.3389/fneur.2021.793745] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/17/2021] [Indexed: 12/22/2022] Open
Abstract
Multiple sclerosis (MS) is a multifaceted, complex and chronic neurological disease that leads to motor, sensory and cognitive deficits. MS symptoms are unpredictable and exceedingly variable. Pain is a frequent symptom of MS and manifests as nociceptive or neuropathic pain, even at early disease stages. Neuropathic pain is one of the most debilitating symptoms that reduces quality of life and interferes with daily activities, particularly because conventional pharmacotherapies do not adequately alleviate neuropathic pain. Despite advances, the mechanisms underlying neuropathic pain in MS remain elusive. The majority of the studies investigating the pathophysiology of MS-associated neuropathic pain have been performed in animal models that replicate some of the clinical and neuropathological features of MS. Experimental autoimmune encephalomyelitis (EAE) is one of the best-characterized and most commonly used animal models of MS. As in the case of individuals with MS, rodents affected by EAE manifest increased sensitivity to pain which can be assessed by well-established assays. Investigations on EAE provided valuable insights into the pathophysiology of neuropathic pain. Nevertheless, additional investigations are warranted to better understand the events that lead to the onset and maintenance of neuropathic pain in order to identify targets that can facilitate the development of more effective therapeutic interventions. The goal of the present review is to provide an overview of several mechanisms implicated in neuropathic pain in EAE by summarizing published reports. We discuss current knowledge gaps and future research directions, especially based on information obtained by use of other animal models of neuropathic pain such as nerve injury.
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Affiliation(s)
- Ersilia Mirabelli
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States.,Department of Biology and Chemistry, School of Health Sciences, Liberty University, Lynchburg, VA, United States
| | - Stella Elkabes
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States
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Javed H, Rehmathulla S, Tariq S, Ali MA, Emerald BS, Shehab S. Co-localization of nociceptive markers in the lumbar dorsal root ganglion and spinal cord of dromedary camel. J Comp Neurol 2021; 529:3710-3725. [PMID: 34468017 DOI: 10.1002/cne.25240] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 11/12/2022]
Abstract
Nociceptive markers in mice have been identified in two distinct peptidergic and nonpeptidergic neurons in the dorsal root ganglion (DRG) and distributed in different laminae of the dorsal horn of the spinal cord. Recently, however, a study in humans showed a significant overlapping in these two populations. In this study, we investigated the distribution of various nociceptive markers in the lumbar DRG and spinal cord of the dromedary camel. Immunohistochemical data showed a remarkable percentage of total neurons in the DRG expressed IB4 binding (54.5%), calcitonin gene-related peptide (CGRP; 49.5%), transient receptor potential vanilloid 1 (TRPV1; 48.2%), and nitric oxide synthase (NOS; 30.6%). The co-localization data showed that 89.6% and 74.0% of CGRP- and TRPV1-labeled neurons, respectively, were IB4 positive. In addition, 61.6% and 84.2% of TRPV1- and NOS-immunoreactive neurons, respectively, were also co-localized with CGRP. The distribution of IB4, CGRP, TRPV1, substance P, and NOS immunoreactivities in the spinal cord were observed in lamina I and outer lamina II (IIo). Quantitative data showed that 82.4% of IB4-positive nerve terminals in laminae I and IIo were co-localized with CGRP, and 86.0% of CGRP-labeled terminals were co-localized with IB4. Similarly, 85.1% of NOS-labeled nerve terminals were co-localized with CGRP. No neuropeptide Y (NPY) or cholecystokinin (CCK) immunoreactivities were detected in the DRG, and no co-localization between IB4, NPY, and CCK were observed in the spinal cord. Our results demonstrate marked convergence of nociceptive markers in the primary afferent neurons in camels, which is similar to humans rather than the mouse. The data also emphasizes the importance of interspecies differences when selecting ideal animal models for studying nociception and treating chronic pain.
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Affiliation(s)
- Hayate Javed
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
| | - Sumisha Rehmathulla
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
| | - Saeed Tariq
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
| | - Mahmoud A Ali
- Department of Pharmacology, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
| | - Safa Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, UAE
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Lee MC, Nahorski MS, Hockley JRF, Lu VB, Ison G, Pattison LA, Callejo G, Stouffer K, Fletcher E, Brown C, Drissi I, Wheeler D, Ernfors P, Menon D, Reimann F, Smith ESJ, Woods CG. Human Labor Pain Is Influenced by the Voltage-Gated Potassium Channel K V6.4 Subunit. Cell Rep 2021; 32:107941. [PMID: 32697988 PMCID: PMC7383234 DOI: 10.1016/j.celrep.2020.107941] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/19/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022] Open
Abstract
By studying healthy women who do not request analgesia during their first delivery, we investigate genetic effects on labor pain. Such women have normal sensory and psychometric test results, except for significantly higher cuff pressure pain. We find an excess of heterozygotes carrying the rare allele of SNP rs140124801 in KCNG4. The rare variant KV6.4-Met419 has a dominant-negative effect and cannot modulate the voltage dependence of KV2.1 inactivation because it fails to traffic to the plasma membrane. In vivo, Kcng4 (KV6.4) expression occurs in 40% of retrograde-labeled mouse uterine sensory neurons, all of which express KV2.1, and over 90% express the nociceptor genes Trpv1 and Scn10a. In neurons overexpressing KV6.4-Met419, the voltage dependence of inactivation for KV2.1 is more depolarized compared with neurons overexpressing KV6.4. Finally, KV6.4-Met419-overexpressing neurons have a higher action potential threshold. We conclude that KV6.4 can influence human labor pain by modulating the excitability of uterine nociceptors. KCNG4 variant highly prevalent in women requiring no analgesia in childbirth KCNG4 variant encodes KV6.4Met-419; KV6.4 is a silent subunit modifying KV activity KV6.4Met-419 is retained in the cytoplasm and acts in a dominant-negative manner KV6.4Met-419 overexpression results in hypoexcitable sensory neurons
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Affiliation(s)
- Michael C Lee
- University Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
| | - Michael S Nahorski
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - James R F Hockley
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Van B Lu
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Gillian Ison
- University Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Luke A Pattison
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Gerard Callejo
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
| | - Kaitlin Stouffer
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Emily Fletcher
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Christopher Brown
- Department of Psychological Sciences, Institute of Psychology, Health and Society, University of Liverpool, Liverpool L69 7ZA, UK
| | - Ichrak Drissi
- University Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Daniel Wheeler
- University Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Patrik Ernfors
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - David Menon
- University Division of Anaesthesia, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
| | | | - C Geoffrey Woods
- Cambridge Institute for Medical Research, Wellcome Trust MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK.
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14
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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: 9] [Impact Index Per Article: 3.0] [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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15
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Bonezzi C, Fornasari D, Cricelli C, Magni A, Ventriglia G. Pharmacological Management of Adults with Chronic Non-Cancer Pain in General Practice. Pain Ther 2020; 9:17-28. [PMID: 33315207 PMCID: PMC7736454 DOI: 10.1007/s40122-020-00218-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/04/2020] [Indexed: 12/29/2022] Open
Abstract
Chronic pain is a public health priority that affects about 20% of the general population, causing disability and impacting productivity and quality of life. It is often managed in the primary care setting. Chronic pain management is most effective when the pain mechanism has been identified and addressed by appropriate therapy. This document provides an overview of pharmacological therapy for chronic non-cancer pain in the primary care setting, with the aim of improving treatment decisions based on the underlying pain mechanisms and pain neuroscience.
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Affiliation(s)
- Cesare Bonezzi
- ICS Maugeri IRCCS, Via Salvatore Maugeri 10, Pavia, Italy
| | - Diego Fornasari
- Department of Medical Biotechnology and Translational Medicine, Università Degli Studi Di Milano, Via Vanvitelli 32, Milan, Italy.
| | - Claudio Cricelli
- SIMG (Italian College of General Practitioners and Primary Care), Via Del Sansovino 179, Florence, Italy
| | - Alberto Magni
- SIMG (Italian College of General Practitioners and Primary Care), Via Del Sansovino 179, Florence, Italy
| | - Giuseppe Ventriglia
- SIMG (Italian College of General Practitioners and Primary Care), Via Del Sansovino 179, Florence, Italy
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16
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Analgesic Effects of Topical Amitriptyline in Patients With Chemotherapy-Induced Peripheral Neuropathy: Mechanistic Insights From Studies in Mice. THE JOURNAL OF PAIN 2020; 22:440-453. [PMID: 33227509 DOI: 10.1016/j.jpain.2020.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/15/2020] [Accepted: 11/03/2020] [Indexed: 12/25/2022]
Abstract
Oral amitriptyline hydrochloride (amitriptyline) is ineffective against some forms of chronic pain and is often associated with dose-limiting adverse events. We evaluated the potential effectiveness of high-dose topical amitriptyline in a preliminary case series of chemotherapy-induced peripheral neuropathy patients and investigated whether local or systemic adverse events associated with the use of amitriptyline were present in these patients. We also investigated the mechanism of action of topically administered amitriptyline in mice. Our case series suggested that topical 10% amitriptyline treatment was associated with pain relief in chemotherapy-induced peripheral neuropathy patients, without the side effects associated with systemic absorption. Topical amitriptyline significantly increased mechanical withdrawal thresholds when applied to the hind paw of mice, and inhibited the firing responses of C-, Aβ- and Aδ-type peripheral nerve fibers in ex vivo skin-saphenous nerve preparations. Whole-cell patch-clamp recordings on cultured sensory neurons revealed that amitriptyline was a potent inhibitor of the main voltage-gated sodium channels (Nav1.7, Nav1.8, and Nav1.9) found in nociceptors. Calcium imaging showed that amitriptyline activated the transient receptor potential cation channel, TRPA1. Our case series indicated that high-dose 10% topical amitriptyline could alleviate neuropathic pain without adverse local or systemic effects. This analgesic action appeared to be mediated through local inhibition of voltage-gated sodium channels. PERSPECTIVE: Our preliminary case series suggested that topical amitriptyline could provide effective pain relief for chemotherapy-induced peripheral neuropathy patients without any systemic or local adverse events. Investigation of the mechanism of this analgesic action in mice revealed that this activity was mediated through local inhibition of nociceptor Nav channels.
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17
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Sameera, Shah FA, Rashid S. Conformational ensembles of non-peptide ω-conotoxin mimetics and Ca +2 ion binding to human voltage-gated N-type calcium channel Ca v2.2. Comput Struct Biotechnol J 2020; 18:2357-2372. [PMID: 32994894 PMCID: PMC7498737 DOI: 10.1016/j.csbj.2020.08.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 02/07/2023] Open
Abstract
Chronic neuropathic pain is the most complex and challenging clinical problem of a population that sets a major physical and economic burden at the global level. Ca2+-permeable channels functionally orchestrate the processing of pain signals. Among them, N-type voltage-gated calcium channels (VGCC) hold prominent contribution in the pain signal transduction and serve as prime targets for synaptic transmission block and attenuation of neuropathic pain. Here, we present detailed in silico analysis to comprehend the underlying conformational changes upon Ca2+ ion passage through Cav2.2 to differentially correlate subtle transitions induced via binding of a conopeptide-mimetic alkylphenyl ether-based analogue MVIIA. Interestingly, pronounced conformational changes were witnessed at the proximal carboxyl-terminus of Cav2.2 that attained an upright orientation upon Ca+2 ion permeability. Moreover, remarkable changes were observed in the architecture of channel tunnel. These findings illustrate that inhibitor binding to Cav2.2 may induce more narrowing in the pore size as compared to Ca2+ binding through modulating the hydrophilicity pattern at the selectivity region. A significant reduction in the tunnel volume at the selectivity filter and its enhancement at the activation gate of Ca+2-bound Cav2.2 suggests that ion binding modulates the outward splaying of pore-lining S6 helices to open the voltage gate. Overall, current study delineates dynamic conformational ensembles in terms of Ca+2 ion and MVIIA-associated structural implications in the Cav2.2 that may help in better therapeutic intervention to chronic and neuropathic pain management.
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Affiliation(s)
- Sameera
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Fawad Ali Shah
- Riphah Institute of Pharmaceutical Sciences, Riphah International University, Islamabad, Pakistan
| | - Sajid Rashid
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
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18
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Analgesic effects of the CTK 01512-2 toxin in different models of orofacial pain in rats. Pharmacol Rep 2020; 72:600-611. [PMID: 32399819 DOI: 10.1007/s43440-020-00108-z] [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: 11/26/2019] [Revised: 04/17/2020] [Accepted: 04/23/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Orofacial pain is clinically challenging, having therapeutic failures and side effects. This study evaluated the antinociceptive activities of the CTK 01512-2 toxin, the TRPA1 channel antagonist, and the selective inhibitor of the N-type voltage-gated calcium channels (N-type VGCC), in different pain models. MATERIALS AND METHODS The trigeminal ganglia were stimulated in vitro with capsaicin. The in vivo models received subcutaneous (sc) injections of formalin into the upper lip of the rats, Freund's Complete Adjuvant (FCA) into the temporomandibular joint (TMJ), and infraorbital nerve constrictions (IONC). CTK 01512-2 at concentrations of 30, 100, and 300 pmol/site, intrathecally (ith), and MVIIA at 10, 30, and 100 pmol/site in the formalin test, guided the doses for the models. The glutamate levels in the CSF of the rats that were submitted to IONC were analyzed. RESULTS CTK 01512-2 decreased the nociceptive behavior in the inflammatory phase of the formalin test (65.94 ± 7.35%) and MVIIA in the neurogenic phase (81.23 ± 3.36%). CTK 01512-2 reduced facial grooming with FCA in the TMJ (96.7 ± 1.6%), and in the IONC neuropathy model, it decreased heat hyperalgesia (100%) and cold hyperalgesia (81.61 ± 9.02%). The levels of glutamate in the trigeminal ganglia in vitro (81.40 ± 8.59%) and in the CSF in vivo (70.0 ± 9.2%) were reduced. CONCLUSIONS The roles of TRPA1 in pain transduction and the performance of CTK 01512-2 in the inhibition of the N-type VGCCs were reinforced. This dual activity may represent an advantage in clinical treatments.
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Antunes FTT, Angelo SG, Dallegrave E, Picada JN, Marroni NP, Schemitt E, Ferraz AG, Gomez MV, de Souza AH. Recombinant peptide derived from the venom the Phoneutria nigriventer spider relieves nociception by nerve deafferentation. Neuropeptides 2020; 79:101980. [PMID: 31711615 DOI: 10.1016/j.npep.2019.101980] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 10/10/2019] [Accepted: 10/13/2019] [Indexed: 12/17/2022]
Abstract
The avulsion of nerve roots of the brachial plexus that is commonly seen in motorcycle accidents is a type of neuropathy due to deafferentation. This type of pain is clinically challenging since therapeutical protocols fail or have severe side effects. Thus, it is proposed to evaluate the antinociceptive activity of the recombinant CTK 01512-2 peptide that is derived from the venom of the Phoneutria nigriventer spider, as a future new therapeutical option. The neuropathic pain was surgically induced by avulsion of the upper brachial plexus trunk in groups of male Wistar rats and after 17 days, they were treated intrathecally with morphine, ziconotide, and CTK 01512-2. Behavioral tests were performed to evaluate mechanical and thermal hyperalgesia, cold allodynia, the functional activity of the front paw, and exploratory locomotion after the treatments. The peripheral blood samples were collected 6 h after the treatments and a comet assay was performed. The spinal cord was removed for the lipoperoxidation dosing of the membranes. The cerebrospinal fluid was analyzed for the dosage of glutamate. The recombinant peptide showed an antinociceptive effect when compared to the other drugs, without affecting the locomotor activity of the animals. Mechanical and thermal hyperalgesia, as well as cold allodynia, were reduced in the first hours of treatment. The levels of glutamate and the damage by membrane lipoperoxidation were shown to be improved, and genotoxicity was not demonstrated. In a scenario of therapeutical failures in the treatment of this type of pain, CTK 01512-2 was shown as a new effective alternative protocol. However, further testing is required to determine pharmacokinetics.
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Affiliation(s)
- Flavia Tasmin Techera Antunes
- Program of Postgraduation in Cellular and Molecular Biology Applied to Health (PPGBioSaúde), Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil
| | | | - Eliane Dallegrave
- Department of Pharmacoscience, University Federal of Science of Health of Porto Alegre (UFCSPA), Rio Grande do Sul, Brazil
| | - Jaqueline Nascimento Picada
- Laboratory of Genetic Toxicology, PPGBioSaúde and PPGGTA, Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil
| | - Norma Possa Marroni
- Laboratory of Oxidative Stress and Antioxidants, PPGBioSaúde and PPGGTA, Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil
| | - Elizangela Schemitt
- Laboratory of Oxidative Stress and Antioxidants, PPGBioSaúde and PPGGTA, Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil
| | - Alice Gomes Ferraz
- Laboratory of Pharmacology, Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil
| | - Marcus Vinicius Gomez
- Nucleus of Postgraduation, Institute of Teaching and Research of Santa Casa de Belo Horizonte, Belo Horizonte, Brazil
| | - Alessandra Hubner de Souza
- Program of Postgraduation in Cellular and Molecular Biology Applied to Health (PPGBioSaúde), Lutheran University of Brazil (ULBRA), Canoas, RS, Brazil.
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Electroacupuncture Stimulation Alleviates CFA-Induced Inflammatory Pain Via Suppressing P2X3 Expression. Int J Mol Sci 2019; 20:ijms20133248. [PMID: 31269659 PMCID: PMC6651287 DOI: 10.3390/ijms20133248] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/25/2019] [Accepted: 06/28/2019] [Indexed: 12/13/2022] Open
Abstract
Chronic inflammatory pain is one of the most common complaints that seriously affects patients’ quality of life. Previous studies have demonstrated that the analgesic effect of electroacupuncture (EA) stimulation on inflammatory pain is related to its frequency. In this study, we focused on whether the analgesic effects of EA are related to the period of stimulation. Purinergic receptor P2X3 (P2X3) is involved in the pathological process underlying chronic inflammatory pain and neuropathic pain. We hypothesized that 100 Hz EA stimulation alleviated Freund’s complete adjuvant (CFA) induced inflammatory pain via regulating P2X3 expression in the dorsal root ganglion (DRG) and/or spinal cord dorsal horn (SCDH). We also assumed that the analgesic effect of EA might be related to the period of stimulation. We found that both short-term (three day) and long-term (14 day) 100 Hz EA stimulation effectively increased the paw withdrawal threshold (PWT) and reversed the elevation of P2X3 in the DRG and SCDH of CFA rats. However, the analgesic effects of 100 Hz EA were not dependent on the period of stimulation. Moreover, P2X3 inhibition or activation may contribute to or attenuate the analgesic effects of 100 Hz EA on CFA-induced inflammatory pain. This result indicated that EA reduced pain hypersensitivity through P2X3 modulation.
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21
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Getting a handle on Ca V2.2 (N-type) voltage-gated Ca 2+ channels. Proc Natl Acad Sci U S A 2018; 115:12848-12850. [PMID: 30538200 DOI: 10.1073/pnas.1818608115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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