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Zamith Cunha R, Semprini A, Salamanca G, Gobbo F, Morini M, Pickles KJ, Roberts V, Chiocchetti R. Expression of Cannabinoid Receptors in the Trigeminal Ganglion of the Horse. Int J Mol Sci 2023; 24:15949. [PMID: 37958932 PMCID: PMC10648827 DOI: 10.3390/ijms242115949] [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: 09/10/2023] [Revised: 10/17/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023] Open
Abstract
Cannabinoid receptors are expressed in human and animal trigeminal sensory neurons; however, the expression in the equine trigeminal ganglion is unknown. Ten trigeminal ganglia from five horses were collected post-mortem from an abattoir. The expression of cannabinoid receptors type 1 (CB1R) and type 2 (CB2R), and the cannabinoid-related receptors like transient receptor potential vanilloid type 1 (TRPV1), peroxisome proliferator-activated receptor gamma (PPARɣ), and G protein-related receptor 55 (GPR55) in the trigeminal ganglia (TG) of the horse were studied, using immunofluorescence on cryosections and formalin-fixed paraffin-embedded (FFPE) sections. Neurons and glial cells were identified using fluorescent Nissl staining NeuroTrace® and an antibody directed against the glial marker glial fibrillary acidic protein (GFAP), respectively. Macrophages were identified by means of an antibody directed against the macrophages/microglia marker ionized calcium-binding adapter molecule 1 (IBA1). The protein expression of CB1R, CB2R, TRPV1, and PPARɣ was found in the majority of TG neurons in both cryosections and FFPE sections. The expression of GPR55 immunoreactivity was mainly detectable in FFPE sections, with expression in the majority of sensory neurons. Some receptors were also observed in glial cells (CB2R, TRPV1, PPARγ, and GPR55) and inflammatory cells (PPARγ and GPR55). These results support further investigation of such receptors in disorders of equine trigeminal neuronal excitability.
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Affiliation(s)
- Rodrigo Zamith Cunha
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
| | - Alberto Semprini
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
| | - Giulia Salamanca
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
| | - Francesca Gobbo
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
| | - Maria Morini
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
| | - Kirstie J. Pickles
- School of Veterinary Medicine and Science, University of Nottingham, Nottingham LE12 5RD, UK;
| | - Veronica Roberts
- Bristol Vet School, University of Bristol, Bristol BS40 5DU, UK;
| | - Roberto Chiocchetti
- Department of Veterinary Medical Sciences, University of Bologna, 37200 Bologna, Italy; (R.Z.C.); (A.S.); (G.S.); (F.G.); (M.M.)
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Mussetto V, Moen A, Trofimova L, Sandkühler J, Hogri R. Differential activation of spinal and parabrachial glial cells in a neuropathic pain model. Front Cell Neurosci 2023; 17:1163171. [PMID: 37082205 PMCID: PMC10110840 DOI: 10.3389/fncel.2023.1163171] [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: 02/10/2023] [Accepted: 03/17/2023] [Indexed: 04/22/2023] Open
Abstract
The clinical burden faced by chronic pain patients is compounded by affective comorbidities, such as depression and anxiety disorders. Emerging evidence suggests that reactive glial cells in the spinal cord dorsal horn play a key role in the chronification of pain, while supraspinal glia are important for psychological aspects of chronic pain. The lateral parabrachial nucleus (LPBN) in the brainstem is a key node in the ascending pain system, and is crucial for the emotional dimension of pain. Yet, whether astrocytes and microglia in the LPBN are activated during chronic pain is unknown. Here, we evaluated the occurrence of glial activation in the LPBN of male Sprague-Dawley rats 1, 4, and 7 weeks after inducing a chronic constriction injury (CCI) of the sciatic nerve, a prevalent neuropathic pain model. CCI animals developed mechanical and thermal hypersensitivity that persisted for at least 4 weeks, and was mostly reversed after 7 weeks. Using immunohistochemical staining and confocal imaging, we found that CCI caused a strong increase in the expression of the astrocytic marker GFAP and the microglial marker Iba1 in the ipsilateral spinal dorsal horn, with peak expression observed 1 week post-injury. Moreover, morphology analysis revealed changes in microglial phenotype, indicative of microglia activation. In contrast, CCI did not induce any detectable changes in either astrocytes or microglia in the LPBN, at any time point. Thus, our results indicate that while neuropathic pain induces a robust glial reaction in the spinal dorsal horn, it fails to activate glial cells in the LPBN.
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Affiliation(s)
| | | | | | | | - Roni Hogri
- Department of Neurophysiology, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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Shafiei-Irannejad V, Abbaszadeh S, Janssen PML, Soraya H. Memantine and its benefits for cancer, cardiovascular and neurological disorders. Eur J Pharmacol 2021; 910:174455. [PMID: 34461125 DOI: 10.1016/j.ejphar.2021.174455] [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: 02/19/2021] [Revised: 08/19/2021] [Accepted: 08/26/2021] [Indexed: 01/10/2023]
Abstract
Memantine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist that was initially indicated for the treatment of moderate to severe Alzheimer's disease. It is now also considered for a variety of other pathologies in which activation of NMDA receptors apparently contributes to the pathogenesis and progression of disease. In addition to the central nervous system (CNS), NMDA receptors can be found in non-neuronal cells and tissues that recently have become an interesting research focus. Some studies have shown that glutamate signaling plays a role in cell transformation and cancer progression. In addition, these receptors may play a role in cardiovascular disorders. In this review, we focus on the most recent findings for memantine with respect to its pharmacological effects in a range of diseases, including inflammatory disorders, cardiovascular diseases, cancer, neuropathy, as well as retinopathy.
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Affiliation(s)
- Vahid Shafiei-Irannejad
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran
| | - Samin Abbaszadeh
- Department of Pharmacology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | - Hamid Soraya
- Cellular and Molecular Research Center, Cellular and Molecular Medicine Institute, Urmia University of Medical Sciences, Urmia, Iran; Department of Pharmacology, Faculty of Pharmacy, Urmia University of Medical Sciences, Urmia, Iran.
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Role of neuroglia in neuropathic pain and depression. Pharmacol Res 2021; 174:105957. [PMID: 34688904 DOI: 10.1016/j.phrs.2021.105957] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/06/2021] [Accepted: 10/20/2021] [Indexed: 12/30/2022]
Abstract
Patients with neuropathic pain induced by nerve injury usually present with co-morbid affective changes, such as depression. Neuroglia was reported to play an important role in the development and maintenance of neuropathic pain both centrally and peripherally. Meanwhile, there have been studies showing that neuroglia participated in the development of depression. However, the specific role of neuroglia in neuropathic pain and depression has not been reviewed comprehensively. Therefore, we summarized the recent findings on the role of neuroglia in neuropathic pain and depression. Based on this review, we found a bridge-like role of neuroglia in neuropathic pain co-morbid with depression. This review may provide therapeutic implications in the treatment of neuropathic pain and offer potential help in the studies of mechanisms in the future.
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McIlwrath SL, Starr ME, High AE, Saito H, Westlund KN. Effect of acetyl-L-carnitine on hypersensitivity in acute recurrent caerulein-induced pancreatitis and microglial activation along the brain’s pain circuitry. World J Gastroenterol 2021; 27:794-814. [PMID: 33727771 PMCID: PMC7941858 DOI: 10.3748/wjg.v27.i9.794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/08/2020] [Accepted: 01/15/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Acute pancreatitis (AP) and recurring AP are serious health care problems causing excruciating pain and potentially lethal outcomes due to sepsis. The validated caerulein- (CAE) induced mouse model of acute/recurring AP produces secondary persistent hypersensitivity and anxiety-like behavioral changes for study.
AIM To determine efficacy of acetyl-L-carnitine (ALC) to reduce pain-related behaviors and brain microglial activation along the pain circuitry in CAE-pancreatitis.
METHODS Pancreatitis was induced with 6 hly intraperitoneal (i.p.) injections of CAE (50 µg/kg), 3 d a week for 6 wk in male C57BL/6J mice. Starting in week 4, mice received either vehicle or ALC until experiment’s end. Mechanical hyper-sensitivity was assessed with von Frey filaments. Heat hypersensitivity was determined with the hotplate test. Anxiety-like behavior was tested in week 6 using elevated plus maze and open field tests. Microglial activation in brain was quantified histologically by immunostaining for ionized calcium-binding adaptor molecule 1 (Iba1).
RESULTS Mice with CAE-induced pancreatitis had significantly reduced mechanical withdrawal thresholds and heat response latencies, indicating ongoing pain. Treatment with ALC attenuated inflammation-induced hypersensitivity, but hypersensitivity due to abdominal wall injury caused by repeated intraperitoneal injections persisted. Animals with pancreatitis displayed spontaneous anxiety-like behavior in the elevated plus maze compared to controls. Treatment with ALC resulted in increased numbers of rearing activity events, but time spent in “safety” was not changed. After all the abdominal injections, pancreata were translucent if excised at experiment’s end and opaque if excised on the subsequent day, indicative of spontaneous healing. Post mortem histopathological analysis performed on pancreas sections stained with Sirius Red and Fast Green identified wide-spread fibrosis and acinar cell atrophy in sections from mice with CAE-induced pancreatitis that was not rescued by treatment with ALC. Microglial Iba1 immunostaining was significantly increased in hippocampus, thalamus (intralaminar nuclei), hypothalamus, and amygdala of mice with CAE-induced pancreatitis compared to naïve controls but unchanged in the primary somatosensory cortex compared to naïves.
CONCLUSION CAE-induced pancreatitis caused increased pain-related behaviors, pancreatic fibrosis, and brain microglial changes. ALC alleviated CAE-induced mechanical and heat hypersensitivity but not abdominal wall injury-induced hypersensitivity caused by the repeated injections.
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Affiliation(s)
- Sabrina L McIlwrath
- Research Service, New Mexico Veterans Affairs Healthcare System, Albuquerque, NM 87108, United States
| | - Marlene E Starr
- Department of Surgery, University of Kentucky, Lexington, KY 40536, United States
| | - Abigail E High
- College of Liberal Arts, University of Texas, Austin, TX 78712, United States
| | - Hiroshi Saito
- Department of Surgery, University of Kentucky, Lexington, KY 40536, United States
| | - Karin N Westlund
- Research Service, New Mexico Veterans Affairs Healthcare System, Albuquerque, NM 87108, United States
- Department of Anesthesiology and Critical Care Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
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Kapoor T, Mehan S. Neuroprotective Methodologies in the Treatment of Multiple Sclerosis Current Status of Clinical and Pre-clinical Findings. Curr Drug Discov Technol 2021; 18:31-46. [PMID: 32031075 DOI: 10.2174/1570163817666200207100903] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/02/2019] [Accepted: 11/26/2019] [Indexed: 11/22/2022]
Abstract
Multiple sclerosis is an idiopathic and autoimmune associated motor neuron disorder that affects myelinated neurons in specific brain regions of young people, especially females. MS is characterized by oligodendrocytes destruction further responsible for demyelination, neuroinflammation, mitochondrial abnormalities, oxidative stress and neurotransmitter deficits associated with motor and cognitive dysfunctions, vertigo and muscle weakness. The limited intervention of pharmacologically active compounds like interferon-β, mitoxantrone, fingolimod and monoclonal antibodies used clinically are majorly associated with adverse drug reactions. Pre-clinically, gliotoxin ethidium bromide mimics the behavioral and neurochemical alterations in multiple sclerosis- like in experimental animals associated with the down-regulation of adenyl cyclase/cAMP/CREB, which is further responsible for a variety of neuropathogenic factors. Despite the considerable investigation of neuroprotection in curing multiple sclerosis, some complications still remain. The available medications only provide symptomatic relief but do not stop the disease progression. In this way, the development of unused beneficial methods tends to be ignored. The limitations of the current steady treatment may be because of their activity at one of the many neurotransmitters included or their failure to up direct signaling flag bearers detailed to have a vital part in neuronal sensitivity, biosynthesis of neurotransmitters and its discharge, development, and separation of the neuron, synaptic versatility and cognitive working. Therefore, the current review strictly focused on the exploration of various clinical and pre-clinical features available for multiple sclerosis to understand the pathogenic mechanisms and to introduce pharmacological interventions associated with the upregulation of intracellular adenyl cyclase/cAMP/CREB activation to ameliorate multiple sclerosis-like features.
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Affiliation(s)
- Tarun Kapoor
- Neuropharmacology Division, ISF College of Pharmacy, Moga, Punjab, India
| | - Sidharth Mehan
- Neuropharmacology Division, ISF College of Pharmacy, Moga, Punjab, India
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Teixeira-Santos L, Albino-Teixeira A, Pinho D. Neuroinflammation, oxidative stress and their interplay in neuropathic pain: Focus on specialized pro-resolving mediators and NADPH oxidase inhibitors as potential therapeutic strategies. Pharmacol Res 2020; 162:105280. [PMID: 33161139 DOI: 10.1016/j.phrs.2020.105280] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 10/24/2020] [Accepted: 10/27/2020] [Indexed: 02/08/2023]
Abstract
Neuropathic pain (NP) is a chronic condition that results from a lesion or disease of the nervous system, greatly impacting patients' quality of life. Current pharmacotherapy options deliver inadequate and/or insufficient responses and thus a significant unmet clinical need remains for alternative treatments in NP. Neuroinflammation, oxidative stress and their reciprocal relationship are critically involved in NP pathophysiology. In this context, new pharmacological approaches, aiming at enhancing the resolution phase of inflammation and/or restoring redox balance by targeting specific reactive oxygen species (ROS) sources, are emerging as potential therapeutic strategies for NP, with improved efficacy and safety profiles. Several reports have demonstrated that administration of exogenous specialized pro-resolving mediators (SPMs) ameliorates NP pathophysiology. Likewise, deletion or inhibition of the ROS-generating enzyme NADPH oxidase (NOX), particularly its isoforms 2 and 4, results in beneficial effects in NP models. Notably, SPMs also modulate oxidative stress and NOX also regulates neuroinflammation. By targeting neuroinflammatory and oxidative pathways, both SPMs analogues and isoform-specific NOX inhibitors are promising therapeutic strategies for NP.
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Affiliation(s)
- Luísa Teixeira-Santos
- Departamento de Biomedicina - Unidade de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Portugal; MedInUP - Centro de Investigação Farmacológica e Inovação Medicamentosa, Universidade do Porto, Portugal.
| | - António Albino-Teixeira
- Departamento de Biomedicina - Unidade de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Portugal; MedInUP - Centro de Investigação Farmacológica e Inovação Medicamentosa, Universidade do Porto, Portugal.
| | - Dora Pinho
- Departamento de Biomedicina - Unidade de Farmacologia e Terapêutica, Faculdade de Medicina, Universidade do Porto, Portugal; MedInUP - Centro de Investigação Farmacológica e Inovação Medicamentosa, Universidade do Porto, Portugal.
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A Fatal Alliance between Microglia, Inflammasomes, and Central Pain. Int J Mol Sci 2020; 21:ijms21113764. [PMID: 32466593 PMCID: PMC7312017 DOI: 10.3390/ijms21113764] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/20/2020] [Accepted: 05/25/2020] [Indexed: 12/22/2022] Open
Abstract
Microglia are the resident immune cells in the CNS, which survey the brain parenchyma for pathogens, initiate inflammatory responses, secrete inflammatory mediators, and phagocyte debris. Besides, they play a role in the regulation of brain ion homeostasis and in pruning synaptic contacts and thereby modulating neural networks. More recent work shows that microglia are embedded in brain response related to stress phenomena, the development of major depressive disorders, and pain-associated neural processing. The microglia phenotype varies between activated-toxic-neuroinflammatory to non-activated-protective-tissue remodeling, depending on the challenges and regulatory signals. Increased inflammatory reactions result from brain damage, such as stroke, encephalitis, as well as chronic dysfunctions, including stress and pain. The dimension of damage/toxic stimuli defines the amplitude of inflammation, ranging from an on-off event to low but continuous simmering to uncontrollable. Pain, either acute or chronic, involves inflammasome activation at the point of origin, the different relay stations, and the sensory and processing cortical areas. This short review aimed at identifying a sinister role of the microglia-inflammasome platform for the development and perpetuation of acute and chronic central pain and its association with changes in CNS physiology.
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Chen Y, Shi Y, Wang G, Li Y, Cheng L, Wang Y. Memantine selectively prevented the induction of dynamic allodynia by blocking Kir2.1 channel and inhibiting the activation of microglia in spinal dorsal horn of mice in spared nerve injury model. Mol Pain 2019; 15:1744806919838947. [PMID: 30845882 PMCID: PMC6487752 DOI: 10.1177/1744806919838947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Memantine is one of the important clinical medications in treating moderate to severe Alzheimer disease. The effect of memantine on preventing or treating punctate allodynia has been thoroughly studied but not on the induction of dynamic allodynia. The aim of this study is to investigate whether memantine could prevent the induction of dynamic allodynia and its underlying spinal mechanisms. Results (1) In in vivo spared nerve injury pain model, pretreatment with memantine at a lower dose (10 nmol, intrathecal; memantine-10) selectively prevented the induction of dynamic allodynia but not the punctate allodynia. (2) Pretreatment with either MK801-10 (MK801-10 nmol, intrathecal) or higher dose of memantine (30 nmol, intrathecal; memantine-30) prevented the induction of both dynamic and punctate allodynia. (3) Memantine-10 showed significant effect on the inhibition of the spared nerve injury-induced overactivation of microglia in spinal dorsal horn. (4) In contrast, in complete freund′s adjuvant (CFA) model, memantine-10 neither affected the CFA injection-induced activation of microglia in spinal dorsal horn nor the induction of dynamic allodynia. (5) Immunohistological studies showed Kir2.1 channel distributed widely and co-localized with microglia in the spinal dorsal horn of mice. (6) Pretreatment with either minocycline, a microglia inhibitor, or ML133, a Kir2.1 inhibitor, both selectively prevented the overactivation of microglia in spinal dorsal horn and the induction of dynamic allodynia following spared nerve injury. Conclusion The selective inhibitory effect on the induction of dynamic allodynia in spared nerve injury model by low dose of the memantine (memantine-10) was tightly correlated with the blockade of microglia Kir2.1 channel to suppress the microglia activation.
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Affiliation(s)
- Yangyang Chen
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yiqian Shi
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guoxiang Wang
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yimei Li
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Longzhen Cheng
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yun Wang
- 1 Neurology Department, Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Zhongshan Hospital, Fudan University, Shanghai, China
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Ferrari A, Rustichelli C, Baraldi C. Glutamate receptor antagonists with the potential for migraine treatment. Expert Opin Investig Drugs 2017; 26:1321-1330. [PMID: 29050521 DOI: 10.1080/13543784.2017.1395411] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Preclinical, clinical, and other (e.g., genetic) evidence support the concept that migraine susceptibility may at least partially result from a glutamatergic system disorder. Therefore, the receptors of the glutamatergic system are considered relatively new targets for investigational drugs to treat migraine. Investigational and established glutamate receptor antagonists (GluRAs) have been shown to possess antinociceptive properties in preclinical models of trigeminovascular nociception and have been evaluated in clinical trials. This review focuses on preclinical and clinical studies of GluRAs for the treatment of migraine. Areas covered: A PubMed database search (from 1987 to December 2016) and a review of published studies on GluRAs in migraine were conducted. Expert opinion: All published clinical trials of investigational GluRAs have been unsuccessful in establishing benefit for acute migraine treatment. Clinical trial results contrast with the preclinical data, suggesting that glutamate (Glu) does not play a decisive role after the attack has already been triggered. These antagonists may instead be useful for migraine prophylaxis. Improving patient care requires further investigating and critically analyzing the role of Glu in migraine, designing experimental models to study more receptors and their corresponding antagonists, and identifying biomarkers to facilitate trials designed to target specific subgroups of migraine patients.
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Affiliation(s)
- Anna Ferrari
- a Unit of Medical Toxicology, Headache and Drug Abuse Centre; Department of Diagnostic, Clinical and Public Health Medicine , University of Modena and Reggio Emilia , Modena , Italy
| | - Cecilia Rustichelli
- b Department of Life Sciences , University of Modena and Reggio Emilia , Modena , Italy
| | - Carlo Baraldi
- a Unit of Medical Toxicology, Headache and Drug Abuse Centre; Department of Diagnostic, Clinical and Public Health Medicine , University of Modena and Reggio Emilia , Modena , Italy
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Yan YY, Li CY, Zhou L, Ao LY, Fang WR, Li YM. Research progress of mechanisms and drug therapy for neuropathic pain. Life Sci 2017; 190:68-77. [PMID: 28964813 DOI: 10.1016/j.lfs.2017.09.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 09/09/2017] [Accepted: 09/25/2017] [Indexed: 12/13/2022]
Abstract
Neuropathic pain is maladaptive pain caused by injury or dysfunction in peripheral and central nervous system, and remains a worldwide thorny problem leading to decreases in physical and mental quality of people's life. Currently, drug therapy is the main treatment regimen for resolving pain, while effective drugs are still unmet in medical need, and commonly used drugs such as anticonvulsants and antidepressants often make patients experience adverse drug reactions like dizziness, somnolence, severe headache, and high blood pressure. Thus, in this review we overview the anatomical physiology, underlying mechanisms of neuropathic pain to provide a better understanding in the initiation, development, maintenance, and modulation of this pervasive disease, and inspire research in the unclear mechanisms as well as potential targets. Furthermore, we summarized the existing drug therapies and new compounds that have shown antalgic effects in laboratory studies to be helpful for rational regimens in clinical treatment and promotion in novel drug discovery.
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Affiliation(s)
- Yun-Yi Yan
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China
| | - Cheng-Yuan Li
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China
| | - Lin Zhou
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China
| | - Lu-Yao Ao
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China
| | - Wei-Rong Fang
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China.
| | - Yun-Man Li
- State Key Laboratory of Natural Medicines, School of Basic Medicine and Clinical Pharmacy, China Pharmaceutical University, Nanjing 210009, PR China.
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Pickering G, Morel V. Memantine for the treatment of general neuropathic pain: a narrative review. Fundam Clin Pharmacol 2017; 32:4-13. [DOI: 10.1111/fcp.12316] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/04/2017] [Accepted: 08/10/2017] [Indexed: 12/26/2022]
Affiliation(s)
- Gisèle Pickering
- CHU Clermont-Ferrand; Centre de Pharmacologie Clinique; F-63003 Clermont-Ferrand France
- Inserm, CIC 1405; Neurodol 1107 F-63003 Clermont-Ferrand France
- Laboratoire de Pharmacologie; Faculté de Médecine; Clermont Université; F-63001 Clermont-Ferrand France
| | - Véronique Morel
- CHU Clermont-Ferrand; Centre de Pharmacologie Clinique; F-63003 Clermont-Ferrand France
- Inserm, CIC 1405; Neurodol 1107 F-63003 Clermont-Ferrand France
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13
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Liu Y, Zhou LJ, Wang J, Li D, Ren WJ, Peng J, Wei X, Xu T, Xin WJ, Pang RP, Li YY, Qin ZH, Murugan M, Mattson MP, Wu LJ, Liu XG. TNF-α Differentially Regulates Synaptic Plasticity in the Hippocampus and Spinal Cord by Microglia-Dependent Mechanisms after Peripheral Nerve Injury. J Neurosci 2017; 37:871-881. [PMID: 28123022 PMCID: PMC5296781 DOI: 10.1523/jneurosci.2235-16.2016] [Citation(s) in RCA: 237] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/18/2016] [Accepted: 12/02/2016] [Indexed: 12/30/2022] Open
Abstract
Clinical studies show that chronic pain is accompanied by memory deficits and reduction in hippocampal volume. Experimental studies show that spared nerve injury (SNI) of the sciatic nerve induces long-term potentiation (LTP) at C-fiber synapses in spinal dorsal horn, but impairs LTP in the hippocampus. The opposite changes may contribute to neuropathic pain and memory deficits, respectively. However, the cellular and molecular mechanisms underlying the functional synaptic changes are unclear. Here, we show that the dendrite lengths and spine densities are reduced significantly in hippocampal CA1 pyramidal neurons, but increased in spinal neurokinin-1-positive neurons in mice after SNI, indicating that the excitatory synaptic connectivity is reduced in hippocampus but enhanced in spinal dorsal horn in this neuropathic pain model. Mechanistically, tumor necrosis factor-alpha (TNF-α) is upregulated in bilateral hippocampus and in ipsilateral spinal dorsal horn, whereas brain-derived neurotrophic factor (BDNF) is decreased in the hippocampus but increased in the ipsilateral spinal dorsal horn after SNI. Importantly, the SNI-induced opposite changes in synaptic connectivity and BDNF expression are prevented by genetic deletion of TNF receptor 1 in vivo and are mimicked by TNF-α in cultured slices. Furthermore, SNI activated microglia in both spinal dorsal horn and hippocampus; pharmacological inhibition or genetic ablation of microglia prevented the region-dependent synaptic changes, neuropathic pain, and memory deficits induced by SNI. The data suggest that neuropathic pain involves different structural synaptic alterations in spinal and hippocampal neurons that are mediated by overproduction of TNF-α and microglial activation and may underlie chronic pain and memory deficits. SIGNIFICANCE STATEMENT Chronic pain is often accompanied by memory deficits. Previous studies have shown that peripheral nerve injury produces both neuropathic pain and memory deficits and induces long-term potentiation (LTP) at C-fiber synapses in spinal dorsal horn (SDH) but inhibits LTP in hippocampus. The opposite changes in synaptic plasticity may contribute to chronic pain and memory deficits, respectively. However, the structural and molecular bases of these alterations of synaptic plasticity are unclear. Here, we show that the complexity of excitatory synaptic connectivity and brain-derived neurotrophic factor (BDNF) expression are enhanced in SDH but reduced in the hippocampus in neuropathic pain and the opposite changes depend on tumor necrosis factor-alpha/tumor necrosis factor receptor 1 signaling and microglial activation. The region-dependent synaptic alterations may underlie chronic neuropathic pain and memory deficits induced by peripheral nerve injury.
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Affiliation(s)
- Yong Liu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
| | - Li-Jun Zhou
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
| | - Jun Wang
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Dai Li
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Wen-Jie Ren
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Jiyun Peng
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, and
| | - Xiao Wei
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Ting Xu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Wen-Jun Xin
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, 510080 China
| | - Rui-Ping Pang
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Yong-Yong Li
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China
| | - Zhi-Hai Qin
- National Laboratory of Biomacromolecules, Chinese Academy of Sciences-University of Tokyo Joint Laboratory of Structural Virology and Immunology, Beijing, 100101 China
| | - Madhuvika Murugan
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854
- Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, and
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Long-Jun Wu
- Department of Cell Biology and Neuroscience, Rutgers University, Piscataway, New Jersey 08854,
- Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, and
| | - Xian-Guo Liu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, Guangzhou 510080, China,
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, 510080 China
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14
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Fiore NT, Austin PJ. Are the emergence of affective disturbances in neuropathic pain states contingent on supraspinal neuroinflammation? Brain Behav Immun 2016; 56:397-411. [PMID: 27118632 DOI: 10.1016/j.bbi.2016.04.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/11/2016] [Accepted: 04/22/2016] [Indexed: 12/28/2022] Open
Abstract
Neuro-immune interactions contribute to the pathogenesis of neuropathic pain due to peripheral nerve injury. A large body of preclinical evidence supports the idea that the immune system acts to modulate the sensory symptoms of neuropathy at both peripheral and central nervous system sites. The potential involvement of neuro-immune interactions in the highly debilitating affective disturbances of neuropathic pain, such as depression, anhedonia, impaired cognition and reduced motivation has received little attention. This is surprising given the widely accepted view that sickness behaviour, depression, cognitive impairment and other neuropsychiatric conditions can arise from inflammatory mechanisms. Moreover, there is a set of well-described immune-to-brain transmission mechanisms that explain how peripheral inflammation can lead to supraspinal neuroinflammation. In the last 5years increasing evidence has emerged that peripheral nerve injury induces supraspinal changes in cytokine or chemokine expression and alters glial cell activity. In this systematic review, based on strong preclinical evidence, we advance the argument that the emergence of affective disturbances in neuropathic pain states are contingent on pro-inflammatory mediators in the interconnected hippocampal-medial prefrontal circuitry that subserve affective behaviours. We explore how dysregulation of inflammatory mediators in these networks may result in affective disturbances through a wide variety of neuromodulatory mechanisms. There are also promising results from clinical trials showing that anti-inflammatory agents have efficacy in the treatment of a variety of neuropsychiatric conditions including depression and appear suited to sub-groups of patients with elevated pro-inflammatory profiles. Thus, although further research is required, aggressively targeting supraspinal pro-inflammatory mediators at critical time-points in appropriate clinical populations is likely to be a novel avenue to treat debilitating affective disturbances in neuropathic conditions.
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Affiliation(s)
- Nathan T Fiore
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Paul J Austin
- Discipline of Anatomy & Histology, School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia.
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15
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Fenton BW, Shih E, Zolton J. The neurobiology of pain perception in normal and persistent pain. Pain Manag 2015; 5:297-317. [DOI: 10.2217/pmt.15.27] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
SUMMARY Pain is a significant national burden in terms of patient suffering, expenditure and lost productivity. Understanding pain is fundamental to improving evaluation, treatment and innovation in the management of acute and persistent pain syndromes. Pain perception begins in the periphery, and then ascends in several tracts, relaying at different levels. Pain signals arrive in the thalamus and midbrain structures which form the pain neuromatrix, a constantly shifting set of networks and connections that determine conscious perception. Several cortical regions become active simultaneously during pain perception; activity in the cortical pain matrix evolves over time to produce a complex pain perception network. Dysfunction at any level has the potential to produce unregulated, persistent pain.
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Affiliation(s)
- Bradford W Fenton
- Summa Health System, Department of Obstetrics & Gynecology, 75 Arch St Ste 102, Akron, OH 44304, USA
| | - Elim Shih
- Women's Health Fellow, Cleveland Clinic Foundation, 9500 Euclid Avenue, Desk A10, Cleveland, OH 44195, USA
| | - Jessica Zolton
- Summa Health System, Department of Obstetrics & Gynecology, 75 Arch St Ste 102, Akron, OH 44304, USA
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16
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Evidence for a distinct neuro-immune signature in rats that develop behavioural disability after nerve injury. J Neuroinflammation 2015; 12:96. [PMID: 25986444 PMCID: PMC4506439 DOI: 10.1186/s12974-015-0318-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 05/05/2015] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Chronic neuropathic pain is a neuro-immune disorder, characterised by allodynia, hyperalgesia and spontaneous pain, as well as debilitating affective-motivational disturbances (e.g., reduced social interactions, sleep-wake cycle disruption, anhedonia, and depression). The role of the immune system in altered sensation following nerve injury is well documented. However, its role in the development of affective-motivational disturbances remains largely unknown. Here, we aimed to characterise changes in the immune response at peripheral and spinal sites in a rat model of neuropathic pain and disability. METHODS Sixty-two rats underwent sciatic nerve chronic constriction injury (CCI) and were characterised as either Pain and disability, Pain and transient disability or Pain alone on the basis of sensory threshold testing and changes in post-CCI dominance behaviour in resident-intruder interactions. Nerve ultrastructure was assessed and the number of T lymphocytes and macrophages were quantified at the site of injury on day six post-CCI. ATF3 expression was quantified in the dorsal root ganglia (DRG). Using a multiplex assay, eight cytokines were quantified in the sciatic nerve, DRG and spinal cord. RESULTS All CCI rats displayed equal levels of mechanical allodynia, structural nerve damage, and reorganisation. All CCI rats had significant infiltration of macrophages and T lymphocytes to both the injury site and the DRG. Pain and disability rats had significantly greater numbers of T lymphocytes. CCI increased IL-6 and MCP-1 in the sciatic nerve. Examination of disability subgroups revealed increases in IL-6 and MCP-1 were restricted to Pain and disability rats. Conversely, CCI led to a decrease in IL-17, which was restricted to Pain and transient disability and Pain alone rats. CCI significantly increased IL-6 and MCP-1 in the DRG, with IL-6 restricted to Pain and disability rats. CCI rats had increased IL-1β, IL-6 and MCP-1 in the spinal cord. Amongst subgroups, only Pain and disability rats had increased IL-1β. CONCLUSIONS This study has defined individual differences in the immune response at peripheral and spinal sites following CCI in rats. These changes correlated with the degree of disability. Our data suggest that individual immune signatures play a significant role in the different behavioural trajectories following nerve injury, and in some cases may lead to persistent affective-motivational disturbances.
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17
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Yalcin I, Barthas F, Barrot M. Emotional consequences of neuropathic pain: insight from preclinical studies. Neurosci Biobehav Rev 2014; 47:154-64. [PMID: 25148733 DOI: 10.1016/j.neubiorev.2014.08.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/15/2014] [Accepted: 08/03/2014] [Indexed: 01/12/2023]
Abstract
Mood disorders such as depression and anxiety are frequently observed in patients suffering from chronic pain, including neuropathic pain. While this comorbidity is clinically well established, the underlying mechanism(s) remained unclear. The recent development of animal models now allows addressing the consequences of neuropathic pain. In this review, we report the preclinical evidences from anatomical, neuroimaging, behavioral, pharmacological and biochemical studies that address the anxiodepressive consequences of neuropathic pain. We present an overview of rodent models of these consequences and we discuss the challenges and parameters to consider for generating these models. We then discuss the possible mechanism(s) underlying anxiodepressive consequences by describing morphological and functional changes. Information is provided concerning neuroanatomical changes and plasticity, including LTP and LTD, in the anterior cingulate cortex, the insula, the hippocampus, the amygdala and the mesolimbic system, neuroendocrine parameters concerning the hypothalamo-pituitary-adrenal axis, neuroimmune response including the role of glial cells and cytokines, monoamine systems and changes in locus coeruleus noradrenergic system, and neurotrophic factors such as BDNF.
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Affiliation(s)
- Ipek Yalcin
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, 67084 Strasbourg, France.
| | - Florent Barthas
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, 67084 Strasbourg, France; Université de Strasbourg, 67084 Strasbourg, France
| | - Michel Barrot
- Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, 67084 Strasbourg, France
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18
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Morel V, Pickering G, Etienne M, Dupuis A, Privat AM, Chalus M, Eschalier A, Daulhac L. Low doses of dextromethorphan have a beneficial effect in the treatment of neuropathic pain. Fundam Clin Pharmacol 2014; 28:671-80. [PMID: 24702319 DOI: 10.1111/fcp.12076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 03/20/2014] [Accepted: 04/01/2014] [Indexed: 12/30/2022]
Abstract
N-methyl-D-aspartate receptor (NMDAR) antagonists may be given in persistent neuropathic pain, but adverse events especially with ketamine may limit their clinical use. Less central and cognitive adverse events are described with dextromethorphan and memantine. These molecules have been explored in many preclinical and clinical studies, but data are conflicting as regards neuropathic pain alleviation. Dextromethorphan and memantine have been administered to animals after spinal nerve ligation (SNL) to evaluate their antinociceptive/cognitive effects and associated molecular events, including the phosphorylation of several tyrosine (pTyr(1336), pTyr(1472)) residues in the NR2B NMDAR subunit. Spinal nerve ligation and sham animals received dextromethorphan (10 mg/kg, i.p.), memantine (20 mg/kg, i.p.) or saline (1 mL/kg, i.p.). These drugs were administered once symptoms of allodynia and hyperalgesia had developed. Tests were carried out before and after surgery. Tactile allodynia, mechanical hyperalgesia and spatial memory were, respectively, evaluated by von Frey, Randall & Selitto and Y-maze tests and molecular events by Western blot analysis. Spinal nerve-ligated animals displayed nociception and impaired spatial memory. Dextromethorphan, but not memantine, reversed neuropathic pain (NP) symptoms, restored spatial memory integrity and decreased the expression of pTyr(1336)NR2B. Following postoperative administration of dextromethorphan, this study has demonstrated for the first time a concordance between behaviour, cognitive function and molecular events via pTyr(1336)NR2B for neuropathic pain alleviation. Confirmation of these findings in patients would constitute a major step forward in the treatment of neuropathic pain and in the improvement of cognitive function and quality of life.
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Affiliation(s)
- Véronique Morel
- Facultés de Médecine/Pharmacie, Laboratoire de Pharmacologie, Clermont Université, Université d'Auvergne, Pharmacologie Fondamentale et Clinique de la Douleur, F-63000, Clermont-Ferrand, France; Inserm, U1107 Neuro-Dol, F-63001, Clermont-Ferrand, France; Centre de Pharmacologie Clinique, CHU Clermont-Ferrand, Inserm CIC 501, F-63003, Clermont-Ferrand, France
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19
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Memantine, a promising drug for the prevention of neuropathic pain in rat. Eur J Pharmacol 2013; 721:382-90. [DOI: 10.1016/j.ejphar.2013.06.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/04/2013] [Accepted: 06/19/2013] [Indexed: 01/01/2023]
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20
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Novel treatment with neuroprotective and antiviral properties against a neuroinvasive human respiratory virus. J Virol 2013; 88:1548-63. [PMID: 24227863 DOI: 10.1128/jvi.02972-13] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Human coronaviruses (HCoVs) are recognized respiratory pathogens with neuroinvasive and neurotropic properties in mice and humans. HCoV strain OC43 (HCoV-OC43) can infect and persist in human neural cells and activate neuroinflammatory and neurodegenerative mechanisms, suggesting that it could be involved in neurological disease of unknown etiology in humans. Moreover, we have shown that HCoV-OC43 is neurovirulent in susceptible mice, causing encephalitis, and that a viral mutant with a single point mutation in the viral surface spike (S) protein induces a paralytic disease that involves glutamate excitotoxicity in susceptible mice. Herein, we show that glutamate recycling via the glial transporter 1 protein transporter and glutamine synthetase are central to the dysregulation of glutamate homeostasis and development of motor dysfunctions and paralytic disease in HCoV-OC43-infected mice. Moreover, memantine, an N-methyl-d-aspartate receptor antagonist widely used in the treatment of neurological diseases in humans, improved clinical scores related to paralytic disease and motor disabilities by partially restoring the physiological neurofilament phosphorylation state in virus-infected mice. Interestingly, memantine attenuated mortality rates and body weight loss and reduced HCoV-OC43 replication in the central nervous system in a dose-dependent manner. This novel action of memantine on viral replication strongly suggests that it could be used as an antiviral agent to directly limit viral replication while improving neurological symptoms in various neurological diseases with a viral involvement. Mutations in the surface spike (S) protein of human respiratory coronavirus OC43 appear after persistent infection of human cells of the central nervous system, a possible viral adaptation to this environment. Furthermore, a single amino acid change in the viral S protein modulated virus-induced neuropathology in mice from an encephalitis to a neuropathology characterized by flaccid paralysis, which involves glutamate excitotoxicity. We now show that memantine, a drug that is used for alleviating symptoms associated with neuropathology, such as Alzheimer's disease, can partially restore the physiological state of infected mice by limiting both neurodegeneration and viral replication. This suggests that memantine could be used as an antiviral agent while improving neurological symptoms in various neurological diseases with a viral involvement.
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Abstract
Inflammation is the process by which an organism responds to tissue injury involving both immune cell recruitment and mediator release. Diverse causes of neuropathic pain are associated with excessive inflammation in both the peripheral and central nervous system which may contribute to the initiation and maintenance of persistent pain. Chemical mediators, such as cytokines, chemokines, and lipid mediators, released during an inflammatory response have the undesired effect of sensitizing and stimulating nociceptors, their central synaptic targets or both. These changes can promote long-term maladaptive plasticity resulting in persistent neuropathic pain. This review aims to provide an overview of inflammatory mechanisms at differing levels of the sensory neuroaxis with a focus on neuropathic pain. We will compare and contrast neuropathic pain states such as traumatic nerve injury which is associated with a vigorous inflammatory response and chemotherapy induced pain in which the inflammatory response is much more modest. Targeting excessive inflammation in neuropathic pain provides potential therapeutic opportunities and we will discuss some of the opportunities but also the clinical challenges in such an approach.
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Affiliation(s)
- A Ellis
- King's College London, Wolfson Wing, Hodgkin Building, Guy's Campus, London SE1 1UL, UK.
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22
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Svízenská IH, Brázda V, Klusáková I, Dubový P. Bilateral changes of cannabinoid receptor type 2 protein and mRNA in the dorsal root ganglia of a rat neuropathic pain model. J Histochem Cytochem 2013; 61:529-47. [PMID: 23657829 DOI: 10.1369/0022155413491269] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cannabinoid receptor type 2 (CB2R) plays a critical role in nociception. In contrast to cannabinoid receptor type 1 ligands, CB2R agonists do not produce undesirable central nervous system effects and thus promise to treat neuropathic pain that is often resistant to medical therapy. In the study presented here, we evaluated the bilateral distribution of the CB2R protein and messenger RNA (mRNA) in rat dorsal root ganglia (DRG) after unilateral peripheral nerve injury using immunohistochemistry, western blot, and in situ hybridization analysis. Unilateral chronic constriction injury (CCI) of the sciatic nerve induced neuropathic pain behavior and bilateral elevation of both CB2R protein and mRNA in lumbar L4-L5 as well as cervical C7-C8 DRG when compared with naive animals. CB2R protein and mRNA were increased not only in DRG neurons but also in satellite glial cells. The fact that changes appear bilaterally and (albeit at a lower level) even in the remote cervical DRG can be related to propagation of neuroinflammation alongside the neuraxis and to the neuroprotective effects of CB2R.
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Mika J, Zychowska M, Popiolek-Barczyk K, Rojewska E, Przewlocka B. Importance of glial activation in neuropathic pain. Eur J Pharmacol 2013; 716:106-19. [PMID: 23500198 DOI: 10.1016/j.ejphar.2013.01.072] [Citation(s) in RCA: 325] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 12/17/2012] [Accepted: 01/09/2013] [Indexed: 12/13/2022]
Abstract
Glia plays a crucial role in the maintenance of neuronal homeostasis in the central nervous system. The microglial production of immune factors is believed to play an important role in nociceptive transmission. Pain may now be considered a neuro-immune disorder, since it is known that the activation of immune and immune-like glial cells in the dorsal root ganglia and spinal cord results in the release of both pro- and anti-inflammatory cytokines, as well as algesic and analgesic mediators. In this review we presented an important role of cytokines (IL-1alfa, IL-1beta, IL-2, IL-4, IL-6, IL-10, IL-15, IL-18, TNFalpha, IFNgamma, TGF-beta 1, fractalkine and CCL2); complement components (C1q, C3, C5); metaloproteinases (MMP-2,-9) and many other factors, which become activated on spinal cord and DRG level under neuropathic pain. We discussed the role of the immune system in modulating chronic pain. At present, unsatisfactory treatment of neuropathic pain will seek alternative targets for new drugs and it is possible that anti-inflammatory factors like IL-10, IL-4, IL-1alpha, TGF-beta 1 would fulfill this role. Another novel approach for controlling neuropathic pain can be pharmacological attenuation of glial and immune cell activation. It has been found that propentofylline, pentoxifylline, minocycline and fluorocitrate suppress the development of neuropathic pain. The other way of pain control can be the decrease of pro-nociceptive agents like transcription factor synthesis (NF-kappaB, AP-1); kinase synthesis (MEK, p38MAPK, JNK) and protease activation (cathepsin S, MMP9, MMP2). Additionally, since it is known that the opioid-induced glial activation opposes opioid analgesia, some glial inhibitors, which are safe and clinically well tolerated, are proposed as potential useful ko-analgesic agents for opioid treatment of neuropathic pain. This review pointed to some important mechanisms underlying the development of neuropathic pain, which led to identify some possible new approaches to the treatment of neuropathic pain, based on the more comprehensive knowledge of the interaction between the nervous system and glial and immune cells.
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Affiliation(s)
- Joanna Mika
- Department of Pain Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smetna Street, 31-343 Krakow, Poland.
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Inflaming the brain: CRPS a model disease to understand neuroimmune interactions in chronic pain. J Neuroimmune Pharmacol 2012. [PMID: 23188523 DOI: 10.1007/s11481-012-9422-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We review current concepts in CRPS from a neuroimaging perspective and point out topics and potential mechanisms that are suitable to be investigated in the next step towards understanding the pathophysiology of CRPS. We have outlined functional aspects of the syndrome, from initiating lesion via inflammatory mechanisms to CNS change and associated sickness behavior, with current evidence for up-regulation of immunological factors in CRPS, neuroimaging of systemic inflammation, and neuroimaging findings in CRPS. The initiation, maintenances and CNS targets implicated in CRPS and in the neuro-inflammatory reflex are discussed in terms of CRPS symptoms and recent preclinical studies. Potential avenues for investigating CRPS with PET and fMRI are described, along with roles of inflammation, treatment and behavior in CRPS. It is our hope that this outline will provoke discussion and promote further empirical studies on the interactions between central and peripheral inflammatory pathways manifest in CRPS.
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Calvo M, Dawes JM, Bennett DLH. The role of the immune system in the generation of neuropathic pain. Lancet Neurol 2012; 11:629-42. [PMID: 22710756 DOI: 10.1016/s1474-4422(12)70134-5] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Persistent pain is a sequela of several neurological conditions with a primary immune basis, such as Guillain-Barré syndrome and multiple sclerosis. Additionally, diverse forms of injury to the peripheral or the central nervous systems--whether traumatic, metabolic, or toxic--result in substantial recruitment and activation of immune cells. This response involves the innate immune system, but evidence also exists of T-lymphocyte recruitment, and in some patient cohorts antibodies to neuronal antigens have been reported. Mediators released by immune cells, such as cytokines, sensitise nociceptive signalling in the peripheral and central nervous systems. Preclinical data suggest an immune pathogenesis of neuropathic pain, but clinical evidence of a central role of the immune system is less clear. An important challenge for the future is to establish to what extent this immune response initiates or maintains neuropathic pain in patients and thus whether it is amenable to therapy.
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Affiliation(s)
- Margarita Calvo
- Department of Neurorestoration, Wolfson CARD, King's College London, London, UK
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26
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Spinal cord stimulation modulates cerebral function: an fMRI study. Neuroradiology 2012; 54:1399-407. [PMID: 22941431 DOI: 10.1007/s00234-012-1087-8] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Accepted: 08/16/2012] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Although spinal cord stimulation (SCS) is widely used for chronic neuropathic pain after failed spinal surgery, little is known about the underlying physiological mechanisms. This study aims to investigate the neural substrate underlying short-term (30 s) SCS by means of functional magnetic resonance imaging in 20 patients with failed back surgery syndrome (FBSS). METHODS Twenty patients with FBSS, treated with externalized SCS, participated in a blocked functional magnetic resonance imaging design with stimulation and rest phases of 30 s each, repeated eight times in a row. During scanning, patients rated pain intensity over time using an 11-point numerical rating scale with verbal anchors (0 = no pain at all to 10 = worst pain imaginable) by pushing buttons (left hand, lesser pain; right hand, more pain). This scale was back projected to the patients on a flat screen allowing them to manually direct the pain indicator. To increase the signal-to-noise ratio, the 8-min block measurements were repeated three times. RESULTS Marked deactivation of the bilateral medial thalamus and its connections to the rostral and caudal cingulate cortex and the insula was found; the study also showed immediate pain relief obtained by short-term SCS correlated negatively with activity in the inferior olivary nucleus, the cerebellum, and the rostral anterior cingulate cortex. CONCLUSIONS Results indicate the key role of the medial thalamus as a mediator and the involvement of a corticocerebellar network implicating the modulation and regulation of averse and negative affect related to pain. The observation of a deactivation of the ipsilateral antero-medial thalamus might be used as a region of interest for further response SCS studies.
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Kim JH, Lee HW, Hwang J, Kim J, Lee MJ, Han HS, Lee WH, Suk K. Microglia-inhibiting activity of Parkinson's disease drug amantadine. Neurobiol Aging 2011; 33:2145-59. [PMID: 22035588 DOI: 10.1016/j.neurobiolaging.2011.08.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 07/28/2011] [Accepted: 08/18/2011] [Indexed: 12/17/2022]
Abstract
Amantadine is currently used as an antiviral and an antiparkinsonian drug. Although the drug is known to bind a viral proton channel protein, the mechanism of action in Parkinson's disease (PD) remains to be determined. This study investigated whether the drug has an inhibitory effect on microglial activation and neuroinflammation, which have been implicated in the progression of neurodegenerative processes. Using cultured microglial cells, it was demonstrated that the drug inhibited inflammatory activation of microglia and a signaling pathway that governs the microglial activation. The drug reduced the expression and production of proinflammatory mediators in bacterial lipopolysaccharide-stimulated microglia cells. The microglia-inhibiting activity of amantadine was also demonstrated in a microglia/neuron coculture and animal models of neuroinflammation and Parkinson's disease. Collectively, our results suggest that amantadine may act on microglia in the central nervous system to inhibit their inflammatory activation, thereby attenuating neuroinflammation. These results provide a molecular basis of the glia-targeted mechanism of action for amantadine.
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Affiliation(s)
- Jong-Heon Kim
- Department of Pharmacology, Kyungpook National University School of Medicine, Daegu, Korea
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Panigada T, Gosselin RD. Behavioural alteration in chronic pain: Are brain glia involved? Med Hypotheses 2011; 77:584-8. [DOI: 10.1016/j.mehy.2011.06.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 06/06/2011] [Accepted: 06/15/2011] [Indexed: 12/24/2022]
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Role of different brain areas in peripheral nerve injury-induced neuropathic pain. Brain Res 2011; 1381:187-201. [DOI: 10.1016/j.brainres.2011.01.002] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 12/16/2010] [Accepted: 01/03/2011] [Indexed: 02/07/2023]
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