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Salavatian S, Robbins EM, Kuwabara Y, Castagnola E, Cui XT, Mahajan A. Real-time in vivo thoracic spinal glutamate sensing during myocardial ischemia. Am J Physiol Heart Circ Physiol 2023; 325:H1304-H1317. [PMID: 37737733 PMCID: PMC10908408 DOI: 10.1152/ajpheart.00299.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/18/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
In the spinal cord, glutamate serves as the primary excitatory neurotransmitter. Monitoring spinal glutamate concentrations offers valuable insights into spinal neural processing. Consequently, spinal glutamate concentration has the potential to emerge as a useful biomarker for conditions characterized by increased spinal neural network activity, especially when uptake systems become dysfunctional. In this study, we developed a multichannel custom-made flexible glutamate-sensing probe for the large-animal model that is capable of measuring extracellular glutamate concentrations in real time and in vivo. We assessed the probe's sensitivity and specificity through in vitro and ex vivo experiments. Remarkably, this developed probe demonstrates nearly instantaneous glutamate detection and allows continuous monitoring of glutamate concentrations. Furthermore, we evaluated the mechanical and sensing performance of the probe in vivo, within the pig spinal cord. Moreover, we applied the glutamate-sensing method using the flexible probe in the context of myocardial ischemia-reperfusion (I/R) injury. During I/R injury, cardiac sensory neurons in the dorsal root ganglion transmit excitatory signals to the spinal cord, resulting in sympathetic activation that potentially leads to fatal arrhythmias. We have successfully shown that our developed glutamate-sensing method can detect this spinal network excitation during myocardial ischemia. This study illustrates a novel technique for measuring spinal glutamate at different spinal cord levels as a surrogate for the spinal neural network activity during cardiac interventions that engage the cardio-spinal neural pathway.NEW & NOTEWORTHY In this study, we have developed a new flexible sensing probe to perform an in vivo measurement of spinal glutamate signaling in a large animal model. Our initial investigations involved precise testing of this probe in both in vitro and ex vivo environments. We accurately assessed the sensitivity and specificity of our glutamate-sensing probe and demonstrated its performance. We also evaluated the performance of our developed flexible probe during the insertion and compared it with the stiff probe during animal movement. Subsequently, we used this innovative technique to monitor the spinal glutamate signaling during myocardial ischemia and reperfusion that can cause fatal ventricular arrhythmias. We showed that glutamate concentration increases during the myocardial ischemia, persists during the reperfusion, and is associated with sympathoexcitation and increases in myocardial substrate excitability.
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Affiliation(s)
- Siamak Salavatian
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Division of Cardiology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Elaine Marie Robbins
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Yuki Kuwabara
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Elisa Castagnola
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Xinyan Tracy Cui
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Center for Neural Basis of Cognition, Pittsburgh, Pennsylvania, United States
- McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania, United States
| | - Aman Mahajan
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
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Ca 2+-Permeable AMPA Receptors Contribute to Changed Dorsal Horn Neuronal Firing and Inflammatory Pain. Int J Mol Sci 2023; 24:ijms24032341. [PMID: 36768663 PMCID: PMC9916706 DOI: 10.3390/ijms24032341] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/26/2023] Open
Abstract
The dorsal horn (DH) neurons of the spinal cord play a critical role in nociceptive input integration and processing in the central nervous system. Engaged neuronal classes and cell-specific excitability shape nociceptive computation within the DH. The DH hyperexcitability (central sensitisation) has been considered a fundamental mechanism in mediating nociceptive hypersensitivity, with the proven role of Ca2+-permeable AMPA receptors (AMPARs). However, whether and how the DH hyperexcitability relates to changes in action potential (AP) parameters in DH neurons and if Ca2+-permeable AMPARs contribute to these changes remain unknown. We examined the cell-class heterogeneity of APs generated by DH neurons in inflammatory pain conditions to address these. Inflammatory-induced peripheral hypersensitivity increased DH neuronal excitability. We found changes in the AP threshold and amplitude but not kinetics (spike waveform) in DH neurons generating sustained or initial bursts of firing patterns. In contrast, there were no changes in AP parameters in the DH neurons displaying a single spike firing pattern. Genetic knockdown of the molecular mechanism responsible for the upregulation of Ca2+-permeable AMPARs allowed the recovery of cell-specific AP changes in peripheral inflammation. Selective inhibition of Ca2+-permeable AMPARs in the spinal cord alleviated nociceptive hypersensitivity, both thermal and mechanical modalities, in animals with peripheral inflammation. Thus, Ca2+-permeable AMPARs contribute to shaping APs in DH neurons and nociceptive hypersensitivity. This may represent a neuropathological mechanism in the DH circuits, leading to aberrant signal transfer to other nociceptive pathways.
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Wanasuntronwong A, Kaewsrisung S, Rotpenpian N, Arayapisit T, Pavasant P, Supronsinchai W. Efficacy and mechanism of the antinociceptive effects of cannabidiol on acute orofacial nociception induced by Complete Freund’s Adjuvant in male Mus musculus mice. Arch Oral Biol 2022; 144:105570. [DOI: 10.1016/j.archoralbio.2022.105570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 10/10/2022] [Accepted: 10/10/2022] [Indexed: 11/28/2022]
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Kwon HJ, Kim YJ, Lee D, Lee D, Kim D, Cho H, Kim DH, Lee JH, Jeong SM. Factors Associated with Rebound Pain After Patient-controlled Epidural Analgesia in Patients Undergoing Major Abdominal Surgery: A Retrospective Study. Clin J Pain 2022; 38:632-639. [PMID: 36037091 DOI: 10.1097/ajp.0000000000001067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 08/18/2022] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Although patient-controlled epidural analgesia (PCEA) is an effective form of regional analgesia for abdominal surgery, some patients experience significant rebound pain after the discontinuation of PCEA. However, risk factors for rebound pain associated with PCEA in major abdominal surgery remain unknown. This study evaluated the incidence of rebound pain related to PCEA and explored potential associated risk factors. METHODS We performed a retrospective review of 236 patients using PCEA following hepatobiliary and pancreas surgery between 2018 and 2020 in a tertiary hospital in South Korea. Rebound pain was defined as an increase from well-controlled pain (numeric rating scale <4) during epidural analgesia to severe pain (numeric rating scale ≥7) within 24 hours of discontinuation of PCEA. Logistic regression analysis was performed to determine the factors associated with rebound pain. RESULTS A total of 236 patients were included in this study. Patients were categorized into the non-rebound pain group (170 patients; 72%) and the rebound pain group (66 patients; 28%). Multivariable logistic regression analysis revealed that preoperative prognostic nutritional index (PNI) below 45 (odds ratio [OR]=2.080, 95% confidential interval [CI]=1.061-4.079, P=0.033) and intraoperative transfusion (OR=4.190, 95% CI=1.436-12.226, P=0.009) were independently associated with rebound pain after PCEA discontinuation. DISCUSSION Rebound pain after PCEA occurred in approximately 30% of patients who underwent major abdominal surgery, resulting in insufficient postoperative pain management. Preoperative low PNI and intraoperative transfusion may be associated with rebound pain after PCEA discontinuation.
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Affiliation(s)
- Hyun-Jung Kwon
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Yeon Ju Kim
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Dokyeong Lee
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Dongreul Lee
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Dongseok Kim
- Department of Anesthesiology and Pain Medicine, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Hakmoo Cho
- Department of Anesthesiology and Pain Medicine, Veterans Health Service Medical Center, Seoul, Republic of Korea
| | - Doo-Hwan Kim
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Jong-Hyuk Lee
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
| | - Sung-Moon Jeong
- Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea
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Viatchenko-Karpinski V, Kong L, Weng HR. Activation of microglial GPR109A alleviates thermal hyperalgesia in female lupus mice by suppressing IL-18 and glutamatergic synaptic activity. Glia 2021; 70:634-649. [PMID: 34919284 DOI: 10.1002/glia.24130] [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: 05/13/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/10/2022]
Abstract
Many patients with systemic lupus erythematosus (SLE) live with chronic pain despite advances in medical management in reducing mortality related to SLE. Few animal studies have addressed mechanisms and treatment for chronic pain caused by SLE. In this study, we provide the first evidence for the analgesic effects of a GPR109A specific agonist (MK1903) and its action mechanisms in thermal hyperalgesia in female MRL/lpr mice, an SLE mouse model. Specifically, we show that MRL/lpr mice had a higher sensitivity to thermal stimuli at age 11-16 weeks, which was accompanied with significantly microglial and astrocytic activation, increases in p38 MAPK and glutamatergic synaptic activities in the spinal dorsal horn. We demonstrate that thermal hyperalgesia in MRL/lpr mice was significantly attenuated by intrathecal injection of MK1903. GPR109A was expressed in spinal microglia but not astrocytes or neurons. Its expression was significantly increased in MRL/lpr mice with thermal hyperalgesia. Activation of GPR109A receptors in microglia attenuated glutamatergic synaptic activity via suppressing production of interleukin-18 (IL-18). We provide evidence that activation of GPR109A attenuated thermal hyperalgesia in the SLE animal model via suppressing p38 MAPK activity and production of IL-18. Our study suggests that targeting the microglial GPR109A is a potent approach for reversing spinal neuroinflammation, abnormal excitatory synaptic activity, and management of thermal hyperalgesia caused by SLE.
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Affiliation(s)
| | - Lingwei Kong
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, Georgia, USA
| | - Han-Rong Weng
- Department of Biomedical Sciences, Mercer University School of Medicine, Macon, Georgia, USA.,Department of Basic Sciences, California Northstate University College of Medicine, Elk Grove, Georgia, USA
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Kopach O, Voitenko N. Spinal AMPA receptors: Amenable players in central sensitization for chronic pain therapy? Channels (Austin) 2021; 15:284-297. [PMID: 33565904 PMCID: PMC7889122 DOI: 10.1080/19336950.2021.1885836] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 02/08/2023] Open
Abstract
The activity-dependent trafficking of AMPA receptors (AMPAR) mediates synaptic strength and plasticity, while the perturbed trafficking of the receptors of different subunit compositions has been linked to memory impairment and to causing neuropathology. In the spinal cord, nociceptive-induced changes in AMPAR trafficking determine the central sensitization of the dorsal horn (DH): changes in AMPAR subunit composition compromise the balance between synaptic excitation and inhibition, rendering interneurons hyperexcitable to afferent inputs, and promoting Ca2+ influx into the DH neurons, thereby amplifying neuronal hyperexcitability. The DH circuits become over-excitable and carry out aberrant sensory processing; this causes an increase in pain sensation in central sensory pathways, giving rise to chronic pain syndrome. Current knowledge of the contribution of spinal AMPAR to the cellular mechanisms relating to chronic pain provides opportunities for developing target-based therapies for chronic pain intervention.
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Affiliation(s)
- Olga Kopach
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
- Present Address: Department of Clinical and Experimental Epilepsy, Queen Square Institute of Neurology, University College London, London, UK
| | - Nana Voitenko
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
- Kyiv Academic University, Kyiv, Ukraine
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Duzhyy DE, Voitenko NV, Belan PV. Peripheral Inflammation Results in Increased Excitability of Capsaicin-Insensitive Nociceptive DRG Neurons Mediated by Upregulation of ASICs and Voltage-Gated Ion Channels. Front Cell Neurosci 2021; 15:723295. [PMID: 34733139 PMCID: PMC8558483 DOI: 10.3389/fncel.2021.723295] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
Previously, we have characterized the capsaicin-insensitive low pH-sensitive (caps−lpH+) subtype of small-sized nociceptive dorsal root ganglion (DRG) neurons that express acid-sensing ion channels, T-type Ca2+ channels, and have isolectin B4-negative phenotype. These neurons demonstrated increased excitability in a model of long-term diabetes, contributing to chronic pain sensation. Here we studied changes in the excitability of the caps−lpH+ neurons and underlying changes in the functional expression and gating properties of ion channels under complete Freund's adjuvant (CFA)-induced peripheral inflammation. We have found that, under these pathological conditions, the functional expression of the acid-sensing ion channels (ASICs) and voltage-gated Na+ channels, was increased. In addition, T-type Ca2+ current was significantly increased in the neurons at the membrane potentials close to its resting value. Altogether, the observed changes in the channel functioning shifted a pH level evoking an action potential (AP) toward its physiological value and led to an increase of evoked and spontaneous excitability of the caps−lpH+ neurons that may contribute to hyperalgesia and chronic inflammatory pain.
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Affiliation(s)
- Dmytro E Duzhyy
- Department of Sensory Signaling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Nana V Voitenko
- Department of Sensory Signaling, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Department of Molecular Physiology and Biophysics, Kyiv Academic University, Kyiv, Ukraine.,Research Center, Dobrobut Academy, Kyiv, Ukraine
| | - Pavel V Belan
- Research Center, Dobrobut Academy, Kyiv, Ukraine.,Department of Molecular Biophysics, Bogomoletz Institute of Physiology, Kyiv, Ukraine
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AKAP150 and its Palmitoylation Contributed to Pain Hypersensitivity Via Facilitating Synaptic Incorporation of GluA1-Containing AMPA Receptor in Spinal Dorsal Horn. Mol Neurobiol 2021; 58:6505-6519. [PMID: 34559357 DOI: 10.1007/s12035-021-02570-z] [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: 07/05/2021] [Accepted: 09/14/2021] [Indexed: 10/20/2022]
Abstract
The A-kinase anchoring protein 150 (AKAP150) organizes kinases and phosphatases to regulate AMPA receptors (AMPARs) that are pivotal for synaptic plasticity. AKAP150 itself undergoes S-palmitoylation. However, the roles of AKAP150 and its palmitoylation in spinal nociceptive processing remain unknown. In this study, we found that intraplantar injection of complete Freund's adjuvant (CFA) significantly increased the synaptic expression of AKAP150 and caused a reorganization of AKAP150 signaling complex in spinal dorsal horn. Knockdown of AKAP150 or interruption of its interactions with kinases effectively suppressed the CFA-induced synaptic expression of GluA1 subunit of AMPARs. Our data also showed that an upregulation of AKAP150 palmitoylation was involved in the synaptic redistribution of AKAP150. Inhibition of AKAP150 palmitoylation by expression of palmitoylation-defective mutant AKAP150 (C36, 123S) effectively repressed the CFA-induced phosphorylation and synaptic expression of GluA1 subunit, meanwhile, attenuated the development of mechanical allodynia and thermal hyperalgesia. Furthermore, we found that an increased expression of palmitoyl acyltransferase ZDHHC2 contributed to the upregulation of AKAP150 palmitoylation and GluA1 accumulation in inflamed mouse. These data indicated that AKAP150 and its palmitoylation were involved in AMPA receptor-dependent modification of nociceptive transmission, and the manipulations of AKAP150 signaling complex and palmitoylation might serve as potential therapeutic strategies for persistent pain after inflammation.
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Chase Huizar C, Ji N, Reddick R, Ostroff GR, Forsthuber TG. Glucan particles as a novel adjuvant for the induction of experimental autoimmune encephalomyelitis. Cell Immunol 2021; 366:104383. [PMID: 34111646 DOI: 10.1016/j.cellimm.2021.104383] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/29/2021] [Accepted: 05/17/2021] [Indexed: 10/21/2022]
Abstract
For over 70 years experimental autoimmune encephalomyelitis (EAE) has been induced with myelin autoantigens emulsified in complete Freund's adjuvant (CFA) which has significant side effects such as pain, inflammation, and tissue necrosis at the injection site. β-1,3-d-glucan particles (GPs) are hollow microcapsules prepared from Saccharomyces cerevisiae cell walls that induce potent Th17 cell responses without causing strong injection site tissue reactions. We evaluated the potential of GPs complexed with neuroantigens to induce EAE while avoiding undesirable side effects. GPs loaded with myelin oligodendrocyte glycoprotein 35-55 (MOG35-55) or proteolipid protein 139-151 (PLP139-151) peptides effectively induced EAE in C57BL/6 mice and SJL mice. Disease severity, CNS pathology and immune responses were comparable between GP- and CFA-immunized mice. Importantly, injection with GPs resulted in significantly decreased inflammation compared with CFA. We posit that use of GPs provides an alternative means for inducing EAE that results in comparable disease, but less discomfort to animals.
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Affiliation(s)
- Carol Chase Huizar
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Niannian Ji
- Department of Urology, University of Texas Health San Antonio Long School of Medicine, San Antonio, TX, USA
| | - Robert Reddick
- Department of Pathology, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Gary R Ostroff
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Thomas G Forsthuber
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA.
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Ma Y, Zhang X, Li C, Liu S, Xing Y, Tao F. <p>Spinal N-Cadherin/CREB Signaling Contributes to Chronic Alcohol Consumption-Enhanced Postsurgical Pain</p>. J Pain Res 2020; 13:2065-2072. [PMID: 32848450 PMCID: PMC7429188 DOI: 10.2147/jpr.s267778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 07/31/2020] [Indexed: 11/25/2022] Open
Abstract
Background It has been reported that N-cadherin and cAMP response element binding protein (CREB) in the spinal cord are critical for synaptogenesis and regulation of excitatory synapse function, which could underlie chronic pain development. The aim of the present study was to investigate the role of spinal N-cadherin/CREB signaling in postsurgical pain chronicity following chronic alcohol consumption. Methods C57BL/6 male mice were randomly assigned into different groups. Plantar incision was used to induce postsurgical pain. Chronic alcohol consumption was conducted by giving mice unlimited access to different concentrations of ethanol for five weeks. We measured paw withdrawal thresholds to test postsurgical pain. Using Western blotting, we examined the expression of N-Cadherin and CREB in the spinal dorsal horn. We further performed intrathecal injection of specific N-cadherin and CREB inhibitors to assess the role of spinal N-cadherin/CREB signaling in chronic alcohol consumption-enhanced postsurgical pain. Results We observed that the chronic alcohol consumption significantly prolonged postsurgical pain and enhanced plantar incision-increased N-cadherin expression and CREB phosphorylation at the Ser133 in the spinal cord. Intrathecal injection of specific N-cadherin and CREB inhibitors attenuated chronic alcohol consumption-prolonged postsurgical pain. Conclusion Our results suggest that spinal N-cadherin/CREB signaling is involved in chronic alcohol consumption-caused postsurgical pain chronicity.
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Affiliation(s)
- Yajing Ma
- Department of Physiology and Neurobiology, Zhengzhou University School of Basic Medical Sciences, Zhengzhou, Henan, People’s Republic of China
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Xinye Zhang
- Department of Physiology and Neurobiology, Zhengzhou University School of Basic Medical Sciences, Zhengzhou, Henan, People’s Republic of China
| | - Changsheng Li
- Department of Anesthesiology, Zhengzhou University School of Medicine, Zhengzhou, People’s Republic of China
| | - Sufang Liu
- Department of Physiology and Neurobiology, Zhengzhou University School of Basic Medical Sciences, Zhengzhou, Henan, People’s Republic of China
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
| | - Ying Xing
- Department of Physiology and Neurobiology, Zhengzhou University School of Basic Medical Sciences, Zhengzhou, Henan, People’s Republic of China
- Correspondence: Ying Xing Department of Physiology and Neurobiology, Zhengzhou University School of Basic Medical Sciences, 100 Ke Xue Ave, Zhengzhou, Henan450001, People’s Republic of ChinaTel +86-371-67780665 Email
| | - Feng Tao
- Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA
- Feng Tao Department of Biomedical Sciences, Texas A&M University College of Dentistry, 3302 Gaston Ave, Dallas, TX75246, USATel +1-214-828-8272 Email
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Cseh EK, Veres G, Körtési T, Polyák H, Nánási N, Tajti J, Párdutz Á, Klivényi P, Vécsei L, Zádori D. Neurotransmitter and tryptophan metabolite concentration changes in the complete Freund's adjuvant model of orofacial pain. J Headache Pain 2020; 21:35. [PMID: 32316909 PMCID: PMC7175490 DOI: 10.1186/s10194-020-01105-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/08/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The neurochemical background of the evolution of headache disorders, still remains partially undiscovered. Accordingly, our aim was to further explore the neurochemical profile of Complete Freund's adjuvant (CFA)-induced orofacial pain, involving finding the shift point regarding small molecule neurotransmitter concentrations changes vs. that of the previously characterized headache-related neuropeptides. The investigated neurotransmitters consisted of glutamate, γ-aminobutyric acid, noradrenalin and serotonin. Furthermore, in light of its influence on glutamatergic neurotransmission, we measured the level of kynurenic acid (KYNA) and its precursors in the kynurenine (KYN) pathway (KP) of tryptophan metabolism. METHODS The effect of CFA was evaluated in male Sprague Dawley rats. Animals were injected with CFA (1 mg/ml, 50 μl/animal) into the right whisker pad. We applied high-performance liquid chromatography to determine the concentrations of the above-mentioned compounds from the trigeminal nucleus caudalis (TNC) and somatosensory cortex (ssCX) of rats. Furthermore, we measured some of these metabolites from the cerebrospinal fluid and plasma as well. Afterwards, we carried out permutation t-tests as post hoc analysis for pairwise comparison. RESULTS Our results demonstrated that 24 h after CFA treatment, the level of glutamate, KYNA and that of its precursor, KYN was still elevated in the TNC, all diminishing by 48 h. In the ssCX, significant concentration increases of KYNA and serotonin were found. CONCLUSION This is the first study assessing neurotransmitter changes in the TNC and ssCX following CFA treatment, confirming the dominant role of glutamate in early pain processing and a compensatory elevation of KYNA with anti-glutamatergic properties. Furthermore, the current findings draw attention to the limited time interval where medications can target the glutamatergic pathways.
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Affiliation(s)
- Edina K Cseh
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - Gábor Veres
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
- MTA-SZTE Neuroscience Research Group, Szeged, Hungary
| | - Tamás Körtési
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - Helga Polyák
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - Nikolett Nánási
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - János Tajti
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - Árpád Párdutz
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - Péter Klivényi
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
| | - László Vécsei
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary
- MTA-SZTE Neuroscience Research Group, Szeged, Hungary
| | - Dénes Zádori
- Department of Neurology, Interdisciplinary Excellence Center, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, Szeged, H-6725, Hungary.
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Vigneri S, Sindaco G, La Grua M, Zanella M, Lo Bianco G, Paci V, Vinci FM, Sciacca C, Ravaioli L, Pari G. Electrocatheter-mediated High-voltage Pulsed Radiofrequency of the Dorsal Root Ganglion in the Treatment of Chronic Lumbosacral Neuropathic Pain: A Randomized Controlled Study. Clin J Pain 2020; 36:25-33. [PMID: 31577546 PMCID: PMC6903354 DOI: 10.1097/ajp.0000000000000766] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 08/21/2019] [Accepted: 09/08/2019] [Indexed: 12/31/2022]
Abstract
OBJECTIVES Despite the interest in scientific community, there is still poor evidence about pulsed radiofrequency (PRF) efficacy in the treatment of neuropathic pain. In order to determine whether high-voltage PRF and epidural adhesiolysis (PRF-EA) showed better results than epidural adhesiolysis alone (EA), a randomized, double-blind, comparative-effectiveness study was conducted in patients with chronic lumbosacral radiating pain and neuropathic features. MATERIALS AND METHODS A total of 41 patients were randomly allocated to 2 groups. Twenty-one patients were randomized to receive 2 cycles of 240 seconds high-voltage PRF followed by the injection of local anesthetics, hyaluronidase, and betamethasone, whereas 20 patients underwent sham stimulation followed by adhesiolysis. The treatment was delivered at the affected lumbosacral roots and patients, treating physicians and assessors were blinded to intervention. RESULTS A significant reduction of radiating pain was observed in mean Numeric Rating Scale score at follow-up. A change of -3.43 versus -1.75 (P=0.031) after 1 month and -3.34 versus -0.80 (P=0.005) after 6 months was reported in patients undergoing PRF-EA in comparison with EA, respectively. After 1 month, 57% of patients in the PRF-EA group experienced a pain reduction of ≥50% versus only 25% of patients allocated to EA (P=0.037). Improvement decreased to 48% in the PRF-EA group whereas only 10% of EA reported significant pain relief after 6 months (P=0.008). DISCUSSION High-voltage PRF of dorsal root ganglion delivered through multifunctional electrode provided significant pain relief and may be considered a valuable treatment in chronic lumbosacral radicular pain with neuropathic features.
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Affiliation(s)
- Simone Vigneri
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo
| | | | - Marco La Grua
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
| | - Matteo Zanella
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
| | - Giuliano Lo Bianco
- I.R.C.C.S. Centro Regionale Oncologico, Pain Medicine Unit, Rionero in Vulture, Italy
| | - Valentina Paci
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
| | | | - Chiara Sciacca
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
| | - Laura Ravaioli
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
| | - Gilberto Pari
- Santa Maria Maddalena Hospital, Pain Medicine Unit, Occhiobello
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Kopach O, Zheng K, Dong L, Sapelkin A, Voitenko N, Sukhorukov GB, Rusakov DA. Nano-engineered microcapsules boost the treatment of persistent pain. Drug Deliv 2018; 25:435-447. [PMID: 29383961 PMCID: PMC5796488 DOI: 10.1080/10717544.2018.1431981] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 11/17/2022] Open
Abstract
Persistent pain remains a major health issue: common treatments relying on either repeated local injections or systemic drug administration are prone to concomitant side-effects. It is thought that an alternative could be a multifunctional cargo system to deliver medicine to the target site and release it over a prolonged time window. We nano-engineered microcapsules equipped with adjustable cargo release properties and encapsulated the sodium-channel blocker QX-314 using the layer-by-layer (LbL) technology. First, we employed single-cell electrophysiology to establish in vitro that microcapsule application can dampen neuronal excitability in a controlled fashion. Secondly, we used two-photon excitation imaging to monitor and adjust long-lasting release of encapsulated cargo in target tissue in situ. Finally, we explored an established peripheral inflammation model in rodents to find that a single local injection of QX-314-containing microcapsules could provide robust pain relief lasting for over a week. This was accompanied by a recovery of the locomotive deficit and the amelioration of anxiety in animals with persistent inflammation. Post hoc immunohistology confirmed biodegradation of microcapsules over a period of several weeks. The overall remedial effect lasted 10-20 times longer than that of a single focal drug injection. It depended on the QX-314 encapsulation levels, involved TRPV1-channel-dependent cell permeability of QX-314, and showed no detectable side-effects. Our data suggest that nano-engineered encapsulation provides local drug delivery suitable for prolonged pain relief, which could be highly advantageous compared to existing treatments.
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Affiliation(s)
- Olga Kopach
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Kayiu Zheng
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
| | - Luo Dong
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Andrei Sapelkin
- Centre for Condensed Matter and Materials Physics, Queen Mary University of London, London, UK
| | - Nana Voitenko
- Department of Sensory Signaling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Gleb B. Sukhorukov
- School of Engineering and Materials Science, Queen Mary University of London, London, UK
| | - Dmitri A. Rusakov
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, University College London, London, UK
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14
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Kopach O, Krotov V, Shysh A, Sotnic A, Viatchenko-Karpinski V, Dosenko V, Voitenko N. Spinal PKCα inhibition and gene-silencing for pain relief: AMPAR trafficking at the synapses between primary afferents and sensory interneurons. Sci Rep 2018; 8:10285. [PMID: 29980697 PMCID: PMC6035211 DOI: 10.1038/s41598-018-28512-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 06/22/2018] [Indexed: 01/21/2023] Open
Abstract
Upregulation of Ca2+-permeable AMPA receptors (CP-AMPARs) in dorsal horn (DH) neurons has been causally linked to persistent inflammatory pain. This upregulation, demonstrated for both synaptic and extrasynaptic AMPARs, depends on the protein kinase C alpha (PKCα) activation; hence, spinal PKC inhibition has alleviated peripheral nociceptive hypersensitivity. However, whether targeting the spinal PKCα would alleviate both pain development and maintenance has not been explored yet (essential to pharmacological translation). Similarly, if it could balance the upregulated postsynaptic CP-AMPARs also remains unknown. Here, we utilized pharmacological and genetic inhibition of spinal PKCα in various schemes of pain treatment in an animal model of long-lasting peripheral inflammation. Pharmacological inhibition (pre- or post-treatment) reduced the peripheral nociceptive hypersensitivity and accompanying locomotive deficit and anxiety in rats with induced inflammation. These effects were dose-dependent and observed for both pain development and maintenance. Gene-therapy (knockdown of PKCα) was also found to relieve inflammatory pain when applied as pre- or post-treatment. Moreover, the revealed therapeutic effects were accompanied with the declined upregulation of CP-AMPARs at the DH synapses between primary afferents and sensory interneurons. Our results provide a new focus on the mechanism-based pain treatment through interference with molecular mechanisms of AMPAR trafficking in central pain pathways.
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Affiliation(s)
- Olga Kopach
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine. .,Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.
| | - Volodymyr Krotov
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Angela Shysh
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Andrij Sotnic
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Viacheslav Viatchenko-Karpinski
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,The University of Alabama at Birmingham, Birmingham, United States
| | - Victor Dosenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, Kyiv, Ukraine.,Kyiv Academic University, Kyiv, Ukraine
| | - Nana Voitenko
- Department of Sensory Signalling, Bogomoletz Institute of Physiology, Kyiv, Ukraine. .,Kyiv Academic University, Kyiv, Ukraine.
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15
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Lian YN, Lu Q, Chang JL, Zhang Y. The role of glutamate and its receptors in central nervous system in stress-induced hyperalgesia. Int J Neurosci 2017; 128:283-290. [DOI: 10.1080/00207454.2017.1387112] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Yan-Na Lian
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Qi Lu
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Jin-Long Chang
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
| | - Ying Zhang
- Department of Physiology, Harbin Medical University, Harbin, P. R. China
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16
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Opposite, bidirectional shifts in excitation and inhibition in specific types of dorsal horn interneurons are associated with spasticity and pain post-SCI. Sci Rep 2017; 7:5884. [PMID: 28724992 PMCID: PMC5517549 DOI: 10.1038/s41598-017-06049-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 06/01/2017] [Indexed: 11/23/2022] Open
Abstract
Spasticity, a common complication after spinal cord injury (SCI), is frequently accompanied by chronic pain. The physiological origin of this pain (critical to its treatment) remains unknown, although spastic motor dysfunction has been related to the hyperexcitability of motoneurons and to changes in spinal sensory processing. Here we show that the pain mechanism involves changes in sensory circuits of the dorsal horn (DH) where nociceptive inputs integrate for pain processing. Spasticity is associated with the DH hyperexcitability resulting from an increase in excitation and disinhibition occurring in two respective types of sensory interneurons. In the tonic-firing inhibitory lamina II interneurons, glutamatergic drive was reduced while glycinergic inhibition was potentiated. In contrast, excitatory drive was boosted to the adapting-firing excitatory lamina II interneurons while GABAergic and glycinergic inhibition were reduced. Thus, increased activity of excitatory DH interneurons coupled with the reduced excitability of inhibitory DH interneurons post-SCI could provide a neurophysiological mechanism of central sensitization and chronic pain associated with spasticity.
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17
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Kopach O, Krotov V, Goncharenko J, Voitenko N. Inhibition of Spinal Ca(2+)-Permeable AMPA Receptors with Dicationic Compounds Alleviates Persistent Inflammatory Pain without Adverse Effects. Front Cell Neurosci 2016; 10:50. [PMID: 26973464 PMCID: PMC4770326 DOI: 10.3389/fncel.2016.00050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 02/13/2016] [Indexed: 11/17/2022] Open
Abstract
Upregulation of Ca2+-permeable AMPA receptors (CP-AMPARs) in the dorsal horn (DH) neurons of the spinal cord has been causally linked to the maintenance of persistent inflammatory pain. Therefore, inhibition of CP-AMPARs could potentially alleviate an, otherwise, poorly treatable chronic pain. However, a loss of CP-AMPARs could produce considerable side effects because of the crucial role of CP-AMPARs in synaptic plasticity. Here we have tested whether the inhibition of spinal CP-AMPARs with dicationic compounds, the open-channel antagonists acting in an activity-dependent manner, can relieve inflammatory pain without adverse effects being developed. Dicationic compounds, N1-(1-phenylcyclohexyl)pentane-1,5-diaminium bromide (IEM-1925) and 1-trimethylammonio-5-1-adamantane-methyl-ammoniopentane dibromide (IEM-1460) were applied intrathecally (i.t.) as a post-treatment for inflammatory pain in the model of complete Freund’s adjuvant (CFA)-induced long-lasting peripheral inflammation. The capability of dicationic compounds to ameliorate inflammatory pain was tested in rats in vivo using the Hargreaves, the von Frey and the open-field tests. Treatment with IEM-1460 or IEM-1925 resulted in profound alleviation of inflammatory pain. The pain relief appeared shortly after compound administration. The effects were concentration-dependent, displaying a high potency of dicationic compounds for alleviation of inflammatory hyperalgesia in the micromolar range, for both acute and long-lasting responses. The period of pain maintenance was shortened following treatment. Treatment with IEM-1460 or IEM-1925 changed neither thermal and mechanical basal sensitivities nor animal locomotion, suggesting that inhibition of CP-AMPARs with dicationic compounds does not give rise to detectable side effects. Thus, the ability of dicationic compounds to alleviate persistent inflammatory pain may provide new routes in the treatment of chronic pain.
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Affiliation(s)
- Olga Kopach
- Laboratory of Sensory Signaling, Bogomoletz Institute of PhysiologyKyiv, Ukraine; Laboratory of Synaptic Imaging, Institute of Neurology, University College LondonLondon, UK
| | - Volodymyr Krotov
- Laboratory of Sensory Signaling, Bogomoletz Institute of Physiology Kyiv, Ukraine
| | - Julia Goncharenko
- Laboratory of Sensory Signaling, Bogomoletz Institute of Physiology Kyiv, Ukraine
| | - Nana Voitenko
- Laboratory of Sensory Signaling, Bogomoletz Institute of PhysiologyKyiv, Ukraine; International Center for Molecular Physiology, Bogomoletz Institute of PhysiologyKyiv, Ukraine
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18
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Metabolic Connection of Inflammatory Pain: Pivotal Role of a Pyruvate Dehydrogenase Kinase-Pyruvate Dehydrogenase-Lactic Acid Axis. J Neurosci 2016; 35:14353-69. [PMID: 26490872 DOI: 10.1523/jneurosci.1910-15.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
UNLABELLED Pyruvate dehydrogenase kinases (PDK1-4) are mitochondrial metabolic regulators that serve as decision makers via modulation of pyruvate dehydrogenase (PDH) activity to convert pyruvate either aerobically to acetyl-CoA or anaerobically to lactate. Metabolic dysregulation and inflammatory processes are two sides of the same coin in several pathophysiological conditions. The lactic acid surge associated with the metabolic shift has been implicated in diverse painful states. In this study, we investigated the role of PDK-PDH-lactic acid axis in the pathogenesis of chronic inflammatory pain. Deficiency of Pdk2 and/or Pdk4 in mice attenuated complete Freund's adjuvant (CFA)-induced pain hypersensitivities. Likewise, Pdk2/4 deficiency attenuated the localized lactic acid surge along with hallmarks of peripheral and central inflammation following intraplantar administration of CFA. In vitro studies supported the role of PDK2/4 as promoters of classical proinflammatory activation of macrophages. Moreover, the pharmacological inhibition of PDKs or lactic acid production diminished CFA-induced inflammation and pain hypersensitivities. Thus, a PDK-PDH-lactic acid axis seems to mediate inflammation-driven chronic pain, establishing a connection between metabolism and inflammatory pain. SIGNIFICANCE STATEMENT The mitochondrial pyruvate dehydrogenase (PDH) kinases (PDKs) and their substrate PDH orchestrate the conversion of pyruvate either aerobically to acetyl-CoA or anaerobically to lactate. Lactate, the predominant end product of glycolysis, has recently been identified as a signaling molecule for neuron-glia interactions and neuronal plasticity. Pathological metabolic shift and subsequent lactic acid production are thought to play an important role in diverse painful states; however, their contribution to inflammation-driven pain is still to be comprehended. Here, we report that the PDK-PDH-lactic acid axis constitutes a key component of inflammatory pain pathogenesis. Our findings establish an unanticipated link between metabolism and inflammatory pain. This study unlocks a previously ill-explored research avenue for the metabolic control of inflammatory pain pathogenesis.
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Inflammatory-induced changes in synaptic drive and postsynaptic AMPARs in lamina II dorsal horn neurons are cell-type specific. Pain 2015; 156:428-438. [DOI: 10.1097/01.j.pain.0000460318.65734.00] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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20
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Harris BM, Hughes DI, Bolton PS, Tadros MA, Callister RJ, Graham BA. Contrasting alterations to synaptic and intrinsic properties in upper-cervical superficial dorsal horn neurons following acute neck muscle inflammation. Mol Pain 2014; 10:25. [PMID: 24725960 PMCID: PMC4032164 DOI: 10.1186/1744-8069-10-25] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 04/07/2014] [Indexed: 11/10/2022] Open
Abstract
Background Acute and chronic pain in axial structures, like the back and neck, are difficult to treat, and have incidence as high as 15%. Surprisingly, most preclinical work on pain mechanisms focuses on cutaneous structures in the limbs and animal models of axial pain are not widely available. Accordingly, we developed a mouse model of acute cervical muscle inflammation and assessed the functional properties of superficial dorsal horn (SDH) neurons. Results Male C57/Bl6 mice (P24-P40) were deeply anaesthetised (urethane 2.2 g/kg i.p) and the rectus capitis major muscle (RCM) injected with 40 μl of 2% carrageenan. Sham animals received vehicle injection and controls remained anaesthetised for 2 hrs. Mice in each group were sacrificed at 2 hrs for analysis. c-Fos staining was used to determine the location of activated neurons. c-Fos labelling in carrageenan-injected mice was concentrated within ipsilateral (87% and 63% of labelled neurons in C1 and C2 segments, respectively) and contralateral laminae I - II with some expression in lateral lamina V. c-Fos expression remained below detectable levels in control and sham animals. In additional experiments, whole cell recordings were obtained from visualised SDH neurons in transverse slices in the ipsilateral C1 and C2 spinal segments. Resting membrane potential and input resistance were not altered. Mean spontaneous EPSC amplitude was reduced by ~20% in neurons from carrageenan-injected mice versus control and sham animals (20.63 ± 1.05 vs. 24.64 ± 0.91 and 25.87 ± 1.32 pA, respectively). The amplitude (238 ± 33 vs. 494 ± 96 and 593 ± 167 pA) and inactivation time constant (12.9 ± 1.5 vs. 22.1 ± 3.6 and 15.3 ± 1.4 ms) of the rapid A type potassium current (IAr), the dominant subthreshold current in SDH neurons, were reduced in carrageenan-injected mice. Conclusions Excitatory synaptic drive onto, and important intrinsic properties (i.e., IAr) within SDH neurons are reduced two hours after acute muscle inflammation. We propose this time point represents an important transition period between peripheral and central sensitisation with reduced excitatory drive providing an initial neuroprotective mechanism during the early stages of the progression towards central sensitisation.
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Affiliation(s)
| | | | | | | | | | - Brett A Graham
- School of Biomedical Sciences and Pharmacy, Faculty of Health and Medicine, The University of Newcastle and Hunter Medical Research Institute, Room 411 Medical Sciences Building, University Drive, Newcastle, NSW 2308, Australia.
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21
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The pivotal role played by lipocalin-2 in chronic inflammatory pain. Exp Neurol 2014; 254:41-53. [DOI: 10.1016/j.expneurol.2014.01.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 12/13/2013] [Accepted: 01/07/2014] [Indexed: 12/30/2022]
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22
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Ma W, Quirion R. Targeting cell surface trafficking of pain-facilitating receptors to treat chronic pain conditions. Expert Opin Ther Targets 2014; 18:459-72. [DOI: 10.1517/14728222.2014.887683] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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23
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Kopach O, Voitenko N. Extrasynaptic AMPA receptors in the dorsal horn: Evidence and functional significance. Brain Res Bull 2013. [DOI: 10.1016/j.brainresbull.2012.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Liu T, Jiang CY, Fujita T, Luo SW, Kumamoto E. Enhancement by interleukin-1β of AMPA and NMDA receptor-mediated currents in adult rat spinal superficial dorsal horn neurons. Mol Pain 2013; 9:16. [PMID: 23537341 PMCID: PMC3622562 DOI: 10.1186/1744-8069-9-16] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 03/14/2013] [Indexed: 11/10/2022] Open
Abstract
Background Proinflammatory cytokine interleukin-1β (IL-1β) released from spinal microglia plays an important role in the maintenance of acute and chronic pain states. However, the cellular basis of this action remains poorly understood. Using whole-cell patch-clamp recordings, we examined the action of IL-1β on AMPA- and NMDA-receptor-mediated currents recorded from substantia gelatinosa (SG) neurons of adult rat spinal cord slices which are key sites for regulating nociceptive transmission from the periphery. Results AMPA- and NMDA-induced currents were increased in peak amplitude by IL-1β in a manner different from each other in SG neurons. These facilitatory actions of IL-1β were abolished by IL-1 receptor (IL-1R) antagonist (IL-1ra), which by itself had no detectable effects on AMPA- and NMDA-induced currents. The AMPA- but not NMDA-induced current facilitated by IL-1β was recovered to control level 30 min after IL-1β washout and largely depressed in Na+-channel blocker tetrodotoxin-containing or nominally Ca2+-free Krebs solution. Minocycline, a microglia inhibitor, blocked the facilitatory effect of IL-1β on AMPA- but not NMDA-induced currents, where minocycline itself depressed NMDA- but had not any effects on AMPA-induced currents. Conclusions IL-1β enhances AMPA and NMDA responses in SG neurons through IL-1R activation; the former but not latter action is reversible and due to an increase in neuronal activity in a manner dependent on extracellular Ca2+ and minocycline. It is suggested that AMPA and NMDA receptors are positively modulated by IL-1β in a manner different from each other; the former but not latter is mediated by a neurotransmitter released as a result of an increase in neuronal activity. Since IL-1β contributes to nociceptive behavior induced by peripheral nerve or tissue injury, the present findings also reveal an important cellular link between neuronal and glial cells in the spinal dorsal horn.
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Affiliation(s)
- Tao Liu
- Center for Laboratory Medicine, the First Affiliated Hospital of Nanchang University, Nanchang, China.
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