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Niu L, Zuo CJ, Zhang YL, Ma CX, Zhou XW, Sun SR, Tang XX, Huang GQ, Zhai SC. Oxidative stress mediated decrement of spinal endomorphin-2 contributes to lumbar disc herniation sciatica in rats. Neurochem Int 2024; 177:105764. [PMID: 38729355 DOI: 10.1016/j.neuint.2024.105764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 05/02/2024] [Accepted: 05/07/2024] [Indexed: 05/12/2024]
Abstract
Increasing evidence supported that oxidative stress induced by herniated lumbar disc played important role in the formation of lumbar disc herniation sciatica (LDHS), however, the neural mechanisms underlying LDHS need further clarification. Endomorphin-2 (EM2) is the endogenous ligand for mu-opioid receptor (MOR), and there is increasing evidence implicating the involvement of spinal EM2 in neuropathic pain. In this study, using an nucleus pulposus implantation induced LDHS rat model that displayed obvious mechanical allodynia, it was found that the expression of EM2 in dorsal root ganglion (DRG) and spinal cord was significantly decreased. It was further found that oxidative stress in DRG and spinal cord was significantly increased in LDHS rats, and the reduction of EM2 in DRG and spinal cord was determined by oxidative stress dominated increment of dipeptidylpeptidase IV activity. A systemic treatment with antioxidant could prevent the forming of mechanical allodynia in LDHS rats. In addition, MOR expression in DRG and spinal cord remained unchanged in LDHS rats. Intrathecal injection of MOR antagonist promoted pain behavior in LDHS rats, and the analgesic effect of intrathecal injection of EM2 was stronger than that of endomorphin-1 and morphine. Taken together, our findings suggest that oxidative stress mediated decrement of EM2 in DRG and spinal cord causes the loss of endogenous analgesic effects and enhances the pain sensation of LDHS.
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Affiliation(s)
- Le Niu
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China; The Xi'an DaXing Hospital, 353 Laodong North Road, Xi'an, 710016, PR China.
| | - Chun-Jiang Zuo
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Yong-Ling Zhang
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Cui-Xia Ma
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Xiang-Wen Zhou
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Shi-Ru Sun
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Xue-Xue Tang
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Guo-Quan Huang
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China
| | - Si-Cheng Zhai
- Haojing College of Shaanxi University of Science&Technology, Unified Avenue, Xianyang, 712046, PR China.
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Zhang Q, Ding R, Li Y, Qiao D, Kang J, Zong L, Li Y, Yuan Y, Jiao Y, Wang C, Yu Y, Zhang L, Li Y. Euchromatin histone-lysine N-methyltransferase 2 regulates the expression of potassium-sodium-activated channel subfamily T member 1 in primary sensory neurons and contributes to remifentanil-induced pain sensitivity. Brain Res Bull 2024; 212:110966. [PMID: 38670469 DOI: 10.1016/j.brainresbull.2024.110966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 04/17/2024] [Accepted: 04/22/2024] [Indexed: 04/28/2024]
Abstract
Intraoperative remifentanil administration has been linked to increased postoperative pain sensitivity. Recent studies have identified the involvement of euchromatic histone-lysine N-methyltransferase 2 (Ehmt2/G9a) in neuropathic pain associated with the transcriptional silencing of many potassium ion channel genes. This study investigates whether G9a regulates the potassium sodium-activated channel subfamily T member 1 (Slo2.2) in remifentanil-induced post-incisional hyperalgesia (RIH) in rodents. We performed remifentanil infusion (1 μg·kg-1·min-1 for 60 min) followed by plantar incision to induce RIH in rodents. Our results showed that RIH was accompanied by increased G9a and H3K9me2 production and decreased Slo2.2 expression 48 h postoperatively. Deletion of G9a rescued Slo2.2 expression in DRG and reduced RIH intensity. Slo2.2 overexpression also reversed this hyperalgesia phenotype. G9a overexpression decreased Slo2.2-mediated leak current and increased excitability in the small-diameter DRG neurons and laminal II small-diameter neurons in the spinal dorsal horn, which was implicated in peripheral and central sensitization. These results suggest that G9a contributes to the development of RIH by epigenetically silencing Slo2.2 in DRG neurons, leading to decreased central sensitization in the spinal cord. The findings may have implications for the development of novel therapeutic targets for the treatment of postoperative pain.
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Affiliation(s)
- Qiang Zhang
- Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China; Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Ran Ding
- Chinese Institute for Brain Research and Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yuanjie Li
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Dan Qiao
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Jiamin Kang
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Linyue Zong
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yun Li
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuan Yuan
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yang Jiao
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Chunyan Wang
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yonghao Yu
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Linlin Zhang
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.
| | - Yize Li
- Tianjin Research Institute of Anesthesiology and Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China.
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Ghanbari A, Ghasemi S, Khaleghian A. Effects of swimming exercise on neuropathic pain in a rat model: role of glutamate. Neurol Res 2024; 46:330-338. [PMID: 38323336 DOI: 10.1080/01616412.2024.2313901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 01/30/2024] [Indexed: 02/08/2024]
Abstract
OBJECTIVE The pain-reducing effects of the exercise were exerted through different mechanisms. Knowing more clear mechanisms helps to find more approach that is therapeutic. The objective of the present study is the evaluation of cerebrospinal fluid (CSF) glutamate level alteration in neuropathic pain rats and whether physical activity could modulate it. METHODS In the present study 104 male Wistar rats weighing 180-220 g were randomly divided into 4 groups (Sham, Sham + Exe, Neuropathy, and Neuropathy + Exe) which in turn each group subdivided into 4 groups according to time points for behavioral testing and CSF sampling (Baseline, 2 weeks, 3 weeks, and 4 weeks). To induction of neuropathy (by chronic constriction injury,), after anesthetizing with a mixture of ketamine (80 mg/kg) and xylazine (10 mg/kg), the animal's right sciatic nerve was exposed and was ligated using four movable catgut chromic suture 4/0. The exercise protocol included 25 min of daily swimming, 5 days a week for 4 weeks. Thermal hyperalgesia and mechanical tactile threshold were detected using the plantar test and Von Frey filaments, respectively. CSF glutamate level was determined using high-performance liquid chromatography. RESULTS Findings indicated that mechanical and thermal thresholds significantly (p < 0.01, p < 0.05 respectively) decreased in the neuropathy group against that in sham groups. On the other hand, exercise significantly increased mechanical tactile threshold (p < 0.0012) and thermal threshold (p < 0.05) compared to the neuropathy group. Moreover, CSF glutamate level prominently (p < 0.01) was increased in the neuropathy group compared to the sham group, and swimming exercise significantly (p < 0.001) reduced it. IN CONCLUSION The present findings provide new evidence showing that medium-intensity swimming exercise attenuates pain-like behaviors in neuropathic pain animals, which is possibly due to decreasing CSF glutamate level and its neurotransmission.
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Affiliation(s)
- Ali Ghanbari
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran
| | - Sahar Ghasemi
- Student Research Committee, Semnan University of Medical Sciences, Semnan, Iran
| | - Ali Khaleghian
- Department of Biochemistry, Faculty of Medicine, Semnan University of Medical Sciences, Semnan, Iran
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Qi Y, Nelson TS, Prasoon P, Norris C, Taylor BK. Contribution of µ Opioid Receptor-expressing Dorsal Horn Interneurons to Neuropathic Pain-like Behavior in Mice. Anesthesiology 2023; 139:840-857. [PMID: 37566700 PMCID: PMC10840648 DOI: 10.1097/aln.0000000000004735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2023]
Abstract
BACKGROUND Intersectional genetics have yielded tremendous advances in our understanding of molecularly identified subpopulations and circuits within the dorsal horn in neuropathic pain. The authors tested the hypothesis that spinal µ opioid receptor-expressing neurons (Oprm1-expressing neurons) contribute to behavioral hypersensitivity and neuronal sensitization in the spared nerve injury model in mice. METHODS The authors coupled the use of Oprm1Cre transgenic reporter mice with whole cell patch clamp electrophysiology in lumbar spinal cord slices to evaluate the neuronal activity of Oprm1-expressing neurons in the spared nerve injury model of neuropathic pain. The authors used a chemogenetic approach to activate or inhibit Oprm1-expressing neurons, followed by the assessment of behavioral signs of neuropathic pain. RESULTS The authors reveal that spared nerve injury yielded a robust neuroplasticity of Oprm1-expressing neurons. Spared nerve injury reduced Oprm1 gene expression in the dorsal horn as well as the responsiveness of Oprm1-expressing neurons to the selective µ agonist (D-Ala2, N-MePhe4, Gly-ol)-enkephalin (DAMGO). Spared nerve injury sensitized Oprm1-expressing neurons, as reflected by an increase in their intrinsic excitability (rheobase, sham 38.62 ± 25.87 pA [n = 29]; spared nerve injury, 18.33 ± 10.29 pA [n = 29], P = 0.0026) and spontaneous synaptic activity (spontaneous excitatory postsynaptic current frequency in delayed firing neurons: sham, 0.81 ± 0.67 Hz [n = 14]; spared nerve injury, 1.74 ± 1.68 Hz [n = 10], P = 0.0466), and light brush-induced coexpression of the immediate early gene product, Fos in laminae I to II (%Fos/tdTomato+: sham, 0.42 ± 0.57% [n = 3]; spared nerve injury, 28.26 ± 1.92% [n = 3], P = 0.0001). Chemogenetic activation of Oprm1-expressing neurons produced mechanical hypersensitivity in uninjured mice (saline, 2.91 ± 1.08 g [n = 6]; clozapine N-oxide, 0.65 ± 0.34 g [n = 6], P = 0.0006), while chemogenetic inhibition reduced behavioral signs of mechanical hypersensitivity (saline, 0.38 ± 0.37 g [n = 6]; clozapine N-oxide, 1.05 ± 0.42 g [n = 6], P = 0.0052) and cold hypersensitivity (saline, 6.89 ± 0.88 s [n = 5] vs. clozapine N-oxide, 2.31 ± 0.52 s [n = 5], P = 0.0017). CONCLUSIONS The authors conclude that nerve injury sensitizes pronociceptive µ opioid receptor-expressing neurons in mouse dorsal horn. Nonopioid strategies to inhibit these interneurons might yield new treatments for neuropathic pain. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Yanmei Qi
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Christopher Norris
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Kohno T, Takaki K, Kishita K, Mitsutake K, Tofuku N, Kishita I. Neuromodulation Through Magnetic Fields Irradiation with AT-04 Improves Hyperalgesia in a Rat Model of Neuropathic Pain via Descending Pain Modulatory Systems and Opioid Analgesia. Cell Mol Neurobiol 2023; 43:4345-4362. [PMID: 37934363 PMCID: PMC10660917 DOI: 10.1007/s10571-023-01430-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023]
Abstract
Neuromodulation through magnetic fields irradiation with ait® (AT-04), a device that irradiates a mixed alternating magnetic fields (2 kHz and 83.3 MHz), has been shown to have high efficacy for fibromyalgia and low back pain in our previous clinical trials. The aim of this study was to elucidate the underlying analgesic mechanism of the AT-04 using the partial sciatic nerve ligation (PSL) model as an animal model of neuropathic pain. AT-04 was applied to PSL model rats with hyperalgesia and its pain-improving effect was verified by examining mechanical allodynia using the von Frey method. The results demonstrated a significant improvement in hyperalgesia in PSL model rats. We also examined the involvement of descending pain modulatory systems in the analgesic effects of AT-04 using antagonism by serotonin and noradrenergic receptor antagonists. These antagonists significantly reduced the analgesic effect of AT-04 on pain in PSL model rats by approximately 50%. We also measured the amount of serotonin and noradrenaline in the spinal fluid of PSL model rats using microdialysis during AT-04 treatment. Both monoamines were significantly increased by magnetic fields irradiation with AT-04. Furthermore, we evaluated the involvement of opioid analgesia in the analgesic effects of AT-04 using naloxone, the main antagonist of the opioid receptor, and found that it significantly antagonized the effects by approximately 60%. Therefore, the analgesic effects of AT-04 in PSL model rats involve both the endogenous pain modulation systems, including the descending pain modulatory system and the opioid analgesic system.
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Affiliation(s)
- Tatsuro Kohno
- Anesthesiology and Intensive Care Medicine, International University of Health and Welfare, 852 Hatakeda, Narita City, Chiba, 286-0124, Japan
| | - Kaori Takaki
- Peace of Mind Co., Ltd, 2-8-6 Tokuo, Kita-Ku, Kumamoto City, Kumamoto, 861-5525, Japan
| | - Kaori Kishita
- Peace of Mind Co., Ltd, 2-8-6 Tokuo, Kita-Ku, Kumamoto City, Kumamoto, 861-5525, Japan
| | - Kazunori Mitsutake
- Peace of Mind Co., Ltd, 2-8-6 Tokuo, Kita-Ku, Kumamoto City, Kumamoto, 861-5525, Japan
| | - Nozomu Tofuku
- Peace of Mind Co., Ltd, 2-8-6 Tokuo, Kita-Ku, Kumamoto City, Kumamoto, 861-5525, Japan
| | - Iwao Kishita
- Peace of Mind Co., Ltd, 2-8-6 Tokuo, Kita-Ku, Kumamoto City, Kumamoto, 861-5525, Japan.
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Radiansyah RS, Hadi DW. Repetitive transcranial magnetic stimulation in central post-stroke pain: current status and future perspective. Korean J Pain 2023; 36:408-424. [PMID: 37752663 PMCID: PMC10551398 DOI: 10.3344/kjp.23220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/03/2023] [Accepted: 09/14/2023] [Indexed: 09/28/2023] Open
Abstract
Central post-stroke pain (CPSP) is an incapacitating disorder that impacts a substantial proportion of stroke survivors and can diminish their quality of life. Conventional therapies for CPSP, including tricyclic antidepressants, anticonvulsants, and opioids, are frequently ineffective, necessitating the investigation of alternative therapeutic strategies. Repetitive transcranial magnetic stimulation (rTMS) is now recognized as a promising noninvasive pain management method for CPSP. rTMS modulates neural activity through the administration of magnetic pulses to specific cortical regions. Trials analyzing the effects of rTMS on CPSP have generated various outcomes, but the evidence suggests possible analgesic benefits. In CPSP and other neuropathic pain conditions, high-frequency rTMS targeting the primary motor cortex (M1) with figure-eight coils has demonstrated significant pain alleviation. Due to its associaton with analgesic benefits, M1 is the most frequently targeted area. The duration and frequency of rTMS sessions, as well as the stimulation intensity, have been studied in an effort to optimize treatment outcomes. The short-term pain relief effects of rTMS have been observed, but the long-term effects (> 3 months) require further investigation. Aspects such as stimulation frequency, location, and treatment period can influence the efficacy of rTMS and ought to be considered while planning the procedure. Standardized guidelines for using rTMS in CPSP would optimize therapy protocols and improve patient outcomes. This review article provides an up-to-date overview of the incidence, clinical characteristics, outcome of rTMS in CPSP patients, and future perspective in the field.
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Affiliation(s)
- Riva Satya Radiansyah
- Faculty of Medicine and Health, Institut Teknologi Sepuluh Nopember, Surabaya, Indonesia
| | - Deby Wahyuning Hadi
- Department of Neurology, Faculty of Medicine, Universitas Airlangga – Dr. Soetomo General Academic Hospital, Surabaya, Indonesia
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Karádi DÁ, Galambos AR, Lakatos PP, Apenberg J, Abbood SK, Balogh M, Király K, Riba P, Essmat N, Szűcs E, Benyhe S, Varga ZV, Szökő É, Tábi T, Al-Khrasani M. Telmisartan Is a Promising Agent for Managing Neuropathic Pain and Delaying Opioid Analgesic Tolerance in Rats. Int J Mol Sci 2023; 24:7970. [PMID: 37175678 PMCID: PMC10178315 DOI: 10.3390/ijms24097970] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/18/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Despite the large arsenal of analgesic medications, neuropathic pain (NP) management is not solved yet. Angiotensin II receptor type 1 (AT1) has been identified as a potential target in NP therapy. Here, we investigate the antiallodynic effect of AT1 blockers telmisartan and losartan, and particularly their combination with morphine on rat mononeuropathic pain following acute or chronic oral administration. The impact of telmisartan on morphine analgesic tolerance was also assessed using the rat tail-flick assay. Morphine potency and efficacy in spinal cord samples of treated neuropathic animals were assessed by [35S]GTPγS-binding assay. Finally, the glutamate content of the cerebrospinal fluid (CSF) was measured by capillary electrophoresis. Oral telmisartan or losartan in higher doses showed an acute antiallodynic effect. In the chronic treatment study, the combination of subanalgesic doses of telmisartan and morphine ameliorated allodynia and resulted in a leftward shift in the dose-response curve of morphine in the [35S]GTPγS binding assay and increased CSF glutamate content. Telmisartan delayed morphine analgesic-tolerance development. Our study has identified a promising combination therapy composed of telmisartan and morphine for NP and opioid tolerance. Since telmisartan is an inhibitor of AT1 and activator of PPAR-γ, future studies are needed to analyze the effect of each component.
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Affiliation(s)
- David Á. Karádi
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Anna Rita Galambos
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Péter P. Lakatos
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (P.P.L.); (É.S.); (T.T.)
| | - Joost Apenberg
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Sarah K. Abbood
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Mihály Balogh
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
- Pharmaceutical Analysis, Groningen Research Institute of Pharmacy, Faculty of Science and Engineering, University of Groningen, 9700 AD Groningen, The Netherlands
| | - Kornél Király
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Pál Riba
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Nariman Essmat
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Edina Szűcs
- Biological Research Center, Institute of Biochemistry, Temesvári krt. 62, H-6726 Szeged, Hungary; (E.S.); (S.B.)
| | - Sándor Benyhe
- Biological Research Center, Institute of Biochemistry, Temesvári krt. 62, H-6726 Szeged, Hungary; (E.S.); (S.B.)
| | - Zoltán V. Varga
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
| | - Éva Szökő
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (P.P.L.); (É.S.); (T.T.)
| | - Tamás Tábi
- Department of Pharmacodynamics, Faculty of Pharmacy, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (P.P.L.); (É.S.); (T.T.)
| | - Mahmoud Al-Khrasani
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Semmelweis University, Nagyvárad tér 4, H-1089 Budapest, Hungary; (D.Á.K.); (A.R.G.); (J.A.); (S.K.A.); (M.B.); (K.K.); (P.R.); (N.E.); (Z.V.V.)
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8
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Sharma A, Behl T, Sharma L, Shah OP, Yadav S, Sachdeva M, Rashid S, Bungau SG, Bustea C. Exploring the molecular pathways and therapeutic implications of angiogenesis in neuropathic pain. Biomed Pharmacother 2023; 162:114693. [PMID: 37062217 DOI: 10.1016/j.biopha.2023.114693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Revised: 03/26/2023] [Accepted: 04/10/2023] [Indexed: 04/18/2023] Open
Abstract
Recently, much attention has been paid to chronic neuro-inflammatory condition underlying neuropathic pain. It is generally linked with thermal hyperalgesia and tactile allodynia. It results due to injury or infection in the nervous system. The neuropathic pain spectrum covers a variety of pathophysiological states, mostly involved are ischemic injury viral infections associated neuropathies, chemotherapy-induced peripheral neuropathies, autoimmune disorders, traumatic origin, hereditary neuropathies, inflammatory disorders, and channelopathies. In CNS, angiogenesis is evident in inflammation of neurons and pain in bone cancer. The role of chemokines and cytokines is dualistic; their aggressive secretion produces detrimental effects, leading to neuropathic pain. However, whether the angiogenesis contributes and exists in neuropathic pain remains doubtful. In the present review, we elucidated summary of diverse mechanisms of neuropathic pain associated with angiogenesis. Moreover, an overview of multiple targets that have provided insights on the VEGF signaling, signaling through Tie-1 and Tie-2 receptor, erythropoietin pathway promoting axonal growth are also discussed. Because angiogenesis as a result of these signaling, results in inflammation, we focused on the mechanisms of neuropathic pain. These factors are mainly responsible for the activation of post-traumatic regeneration of the PNS and CNS. Furthermore, we also reviewed synthetic and herbal treatments targeting angiogenesis in neuropathic pain.
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Affiliation(s)
- Aditi Sharma
- School of Pharmaceutical Sciences, Shoolini University, Solan 173211, Himachal Pradesh, India
| | - Tapan Behl
- School of Health Sciences and Technology, University of Petroleum and Energy Studies, Bidholi, 248007 Dehradun, Uttarakhand, India.
| | - Lalit Sharma
- School of Pharmaceutical Sciences, Shoolini University, Solan 173211, Himachal Pradesh, India
| | - Om Prakash Shah
- School of Pharmaceutical Sciences, Shoolini University, Solan 173211, Himachal Pradesh, India
| | - Shivam Yadav
- Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences, Chhatrapati Shahu ji Maharaj University, Kanpur 208024, Uttar Pradesh, India
| | - Monika Sachdeva
- Fatima College of Health Sciences, Al Ain 00000, United Arab Emirates
| | - Summya Rashid
- Department of Pharmacology & Toxicology, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia
| | - Simona Gabriela Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea 410028, Romania; Doctoral School of Biomedical Sciences, University of Oradea, Oradea 410028, Romania.
| | - Cristiana Bustea
- Department of Preclinical Disciplines, Faculty of Medicine and Pharmacy, University of Oradea, Oradea 410073, Romania
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9
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Li L, Chen J, Li YQ. The Downregulation of Opioid Receptors and Neuropathic Pain. Int J Mol Sci 2023; 24:ijms24065981. [PMID: 36983055 PMCID: PMC10053236 DOI: 10.3390/ijms24065981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 03/18/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Neuropathic pain (NP) refers to pain caused by primary or secondary damage or dysfunction of the peripheral or central nervous system, which seriously affects the physical and mental health of 7-10% of the general population. The etiology and pathogenesis of NP are complex; as such, NP has been a hot topic in clinical medicine and basic research for a long time, with researchers aiming to find a cure by studying it. Opioids are the most commonly used painkillers in clinical practice but are regarded as third-line drugs for NP in various guidelines due to the low efficacy caused by the imbalance of opioid receptor internalization and their possible side effects. Therefore, this literature review aims to evaluate the role of the downregulation of opioid receptors in the development of NP from the perspective of dorsal root ganglion, spinal cord, and supraspinal regions. We also discuss the reasons for the poor efficacy of opioids, given the commonness of opioid tolerance caused by NP and/or repeated opioid treatments, an angle that has received little attention to date; in-depth understanding might provide a new method for the treatment of NP.
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Affiliation(s)
- Lin Li
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an 710072, China
- Department of Anatomy, Histology and Embryology and K. K. Leung Brain Research Centre, The Fourth Military Medical University, No. 169, West Changle Road, Xi'an 710032, China
| | - Jing Chen
- Department of Anatomy, Histology and Embryology and K. K. Leung Brain Research Centre, The Fourth Military Medical University, No. 169, West Changle Road, Xi'an 710032, China
| | - Yun-Qing Li
- Institute of Medical Research, Northwestern Polytechnical University, Xi'an 710072, China
- Department of Anatomy, Histology and Embryology and K. K. Leung Brain Research Centre, The Fourth Military Medical University, No. 169, West Changle Road, Xi'an 710032, China
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10
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Di Maio G, Villano I, Ilardi CR, Messina A, Monda V, Iodice AC, Porro C, Panaro MA, Chieffi S, Messina G, Monda M, La Marra M. Mechanisms of Transmission and Processing of Pain: A Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3064. [PMID: 36833753 PMCID: PMC9964506 DOI: 10.3390/ijerph20043064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/27/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Knowledge about the mechanisms of transmission and the processing of nociceptive information, both in healthy and pathological states, has greatly expanded in recent years. This rapid progress is due to a multidisciplinary approach involving the simultaneous use of different branches of study, such as systems neurobiology, behavioral analysis, genetics, and cell and molecular techniques. This narrative review aims to clarify the mechanisms of transmission and the processing of pain while also taking into account the characteristics and properties of nociceptors and how the immune system influences pain perception. Moreover, several important aspects of this crucial theme of human life will be discussed. Nociceptor neurons and the immune system play a key role in pain and inflammation. The interactions between the immune system and nociceptors occur within peripheral sites of injury and the central nervous system. The modulation of nociceptor activity or chemical mediators may provide promising novel approaches to the treatment of pain and chronic inflammatory disease. The sensory nervous system is fundamental in the modulation of the host's protective response, and understanding its interactions is pivotal in the process of revealing new strategies for the treatment of pain.
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Affiliation(s)
- Girolamo Di Maio
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Ines Villano
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Ciro Rosario Ilardi
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
- Department of Psychology, University of Campania “Luigi Vanvitelli”, 81100 Caserta, Italy
| | - Antonietta Messina
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Vincenzo Monda
- Department of Movement Sciences and Wellbeing, University of Naples “Parthenope”, 80133 Naples, Italy
| | - Ashlei Clara Iodice
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Chiara Porro
- Department of Clinical and Experimental Medicine, University of Foggia, Viale Pinto, 71100 Foggia, Italy
| | - Maria Antonietta Panaro
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Sergio Chieffi
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, Viale Pinto, 71100 Foggia, Italy
| | - Marcellino Monda
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
| | - Marco La Marra
- Department of Experimental Medicine, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
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11
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Nelson TS, Sinha GP, Santos DFS, Jukkola P, Prasoon P, Winter MK, McCarson KE, Smith BN, Taylor BK. Spinal neuropeptide Y Y1 receptor-expressing neurons are a pharmacotherapeutic target for the alleviation of neuropathic pain. Proc Natl Acad Sci U S A 2022; 119:e2204515119. [PMID: 36343228 PMCID: PMC9674229 DOI: 10.1073/pnas.2204515119] [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: 03/14/2022] [Accepted: 09/25/2022] [Indexed: 11/09/2022] Open
Abstract
Peripheral nerve injury sensitizes a complex network of spinal cord dorsal horn (DH) neurons to produce allodynia and neuropathic pain. The identification of a druggable target within this network has remained elusive, but a promising candidate is the neuropeptide Y (NPY) Y1 receptor-expressing interneuron (Y1-IN) population. We report that spared nerve injury (SNI) enhanced the excitability of Y1-INs and elicited allodynia (mechanical and cold hypersensitivity) and affective pain. Similarly, chemogenetic or optogenetic activation of Y1-INs in uninjured mice elicited behavioral signs of spontaneous, allodynic, and affective pain. SNI-induced allodynia was reduced by chemogenetic inhibition of Y1-INs, or intrathecal administration of a Y1-selective agonist. Conditional deletion of Npy1r in DH neurons, but not peripheral afferent neurons prevented the anti-hyperalgesic effects of the intrathecal Y1 agonist. We conclude that spinal Y1-INs are necessary and sufficient for the behavioral symptoms of neuropathic pain and represent a promising target for future pharmacotherapeutic development of Y1 agonists.
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Affiliation(s)
- Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261
| | - Ghanshyam P. Sinha
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Diogo F. S. Santos
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Peter Jukkola
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Michelle K. Winter
- Kansas Intellectual and Developmental Disabilities Research Center; Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Ken E. McCarson
- Kansas Intellectual and Developmental Disabilities Research Center; Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Bret N. Smith
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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12
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Microglial Activation of GLP-1R Signaling in Neuropathic Pain Promotes Gene Expression Adaption Involved in Inflammatory Responses. Neural Plast 2021; 2021:9923537. [PMID: 34512747 PMCID: PMC8426070 DOI: 10.1155/2021/9923537] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 07/07/2021] [Accepted: 08/04/2021] [Indexed: 01/13/2023] Open
Abstract
Background Neuropathic pain is a common chronic pain, which is related to hypersensitivity to stimulus and greatly affects the quality of life of patients. Maladaptive gene changes and molecular signaling underlie the sensitization of nociceptive pathways. We previously found that the activation of microglial glucagon-like peptide 1 receptor (GLP-1R) could potently relieve formalin-, bone cancer-, peripheral nerve injury-, and diabetes-induced pain hypersensitivity. So far, little is known about how the gene profile changes upon the activation of GLP-1R signaling in the pathophysiology of neuropathic pain. Methods Spinal nerve ligation (SNL) was performed to induce neuropathic pain in rats. Mechanical allodynia was assessed using von Frey filaments. The expression of IL-10, β-endorphin, and μ-opioid receptor (MOR) was examined by real-time quantitative polymerase chain reaction (qPCR) and whole-cell recording. Measurements of cellular excitability of the substantia gelatinosa (SG) neurons by whole-cell recording were carried out. R packages of differential gene expression analysis based on the negative binomial distribution (DESeq2) and weighted correlation network analysis (WGCNA) were used to analyze differential gene expression and the correlated modules among GLP-1R clusters in neuropathic pain. Results The GLP-1R agonist, exenatide, has an antiallodynic effect on neuropathic pain, which could be reversed by intrathecal injections of the microglial inhibitor minocycline. Furthermore, differential gene expression analysis (WGCNA) indicated that intrathecal injections of exenatide could reverse the abnormal expression of 591 genes in the spinal dorsal horn induced by nerve injury. WGCNA revealed 58 modules with a close relationship between the microglial GLP-1R pathway and features of nerve injuries, including pain, ligation, paw withdrawal latency (PWL), and anxiety. The brown module was identified as the highest correlated module, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that inflammatory responses were most correlated with PWL. To further unravel the changes of hyperalgesia-related neuronal electrophysiological activity mediated by microglia GLP-1 receptors, whole-cell recording identified that MOR agonism stimulated a robust outward current in the sham groups compared with the spinal nerve ligation (SNL) groups. This inhibitory effect on the SNL group was more sensitive than that of the sham group after bath application of β-endorphin. Conclusions Our results further confirmed that the GLP-1R pathway is involved in alleviating pain hypersensitivity mediated by spinal microglia activation, and inflammatory responses were the most correlated pathway associated with PWL changes in response to exenatide treatment. We found that the identification of gene regulation in response to GLP-1R activation is an effective strategy for identifying new therapeutic targets for neuropathic pain. Investigation for the activation of spinal microglial GLP-1R which might ameliorate inflammatory responses through gene expression and structural changes is providing a potential biomarker in pain management.
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13
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Ma L, Peng S, Wei J, Zhao M, Ahmad KA, Chen J, Wang YX. Spinal microglial β-endorphin signaling mediates IL-10 and exenatide-induced inhibition of synaptic plasticity in neuropathic pain. CNS Neurosci Ther 2021; 27:1157-1172. [PMID: 34111331 PMCID: PMC8446220 DOI: 10.1111/cns.13694] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 05/22/2021] [Accepted: 05/24/2021] [Indexed: 12/17/2022] Open
Abstract
AIM This study aimed to investigate the regulation of pain hypersensitivity induced by the spinal synaptic transmission mechanisms underlying interleukin (IL)-10 and glucagon-like peptide 1 receptor (GLP-1R) agonist exenatide-induced pain anti-hypersensitivity in neuropathic rats through spinal nerve ligations. METHODS Neuropathic pain model was established by spinal nerve ligation of L5/L6 and verified by electrophysiological recording and immunofluorescence staining. Microglial expression of β-endorphin through autocrine IL-10- and exenatide-induced inhibition of glutamatergic transmission were performed by behavioral tests coupled with whole-cell recording of miniature excitatory postsynaptic currents (mEPSCs) and miniature inhibitory postsynaptic currents (mIPSCs) through application of endogenous and exogenous IL-10 and β-endorphin. RESULTS Intrathecal injections of IL-10, exenatide, and the μ-opioid receptor (MOR) agonists β-endorphin and DAMGO inhibited thermal hyperalgesia and mechanical allodynia in neuropathic rats. Whole-cell recordings of bath application of exenatide, IL-10, and β-endorphin showed similarly suppressed enhanced frequency and amplitude of the mEPSCs in the spinal dorsal horn neurons of laminae II, but did not reduce the frequency and amplitude of mIPSCs in neuropathic rats. The inhibitory effects of IL-10 and exenatide on pain hypersensitive behaviors and spinal synaptic plasticity were totally blocked by pretreatment of IL-10 antibody, β-endorphin antiserum, and MOR antagonist CTAP. In addition, the microglial metabolic inhibitor minocycline blocked the inhibitory effects of IL-10 and exenatide but not β-endorphin on spinal synaptic plasticity. CONCLUSION This suggests that spinal microglial expression of β-endorphin mediates IL-10- and exenatide-induced inhibition of glutamatergic transmission and pain hypersensitivity via presynaptic and postsynaptic MORs in spinal dorsal horn.
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Affiliation(s)
- Le Ma
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Jiao Tong University School of Medicine, Shanghai Mental Health Center, Shanghai, China
| | - Shiyu Peng
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Jiao Tong University School of Medicine, Shanghai Mental Health Center, Shanghai, China.,School of Life Sciences, Westlake Institute for Advanced Study, Westlake University, Hangzhou, China
| | - Jinbao Wei
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Mengjing Zhao
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Khalil Ali Ahmad
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
| | - Jinghong Chen
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Jiao Tong University School of Medicine, Shanghai Mental Health Center, Shanghai, China
| | - Yong-Xiang Wang
- King's Lab, Shanghai Jiao Tong University School of Pharmacy, Shanghai, China
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14
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Needling Interventions for Sciatica: Choosing Methods Based on Neuropathic Pain Mechanisms-A Scoping Review. J Clin Med 2021; 10:jcm10102189. [PMID: 34069357 PMCID: PMC8158699 DOI: 10.3390/jcm10102189] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 02/06/2023] Open
Abstract
Sciatica is a condition often accompanied by neuropathic pain (NP). Acupuncture and dry needling are common treatments for pain, and the current literature supports acupuncture as an effective treatment for sciatica. However, it is unknown if the mechanisms of NP are considered in the delivery of needling interventions for sciatica. Our objective was to assess the efficacy and the effectiveness of needling therapies, to identify common needling practices and to investigate if NP mechanisms are considered in the treatment of sciatica. A scoping review of the literature on needling interventions for sciatica and a review of the literature on mechanisms related to NP and needling interventions were performed. Electronic literature searches were conducted on PubMed, MEDLINE, CINAHL and Cochrane Database of Systematic Reviews from inception to August, 2020 to identify relevant papers. Reference lists of included papers were also manually screened and a related-articles search through PubMed was performed on all included articles. Mapping of the results included description of included studies, summary of results, and identification of gaps in the existing literature. Ten articles were included. All studies used acupuncture for the treatment of sciatica, no studies on dry needling were identified. Current evidence supports the efficacy and effectiveness of acupuncture for sciatica, however, no studies considered underlying NP mechanisms in the acupuncture approach for sciatica and the rationale for using acupuncture was inconsistent among trials. This review reveals that neuropathic pain mechanisms are not routinely considered in needling approaches for patients with sciatica. Studies showed acupuncture to be an effective treatment for sciatic pain, however, further research is warranted to explore if needling interventions for sciatica and NP would be more effective if NP mechanisms are considered.
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15
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Chang C, Liu HK, Yeh CB, Yang ML, Liao WC, Liu CH, Tseng TJ. Cross-Talk of Toll-Like Receptor 5 and Mu-Opioid Receptor Attenuates Chronic Constriction Injury-Induced Mechanical Hyperalgesia through a Protein Kinase C Alpha-Dependent Signaling. Int J Mol Sci 2021; 22:1891. [PMID: 33673008 PMCID: PMC7918001 DOI: 10.3390/ijms22041891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/30/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
Recently, Toll-like receptors (TLRs), a family of pattern recognition receptors, are reported as potential modulators for neuropathic pain; however, the desired mechanism is still unexplained. Here, we operated on the sciatic nerve to establish a pre-clinical rodent model of chronic constriction injury (CCI) in Sprague-Dawley rats, which were assigned into CCI and Decompression groups randomly. In Decompression group, the rats were performed with nerve decompression at post-operative week 4. Mechanical hyperalgesia and mechanical allodynia were obviously attenuated after a month. Toll-like receptor 5 (TLR5)-immunoreactive (ir) expression increased in dorsal horn, particularly in the inner part of lamina II. Additionally, substance P (SP) and isolectin B4 (IB4)-ir expressions, rather than calcitonin-gene-related peptide (CGRP)-ir expression, increased in their distinct laminae. Double immunofluorescence proved that increased TLR5-ir expression was co-expressed mainly with IB4-ir expression. Through an intrathecal administration with FLA-ST Ultrapure (a TLR5 agonist, purified flagellin from Salmonella Typhimurium, only the CCI-induced mechanical hyperalgesia was attenuated dose-dependently. Moreover, we confirmed that mu-opioid receptor (MOR) and phospho-protein kinase Cα (pPKCα)-ir expressions but not phospho-protein kinase A RII (pPKA RII)-ir expression, increased in lamina II, where they mostly co-expressed with IB4-ir expression. Go 6976, a potent protein kinase C inhibitor, effectively reversed the FLA-ST Ultrapure- or DAMGO-mediated attenuated trend towards mechanical hyperalgesia by an intrathecal administration in CCI rats. In summary, our current findings suggest that nerve decompression improves CCI-induced mechanical hyperalgesia that might be through the cross-talk of TLR5 and MOR in a PKCα-dependent manner, which opens a novel opportunity for the development of analgesic therapeutics in neuropathic pain.
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Affiliation(s)
- Ching Chang
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
| | - Hung-Kai Liu
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
| | - Chao-Bin Yeh
- Department of Emergency Medicine, Chung Shan Medical University Hospital, 40201 Taichung, Taiwan;
- Department of Emergency Medicine, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan
| | - Ming-Lin Yang
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
- Department of Medical Education, Chung Shan Medical University Hospital, 40201 Taichung, Taiwan
| | - Wen-Chieh Liao
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
- Department of Medical Education, Chung Shan Medical University Hospital, 40201 Taichung, Taiwan
| | - Chiung-Hui Liu
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
- Department of Medical Education, Chung Shan Medical University Hospital, 40201 Taichung, Taiwan
| | - To-Jung Tseng
- Department of Anatomy, School of Medicine, Chung Shan Medical University, 40201 Taichung, Taiwan; (C.C.); (H.-K.L.); (M.-L.Y.); (W.-C.L.); (C.-H.L.)
- Department of Medical Education, Chung Shan Medical University Hospital, 40201 Taichung, Taiwan
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16
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Zheng BX, Malik A, Xiong M, Bekker A, Tao YX. Nerve trauma-caused downregulation of opioid receptors in primary afferent neurons: Molecular mechanisms and potential managements. Exp Neurol 2020; 337:113572. [PMID: 33340498 DOI: 10.1016/j.expneurol.2020.113572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/06/2020] [Accepted: 12/13/2020] [Indexed: 12/18/2022]
Abstract
Neuropathic pain is the most common clinical disorder destroying the quality of patient life and leading to a marked economic and social burden. Opioids are still last option for pharmacological treatment of this disorder, but their antinociceptive effects are limited in part due to the downregulation of opioid receptors in the primary afferent neurons after peripheral nerve trauma. How this downregulation occurs is not completely understood, but recent studies have demonstrated that peripheral nerve trauma drives the alterations in epigenetic modifications (including DNA methylation, histone methylation and mciroRNAs), expression of transcription factors, post-transcriptional modifications (e.g., RNA methylation) and protein translation initiation in the neurons of nerve trauma-related dorsal root ganglion (DRG) and that these alternations may be associated with nerve trauma-caused downregulation of DRG opioid receptors. This review presents how opioid receptors are downregulated in the DRG after peripheral nerve trauma, specifically focusing on distinct molecular mechanisms underlying transcriptional and translational processes. This review also discusses how this downregulation contributes to the induction and maintenance of neuropathic pain. A deeper understanding of these molecular mechanisms likely provides a novel avenue for prevention and/or treatment of neuropathic pain.
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Affiliation(s)
- Bi-Xin Zheng
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Ayma Malik
- Rutgers Graduate School of Biomedical Sciences, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Ming Xiong
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA.
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17
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Multifunctional Opioid-Derived Hybrids in Neuropathic Pain: Preclinical Evidence, Ideas and Challenges. Molecules 2020; 25:molecules25235520. [PMID: 33255641 PMCID: PMC7728063 DOI: 10.3390/molecules25235520] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/21/2022] Open
Abstract
When the first- and second-line therapeutics used to treat neuropathic pain (NP) fail to induce efficient analgesia—which is estimated to relate to more than half of the patients—opioid drugs are prescribed. Still, the pathological changes following the nerve tissue injury, i.a. pronociceptive neuropeptide systems activation, oppose the analgesic effects of opiates, enforcing the use of relatively high therapeutic doses in order to obtain satisfying pain relief. In parallel, the repeated use of opioid agonists is associated with burdensome adverse effects due to compensatory mechanisms that arise thereafter. Rational design of hybrid drugs, in which opioid ligands are combined with other pharmacophores that block the antiopioid action of pronociceptive systems, delivers the opportunity to ameliorate the NP-oriented opioid treatment via addressing neuropathological mechanisms shared both by NP and repeated exposition to opioids. Therewith, the new dually acting drugs, tailored for the specificity of NP, can gain in efficacy under nerve injury conditions and have an improved safety profile as compared to selective opioid agonists. The current review presents the latest ideas on opioid-comprising hybrid drugs designed to treat painful neuropathy, with focus on their biological action, as well as limitations and challenges related to this therapeutic approach.
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18
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Ma SB, Xian H, Wu WB, Ma SY, Liu YK, Liang YT, Guo H, Kang JJ, Liu YY, Zhang H, Wu SX, Luo C, Xie RG. CCL2 facilitates spinal synaptic transmission and pain via interaction with presynaptic CCR2 in spinal nociceptor terminals. Mol Brain 2020; 13:161. [PMID: 33228784 PMCID: PMC7685578 DOI: 10.1186/s13041-020-00701-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/17/2020] [Indexed: 12/19/2022] Open
Abstract
Previous studies have shown that CCL2 may cause chronic pain, but the exact mechanism of central sensitization is unclear. In this article, we further explore the presynaptic role of CCL2. Behavioral experiments show that intervertebral foramen injection CCR2 antagonists into dorsal root ganglion (DRG) can inhibit the inflammatory pain caused by CCL2 in spinal cord. We raised the question of the role of presynaptic CCR2 in the spinal dorsal horn. Subsequent electron microscopy experiments showed that CCR2 was expressed in the presynaptic CGRP terminal in the spinal dorsal horn. CCL2 can enhance presynaptic calcium signal. Whole-cell patch-clamp recordings showed that CCL2 can enhance NMDAR-eEPSCs through presynaptic effects, and further application of glutamate sensor method proved that CCL2 can act on presynaptic CCR2 to increase the release of presynaptic glutamate. In conclusion, we suggest that CCL2 can directly act on the CCR2 on presynaptic terminals of sensory neurons in the spinal dorsal horn, leading to an increase in the release of presynaptic glutamate and participate in the formation of central sensitization.
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Affiliation(s)
- Sui-Bin Ma
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Hang Xian
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Department of Orthopedics, Xijing Hospital, Fourth Military Medical University, Xi'an, 710032, China
| | - Wen-Bin Wu
- The Fourth Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Shuo-Yao Ma
- The Sixth Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Ke Liu
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Yu-Tong Liang
- The Second Regiment, School of Basic Medicine, Fourth Military Medical University, Xi'an, 710032, China
| | - Huan Guo
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Pain and Related Diseases Research Laboratory, Medical College of Shantou University, Shantou, 515041, China
| | - Jun-Jun Kang
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Ying-Ying Liu
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Hui Zhang
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.,Department of Health Statistics, Fourth Military Medical University, Xi'an, 710032, China
| | - Sheng-Xi Wu
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China
| | - Ceng Luo
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.
| | - Rou-Gang Xie
- Department of Neurobiology, Fourth Military Medical University, Xi'an, 710032, China.
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19
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Smith PA. K + Channels in Primary Afferents and Their Role in Nerve Injury-Induced Pain. Front Cell Neurosci 2020; 14:566418. [PMID: 33093824 PMCID: PMC7528628 DOI: 10.3389/fncel.2020.566418] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 08/21/2020] [Indexed: 12/12/2022] Open
Abstract
Sensory abnormalities generated by nerve injury, peripheral neuropathy or disease are often expressed as neuropathic pain. This type of pain is frequently resistant to therapeutic intervention and may be intractable. Numerous studies have revealed the importance of enduring increases in primary afferent excitability and persistent spontaneous activity in the onset and maintenance of peripherally induced neuropathic pain. Some of this activity results from modulation, increased activity and /or expression of voltage-gated Na+ channels and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. K+ channels expressed in dorsal root ganglia (DRG) include delayed rectifiers (Kv1.1, 1.2), A-channels (Kv1.4, 3.3, 3.4, 4.1, 4.2, and 4.3), KCNQ or M-channels (Kv7.2, 7.3, 7.4, and 7.5), ATP-sensitive channels (KIR6.2), Ca2+-activated K+ channels (KCa1.1, 2.1, 2.2, 2.3, and 3.1), Na+-activated K+ channels (KCa4.1 and 4.2) and two pore domain leak channels (K2p; TWIK related channels). Function of all K+ channel types is reduced via a multiplicity of processes leading to altered expression and/or post-translational modification. This also increases excitability of DRG cell bodies and nociceptive free nerve endings, alters axonal conduction and increases neurotransmitter release from primary afferent terminals in the spinal dorsal horn. Correlation of these cellular changes with behavioral studies provides almost indisputable evidence for K+ channel dysfunction in the onset and maintenance of neuropathic pain. This idea is underlined by the observation that selective impairment of just one subtype of DRG K+ channel can produce signs of pain in vivo. Whilst it is established that various mediators, including cytokines and growth factors bring about injury-induced changes in DRG function and excitability, evidence presently available points to a seminal role for interleukin 1β (IL-1β) in control of K+ channel function. Despite the current state of knowledge, attempts to target K+ channels for therapeutic pain management have met with limited success. This situation may change with the advent of personalized medicine. Identification of specific sensory abnormalities and genetic profiling of individual patients may predict therapeutic benefit of K+ channel activators.
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Affiliation(s)
- Peter A. Smith
- Department of Pharmacology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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20
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Yu K, Niu X, He B. Neuromodulation Management of Chronic Neuropathic Pain in The Central Nervous system. ADVANCED FUNCTIONAL MATERIALS 2020; 30:1908999. [PMID: 34335132 PMCID: PMC8323399 DOI: 10.1002/adfm.201908999] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Indexed: 05/05/2023]
Abstract
Neuromodulation is becoming one of the clinical tools for treating chronic neuropathic pain by transmitting controlled physical energy to the pre-identified neural targets in the central nervous system. Its nature of drug-free, non-addictive and improved targeting have attracted increasing attention among neuroscience research and clinical practices. This article provides a brief overview of the neuropathic pain and pharmacological routines for treatment, summarizes both the invasive and non-invasive neuromodulation modalities for pain management, and highlights an emerging brain stimulation technology, transcranial focused ultrasound (tFUS) with a focus on ultrasound transducer devices and the achieved neuromodulation effects and applications on pain management. Practical considerations of spatial guidance for tFUS are discussed for clinical applications. The safety of transcranial ultrasound neuromodulation and its future prospectives on pain management are also discussed.
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Affiliation(s)
| | | | - Bin He
- Department of Biomedical Engineering, Carnegie Mellon University
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21
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Speltz R, Lunzer MM, Shueb SS, Akgün E, Reed R, Kalyuzhny A, Portoghese PS, Simone DA. The bivalent ligand, MMG22, reduces neuropathic pain after nerve injury without the side effects of traditional opioids. Pain 2020; 161:2041-2057. [PMID: 32345918 PMCID: PMC7606301 DOI: 10.1097/j.pain.0000000000001902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 04/21/2020] [Indexed: 11/26/2022]
Abstract
ABSTRACT Functional interactions between the mu opioid receptor (MOR) and the metabotropic glutamate receptor 5 (mGluR5) in pain and analgesia have been well established. MMG22 is a bivalent ligand containing MOR agonist (oxymorphamine) and mGluR5 antagonist (MPEP) pharmacophores tethered by a 22-atom linker. MMG22 has been shown to produce potent analgesia in several models of chronic inflammatory and neuropathic pain (NP). This study assessed the efficacy of systemic administration of MMG22 at reducing pain behavior in the spared nerve injury (SNI) model of NP in mice, as well as its side-effect profile and abuse potential. MMG22 reduced mechanical hyperalgesia and spontaneous ongoing pain after SNI, with greater potency early (10 days) as compared to late (30 days) after injury. Systemic administration of MMG22 did not induce place preference in naive animals, suggesting absence of abuse liability when compared to traditional opioids. MMG22 also lacked the central locomotor, respiratory, and anxiolytic side effects of its monomeric pharmacophores. Evaluation of mRNA expression showed the transcripts for both receptors were colocalized in cells in the dorsal horn of the lumbar spinal cord and dorsal root ganglia. Thus, MMG22 reduces hyperalgesia after injury in the SNI model of NP without the typical centrally mediated side effects associated with traditional opioids.
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Affiliation(s)
- Rebecca Speltz
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Mary M Lunzer
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States
| | - Sarah S Shueb
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
| | - Eyup Akgün
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States
| | | | - Alex Kalyuzhny
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
- Bio-Techne, Minneapolis, MN, United States
| | - Philip S Portoghese
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, MN, United States
| | - Donald A Simone
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, United States
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22
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On the Role of Peripheral Sensory and Gut Mu Opioid Receptors: Peripheral Analgesia and Tolerance. Molecules 2020; 25:molecules25112473. [PMID: 32466522 PMCID: PMC7321260 DOI: 10.3390/molecules25112473] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/22/2020] [Accepted: 05/24/2020] [Indexed: 02/06/2023] Open
Abstract
There is growing evidence on the role of peripheral µ-opioid receptors (MORs) in analgesia and analgesic tolerance. Opioid analgesics are the mainstay in the management of moderate to severe pain, and their efficacy in the alleviation of pain is well recognized. Unfortunately, chronic treatment with opioid analgesics induces central analgesic tolerance, thus limiting their clinical usefulness. Numerous molecular mechanisms, including receptor desensitization, G-protein decoupling, β-arrestin recruitment, and alterations in the expression of peripheral MORs and microbiota have been postulated to contribute to the development of opioid analgesic tolerance. However, these studies are largely focused on central opioid analgesia and tolerance. Accumulated literature supports that peripheral MORs mediate analgesia, but controversial results on the development of peripheral opioid receptors-mediated analgesic tolerance are reported. In this review, we offer evidence on the consequence of the activation of peripheral MORs in analgesia and analgesic tolerance, as well as approaches that enhance analgesic efficacy and decrease the development of tolerance to opioids at the peripheral sites. We have also addressed the advantages and drawbacks of the activation of peripheral MORs on the sensory neurons and gut (leading to dysbiosis) on the development of central and peripheral analgesic tolerance.
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23
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Llorca-Torralba M, Pilar-Cuéllar F, da Silva Borges G, Mico JA, Berrocoso E. Opioid receptors mRNAs expression and opioids agonist-dependent G-protein activation in the rat brain following neuropathy. Prog Neuropsychopharmacol Biol Psychiatry 2020; 99:109857. [PMID: 31904442 DOI: 10.1016/j.pnpbp.2019.109857] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/24/2019] [Accepted: 12/31/2019] [Indexed: 12/12/2022]
Abstract
Potent opioid-based therapies are often unsuccessful in promoting satisfactory analgesia in neuropathic pain. Moreover, the side effects associated with opioid therapy are still manifested in neuropathy-like diseases, including tolerance, abuse, addiction and hyperalgesia, although the mechanisms underlying these effects remain unclear. Studies in the spinal cord and periphery indicate that neuropathy alters the expression of mu-[MOP], delta-[DOP] or kappa-[KOP] opioid receptors, interfering with their activity. However, there is no consensus as to the supraspinal opioidergic modulation provoked by neuropathy, the structures where the sensory and affective-related pain components are processed. In this study we explored the effect of chronic constriction of the sciatic nerve (CCI) over 7 and 30 days (CCI-7d and CCI-30d, respectively) on MOP, DOP and KOP mRNAs expression, using in situ hybridization, and the efficacy of G-protein stimulation by DAMGO, DPDPE and U-69593 (MOP, DOP and KOP specific agonists, respectively), using [35S]GTPγS binding, within opioid-sensitive brain structures. After CCI-7d, CCI-30d or both, opioid receptor mRNAs expression was altered throughout the brain: MOP - in the paracentral/centrolateral thalamic nuclei, ventral posteromedial thalamic nuclei, superior olivary complex, parabrachial nucleus [PB] and posterodorsal tegmental nucleus; DOP - in the somatosensory cortex [SSC], ventral tegmental area, caudate putamen [CPu], nucleus accumbens [NAcc], raphe magnus [RMg] and PB; and KOP - in the locus coeruleus. Agonist-stimulated [35S]GTPγS binding was altered following CCI: MOP - CPu and RMg; DOP - prefrontal cortex [PFC], SSC, RMg and NAcc; and KOP - PFC and SSC. Thus, this study shows that several opioidergic circuits in the brain are recruited and modified following neuropathy.
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Affiliation(s)
- Meritxell Llorca-Torralba
- Neuropsychopharmacology and Psychobiology Research Group, Department of Neuroscience, University of Cádiz, Cádiz, Spain; Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Institute of Health Carlos III, Madrid, Spain; Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital, University of Cádiz, Cádiz, Spain
| | - Fuencisla Pilar-Cuéllar
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Institute of Health Carlos III, Madrid, Spain; Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC (Universidad de Cantabria, CSIC, SODERCAN), Department of Physiology and Pharmacology, University of Cantabria, Santander, Spain
| | | | - Juan A Mico
- Neuropsychopharmacology and Psychobiology Research Group, Department of Neuroscience, University of Cádiz, Cádiz, Spain; Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Institute of Health Carlos III, Madrid, Spain; Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital, University of Cádiz, Cádiz, Spain
| | - Esther Berrocoso
- Biomedical Research Networking Center for Mental Health Network (CIBERSAM), Institute of Health Carlos III, Madrid, Spain; Biomedical Research and Innovation Institute of Cádiz (INiBICA) Research Unit, Puerta del Mar University Hospital, University of Cádiz, Cádiz, Spain; Neuropsychopharmacology and Psychobiology Research Group, Department of Psychology, University of Cádiz, Cádiz, Spain.
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24
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Mechanical allodynia in mice with tenascin-X deficiency associated with Ehlers-Danlos syndrome. Sci Rep 2020; 10:6569. [PMID: 32300146 PMCID: PMC7162960 DOI: 10.1038/s41598-020-63499-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 03/07/2020] [Indexed: 12/22/2022] Open
Abstract
Tenascin-X (TNX) is a member of the extracellular matrix glycoprotein tenascin family, and TNX deficiency leads to Ehlers-Danlos syndrome, a heritable human disorder characterized mostly by skin hyperextensibility, joint hypermobility, and easy bruising. TNX-deficient patients complain of chronic joint pain, myalgia, paresthesia, and axonal polyneuropathy. However, the molecular mechanisms by which TNX deficiency complicates pain are unknown. Here, we examined the nociceptive behavioral responses of TNX-deficient mice. Compared with wild-type mice, TNX-deficient mice exhibited mechanical allodynia but not thermal hyperalgesia. TNX deficiency also increased pain sensitivity to chemical stimuli and aggravated early inflammatory pain elicited by formalin. TNX-deficient mice were significantly hypersensitive to transcutaneous sine wave stimuli at frequencies of 250 Hz (Aδ fiber responses) and 2000 Hz (Aβ fiber responses), but not to stimuli at frequency of 5 Hz (C fiber responses). In addition, the phosphorylation levels of extracellular signal-related kinase, an active neuronal marker, and the activity of NADPH-diaphorase, a neuronal nitric oxide activation marker, were enhanced in the spinal dorsal horns of TNX-deficient mice. These results suggest that TNX deficiency contributes to the development of mechanical allodynia and hypersensitivity to chemical stimuli, and it induces hypersensitization of myelinated A fibers and activation of the spinal dorsal horn.
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25
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Sandercock DA, Barnett MW, Coe JE, Downing AC, Nirmal AJ, Di Giminiani P, Edwards SA, Freeman TC. Transcriptomics Analysis of Porcine Caudal Dorsal Root Ganglia in Tail Amputated Pigs Shows Long-Term Effects on Many Pain-Associated Genes. Front Vet Sci 2019; 6:314. [PMID: 31620455 PMCID: PMC6760028 DOI: 10.3389/fvets.2019.00314] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 09/03/2019] [Indexed: 12/24/2022] Open
Abstract
Tail amputation by tail docking or as an extreme consequence of tail biting in commercial pig production potentially has serious implications for animal welfare. Tail amputation causes peripheral nerve injury that might be associated with lasting chronic pain. The aim of this study was to investigate the short- and long-term effects of tail amputation in pigs on caudal DRG gene expression at different stages of development, particularly in relation to genes associated with nociception and pain. Microarrays were used to analyse whole DRG transcriptomes from tail amputated and sham-treated pigs 1, 8, and 16 weeks following tail treatment at either 3 or 63 days of age (8 pigs/treatment/age/time after treatment; n = 96). Tail amputation induced marked changes in gene expression (up and down) compared to sham-treated intact controls for all treatment ages and time points after tail treatment. Sustained changes in gene expression in tail amputated pigs were still evident 4 months after tail injury. Gene correlation network analysis revealed two co-expression clusters associated with amputation: Cluster A (759 down-regulated) and Cluster B (273 up-regulated) genes. Gene ontology (GO) enrichment analysis identified 124 genes in Cluster A and 61 genes in Cluster B associated with both “inflammatory pain” and “neuropathic pain.” In Cluster A, gene family members of ion channels e.g., voltage-gated potassium channels (VGPC) and receptors e.g., GABA receptors, were significantly down-regulated compared to shams, both of which are linked to increased peripheral nerve excitability after axotomy. Up-regulated gene families in Cluster B were linked to transcriptional regulation, inflammation, tissue remodeling, and regulatory neuropeptide activity. These findings, demonstrate that tail amputation causes sustained transcriptomic expression changes in caudal DRG cells involved in inflammatory and neuropathic pain pathways.
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Affiliation(s)
- Dale A Sandercock
- Animal and Veterinary Science Research Group, Scotland's Rural College, Roslin Institute Building, Edinburgh, United Kingdom
| | - Mark W Barnett
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer E Coe
- Animal and Veterinary Science Research Group, Scotland's Rural College, Roslin Institute Building, Edinburgh, United Kingdom
| | - Alison C Downing
- Edinburgh Genomics, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ajit J Nirmal
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Pierpaolo Di Giminiani
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Sandra A Edwards
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Tom C Freeman
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
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26
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Liang L, Zhao JY, Kathryn T, Bekker A, Tao YX. BIX01294, a G9a inhibitor, alleviates nerve injury-induced pain hypersensitivities during both development and maintenance periods. ACTA ACUST UNITED AC 2019; 6:106-114. [PMID: 31497620 DOI: 10.31480/2330-4871/097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Genetic knockdown or knockout of the histone methytransferase G9a in the injured dorsal root ganglion (DRG) has been shown to alleviate neuropathic pain development. However, the application of genetic strategy in clinic is highly limited. The present study sought to examine the effect of intrathecal BIX01294, a specific G9a inhibitor, on the development and maintenance of pain hypersensitivities caused by unilateral L5 spinal nerve injury (SNL) or chronic constriction injury (CCI) to the sciatic nerve in rats. We found that intrathecal administration of BIX01294 reduced SNL- or CCI-induced mechanical allodynia, thermal hyperalgesia and cold allodynia not only in the development period but also in the maintenance period. These effects were dose-dependent. Intrathecal administration of BIX01294 also blocked the SNL-induced increase in the level of H3K9me2, a marker of G9a activity, and reversed SNL-induced downregulation of Oprm1 mRNA, Oprk1 mRNA, Oprd1 mRNA, Kcna2 mRNA, and Kcna4 mRNA, the downstream targets of G9a, in the ipsilateral L5 DRG. These findings further implicate that G9a as a potential target in the management of neuropathic pain.
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Affiliation(s)
- Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Jian-Yuan Zhao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Ticehurst Kathryn
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA.,Department of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA.,Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
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27
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Overexpression of µ-Opioid Receptors in Peripheral Afferents, but Not in Combination with Enkephalin, Decreases Neuropathic Pain Behavior and Enhances Opioid Analgesia in Mouse. Anesthesiology 2019; 128:967-983. [PMID: 29334500 DOI: 10.1097/aln.0000000000002063] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND The current study used recombinant herpes simplex virus type I to increase expression of µ-opiate receptors and the opioid ligand preproenkephalin in peripheral nerve fibers in a mouse model of neuropathic pain. It was predicted that viral vector delivery of a combination of genes encoding the µ-opioid receptor and preproenkephalin would attenuate neuropathic pain and enhance opioid analgesia. The behavioral effects would be paralleled by changes in response properties of primary afferent neurons. METHODS Recombinant herpes simplex virus type 1 containing cDNA sequences of the µ-opioid receptor, human preproenkephalin, a combination, or Escherichia coli lacZ gene marker (as a control) was used to investigate the role of peripheral opioids in neuropathic pain behaviors. RESULTS Inoculation with the µ-opioid receptor viral vector (n = 13) reversed mechanical allodynia and thermal hyperalgesia and produced leftward shifts in loperamide (ED50 = 0.6 ± 0.2 mg/kg vs. ED50 = 0.9 ± 0.2 mg/kg for control group, n = 8, means ± SD) and morphine dose-response curves (ED50 = 0.3 ± 0.5 mg/kg vs. ED50 = 1.1 ± 0.1 mg/kg for control group). In µ-opioid receptor viral vector inoculated C-fibers, heat-evoked responses (n = 12) and ongoing spontaneous activity (n = 18) were decreased after morphine application. Inoculation with both µ-opioid receptor and preproenkephalin viral vectors did not alter mechanical and thermal responses. CONCLUSIONS Increasing primary afferent expression of opioid receptors can decrease neuropathic pain-associated behaviors and increase systemic opioid analgesia through inhibition of peripheral afferent fiber activity.
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28
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Increased Expression of Fibronectin Leucine-Rich Transmembrane Protein 3 in the Dorsal Root Ganglion Induces Neuropathic Pain in Rats. J Neurosci 2019; 39:7615-7627. [PMID: 31346030 DOI: 10.1523/jneurosci.0295-19.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/17/2019] [Accepted: 06/06/2019] [Indexed: 01/19/2023] Open
Abstract
Neuropathic pain is a chronic condition that occurs frequently after nerve injury and induces hypersensitivity or allodynia characterized by aberrant neuronal excitability in the spinal cord dorsal horn. Fibronectin leucine-rich transmembrane protein 3 (FLRT3) is a modulator of neurite outgrowth, axon pathfinding, and cell adhesion, which is upregulated in the dorsal horn following peripheral nerve injury. However, the function of FLRT3 in adults remains unknown. Therefore, we aimed to investigate the involvement of spinal FLRT3 in neuropathic pain using rodent models. In the dorsal horns of male rats, FLRT3 protein levels increased at day 4 after peripheral nerve injury. In the DRG, FLRT3 was expressed in activating transcription factor 3-positive, injured sensory neurons. Peripheral nerve injury stimulated Flrt3 transcription in the DRG but not in the spinal cord. Intrathecal administration of FLRT3 protein to naive rats induced mechanical allodynia and GluN2B phosphorylation in the spinal cord. DRG-specific FLRT3 overexpression using adeno-associated virus also produced mechanical allodynia. Conversely, a function-blocking FLRT3 antibody attenuated mechanical allodynia after partial sciatic nerve ligation. Therefore, FLRT3 derived from injured DRG neurons increases dorsal horn excitability and induces mechanical allodynia.SIGNIFICANCE STATEMENT Neuropathic pain occurs frequently after nerve injury and is associated with abnormal neuronal excitability in the spinal cord. Fibronectin leucine-rich transmembrane protein 3 (FLRT3) regulates neurite outgrowth and cell adhesion. Here, nerve injury increased FLRT3 protein levels in the spinal cord dorsal root, despite the fact that Flrt3 transcripts were only induced in the DRG. FLRT3 protein injection into the rat spinal cord induced mechanical hypersensitivity, as did virus-mediated FLRT3 overexpression in DRG. Conversely, FLRT3 inhibition with antibodies attenuated mechanically induced pain after nerve damage. These findings suggest that FLRT3 is produced by injured DRG neurons and increases neuronal excitability in the dorsal horn, leading to pain sensitization. Neuropathic pain induction is a novel function of FLRT3.
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29
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Costa AR, Carvalho P, Flik G, Wilson SP, Reguenga C, Martins I, Tavares I. Neuropathic Pain Induced Alterations in the Opioidergic Modulation of a Descending Pain Facilitatory Area of the Brain. Front Cell Neurosci 2019; 13:287. [PMID: 31316354 PMCID: PMC6610065 DOI: 10.3389/fncel.2019.00287] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 06/13/2019] [Indexed: 12/03/2022] Open
Abstract
Opioids play a major role at descending pain modulation but the effects of neuropathic pain on the brain opioidergic system remain understudied. Since descending facilitation is enhanced during neuropathic pain, we studied the opioidergic modulation of the dorsal reticular nucleus (DRt), a medullary pain facilitatory area, in the spared nerve injury (SNI) model of neuropathic pain. We first performed a series of behavioral experiments in naïve-animals to establish the role of μ-opioid receptor (MOR) in the effects of endogenous and exogenous opioids at the DRt. Specifically, we showed that lentiviral-mediated MOR-knockdown at the DRt increased sensitivity to thermal and mechanical stimuli while the MOR agonist DAMGO induced the opposite effects. Additionally, we showed that MOR-knockdown and the pharmacological blockade of MOR by CTAP at the DRt decreased and inhibited, respectively, the analgesic effects of systemic morphine. Then, we performed in vivo microdialysis to measure enkephalin peptides in the DRt and evaluated MOR expression in the DRt at mRNA, protein and phosphorylated form levels by quantitative real-time PCR and immunohistochemistry, respectively. SNI-animals, compared to sham control, showed higher levels of enkephalin peptides, lower MOR-labeled cells without alterations in MOR mRNA levels, and higher phosphorylated MOR-labeled cells. Finally, we performed behavioral studies in SNI animals to determine the potency of systemic morphine and the effects of the pharmacologic and genetic manipulation of MOR at the DRt. We showed a reduced potency of the antiallodynic effects of systemic morphine in SNI-animals compared to the antinociceptive effects in sham animals. Increasing MOR-cells at the DRt of SNI-animals by lentiviral-mediated MOR-overexpression produced no effects on mechanical allodynia. DAMGO induced anti-allodynia only after MOR-overexpression. These results show that MOR inhibits DRt pain facilitatory actions and that this action contributes to the analgesic effects of systemic opioids. We further show that the inhibitory function of MOR is impaired during neuropathic pain. This is likely due to desensitization and degradation of MOR which are adaptations of the receptor that can be triggered by MOR phosphorylation. Skipping counter-regulatory pathways involved in MOR adaptations might restore the opioidergic inhibition at pain facilitatory areas.
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Affiliation(s)
- Ana Rita Costa
- Departamento de Biomedicina - Unidade de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Paulina Carvalho
- Departamento de Biomedicina - Unidade de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Gunnar Flik
- Charles River Laboratories Den Bosch B.V., 's-Hertogenbosch, Netherlands
| | - Steven P Wilson
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
| | - Carlos Reguenga
- Departamento de Biomedicina - Unidade de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Isabel Martins
- Departamento de Biomedicina - Unidade de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Isaura Tavares
- Departamento de Biomedicina - Unidade de Biologia Experimental, Faculdade de Medicina da Universidade do Porto, Porto, Portugal.,i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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Facilitation of neuropathic pain by the NPY Y1 receptor-expressing subpopulation of excitatory interneurons in the dorsal horn. Sci Rep 2019; 9:7248. [PMID: 31076578 PMCID: PMC6510760 DOI: 10.1038/s41598-019-43493-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/16/2019] [Indexed: 01/24/2023] Open
Abstract
Endogenous neuropeptide Y (NPY) exerts long-lasting spinal inhibitory control of neuropathic pain, but its mechanism of action is complicated by the expression of its receptors at multiple sites in the dorsal horn: NPY Y1 receptors (Y1Rs) on post-synaptic neurons and both Y1Rs and Y2Rs at the central terminals of primary afferents. We found that Y1R-expressing spinal neurons contain multiple markers of excitatory but not inhibitory interneurons in the rat superficial dorsal horn. To test the relevance of this spinal population to the development and/or maintenance of acute and neuropathic pain, we selectively ablated Y1R-expressing interneurons with intrathecal administration of an NPY-conjugated saporin ribosomal neurotoxin that spares the central terminals of primary afferents. NPY-saporin decreased spinal Y1R immunoreactivity but did not change the primary afferent terminal markers isolectin B4 or calcitonin-gene-related peptide immunoreactivity. In the spared nerve injury (SNI) model of neuropathic pain, NPY-saporin decreased mechanical and cold hypersensitivity, but disrupted neither normal mechanical or thermal thresholds, motor coordination, nor locomotor activity. We conclude that Y1R-expressing excitatory dorsal horn interneurons facilitate neuropathic pain hypersensitivity. Furthermore, this neuronal population remains sensitive to intrathecal NPY after nerve injury. This neuroanatomical and behavioral characterization of Y1R-expressing excitatory interneurons provides compelling evidence for the development of spinally-directed Y1R agonists to reduce chronic neuropathic pain.
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Uta D, Kato G, Doi A, Andoh T, Kume T, Yoshimura M, Koga K. Animal models of chronic pain increase spontaneous glutamatergic transmission in adult rat spinal dorsal horn in vitro and in vivo. Biochem Biophys Res Commun 2019; 512:352-359. [DOI: 10.1016/j.bbrc.2019.03.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 03/08/2019] [Indexed: 01/08/2023]
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Temporal and Spatial Changes of μ-Opioid Receptors in the Brain, Spinal Cord and Dorsal Root Ganglion in a Rat Lumbar Disc Herniation Model. Spine (Phila Pa 1976) 2019; 44:85-95. [PMID: 30005035 DOI: 10.1097/brs.0000000000002776] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Controlled, interventional, animal study. OBJECTIVE To investigate the spatial and temporal changes of μ-opioid receptor (MOR) expression in a rat lumbar disc herniation (LDH) model. SUMMARY OF BACKGROUND DATA MORs widely express in the peripheral and central nervous systems, and opioid drugs produce an analgesic effect through their activation. However, the efficacy of opioid drugs is sometimes inadequate in several pathological conditions of pain. MORs in the brain as well as the spinal cord (SC) and dorsal root ganglion (DRG) are thought to be associated with pain-related behavior, but the underlying mechanisms are not completely understood. METHODS In all, 91 adult female Sprague-Dawley rats were used. Autologous nucleus pulposus (NP) was applied onto the left L5 DRG in the NP group rats. Rats were divided into two surgical groups, the NP and the sham group. The von Frey test of left hind paw was performed before surgery, and 2, 7, 14, 21 and 28 days after surgery. Immunohistochemistry and immunoblotting in the DRG, SC, Caudate putamen, nucleus accumbens (NAc) and periaqueductal grey matter were performed before surgery, and 2, 7, 14, 21 and 28 days after surgery. RESULTS The thresholds in the NP group were significantly lower than those in the sham group from day 2 onwards. At days 7 and 14, MOR expression in the injured-side SC and DRG were significantly lower than those in the sham group. At day 21, MOR in the NAc was significantly decreased compared to that in the sham group. CONCLUSION Changes of MOR expression in the NAc, SC and DRG were associated with pain-related behavior. This result might show the underling pathogenesis of the resistance to MOR agonists in the patient with LDH. LEVEL OF EVIDENCE N/A.
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Abstract
Whilst the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) has similar intracellular coupling mechanisms to opioid receptors, it has distinct modulatory effects on physiological functions such as pain. These actions range from agonistic to antagonistic interactions with classical opioids within the spinal cord and brain, respectively. Understanding the electrophysiological actions of N/OFQ has been crucial in ascertaining the mechanisms by which these agonistic and antagonistic interactions occur. These similarities and differences between N/OFQ and opioids are due to the relative location of NOP versus opioid receptors on specific neuronal elements within these CNS regions. These mechanisms result in varied cellular actions including postsynaptic modulation of ion channels and presynaptic regulation of neurotransmitter release.
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Stötzner P, Spahn V, Celik MÖ, Labuz D, Machelska H. Mu-Opioid Receptor Agonist Induces Kir3 Currents in Mouse Peripheral Sensory Neurons - Effects of Nerve Injury. Front Pharmacol 2018; 9:1478. [PMID: 30618766 PMCID: PMC6305728 DOI: 10.3389/fphar.2018.01478] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/03/2018] [Indexed: 11/13/2022] Open
Abstract
Neuropathic pain often arises from damage to peripheral nerves and is difficult to treat. Activation of opioid receptors in peripheral sensory neurons is devoid of respiratory depression, sedation, nausea, and addiction mediated in the brain, and ameliorates neuropathic pain in animal models. Mechanisms of peripheral opioid analgesia have therefore gained interest, but the role of G protein-coupled inwardly rectifying potassium (Kir3) channels, important regulators of neuronal excitability, remains unclear. Whereas functional Kir3 channels have been detected in dorsal root ganglion (DRG) neurons in rats, some studies question their contribution to opioid analgesia in inflammatory pain models in mice. However, neuropathic pain can be diminished by activation of peripheral opioid receptors in mouse models. Therefore, here we investigated effects of the selective μ-opioid receptor (MOR) agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-enkephalin (DAMGO) on potassium conductance in DRG neurons upon a chronic constriction injury (CCI) of the sciatic nerve in mice. For verification, we also tested human embryonic kidney (HEK) 293 cells transfected with MOR and Kir3.2. Using patch clamp, we recorded currents at -80 mV and applied voltage ramps in high extracellular potassium concentrations, which are a highly sensitive measures of Kir3 channel activity. We found a significantly higher rate of HEK cells responding with potassium channel blocker barium-sensitive inward current (233 ± 51 pA) to DAMGO application in transfected than in untransfected group, which confirms successful recordings of inward currents through Kir3.2 channels. Interestingly, DAMGO induced similar inward currents (178 ± 36-207 ± 56 pA) in 15-20% of recorded DRG neurons from naïve mice and in 4-27% of DRG neurons from mice exposed to CCI, measured in voltage clamp or voltage ramp modes. DAMGO-induced currents in naïve and CCI groups were reversed by barium and a more selective Kir3 channel blocker tertiapin-Q. These data indicate the coupling of Kir3 channels with MOR in mouse peripheral sensory neuron cell bodies, which was unchanged after CCI. A comparative analysis of opioid-induced potassium conductance at the axonal injury site and peripheral terminals of DRG neurons could clarify the role of Kir3 channel-MOR interactions in peripheral nerve injury and opioid analgesia.
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Affiliation(s)
- Philip Stötzner
- Department of Experimental Anesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Viola Spahn
- Department of Experimental Anesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Melih Ö Celik
- Department of Experimental Anesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Dominika Labuz
- Department of Experimental Anesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Halina Machelska
- Department of Experimental Anesthesiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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He XT, Zhou KX, Zhao WJ, Zhang C, Deng JP, Chen FM, Gu ZX, Li YQ, Dong YL. Inhibition of Histone Deacetylases Attenuates Morphine Tolerance and Restores MOR Expression in the DRG of BCP Rats. Front Pharmacol 2018; 9:509. [PMID: 29867508 PMCID: PMC5962808 DOI: 10.3389/fphar.2018.00509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/27/2018] [Indexed: 01/21/2023] Open
Abstract
The easily developed morphine tolerance in bone cancer pain (BCP) significantly hindered its clinical use. Increasing evidence suggests that histone deacetylases (HDACs) regulate analgesic tolerance subsequent to continuous opioid exposure. However, whether HDACs contribute to morphine tolerance in the pathogenesis of BCP is still unknown. In the current study, we explored the possible engagement of HDACs in morphine tolerance during the pathogenesis of BCP. After intra-tibia tumor cell inoculation (TCI), we found that the increased expression of HDACs was negatively correlated with the decreased expression of MOR in the DRG following TCI. The paw withdrawal threshold (PWT) and percentage maximum possible effects (MPEs) decreased rapidly in TCI rats when morphine was used alone. In contrast, the concomitant use of SAHA and morphine significantly elevated the PWT and MPEs of TCI rats compared to morphine alone. Additionally, we found that SAHA administration significantly elevated MOR expression in the DRG of TCI rats with or without morphine treatment. Moreover, the TCI-induced increase in the co-expression of MOR and HDAC1 in neurons was significantly decreased after SAHA administration. These results suggest that HDACs are correlated with the downregulation of MOR in the DRG during the pathogenesis of BCP. Inhibition of HDACs using SAHA can be used to attenuate morphine tolerance in BCP.
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Affiliation(s)
- Xiao-Tao He
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China.,Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Kai-Xiang Zhou
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China.,Student Brigade, The Fourth Military Medical University, Xi'an, China
| | - Wen-Jun Zhao
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China.,Student Brigade, The Fourth Military Medical University, Xi'an, China
| | - Chen Zhang
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China.,Student Brigade, The Fourth Military Medical University, Xi'an, China
| | - Jian-Ping Deng
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - Fa-Ming Chen
- Department of Periodontology, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Ze-Xu Gu
- State Key Laboratory of Military Stomatology, Department of Orthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an, China
| | - Yun-Qing Li
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China.,Joint Laboratory of Neuroscience at Hainan Medical University and The Fourth Military Medical University, Hainan Medical University, Haikou, China
| | - Yu-Lin Dong
- Department of Human Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Preclinical School of Medicine, The Fourth Military Medical University, Xi'an, China
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Sun L, Zhao JY, Gu X, Liang L, Wu S, Mo K, Feng J, Guo W, Zhang J, Bekker A, Zhao X, Nestler EJ, Tao YX. Nerve injury-induced epigenetic silencing of opioid receptors controlled by DNMT3a in primary afferent neurons. Pain 2018; 158:1153-1165. [PMID: 28267064 DOI: 10.1097/j.pain.0000000000000894] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Opioids are the gold standard for pharmacological treatment of neuropathic pain, but their analgesic effects are unsatisfactory in part due to nerve injury-induced downregulation of opioid receptors in dorsal root ganglia (DRG) neurons. How nerve injury drives such downregulation remains elusive. DNA methyltransferase (DNMT)-triggered DNA methylation represses gene expression. We show here that blocking the nerve injury-induced increase in DRG DNMT3a (a de novo DNMT) rescued the expression of Oprm1 and Oprk1 mRNAs and their respective encoding mu-opioid receptor (MOR) and kappa-opioid receptor (KOR) proteins in the injured DRG. Blocking this increase also prevented the nerve injury-induced increase in DNA methylation in the promoter and 5'-untranslated region of the Oprm1 gene in the injured DRG, restored morphine or loperamide (a peripheral acting MOR preferring agonist) analgesic effects, and attenuated the development of their analgesic tolerance under neuropathic pain conditions. Mimicking this increase reduced the expression of Oprm1 and Oprk1 mRNAs and their coding MOR and KOR in DRG and augmented MOR-gated neurotransmitter release from the primary afferents. Mechanistically, DNMT3a regulation of Oprm1 gene expression required the methyl-CpG-binding protein 1, MBD1, as MBD1 knockout resulted in the decreased binding of DNMT3a to the Oprm1 gene promoter and blocked the DNMT3a-triggered repression of Oprm1 gene expression in DRG neurons. These data suggest that DNMT3a is required for nerve injury-induced and MBD1-mediated epigenetic silencing of the MOR and KOR in the injured DRG. DNMT3a inhibition may serve as a promising adjuvant therapy for opioid use in neuropathic pain management.
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Affiliation(s)
- Linlin Sun
- aDepartment of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA bState Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China cFishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA dDepartment of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA eDepartments of Cell Biology and Molecular Medicine and Physiology, Pharmacology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
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Woolf CJ. Pain amplification-A perspective on the how, why, when, and where of central sensitization. ACTA ACUST UNITED AC 2018. [DOI: 10.1111/jabr.12124] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Clifford J. Woolf
- FM Kirby Neurobiology Center; Boston Children's Hospital; Boston MA USA
- Department of Neurobiology; Harvard Medical School; Boston MA USA
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Therapeutic effects of diclofenac, pregabalin, and duloxetine on disuse-induced chronic musculoskeletal pain in rats. Sci Rep 2018; 8:3311. [PMID: 29459641 PMCID: PMC5818528 DOI: 10.1038/s41598-018-21429-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 02/01/2018] [Indexed: 12/15/2022] Open
Abstract
The aim of this study was to clarify the mechanism of disuse-induced muscle hyperalgesia through the evaluation of the pharmacological behaviour of muscle hyperalgesia profiles in chronic post-cast pain (CPCP) rats with acute and chronic-phase mirror-image muscle hyperalgesia treated with diclofenac (NSAID), pregabalin (an inhibitor of Ca2+ channel α2δ), and duloxetine (SNRI). After 2 weeks of cast immobilization, the peak cross-sectional area and muscle wet weight of the ipsilateral soleus and gastrocnemius muscles decreased more significantly in CPCP rats than in untreated rats. Histological findings revealed disuse-induced muscle atrophy in CPCP rats. The blood biochemical parameters of CPCP rats in acute and chronic phases did not differ significantly from those of untreated rats. The diclofenac and pregabalin-treated groups exhibited no improvement in acute or chronic muscle hyperalgesia. In contrast, the duloxetine-treated group exhibited an improvement in acute muscle hyperalgesia, but showed no apparent effect on chronic muscle hyperalgesia on ipsilateral or contralateral sides. However, the chronic muscle hyperalgesia was reversed by intrathecal administration of DAMGO (a μ-opioid receptor agonist). The results suggest that chronic muscle hyperalgesia in CPCP rats did not result from an inflammatory mechanism, and there is only a low probability that it's caused by a neuropathic mechanism.
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Tzschentke TM, Linz K, Frosch S, Christoph T. Antihyperalgesic, Antiallodynic, and Antinociceptive Effects of Cebranopadol, a Novel Potent Nociceptin/Orphanin FQ and Opioid Receptor Agonist, after Peripheral and Central Administration in Rodent Models of Neuropathic Pain. Pain Pract 2017; 17:1032-1041. [PMID: 28112482 DOI: 10.1111/papr.12558] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 11/23/2016] [Accepted: 12/10/2016] [Indexed: 12/14/2022]
Abstract
Cebranopadol is a novel and highly potent analgesic acting via nociceptin/orphanin FQ peptide (NOP) and opioid receptors. Since NOP and opioid receptors are expressed in the central nervous system as well as in the periphery, this study addressed the question of where cebranopadol exerts its effects in animal models of chronic neuropathic pain. Mechanical hypersensitivity in streptozotocin (STZ)-treated diabetic rats, cold allodynia in the chronic constriction injury (CCI) model in rats, and heat hyperalgesia and nociception in STZ-treated diabetic and control mice was determined after intraplantar (i.pl.), intracerebroventricular (i.c.v.), or intrathecal (i.th.) administration. In STZ-treated rats, cebranopadol (i.pl.) reduced mechanical hypersensitivity in the ipsilateral paw, but had no effect at the contralateral paw. In CCI rats, cebranopadol (i.pl.) showed antiallodynic activity at the ipsilateral paw. After administration to the contralateral paw, cebranopadol also showed ipsilateral antiallodynic activity, but with reduced potency and delayed onset. In diabetic mice, cebranopadol i.th. and i.c.v. decreased heat hyperalgesia with full efficacy and similar potency for both routes. Cebranopadol also produced significant antinociception in nondiabetic controls. Thus, cebranopadol exerts potent and efficacious antihyperalgesic, antiallodynic, and antinociceptive effects after local/peripheral, spinal, and supraspinal administration. The contralateral effects after i.pl. administration were likely due to systemic redistribution. After central administration of cebranopadol, antihyperalgesic efficacy is reached at doses that are not yet antinociceptive. This study shows that cebranopadol is effective after peripheral as well as central administration in nociceptive and chronic neuropathic pain. Thus, it may be well-suited for the treatment of chronic pain conditions with a neuropathic component.
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Affiliation(s)
| | - Klaus Linz
- Preclinical Drug Development, Grünenthal GmbH, Aachen, Germany
| | - Stefanie Frosch
- Preclinical Drug Development, Grünenthal GmbH, Aachen, Germany
| | - Thomas Christoph
- Pharmacology and Biomarker Development, Grünenthal GmbH, Germany
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Neuronal-Glial Interactions Maintain Chronic Neuropathic Pain after Spinal Cord Injury. Neural Plast 2017; 2017:2480689. [PMID: 28951789 PMCID: PMC5603132 DOI: 10.1155/2017/2480689] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 06/26/2017] [Accepted: 07/05/2017] [Indexed: 02/01/2023] Open
Abstract
The hyperactive state of sensory neurons in the spinal cord enhances pain transmission. Spinal glial cells have also been implicated in enhanced excitability of spinal dorsal horn neurons, resulting in pain amplification and distortions. Traumatic injuries of the neural system such as spinal cord injury (SCI) induce neuronal hyperactivity and glial activation, causing maladaptive synaptic plasticity in the spinal cord. Recent studies demonstrate that SCI causes persistent glial activation with concomitant neuronal hyperactivity, thus providing the substrate for central neuropathic pain. Hyperactive sensory neurons and activated glial cells increase intracellular and extracellular glutamate, neuropeptides, adenosine triphosphates, proinflammatory cytokines, and reactive oxygen species concentrations, all of which enhance pain transmission. In addition, hyperactive sensory neurons and glial cells overexpress receptors and ion channels that maintain this enhanced pain transmission. Therefore, post-SCI neuronal-glial interactions create maladaptive synaptic circuits and activate intracellular signaling events that permanently contribute to enhanced neuropathic pain. In this review, we describe how hyperactivity of sensory neurons contributes to the maintenance of chronic neuropathic pain via neuronal-glial interactions following SCI.
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Tseng TJ, Yang ML, Hsieh YL, Ko MH, Hsieh ST. Nerve Decompression Improves Spinal Synaptic Plasticity of Opioid Receptors for Pain Relief. Neurotox Res 2017; 33:362-376. [PMID: 28836121 DOI: 10.1007/s12640-017-9799-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 07/24/2017] [Accepted: 08/10/2017] [Indexed: 01/05/2023]
Abstract
Nerve decompression is an essential therapeutic strategy for pain relief clinically; however, its potential mechanism remains poorly understood. Opioid analgesics acting on opioid receptors (OR) within the various regions of the nervous system have been used widely for pain management. We therefore hypothesized that nerve decompression in a neuropathic pain model of chronic constriction injury (CCI) improves the synaptic OR plasticity in the dorsal horn, which is in response to alleviate pain hypersensitivity. After CCI, the Sprague-Dawley rats were assigned into Decompression group, in which the ligatures around the sciatic nerve were removed at post-operative week 4 (POW 4), and a CCI group, in which the ligatures remained. Pain hypersensitivity, including thermal hyperalgesia and mechanical allodynia, was entirely normalized in Decompression group within the following 4 weeks. Substantial reversal of mu- and delta-OR immunoreactive (IR) expressions in Decompression group was detected in primary afferent terminals in the dorsal horn. In Decompression group, mu-OR antagonist (CTOP, D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 [Disulfide Bridge: 2-7]) and delta-OR antagonist (NTI, 17-(cyclopropylmethyl)-6,7-dehydro-4,5α-epoxy-3,14-dihydroxy-6,7-2',3'-indolomorphinan hydrochloride) re-induced pain hypersensitivity by intrathecal administration in a dose-responsive manner. Additionally, mu-OR agonist (DAMGO, [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin) and delta-OR agonist (SNC80, ((+)-4-[(αR)-α-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethyl-benzamide) were administrated intrathecally to attenuating CCI-induced chronic and acute pain hypersensitivity dose-dependently. Our current results strongly suggested that nerve decompression provides the opportunity for improving the synaptic OR plasticity in the dorsal horn and pharmacological blockade presents a novel insight into the therapeutic strategy for pain hypersensitivity.
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Affiliation(s)
- To-Jung Tseng
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, 40201, Taiwan.,Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan
| | - Ming-Ling Yang
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, 40201, Taiwan.,Department of Medical Education, Chung Shan Medical University Hospital, Taichung, 40201, Taiwan
| | - Yu-Lin Hsieh
- Department of Anatomy, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan
| | - Miau-Hwa Ko
- Department of Anatomy, China Medical University, Taichung, 40402, Taiwan
| | - Sung-Tsang Hsieh
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, 1 Jen-Ai Road, Sec 1, Taipei, 10051, Taiwan. .,Department of Neurology, National Taiwan University Hospital, Taipei, 10002, Taiwan.
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Spinal Fbxo3-Dependent Fbxl2 Ubiquitination of Active Zone Protein RIM1α Mediates Neuropathic Allodynia through CaV2.2 Activation. J Neurosci 2017; 36:9722-38. [PMID: 27629721 DOI: 10.1523/jneurosci.1732-16.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/28/2016] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED Spinal plasticity, a key process mediating neuropathic pain development, requires ubiquitination-dependent protein turnover. Presynaptic active zone proteins have a crucial role in regulating vesicle exocytosis, which is essential for synaptic plasticity. Nevertheless, the mechanism for ubiquitination-regulated turnover of presynaptic active zone proteins in the progression of spinal plasticity-associated neuropathic pain remains unclear. Here, after research involving Sprague Dawley rats, we reported that spinal nerve ligation (SNL), in addition to causing allodynia, enhances the Rab3-interactive molecule-1α (RIM1α), a major active zone protein presumed to regulate neural plasticity, specifically in the synaptic plasma membranes (SPMs) of the ipsilateral dorsal horn. Spinal RIM1α-associated allodynia was mediated by Fbxo3, which abates Fbxl2-dependent RIM1α ubiquitination. Subsequently, following deubiquitination, enhanced RIM1α directly binds to CaV2.2, resulting in increased CaV2.2 expression in the SPMs of the dorsal horn. While exhibiting no effect on Fbxo3/Fbxl2 signaling, the focal knockdown of spinal RIM1α expression reversed the SNL-induced allodynia and increased spontaneous EPSC (sEPSC) frequency by suppressing RIM1α-facilitated CaV2.2 expression in the dorsal horn. Intrathecal applications of BC-1215 (a Fbxo3 activity inhibitor), Fbxl2 mRNA-targeting small-interfering RNA, and ω-conotoxin GVIA (a CaV2.2 blocker) attenuated RIM1α upregulation, enhanced RIM1α expression, and exhibited no effect on RIM1α expression, respectively. These results confirm the prediction that spinal presynaptic Fbxo3-dependent Fbxl2 ubiquitination promotes the subsequent RIM1α/CaV2.2 cascade in SNL-induced neuropathic pain. Our findings identify a role of the presynaptic active zone protein in pain-associated plasticity. That is, RIM1α-facilitated CaV2.2 expression plays a role in the downstream signaling of Fbxo3-dependent Fbxl2 ubiquitination/degradation to promote spinal plasticity underlying the progression of nociceptive hypersensitivity following neuropathic injury. SIGNIFICANCE STATEMENT Ubiquitination is a well known process required for protein degradation. Studies investigating pain pathology have demonstrated that ubiquitination contributes to chronic pain by regulating the turnover of synaptic proteins. Here, we found that the spinal presynaptic active zone protein Rab3-interactive molecule-1α (RIM1α) participates in neuropathic pain development by binding to and upregulating the expression of CaV2.2. In addition, Fbxo3 modifies this pathway by inhibiting Fbxl2-mediated RIM1α ubiquitination, suggesting that presynaptic protein ubiquitination makes a crucial contribution to the development of neuropathic pain. Research in this area, now in its infancy, could potentially provide a novel therapeutic strategy for pain relief.
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Promoted Interaction of C/EBPα with Demethylated Cxcr3 Gene Promoter Contributes to Neuropathic Pain in Mice. J Neurosci 2017; 37:685-700. [PMID: 28100749 DOI: 10.1523/jneurosci.2262-16.2016] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 11/22/2016] [Accepted: 12/02/2016] [Indexed: 12/29/2022] Open
Abstract
DNA methylation has been implicated in the pathogenesis of chronic pain. However, the specific genes regulated by DNA methylation under neuropathic pain condition remain largely unknown. Here we investigated how chemokine receptor CXCR3 is regulated by DNA methylation and how it contributes to neuropathic pain induced by spinal nerve ligation (SNL) in mice. SNL increased Cxcr3 mRNA and protein expression in the neurons of the spinal cord. Meanwhile, the CpG (5'-cytosine-phosphate-guanine-3') island in the Cxcr3 gene promoter region was demethylated, and the expression of DNA methyltransferase 3b (DNMT3b) was decreased. SNL also increased the binding of CCAAT (cytidine-cytidine-adenosine-adenosine-thymidine)/enhancer binding protein α (C/EBPα) with Cxcr3 promoter and decreased the binding of DNMT3b with Cxcr3 promoter in the spinal cord. C/EBPα expression was increased in spinal neurons after SNL, and inhibition of C/EBPα by intrathecal small interfering RNA attenuated SNL-induced pain hypersensitivity and reduced Cxcr3 expression. Furthermore, SNL-induced mechanical allodynia and heat hyperalgesia were markedly reduced in Cxcr3-/- mice. Spinal inhibition of Cxcr3 by shRNA or CXCR3 antagonist also attenuated established neuropathic pain. Moreover, CXCL10, the ligand of CXCR3, was increased in spinal neurons and astrocytes after SNL. Superfusing spinal cord slices with CXCL10 enhanced spontaneous EPSCs and potentiated NMDA-induced and AMPA-induced currents of lamina II neurons. Finally, intrathecal injection of CXCL10 induced CXCR3-dependent pain hypersensitivity in naive mice. Collectively, our results demonstrated that CXCR3, increased by DNA demethylation and the enhanced interaction with C/EBPα, can be activated by CXCL10 to facilitate excitatory synaptic transmission and contribute to the maintenance of neuropathic pain. SIGNIFICANCE STATEMENT Peripheral nerve injury induces changes of gene expression in the spinal cord that may contribute to the pathogenesis of neuropathic pain. CXCR3 is a chemokine receptor. Whether it is involved in neuropathic pain and how it is regulated after nerve injury remain largely unknown. Our study demonstrates that spinal nerve ligation downregulates the expression of DNMT3b, which may cause demethylation of Cxcr3 gene promoter and facilitate the binding of CCAAT/enhancer binding protein α with Cxcr3 promoter and further increase CXCR3 expression in spinal neurons. The upregulated CXCR3 may contribute to neuropathic pain by facilitating central sensitization. Our study reveals an epigenetic mechanism underlying CXCR3 expression and also suggests that targeting the expression or activation of CXCR3 signaling may offer new therapeutics for neuropathic pain.
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Neuron-restrictive silencer factor-mediated downregulation of μ-opioid receptor contributes to the reduced morphine analgesia in bone cancer pain. Pain 2017; 158:879-890. [PMID: 28415063 PMCID: PMC5402709 DOI: 10.1097/j.pain.0000000000000848] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuron-restrictive silencer factor–induced downregulation of μ-opioid receptor is involved in the reduction of morphine analgesia in sarcoma-induced bone cancer pain. Bone cancer pain has been reported to have unique mechanisms and is resistant to morphine treatment. Recent studies have indicated that neuron-restrictive silencer factor (NRSF) plays a crucial role in modulating the expression of the μ-opioid receptor (MOR) gene. The present study elucidates the regulatory mechanisms of MOR and its ability to affect bone cancer pain. Using a sarcoma-inoculated murine model, pain behaviors that represent continuous or breakthrough pain were evaluated. Expression of NRSF in the dorsal root ganglion (DRG) and spinal dorsal horn was quantified at the transcriptional and translational levels, respectively. Additionally, chromatin immunoprecipitation assays were used to detect NRSF binding to the promoter of MOR. Furthermore, NRSF was genetically knocked out by antisense oligodeoxynucleotide, and the expression of MOR and the effect of morphine were subsequently analyzed. Our results indicated that in a sarcoma murine model, NRSF expression is upregulated in dorsal root ganglion neurons, and the expression of NRSF mRNA is significantly negatively correlated with MOR mRNA expression. Additionally, chromatin immunoprecipitation analysis revealed that NRSF binding to the neuron-restrictive silencer element within the promoter area of the MOR gene is promoted with a hypoacetylation state of histone H3 and H4. Furthermore, genetically knocking down NRSF with antisense oligodeoxynucleotide rescued the expression of MOR and potentiated the systemic morphine analgesia. The present results suggest that in sarcoma-induced bone cancer pain, NRSF-induced downregulation of MOR is involved in the reduction of morphine analgesia. Epigenetically, up-regulation of MOR could substantially improve the effect of system delivery of morphine.
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Morrone LA, Scuteri D, Rombolà L, Mizoguchi H, Bagetta G. Opioids Resistance in Chronic Pain Management. Curr Neuropharmacol 2017; 15:444-456. [PMID: 28503117 PMCID: PMC5405610 DOI: 10.2174/1570159x14666161101092822] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/11/2016] [Accepted: 10/24/2016] [Indexed: 01/07/2023] Open
Abstract
Chronic pain management represents a serious healthcare problem worldwide. Chronic pain affects approximately 20% of the adult European population and is more frequent in women and older people. Unfortunately, its management in the community remains generally unsatisfactory and rarely under the control of currently available analgesics. Opioids have been used as analgesics for a long history and are among the most used drugs; however, while there is no debate over their short term use for pain management, limited evidence supports their efficacy of long-term treatment for chronic non-cancer pain. Therapy with opioids is hampered by inter-individual variability and serious side effects and some opioids often result ineffective in the treatment of chronic pain and their use is controversial. Accordingly, for a better control of chronic pain a deeper knowledge of the molecular mechanisms underlying resistance to opiates is mandatory.
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Affiliation(s)
- Luigi A. Morrone
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
- University Consortium for Adaptive Disorders and Head Pain (UCADH), Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Rende, Italy
| | - Damiana Scuteri
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Laura Rombolà
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Hirokazu Mizoguchi
- Department of Physiology and Anatomy, Tohoku Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Japan
| | - Giacinto Bagetta
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
- University Consortium for Adaptive Disorders and Head Pain (UCADH), Section of Neuropharmacology of Normal and Pathological Neuronal Plasticity, University of Calabria, Rende, Italy
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Wan FP, Bai Y, Kou ZZ, Zhang T, Li H, Wang YY, Li YQ. Endomorphin-2 Inhibition of Substance P Signaling within Lamina I of the Spinal Cord Is Impaired in Diabetic Neuropathic Pain Rats. Front Mol Neurosci 2017; 9:167. [PMID: 28119567 PMCID: PMC5223733 DOI: 10.3389/fnmol.2016.00167] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 12/22/2016] [Indexed: 12/15/2022] Open
Abstract
Opiate analgesia in the spinal cord is impaired in diabetic neuropathic pain (DNP), but until now the reason is unknown. We hypothesized that it resulted from a decreased inhibition of substance P (SP) signaling within the dorsal horn of the spinal cord. To investigate this possibility, we evaluated the effects of endomorphin-2 (EM2), an endogenous ligand of the μ-opioid receptor (MOR), on SP release within lamina I of the spinal dorsal horn (SDH) in rats with DNP. We established the DNP rat model and compared the analgesic efficacy of EM2 between inflammation pain and DNP rat models. Behavioral results suggested that the analgesic efficacy of EM2 was compromised in the condition of painful diabetic neuropathy. Then, we measured presynaptic SP release induced by different stimulating modalities via neurokinin-1 receptor (NK1R) internalization. Although there was no significant change in basal and evoked SP release between control and DNP rats, EM2 failed to inhibit SP release by noxious mechanical and thermal stimuli in DNP but not in control and inflammation pain model. We also observed that EM2 decreased the number of FOS-positive neurons within lamina I of the SDH but did not change the amount of FOS/NK1R double-labeled neurons. Finally, we identified a remarkable decrease in MORs within the primary afferent fibers and dorsal root ganglion (DRG) neurons by Western blot (WB) and immunohistochemistry (IHC). Taken together, these data suggest that reduced presynaptic MOR expression might account for the loss of the inhibitory effect of EM2 on SP signaling, which might be one of the neurobiological foundations for decreased opioid efficacy in the treatment of DNP.
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Affiliation(s)
- Fa-Ping Wan
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Yang Bai
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Zhen-Zhen Kou
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Ting Zhang
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Hui Li
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Ya-Yun Wang
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Yun-Qing Li
- Department of Anatomy and Histology and Embryology, K.K. Leung Brain Research Centre, The Fourth Military Medical UniversityXi'an, China; Collaborative Innovation Center for Brain Science, Fudan UniversityShanghai, China
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Liang L, Zhao JY, Gu X, Wu S, Mo K, Xiong M, Marie Lutz B, Bekker A, Tao YX. G9a inhibits CREB-triggered expression of mu opioid receptor in primary sensory neurons following peripheral nerve injury. Mol Pain 2016; 12:12/0/1744806916682242. [PMID: 27927796 PMCID: PMC5153028 DOI: 10.1177/1744806916682242] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/20/2016] [Accepted: 10/31/2016] [Indexed: 11/17/2022] Open
Abstract
Neuropathic pain, a distressing and debilitating disorder, is still poorly managed in clinic. Opioids, like morphine, remain the mainstay of prescribed medications in the treatment of this disorder, but their analgesic effects are highly unsatisfactory in part due to nerve injury-induced reduction of opioid receptors in the first-order sensory neurons of dorsal root ganglia. G9a is a repressor of gene expression. We found that nerve injury-induced increases in G9a and its catalyzed repressive marker H3K9m2 are responsible for epigenetic silencing of Oprm1, Oprk1, and Oprd1 genes in the injured dorsal root ganglia. Blocking these increases rescued dorsal root ganglia Oprm1, Oprk1, and Oprd1 gene expression and morphine or loperamide analgesia and prevented the development of morphine or loperamide-induced analgesic tolerance under neuropathic pain conditions. Conversely, mimicking these increases reduced the expression of three opioid receptors and promoted the mu opioid receptor-gated release of primary afferent neurotransmitters. Mechanistically, nerve injury-induced increases in the binding activity of G9a and H3K9me2 to the Oprm1 gene were associated with the reduced binding of cyclic AMP response element binding protein to the Oprm1 gene. These findings suggest that G9a participates in the nerve injury-induced reduction of the Oprm1 gene likely through G9a-triggered blockage in the access of cyclic AMP response element binding protein to this gene.
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Affiliation(s)
- Lingli Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Jian-Yuan Zhao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA.,State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, School of Life Sciences, Fudan University, Shanghai, China
| | - Xiyao Gu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Shaogen Wu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Kai Mo
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Ming Xiong
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Brianna Marie Lutz
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA .,Department of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA.,Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, USA
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Kiguchi N, Ding H, Peters CM, Kock ND, Kishioka S, Cline JM, Wagner JD, Ko MC. Altered expression of glial markers, chemokines, and opioid receptors in the spinal cord of type 2 diabetic monkeys. Biochim Biophys Acta Mol Basis Dis 2016; 1863:274-283. [PMID: 27751964 DOI: 10.1016/j.bbadis.2016.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/23/2016] [Accepted: 10/11/2016] [Indexed: 12/18/2022]
Abstract
Neuroinflammation is a pathological condition that underlies diabetes and affects sensory processing. Given the high prevalence of pain in diabetic patients and crosstalk between chemokines and opioids, it is pivotal to know whether neuroinflammation-associated mediators are dysregulated in the central nervous system of diabetic primates. Therefore, the aim of this study was to investigate whether mRNA expression levels of glial markers, chemokines, and opioid receptors are altered in the spinal cord and thalamus of naturally occurring type 2 diabetic monkeys (n=7) compared with age-matched non-diabetic monkeys (n=6). By using RT-qPCR, we found that mRNA expression levels of both GFAP and IBA1 were up-regulated in the spinal dorsal horn (SDH) of diabetic monkeys compared with non-diabetic monkeys. Among all chemokines, expression levels of three chemokine ligand-receptor systems, i.e., CCL2-CCR2, CCL3-CCR1/5, and CCL4-CCR5, were up-regulated in the SDH of diabetic monkeys. Moreover, in the SDH, seven additional chemokine receptors, i.e., CCR4, CCR6, CCR8, CCR10, CXCR3, CXCR5, and CXCR6, were also up-regulated in diabetic monkeys. In contrast, expression levels of MOP, KOP, and DOP, but not NOP receptors, were down-regulated in the SDH of diabetic monkeys, and the thalamus had fewer changes in the glial markers, chemokines and opioids. These findings indicate that neuroinflammation, manifested as glial activation and simultaneous up-regulation of multiple chemokine ligands and receptors, seems to be permanent in type 2 diabetic monkeys. As chemokines and opioids are important pain modulators, this first-in-primate study provides a translational bridge for determining the functional efficacy of spinal drugs targeting their signaling cascades.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA; Department of Pharmacology, Wakayama Medical University, Wakayama, Japan
| | - Huiping Ding
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Christopher M Peters
- Department of Anesthesiology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Nancy D Kock
- Department of Pathology, Center for Comparative Medicine Research, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Shiroh Kishioka
- Department of Pharmacology, Wakayama Medical University, Wakayama, Japan
| | - J Mark Cline
- Department of Pathology, Center for Comparative Medicine Research, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Janice D Wagner
- Department of Pathology, Center for Comparative Medicine Research, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Mei-Chuan Ko
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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50
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Kou ZZ, Wan FP, Bai Y, Li CY, Hu JC, Zhang GT, Zhang T, Chen T, Wang YY, Li H, Li YQ. Decreased Endomorphin-2 and μ-Opioid Receptor in the Spinal Cord Are Associated with Painful Diabetic Neuropathy. Front Mol Neurosci 2016; 9:80. [PMID: 27656127 PMCID: PMC5013037 DOI: 10.3389/fnmol.2016.00080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 08/24/2016] [Indexed: 12/17/2022] Open
Abstract
Painful diabetic neuropathy (PDN) is one of the most common complications in the early stage of diabetes mellitus (DM). Endomorphin-2 (EM2) selectively activates the μ-opioid receptor (MOR) and subsequently induces antinociceptive effects in the spinal dorsal horn. However, the effects of EM2-MOR in PDN have not yet been clarified in the spinal dorsal horn. Therefore, we aimed to explore the role of EM2-MOR in the pathogenesis of PDN. The main findings were the following: (1) streptozotocin (STZ)-induced diabetic rats exhibited hyperglycemia, body weight loss and mechanical allodynia; (2) in the spinal dorsal horn, the expression levels of EM2 and MOR decreased in diabetic rats; (3) EM2 protein concentrations decreased in the brain, lumbar spinal cord and cerebrospinal fluid (CSF) in diabetic rats but were unchanged in the plasma; (4) the frequency but not the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) was significantly higher in diabetic rats than in control rats; and (5) intrathecal injection of EM2 for 14 days in the early stage of PDN partially alleviated mechanical allodynia and reduced MOR expression in diabetic rats. Our results demonstrate that the EM2-MOR signal may be involved in the early stage of PDN.
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Affiliation(s)
- Zhen-Zhen Kou
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Fa-Ping Wan
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Yang Bai
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Chun-Yu Li
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Jia-Chen Hu
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Guo-Tao Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Ting Zhang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Tao Chen
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Ya-Yun Wang
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Hui Li
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical University Xi'an, China
| | - Yun-Qing Li
- Department of Anatomy and K.K. Leung Brain Research Centre, The Fourth Military Medical UniversityXi'an, China; Collaborative Innovation Center for Brain Science, Fudan UniversityShanghai, China
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