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Xu JF, Liu L, Liu Y, Lu KX, Zhang J, Zhu YJ, Fang F, Dou YN. Spinal Nmur2-positive Neurons Play a Crucial Role in Mechanical Itch. THE JOURNAL OF PAIN 2024; 25:104504. [PMID: 38442838 DOI: 10.1016/j.jpain.2024.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 02/23/2024] [Accepted: 02/29/2024] [Indexed: 03/07/2024]
Abstract
The dorsal spinal cord is crucial for the transmission and modulation of multiple somatosensory modalities, such as itch, pain, and touch. Despite being essential for the well-being and survival of an individual, itch and pain, in their chronic forms, have increasingly been recognized as clinical problems. Although considerable progress has been made in our understanding of the neurochemical processing of nociceptive and chemical itch sensations, the neural substrate that is crucial for mechanical itch processing is still unclear. Here, using genetic and functional manipulation, we identified a population of spinal neurons expressing neuromedin U receptor 2 (Nmur2+) as critical elements for mechanical itch. We found that spinal Nmur2+ neurons are predominantly excitatory neurons, and are enriched in the superficial laminae of the dorsal horn. Pharmacogenetic activation of cervical spinal Nmur2+ neurons evoked scratching behavior. Conversely, the ablation of these neurons using a caspase-3-based method decreased von Frey filament-induced scratching behavior without affecting responses to other somatosensory modalities. Similarly, suppressing the excitability of cervical spinal Nmur2+ neurons via the overexpression of functional Kir2.1 potassium channels reduced scratching in response to innocuous mechanical stimuli, but not to pruritogen application. At the lumbar level, pharmacogenetic activation of these neurons evoked licking and lifting behaviors. However, ablating these neurons did not affect the behavior associated with acute pain. Thus, these results revealed the crucial role of spinal Nmur2+ neurons in mechanical itch. Our study provides important insights into the neural basis of mechanical itch, paving the way for developing novel therapies for chronic itch. PERSPECTIVE: Excitatory Nmur2+ neurons in the superficial dorsal spinal cord are essential for mechanical but not chemical itch information processing. These spinal Nmur2+ neurons represent a potential cellular target for future therapeutic interventions against chronic itch. Spinal and supraspinal Nmur2+ neurons may play different roles in pain signal processing.
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Affiliation(s)
- Jun-Feng Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lian Liu
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yuan Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Lingang Laboratory, Shanghai, China
| | - Ke-Xing Lu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Jun Zhang
- Department of Anesthesiology, Daping Hospital, Army Medical University, Chongqing, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Fang Fang
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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Nelson TS, Duran P, Calderon-Rivera A, Gomez K, Loya-Lopez S, Khanna R. Mouse models of non-dystrophic and dystrophic myotonia exhibit nociplastic pain-like behaviors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.19.599732. [PMID: 38948724 PMCID: PMC11212949 DOI: 10.1101/2024.06.19.599732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Pain is a prominent and debilitating symptom in myotonic disorders, yet its physiological mechanisms remain poorly understood. This study assessed preclinical pain-like behavior in murine models of pharmacologically induced myotonia and myotonic dystrophy type 1 (DM1). In both myotonia congenita and DM1, impairment of the CLCN1 gene, which encodes skeletal muscle voltage-gated CLC-1 chloride channels, reduces chloride ion conductance in skeletal muscle cells, leading to prolonged muscle excitability and delayed relaxation after contraction. We used the CLC-1 antagonist anthracene-9-carboxylic acid (9-AC) at intraperitoneal doses of 30 or 60 mg/kg and HSA LR20b DM1 mice to model CLC-1-induced myotonia. Our experimental approach included in vivo pain behavioral testing, ex vivo calcium imaging, and whole-cell current-clamp electrophysiology in mouse dorsal root ganglion (DRG) neurons. A single injection of 9-AC induced myotonia in mice, which persisted for several hours and resulted in long-lasting allodynic pain-like behavior. Similarly, HSA LR20b mice exhibited both allodynia and hyperalgesia. Despite these pain-like behaviors, DRG neurons did not show signs of hyperexcitability in either myotonic model. These findings suggest that myotonia induces nociplastic pain-like behavior in preclinical rodents, likely through central sensitization mechanisms rather than peripheral sensitization. This study provides insights into the pathophysiology of pain in myotonic disorders and highlights the potential of using myotonic mouse models to explore pain mechanisms and assess novel analgesics. Future research should focus on the central mechanisms involved in myotonia-induced pain and develop targeted therapies to alleviate this significant clinical burden.
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Affiliation(s)
- Tyler S. Nelson
- Department of Pharmacology and Therapeutics, McKnight Brain Institute, and Pain and Addiction Therapeutics (PATH) Collaboratory, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Paz Duran
- Department of Molecular Pathobiology, College of Dentistry, New York University, New York, NY 10010, USA
| | - Aida Calderon-Rivera
- Department of Pharmacology and Therapeutics, McKnight Brain Institute, and Pain and Addiction Therapeutics (PATH) Collaboratory, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Kimberly Gomez
- Department of Pharmacology and Therapeutics, McKnight Brain Institute, and Pain and Addiction Therapeutics (PATH) Collaboratory, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Santiago Loya-Lopez
- Department of Pharmacology and Therapeutics, McKnight Brain Institute, and Pain and Addiction Therapeutics (PATH) Collaboratory, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Rajesh Khanna
- Department of Pharmacology and Therapeutics, McKnight Brain Institute, and Pain and Addiction Therapeutics (PATH) Collaboratory, University of Florida College of Medicine, Gainesville, FL 32610, USA
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Xu L, Hou L, Cao C, Li X. Ghrelin Induces the Production of Hypothalamic NPY Through the AMPK-mTOR Pathway to Alleviate Cancer-induced Bone Pain. In Vivo 2024; 38:1133-1142. [PMID: 38688635 PMCID: PMC11059913 DOI: 10.21873/invivo.13548] [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: 09/14/2023] [Revised: 11/10/2023] [Accepted: 11/15/2023] [Indexed: 05/02/2024]
Abstract
BACKGROUND/AIM Cancer-induced bone pain (CIBP) is one of the most common symptoms of bone metastasis of tumor cells. The hypothalamus may play a pivotal role in the regulation of CIBP. However, little is known about the exact mechanisms. MATERIALS AND METHODS First, we established a CIBP model to explore the relationship among hypothalamic ghrelin, NPY and CIBP. Then, we exogenously administered NPY and NPY receptor antagonists to investigate whether hypothalamic NPY exerted an antinociceptive effect through binding to NPY receptors. Finally, we exogenously administered ghrelin to investigate whether ghrelin alleviated CIBP by inducing the production of hypothalamic NPY through the AMPK-mTOR pathway. Body weight, food intake and behavioral indicators of CIBP were measured every 3 days. Hypothalamic ghrelin, NPY and the AMPK-mTOR pathway were also measured. RESULTS The expression of hypothalamic ghrelin and NPY was simultaneously decreased in cancer-bearing rats, which was accompanied by CIBP. Intracerebroventricular (i.c.v.) administration of NPY significantly alleviated CIBP in the short term. The antinociceptive effect of NPY was reversed with the i.c.v. administration of the Y1R and Y2R antagonists. The administration of ghrelin activated the AMPK-mTOR pathway and induced hypothalamic NPY production to alleviate CIBP. This effect of ghrelin on NPY and antinociception was reversed with the administration of a GHS-R1α antagonist. CONCLUSION Ghrelin could induce the production of hypothalamic NPY through the AMPK-mTOR pathway to alleviate CIBP, which can provide a novel therapeutic mechanism for CIBP.
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Affiliation(s)
- Longjie Xu
- Department of General Surgery, Second Affiliated Hospital of Soochow University, Suzhou, P.R. China
| | - Lili Hou
- Department of Thyroid and Breast Surgery, Suzhou Wuzhong People's Hospital, Suzhou, P.R. China
| | - Chun Cao
- Department of General Surgery, Second Affiliated Hospital of Soochow University, Suzhou, P.R. China;
| | - Xiaohua Li
- Department of General Surgery, Second Affiliated Hospital of Soochow University, Suzhou, P.R. China;
- Department of Thyroid and Breast Surgery, Suzhou Wuzhong People's Hospital, Suzhou, P.R. China
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Di Gesù M, Alito A, Borzelli D, Romeo D, Bonomolo F, Calafiore D, de Sire A. Efficacy of ultrasound-guided galvanic electrolysis technique and physical therapy in patients with Achilles' tendinopathy: A pilot randomised controlled trial. J Back Musculoskelet Rehabil 2024; 37:1177-1188. [PMID: 38517770 DOI: 10.3233/bmr-230255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND Ultrasound-guided galvanic electrolysis technique (USGET) is an innovative mini-invasive intervention with the potential to optimise outcomes in the treatment of Achille's tendinopathy (AT). OBJECTIVE The aim of this pilot study is to evaluate the efficacy of adding USGET to conventional eccentric exercise treatment in patients with chronic AT. METHODS Inclusion criteria were patients with unilateral non-insertional AT, pain lasting > 3 months, aged 25-60 years. Patients were randomised in two groups receiving the same physiotherapy treatment (2 sessions per week for 8 weeks). In addition, the experimental group received three USGET stimulations, one every 15 days. Outcome measures were assessment of Achilles tendinopathy severity using the Victorian Institute of Sport Assessment-Achilles (VISA-A) and pain intensity using the Visual Analogue Scale (VAS). Assessment points occurred at the onset of treatment (T0), its conclusion (T1), and subsequent follow-ups at one (T2) and two months (T3). RESULTS Out of the 52 patients who met the study inclusion criteria, two participants withdrew from the study, resulting in a total of 50 subjects who completed the research. None of the parameters showed a different distribution at T1 (p> 0.337). At T2, there was a statistical difference in VISA-A (p= 0.010) and its subscales and VAS (p= 0.002) in the USGET group. At T3, both groups improved with a statistical difference observed in VISA-A (p< 0.001) and its subscales Pain (p= 0.004), Function (p= 0.003) and Sport (p= 0.002), but the EG patients showed a greater improvement. No adverse events were reported. CONCLUSION The effect of USGET combined with eccentric exercise appears to be a safe and effective technique for achieving pain relief and functional recovery in the medium term, supporting the integrated use of USGET as a rehabilitative treatment option for patients with chronic AT.
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Affiliation(s)
| | - Angelo Alito
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Daniele Borzelli
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
- Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Domenico Romeo
- Physiocare: Physiotherapy Rehabilitation Center, Augusta, Italy
| | | | - Dario Calafiore
- Department of Neurosciences, Physical Medicine and Rehabilitation Unit, ASST Carlo Poma, Mantova, Italy
| | - Alessandro de Sire
- Department of Medical and Surgical Sciences, Physical and Rehabilitative Medicine, University of Catanzaro "Magna Graecia", Catanzaro, Italy
- Research Center on Musculoskeletal Health, MusculoSkeletalHealth@UMG, University of Catanzaro "Magna Graecia", Catanzaro, Italy
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Dai D, Zhao T, Li Z, Li W, Chen A, Tang Y, Gao XF, Xiong L. The plasticity of neuropeptide Y-Y1 receptor system on Tac2 neurons contributes to mechanical hyperknesis during chronic itch. Theranostics 2024; 14:363-378. [PMID: 38164144 PMCID: PMC10750199 DOI: 10.7150/thno.89433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/26/2023] [Indexed: 01/03/2024] Open
Abstract
Rationale: In the physiological states, the act of scratching protects the person from harmful substances, while in certain pathological conditions, the patient suffers from chronic itch, both physically and mentally. Chronic itch sufferers are more sensitive to mechanical stimuli, and mechanical hyperknesis relief is essential for chronic itch treatment. While neuropeptide Y-Y1 receptor (NPY-Y1R) system is known to play a crucial role in modulating mechanical itch in physiological conditions, it is elusive how they are altered during chronic itch. We hypothesize that the negative regulatory effect of Y1Rs on Tac2 neurons, the key neurons that transmit mechanical itch, declines during chronic itch. Methods: We combined transgenic mice, chemogenetic manipulation, immunofluorescence, rabies virus circuit tracing, and electrophysiology to investigate the plasticity of Y1Rs on Tac2 neurons during chronic itch. Results: We found that Tac2 neurons receive direct input from Npy neurons and that inhibition of Npy neurons induces activation of Tac2 neurons. Moreover, the expression of Y1Rs on Tac2 neurons is reduced, and the regulatory effect is also reduced during chronic itch. Conclusion: Our study clarifies the plasticity of Y1Rs on Tac2 neurons during chronic itch and further elucidates the mechanism by which NPY-Y1R system is responsible for modulating mechanical itch. We highlight Y1Rs as a promising therapeutic target for mechanical hyperknesis during chronic itch.
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Affiliation(s)
- Danqing Dai
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Tiantian Zhao
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Zhen Li
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Wanrong Li
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Aiwen Chen
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Yali Tang
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Xiao-Fei Gao
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
| | - Lize Xiong
- Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No.1481, Xinshi North Road, Shanghai 200434, China
- Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, No. 1279, Sanmen Road, Shanghai 200434, China
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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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Nelson TS, Allen HN, Basu P, Prasoon P, Nguyen E, Arokiaraj CM, Santos DF, Seal RP, Ross SE, Todd AJ, Taylor BK. Alleviation of neuropathic pain with neuropeptide Y requires spinal Npy1r interneurons that coexpress Grp. JCI Insight 2023; 8:e169554. [PMID: 37824208 PMCID: PMC10721324 DOI: 10.1172/jci.insight.169554] [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: 02/07/2023] [Accepted: 10/04/2023] [Indexed: 10/14/2023] Open
Abstract
Neuropeptide Y targets the Y1 receptor (Y1) in the spinal dorsal horn (DH) to produce endogenous and exogenous analgesia. DH interneurons that express Y1 (Y1-INs; encoded by Npy1r) are necessary and sufficient for neuropathic hypersensitivity after peripheral nerve injury. However, as Y1-INs are heterogenous in composition in terms of morphology, neurophysiological characteristics, and gene expression, we hypothesized that a more precisely defined subpopulation mediates neuropathic hypersensitivity. Using fluorescence in situ hybridization, we found that Y1-INs segregate into 3 largely nonoverlapping subpopulations defined by the coexpression of Npy1r with gastrin-releasing peptide (Grp/Npy1r), neuropeptide FF (Npff/Npy1r), and cholecystokinin (Cck/Npy1r) in the superficial DH of mice, nonhuman primates, and humans. Next, we analyzed the functional significance of Grp/Npy1r, Npff/Npy1r, and Cck/Npy1r INs to neuropathic pain using a mouse model of peripheral nerve injury. We found that chemogenetic inhibition of Npff/Npy1r-INs did not change the behavioral signs of neuropathic pain. Further, inhibition of Y1-INs with an intrathecal Y1 agonist, [Leu31, Pro34]-NPY, reduced neuropathic hypersensitivity in mice with conditional deletion of Npy1r from CCK-INs and NPFF-INs but not from GRP-INs. We conclude that Grp/Npy1r-INs are conserved in higher order mammalian species and represent a promising and precise pharmacotherapeutic target for the treatment of neuropathic pain.
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Affiliation(s)
- Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Center for Neuroscience
| | - Heather N. Allen
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Paramita Basu
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Eileen Nguyen
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Cynthia M. Arokiaraj
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Diogo F.S. Santos
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Rebecca P. Seal
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah E. Ross
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Andrew J. Todd
- Spinal Cord Group, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Silveira MA, Drotos AC, Pirrone TM, Versalle TS, Bock A, Roberts MT. Neuropeptide Y Signaling Regulates Recurrent Excitation in the Auditory Midbrain. J Neurosci 2023; 43:7626-7641. [PMID: 37704372 PMCID: PMC10634549 DOI: 10.1523/jneurosci.0900-23.2023] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023] Open
Abstract
Neuropeptides play key roles in shaping the organization and function of neuronal circuits. In the inferior colliculus (IC), which is in the auditory midbrain, Neuropeptide Y (NPY) is expressed by a class of GABAergic neurons that project locally and outside the IC. Most neurons in the IC have local axon collaterals; however, the organization and function of local circuits in the IC remain unknown. We previously found that excitatory neurons in the IC can express the NPY Y1 receptor (Y1R+) and application of the Y1R agonist, [Leu31, Pro34]-NPY (LP-NPY), decreases the excitability of Y1R+ neurons. As NPY signaling regulates recurrent excitation in other brain regions, we hypothesized that Y1R+ neurons form interconnected local circuits in the IC and that NPY decreases the strength of recurrent excitation in these circuits. To test this hypothesis, we used optogenetics to activate Y1R+ neurons in mice of both sexes while recording from other neurons in the ipsilateral IC. We found that nearly 80% of glutamatergic IC neurons express the Y1 receptor, providing extensive opportunities for NPY signaling to regulate local circuits. Additionally, Y1R+ neuron synapses exhibited modest short-term synaptic plasticity, suggesting that local excitatory circuits maintain their influence over computations during sustained stimuli. We further found that application of LP-NPY decreased recurrent excitation in the IC, suggesting that NPY signaling strongly regulates local circuit function in the auditory midbrain. Our findings show that Y1R+ excitatory neurons form interconnected local circuits in the IC, and their influence over local circuits is regulated by NPY signaling.SIGNIFICANCE STATEMENT Local networks play fundamental roles in shaping neuronal computations in the brain. The IC, localized in the auditory midbrain, plays an essential role in sound processing, but the organization of local circuits in the IC is largely unknown. Here, we show that IC neurons that express the Neuropeptide Y1 receptor (Y1R+ neurons) make up most of the excitatory neurons in the IC and form interconnected local circuits. Additionally, we found that NPY, which is a powerful neuromodulator known to shape neuronal activity in other brain regions, decreases the extensive recurrent excitation mediated by Y1R+ neurons in local IC circuits. Thus, our results suggest that local NPY signaling is a key regulator of auditory computations in the IC.
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Affiliation(s)
- Marina A Silveira
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Audrey C Drotos
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Trinity M Pirrone
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
- Macalester College, St. Paul, Minnesota 55105
| | - Trevor S Versalle
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda Bock
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Michael T Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology-Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
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Boyle KA, Polgar E, Gutierrez-Mecinas M, Dickie AC, Cooper AH, Bell AM, Jumolea E, Casas-Benito A, Watanabe M, Hughes DI, Weir GA, Riddell JS, Todd AJ. Neuropeptide Y-expressing dorsal horn inhibitory interneurons gate spinal pain and itch signalling. eLife 2023; 12:RP86633. [PMID: 37490401 PMCID: PMC10392120 DOI: 10.7554/elife.86633] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023] Open
Abstract
Somatosensory information is processed by a complex network of interneurons in the spinal dorsal horn. It has been reported that inhibitory interneurons that express neuropeptide Y (NPY), either permanently or during development, suppress mechanical itch, with no effect on pain. Here, we investigate the role of interneurons that continue to express NPY (NPY-INs) in the adult mouse spinal cord. We find that chemogenetic activation of NPY-INs reduces behaviours associated with acute pain and pruritogen-evoked itch, whereas silencing them causes exaggerated itch responses that depend on cells expressing the gastrin-releasing peptide receptor. As predicted by our previous studies, silencing of another population of inhibitory interneurons (those expressing dynorphin) also increases itch, but to a lesser extent. Importantly, NPY-IN activation also reduces behavioural signs of inflammatory and neuropathic pain. These results demonstrate that NPY-INs gate pain and itch transmission at the spinal level, and therefore represent a potential treatment target for pathological pain and itch.
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Affiliation(s)
- Kieran A Boyle
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Erika Polgar
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Maria Gutierrez-Mecinas
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Allen C Dickie
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew H Cooper
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew M Bell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Evelline Jumolea
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Adrian Casas-Benito
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - David I Hughes
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Gregory A Weir
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - John S Riddell
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Andrew J Todd
- School of Psychology and Neuroscience, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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10
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Brandner AJ, Baratta AM, Rathod RS, Ferguson C, Taylor BK, Farris SP. Mechanical and Heat Hyperalgesia upon Withdrawal From Chronic Intermittent Ethanol Vapor Depends on Sex, Exposure Duration, and Blood Alcohol Concentration in Mice. THE JOURNAL OF PAIN 2023; 24:1262-1274. [PMID: 36868488 PMCID: PMC10599355 DOI: 10.1016/j.jpain.2023.02.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 02/16/2023] [Accepted: 02/22/2023] [Indexed: 03/05/2023]
Abstract
Approximately half of patients with alcohol use disorder report pain and this can be severe during withdrawal. Many questions remain regarding the importance of biological sex, alcohol exposure paradigm, and stimulus modality to the severity of alcohol withdrawal-induced hyperalgesia. To examine the impact of sex and blood alcohol concentration on the time course of the development of mechanical and heat hyperalgesia, we characterized a mouse model of chronic alcohol withdrawal-induced pain in the presence or absence the alcohol dehydrogenase inhibitor, pyrazole. Male and female C57BL/6J mice underwent chronic intermittent ethanol vapor ± pyrazole exposure for 4 weeks, 4 d/wk to induce ethanol dependence. Hind paw sensitivity to the plantar application of mechanical (von Frey filaments) and radiant heat stimuli were measured during weekly observations at 1, 3, 5, 7, 24, and 48 hours after cessation of ethanol exposure. In the presence of pyrazole, males developed mechanical hyperalgesia after the first week of chronic intermittent ethanol vapor exposure, peaking at 48 hours after cessation of ethanol. By contrast, females did not develop mechanical hyperalgesia until the fourth week; this also required pyrazole and did not peak until 48 hours. Heat hyperalgesia was consistently observed only in females exposed to ethanol and pyrazole; this developed after the first weekly session and peaked at 1 hour. We conclude that Chronic alcohol withdrawal-induced pain develops in a sex-, time-, and blood alcohol concentration-dependent manner in C57BL/6J mice. PERSPECTIVE: Alcohol withdrawal-induced pain is a debilitating condition in individuals with AUD. Our study found mice experience alcohol withdrawal-induced pain in a sex and time course specific manor. These findings will aid in elucidating mechanisms of chronic pain and AUD and will help individuals remain abstinent from alcohol.
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Affiliation(s)
- Adam J Brandner
- Center for Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Annalisa M Baratta
- Center for Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Richa S Rathod
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Carolyn Ferguson
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Bradley K Taylor
- Center for Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Sean P Farris
- Center for Neuroscience, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Pittsburgh Project to end Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Biomedical Informatics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
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11
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Ju SH, Sohn JW. Protocol to prepare mouse spinal cord for patch-clamp and histology experiments. STAR Protoc 2023; 4:102345. [PMID: 37270782 PMCID: PMC10276144 DOI: 10.1016/j.xpro.2023.102345] [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: 02/11/2023] [Revised: 04/15/2023] [Accepted: 05/10/2023] [Indexed: 06/06/2023] Open
Abstract
The spinal cord is a part of the central nervous system located within the spinal canal of the vertebrae. Here, we present a protocol to prepare mouse spinal cord sections for patch-clamp and histology experiments. We describe steps for isolating spinal cord from the spinal canal and obtaining acute slices for patch-clamp experiments. For histology experiments, we detail fixing spinal cord for cryosectioning and imaging. This protocol provides procedures to assess neuronal activity and protein expression of sympathetic preganglionic neurons. For complete details on the use and execution of this protocol, please refer to Ju et al.1.
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Affiliation(s)
- Sang-Hyeon Ju
- Department of Internal Medicine, Chungnam National University Hospital, Daejeon 35015, South Korea.
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea.
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12
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Silveira MA, Drotos AC, Pirrone TM, Versalle TS, Bock A, Roberts MT. Neuropeptide Y signaling regulates recurrent excitation in the auditory midbrain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.540954. [PMID: 37292904 PMCID: PMC10245754 DOI: 10.1101/2023.05.16.540954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Neuropeptides play key roles in shaping the organization and function of neuronal circuits. In the inferior colliculus (IC), which is located in the auditory midbrain, Neuropeptide Y (NPY) is expressed by a large class of GABAergic neurons that project locally as well as outside the IC. The IC integrates information from numerous auditory nuclei making the IC an important hub for sound processing. Most neurons in the IC have local axon collaterals, however the organization and function of local circuits in the IC remains largely unknown. We previously found that neurons in the IC can express the NPY Y1 receptor (Y 1 R + ) and application of the Y 1 R agonist, [Leu 31 , Pro 34 ]-NPY (LP-NPY), decreases the excitability of Y 1 R + neurons. To investigate how Y 1 R + neurons and NPY signaling contribute to local IC networks, we used optogenetics to activate Y 1 R + neurons while recording from other neurons in the ipsilateral IC. Here, we show that 78.4% of glutamatergic neurons in the IC express the Y1 receptor, providing extensive opportunities for NPY signaling to regulate excitation in local IC circuits. Additionally, Y 1 R + neuron synapses exhibit modest short-term synaptic plasticity, suggesting that local excitatory circuits maintain their influence over computations during sustained stimuli. We further found that application of LP-NPY decreases recurrent excitation in the IC, suggesting that NPY signaling strongly regulates local circuit function in the auditory midbrain. Together, our data show that excitatory neurons are highly interconnected in the local IC and their influence over local circuits is tightly regulated by NPY signaling.
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Affiliation(s)
- Marina A. Silveira
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Audrey C. Drotos
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Trinity M. Pirrone
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
- Macalester College, St. Paul, Minnesota 55105
| | - Trevor S. Versalle
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Amanda Bock
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
| | - Michael T. Roberts
- Kresge Hearing Research Institute, Department of Otolaryngology – Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan 48109
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, 48109
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13
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Boivin JC, Zhu J, Ohyama T. Nociception in fruit fly larvae. FRONTIERS IN PAIN RESEARCH 2023; 4:1076017. [PMID: 37006412 PMCID: PMC10063880 DOI: 10.3389/fpain.2023.1076017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 02/28/2023] [Indexed: 03/19/2023] Open
Abstract
Nociception, the process of encoding and processing noxious or painful stimuli, allows animals to detect and avoid or escape from potentially life-threatening stimuli. Here, we provide a brief overview of recent technical developments and studies that have advanced our understanding of the Drosophila larval nociceptive circuit and demonstrated its potential as a model system to elucidate the mechanistic basis of nociception. The nervous system of a Drosophila larva contains roughly 15,000 neurons, which allows for reconstructing the connectivity among them directly by transmission electron microscopy. In addition, the availability of genetic tools for manipulating the activity of individual neurons and recent advances in computational and high-throughput behavior analysis methods have facilitated the identification of a neural circuit underlying a characteristic nocifensive behavior. We also discuss how neuromodulators may play a key role in modulating the nociceptive circuit and behavioral output. A detailed understanding of the structure and function of Drosophila larval nociceptive neural circuit could provide insights into the organization and operation of pain circuits in mammals and generate new knowledge to advance the development of treatment options for pain in humans.
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Affiliation(s)
- Jean-Christophe Boivin
- Department of Biology, McGill University, Montreal, QC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Jiayi Zhu
- Department of Biology, McGill University, Montreal, QC, Canada
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Tomoko Ohyama
- Department of Biology, McGill University, Montreal, QC, Canada
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
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14
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Wu Y, Wang F. Inhibition of NKCC1 in spinal dorsal horn and dorsal root ganglion results in alleviation of neuropathic pain in rats with spinal cord contusion. Mol Pain 2023; 19:17448069231159855. [PMID: 36760008 PMCID: PMC9950615 DOI: 10.1177/17448069231159855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
Previous studies have confirmed the relationship between chloride homeostasis and pain. However, the role of sodium potassium chloride co-transporter isoform 1 (NKCC1) in dorsal horn and dorsal root ganglion neurons (DRGs) in spinal cord injury (SCI)-induced neuropathic pain (NP) remains inconclusive. Therefore, we aimed to explore whether suppression of NKCC1 in the spinal cord and DRGs alleviate the NP of adult rats with thoracic spinal cord contusion. Thirty adult female Sprague-Dawley rats (8 week-old, weighing 250-280 g) were randomly divided into three groups with ten animals in each group (sham, SCI, and bumetanide groups). The paw withdrawal mechanical threshold and paw withdrawal thermal latency were recorded before injury (baseline) and on post-injury days 14, 21, 28, and 35. At the end of experiment, western blotting (WB) analysis, quantitative real-time Polymerase Chain Reaction (PCR) and immunofluorescence were performed to quantify NKCC1 expression. Our results revealed that NKCC1 protein expression in the spinal cord and DRGs was significantly up-regulated in rats with SCI. Intraperitoneal treatment of bumetanide (an NKCC1 inhibitor) reversed the expression of NKCC1 in the dorsal horn and DRGs and ameliorated mechanical ectopic pain and thermal hypersensitivities in the SCI rats. Our study demonstrated the occurrence of NKCC1 overexpression in the spinal cord and DRGs in a rodent model of NP and indicated that changes in the peripheral nervous system also play a major role in promoting pain sensitization after SCI.
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Affiliation(s)
- Yao Wu
- School of Rehabilitation Medicine, 12517Capital Medical University, Beijing, China.,Department of Spine Surgery, Beijing Bo'ai Hospital, China Rehabilitation Research Center, Beijing, China
| | - Fangyong Wang
- School of Rehabilitation Medicine, 12517Capital Medical University, Beijing, China.,Department of Spine Surgery, Beijing Bo'ai Hospital, China Rehabilitation Research Center, Beijing, China
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15
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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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16
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Microarray and Bioinformatics Analysis of Differential Gene and lncRNA Expression during Erythropoietin Treatment of Acute Spinal Cord Injury in Rats. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2022; 2022:4121910. [PMID: 36092786 PMCID: PMC9462987 DOI: 10.1155/2022/4121910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/10/2022] [Accepted: 08/20/2022] [Indexed: 11/18/2022]
Abstract
Purpose We performed a genome-wide analysis of long noncoding RNA (lncRNA) expression to identify novel targets for the further study of recombinant human erythropoietin (rhEPO) treatment of acute spinal cord injury (SCI) in rats. Methods Nine rats were randomly divided into 3 groups. No operation was performed in group 1. In groups 2 and 3, a laminectomy was performed at the 10th thoracic vertebra, and a contusion injury was induced by extradural application of an aneurysm clip. Group 1 rats did not receive any treatment, group 2 rats received a single intraperitoneal injection of normal saline, and group 3 rats received rhEPO. Three days after injury, spinal cord tissues were collected for RNA-Seq, microarray, differentially expressed genes (DEGs), Gene Ontology (GO) function enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and protein-protein interaction (PPI) analyses. Results Compared with group 1, 4,446 genes were found to be differentially expressed in group 2. Furthermore, 99 lncRNAs were found to be changed in the injury group. The data indicate that 2,471 mRNAs were upregulated, and 1,975 mRNAs were downregulated in group 2 as compared with group 1. In addition, 45 of the lncRNAs were upregulated, and the other 44 lncRNAs were downregulated. The top 5 upregulated and top 5 downregulated lncRNAs that were different between group 2 and group 1 are shown. The top 5 downregulated and the top 5 upregulated lncRNAs that were different between group 3 and group 2 are shown. Conclusion RhEPO treatment alters the expression profiles of the differentially expressed lncRNAs and genes beneficial to the development of new treatments.
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17
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Lippi L, de Sire A, Folli A, D’Abrosca F, Grana E, Baricich A, Carda S, Invernizzi M. Multidimensional Effectiveness of Botulinum Toxin in Neuropathic Pain: A Systematic Review of Randomized Clinical Trials. Toxins (Basel) 2022; 14:308. [PMID: 35622555 PMCID: PMC9145715 DOI: 10.3390/toxins14050308] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 04/24/2022] [Accepted: 04/24/2022] [Indexed: 02/06/2023] Open
Abstract
Although botulinum toxin (BoNT) has been suggested as a treatment to counter neuropathic pain, no previous systematic reviews investigated the multidimensional effects of BoNT on pain relief and Health-Related Quality of Life (HR-QoL). The aim of this systematic review is to summarize the current evidence on the effectiveness of BoNT treatment for neuropathic pain, and to characterize its multidimensional effectiveness in order to guide physicians in clinical practice. Five databases were systematically searched up to 4 April 2022, to identify randomized controlled trials satisfying the following criteria: adults suffering from neuropathic pain, BoNT administration, any comparator, multidimensional assessment of pain as primary outcome, HR-QoL, physical function, anxiety and depression, and sleep quality as secondary outcomes. Twelve studies were included. The multidimensional pain scales used were short-form McGill Pain Questionnaire, Neuropathic pain scale, Neuropathic Pain Symptom Inventory, International SCI Pain Basic Data Set, West Haven-Yale Multidimensional Pain Inventory, Brief Pain Inventory, and Douleur Neuropathique 4. These scales highlighted the positive effects of BoNT administration. According to the Jadad scale, all the RCTs included were high-quality studies. BoNT administration might be effectively introduced in the comprehensive management of neuropathic pain. Further research should focus on optimal and cost-effective therapeutic protocols.
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Affiliation(s)
- Lorenzo Lippi
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont “A. Avogadro”, 28100 Novara, Italy; (L.L.); (A.F.); (F.D.); (A.B.)
- Translational Medicine, Dipartimento Attività Integrate Ricerca e Innovazione (DAIRI), Azienda Ospedaliera SS. Antonio e Biagio e Cesare Arrigo, 15121 Alessandria, Italy
| | - Alessandro de Sire
- Physical Medicine and Rehabilitation Unit, Department of Medical and Surgical Sciences, University of Catanzaro Magna Graecia, 88100 Catanzaro, Italy;
| | - Arianna Folli
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont “A. Avogadro”, 28100 Novara, Italy; (L.L.); (A.F.); (F.D.); (A.B.)
| | - Francesco D’Abrosca
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont “A. Avogadro”, 28100 Novara, Italy; (L.L.); (A.F.); (F.D.); (A.B.)
| | - Elisa Grana
- Neuropsychology and Neurorehabilitation Service, Department of Clinical Neuroscience, Lausanne University Hospital, 1004 Lausanne, Switzerland; (E.G.); (S.C.)
| | - Alessio Baricich
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont “A. Avogadro”, 28100 Novara, Italy; (L.L.); (A.F.); (F.D.); (A.B.)
- Physical and Rehabilitation Medicine, “Ospedale Maggiore della Carità” University Hospital, 28100 Novara, Italy
| | - Stefano Carda
- Neuropsychology and Neurorehabilitation Service, Department of Clinical Neuroscience, Lausanne University Hospital, 1004 Lausanne, Switzerland; (E.G.); (S.C.)
| | - Marco Invernizzi
- Physical and Rehabilitative Medicine, Department of Health Sciences, University of Eastern Piedmont “A. Avogadro”, 28100 Novara, Italy; (L.L.); (A.F.); (F.D.); (A.B.)
- Translational Medicine, Dipartimento Attività Integrate Ricerca e Innovazione (DAIRI), Azienda Ospedaliera SS. Antonio e Biagio e Cesare Arrigo, 15121 Alessandria, Italy
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18
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Ma Q. A functional subdivision within the somatosensory system and its implications for pain research. Neuron 2022; 110:749-769. [PMID: 35016037 PMCID: PMC8897275 DOI: 10.1016/j.neuron.2021.12.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/07/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022]
Abstract
Somatosensory afferents are traditionally classified by soma size, myelination, and their response specificity to external and internal stimuli. Here, we propose the functional subdivision of the nociceptive somatosensory system into two branches. The exteroceptive branch detects external threats and drives reflexive-defensive reactions to prevent or limit injury. The interoceptive branch senses the disruption of body integrity, produces tonic pain with strong aversive emotional components, and drives self-caring responses toward to the injured region to reduce suffering. The central thesis behind this functional subdivision comes from a reflection on the dilemma faced by the pain research field, namely, the use of reflexive-defensive behaviors as surrogate assays for interoceptive tonic pain. The interpretation of these assays is now being challenged by the discovery of distinct but interwoven circuits that drive exteroceptive versus interoceptive types of behaviors, with the conflation of these two components contributing partially to the poor translation of therapies from preclinical studies.
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Affiliation(s)
- Qiufu Ma
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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19
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Abstract
Itch is one of the most primal sensations, being both ubiquitous and important for the well-being of animals. For more than a century, a desire to understand how itch is encoded by the nervous system has prompted the advancement of many theories. Within the past 15 years, our understanding of the molecular and neural mechanisms of itch has undergone a major transformation, and this remarkable progress continues today without any sign of abating. Here I describe accumulating evidence that indicates that itch is distinguished from pain through the actions of itch-specific neuropeptides that relay itch information to the spinal cord. According to this model, classical neurotransmitters transmit, inhibit and modulate itch information in a context-, space- and time-dependent manner but do not encode itch specificity. Gastrin-releasing peptide (GRP) is proposed to be a key itch-specific neuropeptide, with spinal neurons expressing GRP receptor (GRPR) functioning as a key part of a convergent circuit for the conveyance of peripheral itch information to the brain.
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20
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Hu Y, Li M, Li J, Lyu Q, Jiang R, Du Y. Effects of ultrasound-guided erector spinae plane block on the immune function and postoperative recovery of patients undergoing radical mastectomy. Gland Surg 2021; 10:2901-2909. [PMID: 34804878 PMCID: PMC8575707 DOI: 10.21037/gs-21-603] [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: 08/17/2021] [Accepted: 09/24/2021] [Indexed: 01/20/2023]
Abstract
BACKGROUND To explore the effects of ultrasound-guided erector spinae plane (ESP) block on the immune function and postoperative recovery of patients undergoing radical mastectomy. METHODS One hundred and four patients with breast cancer were randomly divided into the observation group and control group, with 52 cases in each group. The control group underwent induction of routine general anesthesia and thoracic paravertebral block, while the observation group underwent ultrasound-guided ESP block combined with general anesthesia. The recovery of autonomous respiration, eye opening, extubation time, postoperative eating, first anal exhaust, leaving bed and hospitalization time in both groups were statistically analyzed after surgery. The immune function indexes [CD4+, CD8+, interferon-γ (IFN-γ)] and the expression levels of serum neuropeptide Y (NPY), prostaglandin E2 (PGE2) and serotonin (5-HT) were compared between the two groups at 24 and 48 h before and after surgery. The visual analog scale (VAS) scores at rest and during exercise were recorded at 6, 12, 24, and 48 h after surgery. RESULTS There was no significant difference in the recovery of autonomous respiration, eye opening, and extubation time between the two groups (P>0.05). However, postoperative eating, first anal exhaust, leaving bed, and hospitalization time in the observation group were shorter than those in the control group (P<0.05). At 24 and 48 h after surgery, compared with the control group, CD4+ and IFN-γ levels were increased significantly (P<0.05), CD8+ and levels of serum NPY, PGE2, 5-HT and the incidence of postoperative complications was decreased significantly in the observation group (P<0.05). VAS scores at rest and during exercise in the observation group were lower than those in the control group (P<0.05). At 5 and 10 min after intubation, the observation group had higher epinephrine (E) level and lower serum cortisol (Cor) level than the control group (P<0.05). CONCLUSIONS The analgesic effect of ultrasound-guided ESP block is significant after radical mastectomy. There are few adverse reactions and few effects on immune function, and it can promote the postoperative recovery of patients.
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Affiliation(s)
- Yunxia Hu
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Meiting Li
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Jiacen Li
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Qiang Lyu
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Rong Jiang
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
| | - Yu Du
- Department of Anesthesiology, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, China;,Chinese Academy of Sciences Sichuan Translational Medicine Research Hospital, Chengdu, China
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21
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Effectiveness of Combined Treatment Using Physical Exercise and Ultrasound-Guided Radiofrequency Ablation of Genicular Nerves in Patients with Knee Osteoarthritis. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11104338] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Radiofrequency (RF) is a mini-invasive neuromodulation intervention that is commonly used in chronic pain conditions including general musculoskeletal pain related to several diseases, including knee osteoarthritis (KOA). However, to date, few studies investigated synergistic therapeutic approaches combining RF with rehabilitative physical exercise protocols in KOA patients. This prospective cohort study aimed at assessing the short-term effects on pain in KOA patients of a multimodal intervention consisting of ultrasound (US)-guided RF geniculate ablation and concomitant rehabilitative physical exercise. We included grade III KOA patients with knee pain (Numerical Pain Rating Scale, NPRS >4) not responsive to conventional treatments. They underwent a combined intervention including US-guided RF geniculate ablation and a 2-week physical exercise program. At the baseline (T0) and 1 month after (T1) we assessed: NPRS, Knee Injury and Osteoarthritis Outcome Scale (KOOS), quality of life, exercise adherence, and safety. All the 47 KOA patients enrolled (68.8 ± 13.7 years old) showed a reduction of pain (NPRS: 7.48 ± 1.74; 3.63 ± 1.68; p < 0.001). In addition, there was a significant improvement (p < 0.05) also in the other functioning and HRQoL outcomes. Adherence to the exercise program was over 80% in more than half (28) of the patients. No major adverse events were reported. These findings suggested that US-guided RF ablation of genicular nerves combined with rehabilitative exercise therapy might be considered a safe and effective approach in the complex management of KOA patients.
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22
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Percutaneous Electrical Nerve Stimulation (PENS) as a Rehabilitation Approach for Reducing Mixed Chronic Pain in Patients with Musculoskeletal Disorders. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11094257] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
“Mixed pain” is a term recently introduced to define the overlapping of nociceptive, neuropathic and nociplastic pain. To date, it has been reported that pharmacological treatments might have a modest effectiveness on patients affected by mixed chronic pain, with detrimental consequences in terms of disability, physical function and health-related quality of life. In this scenario, Percutaneous Electrical Nerve Stimulation (PENS), a mini-invasive neuromodulation technique, has been recently suggested as a promising approach for the complex management of mixed pain in musculoskeletal disorders. Albeit PENS showed to be effective in reducing unspecified pain in several chronic pain conditions, there is still a lack of evidence in the literature about its role in the management of neuropathic or mixed pain not responsive to pharmacological treatments. Therefore, by the present scoping review, we portray the potential effects of PENS in the multidisciplinary and multidimensional management of mixed chronic pain in patients with musculoskeletal disorders.
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23
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24
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Sinha GP, Prasoon P, Smith BN, Taylor BK. Fast A-type currents shape a rapidly adapting form of delayed short latency firing of excitatory superficial dorsal horn neurons that express the neuropeptide Y Y1 receptor. J Physiol 2021; 599:2723-2750. [PMID: 33768539 DOI: 10.1113/jp281033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/17/2021] [Indexed: 01/29/2023] Open
Abstract
KEY POINTS Neuropeptide Y Y1 receptor-expressing neurons in the dorsal horn of the spinal cord contribute to chronic pain. For the first time, we characterized the firing patterns of Y1-expressing neurons in Y1eGFP reporter mice. Under hyperpolarized conditions, most Y1eGFP neurons exhibited fast A-type potassium currents and delayed, short-latency firing (DSLF). Y1eGFP DSLF neurons were almost always rapidly adapting and often exhibited rebound spiking, characteristics of spinal pain neurons under the control of T-type calcium channels. These results will inspire future studies to determine whether tissue or nerve injury downregulates the channels that underlie A-currents, thus unmasking membrane hyperexcitability in Y1-expressing dorsal horn neurons, leading to persistent pain. ABSTRACT Neuroanatomical and behavioural evidence indicates that neuropeptide Y Y1 receptor-expressing interneurons (Y1-INs) in the superficial dorsal horn (SDH) are predominantly excitatory and contribute to chronic pain. Using an adult ex vivo spinal cord slice preparation from Y1eGFP reporter mice, we characterized firing patterns in response to steady state depolarizing current injection of GFP-positive cells in lamina II, the great majority of which expressed Y1 mRNA (88%). Randomly sampled (RS) and Y1eGFP neurons exhibited five firing patterns: tonic, initial burst, phasic, delayed short-latency <180 ms (DSLF) and delayed long-latency >180 ms (DLLF). When studied at resting membrane potential, most RS neurons exhibited delayed firing, while most Y1eGFP neurons exhibited phasic firing. A preconditioning membrane hyperpolarization produced only subtle changes in the firing patterns of RS neurons, but dramatically shifted Y1eGFP neurons to DSLF (46%) and DLLF (24%). In contrast to RS DSLF neurons, which rarely exhibited spike frequency adaptation, Y1eGFP DSLF neurons were almost always rapidly adapting, a characteristic of nociceptive-responsive SDH neurons. Rebound spiking was more prevalent in Y1eGFP neurons (6% RS vs. 32% Y1eGFP), indicating enrichment of T-type calcium currents. Y1eGFP DSLF neurons exhibited fast A-type potassium currents that are known to delay or limit action potential firing and exhibited smaller current density as compared to RS DSLF neurons. Our results will inspire future studies to determine whether tissue or nerve injury downregulates channels that contribute to A-currents, thus potentially unmasking T-type calcium channel activity and membrane hyperexcitability in Y1-INs, leading to persistent pain.
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Affiliation(s)
- Ghanshyam P Sinha
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bret N Smith
- Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Bradley K Taylor
- Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research, and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA
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25
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Spinal Inhibitory Ptf1a-Derived Neurons Prevent Self-Generated Itch. Cell Rep 2020; 33:108422. [PMID: 33238109 DOI: 10.1016/j.celrep.2020.108422] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/27/2020] [Accepted: 11/02/2020] [Indexed: 01/13/2023] Open
Abstract
Chronic itch represents an incapacitating burden on patients suffering from a spectrum of diseases. Despite recent advances in our understanding of the cells and circuits implicated in the processing of itch information, chronic itch often presents itself without an apparent cause. Here, we identify a spinal subpopulation of inhibitory neurons defined by the expression of Ptf1a, involved in gating mechanosensory information self-generated during movement. These neurons receive tactile and motor input and establish presynaptic inhibitory contacts on mechanosensory afferents. Loss of Ptf1a neurons leads to increased hairy skin sensitivity and chronic itch, partially mediated by the classic itch pathway involving gastrin-releasing peptide receptor (GRPR) spinal neurons. Conversely, chemogenetic activation of GRPR neurons elicits itch, which is suppressed by concomitant activation of Ptf1a neurons. These findings shed light on the circuit mechanisms implicated in chronic itch and open novel targets for therapy developments.
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26
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A spinal neural circuitry for converting touch to itch sensation. Nat Commun 2020; 11:5074. [PMID: 33033265 PMCID: PMC7545208 DOI: 10.1038/s41467-020-18895-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/17/2020] [Indexed: 12/14/2022] Open
Abstract
Touch and itch sensations are crucial for evoking defensive and emotional responses, and light tactile touch may induce unpleasant itch sensations (mechanical itch or alloknesis). The neural substrate for touch-to-itch conversion in the spinal cord remains elusive. We report that spinal interneurons expressing Tachykinin 2-Cre (Tac2Cre) receive direct Aβ low threshold mechanoreceptor (LTMR) input and form monosynaptic connections with GRPR neurons. Ablation or inhibition markedly reduces mechanical but not acute chemical itch nor noxious touch information. Chemogenetic inhibition of Tac2Cre neurons also displays pronounced deficit in chronic dry skin itch, a type of chemical itch in mice. Consistently, ablation of gastrin-releasing peptide receptor (GRPR) neurons, which are essential for transmitting chemical itch, also abolishes mechanical itch. Together, these results suggest that innocuous touch and chemical itch information converge on GRPR neurons and thus map an exquisite spinal circuitry hard-wired for converting innocuous touch to irritating itch.
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27
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Zhou RH, Chen C, Jin SH, Li J, Xu ZH, Ye L, Zhou JG. Co-expression gene modules involved in cisplatin-induced peripheral neuropathy according to sensitivity, status, and severity. J Peripher Nerv Syst 2020; 25:366-376. [PMID: 32779320 DOI: 10.1111/jns.12407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 02/05/2023]
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is among the most disabling and frustrating problems for cancer survivors. The neurotoxicity caused by cisplatin varies greatly among patients, and few predictors of appearance, duration of symptoms, susceptibility, or severity are available. A deeper understanding of the mechanisms underlying individual differences in status, severity, or sensitivity in response to cisplatin treatment is therefore required. By analyzing the GSE64174 gene expression profile and constructing a weighted gene co-expression network analysis (WGCNA) network, we screened gene modules and hub genes related to CIPN status, severity and sensitivity. We first identified the transcriptome profile of mouse dorsal root ganglion (DRG) samples and transformed their genes to human DRG counterparts. We then constructed WGCNA gene modules via optimal soft-threshold power-identification and module-preservation analysis. Comprehensive analysis and identification of module hub genes were performed via functional-enrichment analysis and significant common hub genes were identified, including "Cytoscape_cytoHubba," "Cytoscape_MCODE," and "Metascape_MCODE." Brown, green, and blue modules were selected to represent CIPN sensitivity, status, and severity, respectively, via trait-module correlational analysis. Additionally, functional enrichment analysis results indicated that these three modules were associated with some crucial biological functions, such as neutrophil migration, chemokine-mediated signaling pathway, and PI3K-Akt signaling pathway. We then identified seven common hub genes via three methods, including CXCL10, CCL21, CCR2, CXCR4, TLR4, NPY1R, and GALR2, related to CIPN status, severity and sensitivity. Our results provide possible targets and mechanism insights into the development and progress of CIPN, which can guide further transformation and pre-clinical research.
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Affiliation(s)
- Rui-Hao Zhou
- Department of Pain Management, West China Hospital, Sichuan University, Chengdu, China
| | - Chan Chen
- Department of Anesthesiology and Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China
| | - Su-Han Jin
- Department of Orthodontics, Affiliated Stomatological Hospital of Zunyi Medical University, Zunyi, China
| | - Jun Li
- Department of Pain Management, West China Hospital, Sichuan University, Chengdu, China
| | - Zi-Hao Xu
- School of Public Health, Nanchang University, Nanchang, China
| | - Ling Ye
- Department of Pain Management, West China Hospital, Sichuan University, Chengdu, China
| | - Jian-Guo Zhou
- Department of Oncology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Department of Radiation Oncology, Universitätsklinikum Erlangen, Erlangen, Germany
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28
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Nelson TS, Taylor BK. Targeting spinal neuropeptide Y1 receptor-expressing interneurons to alleviate chronic pain and itch. Prog Neurobiol 2020; 196:101894. [PMID: 32777329 DOI: 10.1016/j.pneurobio.2020.101894] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/08/2020] [Accepted: 08/03/2020] [Indexed: 02/06/2023]
Abstract
An accelerating basic science literature is providing key insights into the mechanisms by which spinal neuropeptide Y (NPY) inhibits chronic pain. A key target of pain inhibition is the Gi-coupled neuropeptide Y1 receptor (Y1). Y1 is located in key sites of pain transmission, including the peptidergic subpopulation of primary afferent neurons and a dense subpopulation of small, excitatory, glutamatergic/somatostatinergic interneurons (Y1-INs) that are densely expressed in the dorsal horn, particularly in superficial lamina I-II. Selective ablation of spinal Y1-INs with an NPY-conjugated saporin neurotoxin attenuates the development of peripheral nerve injury-induced mechanical and cold hypersensitivity. Conversely, conditional knockdown of NPY expression or intrathecal administration of Y1 antagonists reinstates hypersensitivity in models of chronic latent pain sensitization. These and other results indicate that spinal NPY release and the consequent inhibition of pain facilitatory Y1-INs represent an important mechanism of endogenous analgesia. This mechanism can be mimicked with exogenous pharmacological approaches (e.g. intrathecal administration of Y1 agonists) to inhibit mechanical and thermal hypersensitivity and spinal neuron activity in rodent models of neuropathic, inflammatory, and postoperative pain. Pharmacological activation of Y1 also inhibits mechanical- and histamine-induced itch. These immunohistochemical, pharmacological, and cell type-directed lesioning data, in combination with recent transcriptomic findings, point to Y1-INs as a promising therapeutic target for the development of spinally directed NPY-Y1 agonists to treat both chronic pain and itch.
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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, USA; Center for the Neural Basis of Cognition, University of Pittsburgh, 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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29
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Clark CM, Clark RM, Hoyle JA, Dickson TC. Pathogenic or protective? Neuropeptide Y in amyotrophic lateral sclerosis. J Neurochem 2020; 156:273-289. [PMID: 32654149 DOI: 10.1111/jnc.15125] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 12/13/2022]
Abstract
Neuropeptide Y (NPY) is an endogenous peptide of the central and enteric nervous systems which has gained significant interest as a potential neuroprotective agent for treatment of neurodegenerative disease. Amyotrophic lateral sclerosis (ALS) is an aggressive and fatal neurodegenerative disease characterized by motor deficits and motor neuron loss. In ALS, recent evidence from ALS patients and animal models has indicated that NPY may have a role in the disease pathogenesis. Increased NPY levels were found to correlate with disease progression in ALS patients. Similarly, NPY expression is increased in the motor cortex of ALS mice by end stages of the disease. Although the functional consequence of increased NPY levels in ALS is currently unknown, NPY has been shown to exert a diverse range of neuroprotective roles in other neurodegenerative diseases; through modulation of potassium channel activity, increased production of neurotrophins, inhibition of endoplasmic reticulum stress and autophagy, reduction of excitotoxicity, oxidative stress, neuroinflammation and hyperexcitability. Several of these mechanisms and signalling pathways are heavily implicated in the pathogenesis of ALS. Therefore, in this review, we discuss possible effects of NPY and NPY-receptor signalling in the ALS disease context, as determining NPY's contribution to, or impact on, ALS disease mechanisms will be essential for future studies investigating the NPY system as a therapeutic strategy in this devastating disease.
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Affiliation(s)
- Courtney M Clark
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Rosemary M Clark
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Joshua A Hoyle
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Tracey C Dickson
- Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
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30
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A multi-staged neuropeptide response to traumatic brain injury. Eur J Trauma Emerg Surg 2020; 48:507-517. [DOI: 10.1007/s00068-020-01431-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 06/28/2020] [Indexed: 01/05/2023]
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31
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Sakai K, Akiyama T. New insights into the mechanisms behind mechanical itch. Exp Dermatol 2020; 29:680-686. [PMID: 32621303 DOI: 10.1111/exd.14143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/12/2020] [Accepted: 06/25/2020] [Indexed: 12/25/2022]
Abstract
Gentle tactile stimuli, such as insects crawling on the skin, can cause itching sensation called mechanical itch. Recent studies have begun to shed light on the neural mechanisms of mechanical itch. Interestingly, the neural pathway for mechanical itch is apparently different from that for chemical itch triggered by the activation of pruriceptors with various mediators. Mechanical itch dysesthesia is frequently seen in patients with chronic itch. Mechanisms of this dysesthesia are plausibly involved in central sensitization. In this review, we summarize the current knowledge of mechanical itch under normal and pathological conditions.
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Affiliation(s)
- Kent Sakai
- Dr. Phillip Frost Department of Dermatology & Cutaneous Surgery and Miami Itch Center, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Tasuku Akiyama
- Dr. Phillip Frost Department of Dermatology & Cutaneous Surgery and Miami Itch Center, University of Miami Miller School of Medicine, Miami, FL, USA
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32
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Abstract
Neuropathic pain caused by a lesion or disease of the somatosensory nervous system is a common chronic pain condition with major impact on quality of life. Examples include trigeminal neuralgia, painful polyneuropathy, postherpetic neuralgia, and central poststroke pain. Most patients complain of an ongoing or intermittent spontaneous pain of, for example, burning, pricking, squeezing quality, which may be accompanied by evoked pain, particular to light touch and cold. Ectopic activity in, for example, nerve-end neuroma, compressed nerves or nerve roots, dorsal root ganglia, and the thalamus may in different conditions underlie the spontaneous pain. Evoked pain may spread to neighboring areas, and the underlying pathophysiology involves peripheral and central sensitization. Maladaptive structural changes and a number of cell-cell interactions and molecular signaling underlie the sensitization of nociceptive pathways. These include alteration in ion channels, activation of immune cells, glial-derived mediators, and epigenetic regulation. The major classes of therapeutics include drugs acting on α2δ subunits of calcium channels, sodium channels, and descending modulatory inhibitory pathways.
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Affiliation(s)
- Nanna Brix Finnerup
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Neurology, Aarhus University Hospital, Aarhus, Denmark; and Department of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Rohini Kuner
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Neurology, Aarhus University Hospital, Aarhus, Denmark; and Department of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Troels Staehelin Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Neurology, Aarhus University Hospital, Aarhus, Denmark; and Department of Pharmacology, Heidelberg University, Heidelberg, Germany
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33
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Chen S, Liu XY, Jiao Y, Chen ZF, Yu W. NPY2R signaling gates spontaneous and mechanical, but not thermal, pain transmission. Mol Pain 2020; 15:1744806919887830. [PMID: 31646939 PMCID: PMC6880052 DOI: 10.1177/1744806919887830] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Neuropeptide Y signaling plays an important role in inhibiting chronic
pain in the spinal cord of mice. However, little is known about the
respective roles of two major neuropeptide Y receptors, Y1R and Y2R,
in evoked and spontaneous pain behavior under normal physiological
condition. Using intrathecal administration approach, we found that
pharmacological inhibition of Y2R, unexpectedly, gave rise to
spontaneous pain behavior. In addition, Y2R antagonism also resulted
in long-lasting mechanical but not thermal hypersensitivity. By
contrast, neither overt spontaneous pain behavior nor mechanical and
thermal hypersensitivity were detected after pharmacological
inhibition of Y1R. Remarkably, the activation of Y1R produced powerful
analgesic effect: blocking both evoked and spontaneous pain behavior
resulted from Y2R antagonism. These findings highlight the pivotal
role of endogenous Y2R in gating mechanical and spontaneous pain
transmission. Importantly, our results suggest that Y1R could be a
therapeutic target that may be exploited for alleviating spontaneous
pain without affecting acute pain transmission.
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Affiliation(s)
- Sihan Chen
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, P.R. China.,Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA.,Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Xian-Yu Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA.,Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yingfu Jiao
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, P.R. China
| | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA.,Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA.,Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.,Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Weifeng Yu
- Department of Anesthesiology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, P.R. China
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Peirs C, Dallel R, Todd AJ. Recent advances in our understanding of the organization of dorsal horn neuron populations and their contribution to cutaneous mechanical allodynia. J Neural Transm (Vienna) 2020; 127:505-525. [PMID: 32239353 PMCID: PMC7148279 DOI: 10.1007/s00702-020-02159-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 02/10/2020] [Indexed: 02/07/2023]
Abstract
The dorsal horns of the spinal cord and the trigeminal nuclei in the brainstem contain neuron populations that are critical to process sensory information. Neurons in these areas are highly heterogeneous in their morphology, molecular phenotype and intrinsic properties, making it difficult to identify functionally distinct cell populations, and to determine how these are engaged in pathophysiological conditions. There is a growing consensus concerning the classification of neuron populations, based on transcriptomic and transductomic analyses of the dorsal horn. These approaches have led to the discovery of several molecularly defined cell types that have been implicated in cutaneous mechanical allodynia, a highly prevalent and difficult-to-treat symptom of chronic pain, in which touch becomes painful. The main objective of this review is to provide a contemporary view of dorsal horn neuronal populations, and describe recent advances in our understanding of on how they participate in cutaneous mechanical allodynia.
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Affiliation(s)
- Cedric Peirs
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France.
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - Radhouane Dallel
- Université Clermont Auvergne, CHU Clermont-Ferrand, Inserm, Neuro-Dol, Clermont-Ferrand, F-63000, France
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
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35
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Fu W, Wessel CR, Taylor BK. Neuropeptide Y tonically inhibits an NMDAR➔AC1➔TRPA1/TRPV1 mechanism of the affective dimension of chronic neuropathic pain. Neuropeptides 2020; 80:102024. [PMID: 32145934 PMCID: PMC7456540 DOI: 10.1016/j.npep.2020.102024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 12/18/2019] [Accepted: 01/23/2020] [Indexed: 11/26/2022]
Abstract
Transection of the sural and common peroneal branches of the sciatic nerve produces cutaneous hypersensitivity at the tibial innervation territory of the mouse hindpaw that resolves within a few weeks. We report that interruption of endogenous neuropeptide Y (NPY) signaling during remission, with either conditional NPY knockdown in NPYtet/tet mice or intrathecal administration of the Y1 receptor antagonist BIBO3304, reinstated hypersensitivity. These data indicate that nerve injury establishes a long-lasting latent sensitization of spinal nociceptive neurons that is masked by spinal NPY-Y1 neurotransmission. To determine whether this mechanism extends beyond the sensory component of nociception, we used conditioned place aversion and preference assays to evaluate the affective component of pain. We found that BIBO3304 produced place aversion in mice when administered during remission. Furthermore, the analgesic drug gabapentin produced place preference after NPY knockdown in NPYtet/tet but not control mice. We then used pharmacological agents and deletion mutant mice to investigate the cellular mechanisms of neuropathic latent sensitization. BIBO3304-induced reinstatement of mechanical hypersensitivity and conditioned place aversion could be prevented with intrathecal administration of an N-methyl-d-aspartate receptor antagonist (MK-801) and was absent in adenylyl cyclase type 1 (AC1) deletion mutant mice. BIBO3304-induced reinstatement could also be prevented with intrathecal administration an AC1 inhibitor (NB001) or a TRPV1 channel blocker (AMG9801), but not vehicle. Intrathecal administration of a TRPA1 channel blocker (HC030031) prevented the reinstatement of neuropathic hypersensitivity produced either by BIBO3304, or by NPY knockdown in NPYtet/tet but not control mice. Our results confirm new mediators of latent sensitization: TRPA1 and TRPV1. We conclude that NPY acts at spinal Y1 to tonically inhibit a molecular NMDAR➔AC1 intracellular signaling pathway in the dorsal horn that is induced by peripheral nerve injury and drives both the sensory and affective components of chronic neuropathic pain.
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Affiliation(s)
- Weisi Fu
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA
| | - Caitlin R Wessel
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA
| | - Bradley K Taylor
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, USA; Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA.
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Intra-articular injection of 2-pyridylethylamine produces spinal NPY-mediated antinociception in the formalin-induced rat knee-joint pain model. Brain Res 2020; 1735:146757. [PMID: 32135147 DOI: 10.1016/j.brainres.2020.146757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Revised: 01/27/2020] [Accepted: 02/29/2020] [Indexed: 11/22/2022]
Abstract
Low doses of histamine or H1R agonist 2-pyridylethylamine (2-PEA) into the knee-joint were found to decrease formalin-induced articular nociception in rats. In this study, we evaluated the participation of spinal NPY in the antinociceptive effect produced by 2-PEA. Injection of formalin (1.5%) into one of the knee-joints causes the limping of the respective limb due to nociception, which was registered each 5 min over 60 min. Neuropeptide Y1 receptor (Y1R) content in the spinal cord was evaluated by western-blotting. Intrathecal (i.t.) injection of Y1R agonist Leu31, Pro34-NPY (0.7-7 µmol) decreased nociception, while injection of the antagonist BIBO 3304 (4 μmol), increased nociception. Antinociception produced by 2-PEA was reversed by a sub-effective i.t. dose of the Y1R antagonist. Similarly, this antinociceptive effect was prevented by i.t. pretreatment with the neurotoxin NPY-saporin (750 ng), which also reduced immunoblotting for Y1R in spinal cord homogenates. These data support the idea that antinociception induced by H1R agonists in the knee-joint of rats may be mediated by the spinal release of NPY, and this peptide seems to be acting via Y1R.
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Jakobsson JET, Ma H, Lagerström MC. Neuropeptide Y in itch regulation. Neuropeptides 2019; 78:101976. [PMID: 31668651 DOI: 10.1016/j.npep.2019.101976] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 09/03/2019] [Accepted: 10/07/2019] [Indexed: 12/11/2022]
Abstract
Itch is a somatosensory sensation that informs the organism about the presence of potentially harmful substances or parasites, and initiates scratching to remove the threat. Itch-inducing (pruritogenic) substances activate primary afferent neurons in the skin through interactions with specific receptors that converts the stimulus into an electrical signal. These signals are conveyed to the dorsal horn of the spinal cord through the release of neurotransmitters such as natriuretic polypeptide b and somatostatin, leading to an integrated response within a complex spinal interneuronal network. A large sub-population of somatostatin-expressing spinal interneurons also carry the Neuropeptide Y (NPY) Y1 receptor, indicating that NPY and somatostatin partly regulate the same neuronal pathway. This review focuses on recent findings regarding the role of the NPY/Y1 and somatostatin/SST2A receptor in itch, and also presents data integrating the two neurotransmitter systems.
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Affiliation(s)
- Jon E T Jakobsson
- Department of Neuroscience, Uppsala University, 751 24 Uppsala, Sweden
| | - Haisha Ma
- Department of Neuroscience, Uppsala University, 751 24 Uppsala, Sweden
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Dorsal Horn PKCγ Interneurons Mediate Mechanical Allodynia through 5-HT 2AR-Dependent Structural Reorganization. J Neurosci 2019; 39:6221-6223. [PMID: 31391259 DOI: 10.1523/jneurosci.0291-19.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 05/31/2019] [Accepted: 06/06/2019] [Indexed: 02/06/2023] Open
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Marvizon JC, Chen W, Fu W, Taylor BK. Neuropeptide Y release in the rat spinal cord measured with Y1 receptor internalization is increased after nerve injury. Neuropharmacology 2019; 158:107732. [PMID: 31377198 DOI: 10.1016/j.neuropharm.2019.107732] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 07/31/2019] [Indexed: 12/18/2022]
Abstract
Neuropeptide Y (NPY) modulates nociception in the spinal cord, but little is known about its mechanisms of release. We measured NPY release in situ using the internalization of its Y1 receptor in dorsal horn neurons. Y1 receptor immunoreactivity was normally localized to the cell surface, but addition of NPY to spinal cord slices increased the number of neurons with Y1 internalization in a biphasic fashion (EC50s of 1 nM and 1 μM). Depolarization with KCl, capsaicin, or the protein kinase A activator 6-benzoyl-cAMP also induced Y1 receptor internalization, presumably by releasing NPY. NMDA receptor activation in the presence of BVT948, an inhibitor of protein tyrosine phosphatases, also released NPY. Electrical stimulation of the dorsal horn frequency-dependently induced NPY release; and this was decreased by the Y1 antagonist BIBO3304, the Nav channel blocker lidocaine, or the Cav2 channel blocker ω-conotoxin MVIIC. Dorsal root immersion in capsaicin, but not its electrical stimulation, also induced NPY release. This was blocked by CNQX, suggesting that part of the NPY released by capsaicin was from dorsal horn neurons receiving synapses from primary afferents and not from the afferent themselves. Mechanical stimulation in vivo, with rub or clamp of the hindpaw, elicited robust Y1 receptor internalization in rats with spared nerve injury but not sham surgery. In summary, NPY is released from dorsal horn interneurons or primary afferent terminals by electrical stimulation and by activation of TRPV1, PKA or NMDA receptors in. Furthermore, NPY release evoked by noxious and tactile stimuli increases after peripheral nerve injury.
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Affiliation(s)
- Juan Carlos Marvizon
- Vatche and Tamar Manoukian Division of Digestive Diseases, 900 Veterans Ave., Warren Hall Building, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, 11310 Wilshire Blvd., Building 115, Los Angeles, CA, 90073, USA.
| | - Wenling Chen
- Vatche and Tamar Manoukian Division of Digestive Diseases, 900 Veterans Ave., Warren Hall Building, Department of Medicine, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, CA, 90095, USA; Veteran Affairs Greater Los Angeles Healthcare System, 11310 Wilshire Blvd., Building 115, Los Angeles, CA, 90073, USA.
| | - Weisi Fu
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA.
| | - Bradley K Taylor
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY, USA; Department of Anesthesiology and Perioperative Medicine, Pittsburgh Center for Pain Research and the Pittsburgh Project to end Opioid Misuse, University of Pittsburgh, Pittsburgh, PA, USA.
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