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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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Millecamps M, Sotocinal SG, Austin JS, Stone LS, Mogil JS. Sex-specific effects of neuropathic pain on long-term pain behavior and mortality in mice. Pain 2023; 164:577-586. [PMID: 35916733 DOI: 10.1097/j.pain.0000000000002742] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/15/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT Human epidemiological studies suggest that chronic pain can increase mortality risk. We investigated whether this was true in mice so that underlying mechanisms might be identified. At 10 weeks of age, C57BL/6 mice of both sexes received sham or spared nerve injury (SNI) surgery producing neuropathic pain. Mice were weighed monthly, tested behaviorally for mechanical and cold sensitivity and guarding behavior every 3 months postsurgery, and otherwise left undisturbed in their cages until death by natural causes. Evidence of pain over the lifespan displayed a strikingly sex-specific pattern. Male mice displayed largely stable mechanical and cold hypersensitivity and guarding at 6 to 30 months post-SNI. By contrast, female mice displayed a biphasic temporal pattern of mechanical hypersensitivity and guarding behavior, with a complete resolution of SNI-induced pain behavior at 6 to 9 months post-SNI followed by the return of pain thereafter. Mouse lifespan was not significantly altered by SNI in either sex nor was frailty as assessed by cage inspection in the last 6 months of life. However, in male mice with SNI, we observe a significant correlation between average lifetime mechanical hypersensitivity and lifespan, such that death occurred sooner in male mice exhibiting more evidence of chronic pain. This relationship was not observed in female SNI mice nor in sham-operated mice of either sex. This experiment is the first to investigate pain behavior over an entire adult lifetime and suggests that biology of relevance to human chronic pain is being ignored by the very short timespans of most extant preclinical pain research.
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Affiliation(s)
- Magali Millecamps
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | - Susana G Sotocinal
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Laura S Stone
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Anesthesiology, University of Minnesota, Minneapolis, MN, United States
| | - Jeffrey S Mogil
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Departments of Psychology and Anesthesia, McGill University, Montreal, QC, Canada
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Molecular Changes in the Dorsal Root Ganglion during the Late Phase of Peripheral Nerve Injury-induced Pain in Rodents: A Systematic Review. Anesthesiology 2021; 136:362-388. [PMID: 34965284 DOI: 10.1097/aln.0000000000004092] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
The dorsal root ganglion is widely recognized as a potential target to treat chronic pain. A fundamental understanding of quantitative molecular and genomic changes during the late phase of pain is therefore indispensable. The authors performed a systematic literature review on injury-induced pain in rodent dorsal root ganglions at minimally 3 weeks after injury. So far, slightly more than 300 molecules were quantified on the protein or messenger RNA level, of which about 60 were in more than one study. Only nine individual sequencing studies were performed in which the most up- or downregulated genes varied due to heterogeneity in study design. Neuropeptide Y and galanin were found to be consistently upregulated on both the gene and protein levels. The current knowledge regarding molecular changes in the dorsal root ganglion during the late phase of pain is limited. General conclusions are difficult to draw, making it hard to select specific molecules as a focus for treatment.
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Gerum M, Simonin F. Behavioral characterization, potential clinical relevance and mechanisms of latent pain sensitization. Pharmacol Ther 2021; 233:108032. [PMID: 34763010 DOI: 10.1016/j.pharmthera.2021.108032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/22/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022]
Abstract
Chronic pain is a debilitating disorder that can occur as painful episodes that alternates with bouts of remission and occurs despite healing of the primary insult. Those episodes are often triggered by stressful events. In the last decades, a similar situation has been evidenced in a wide variety of rodent models (including inflammatory pain, neuropathy and opioid-induced hyperalgesia) where animals develop a chronic latent hyperalgesia that silently persists after behavioral signs of pain resolution. This state, referred as latent pain sensitization, is due to the compensatory activation of antinociceptive systems, such as the opioid system or NPY and its receptors. A transitory phase of hyperalgesia can then be reinstated by pharmacological or genetic blockade of these antinociceptive systems or by submitting animals to acute stress. Those observations reveal that there is a constant endogenous analgesia responsible for chronic pain inhibition that might paradoxically contribute to maintain this maladaptive state and could then participate to the transition from acute to chronic pain. Thus, demonstration of the existence of this phenomenon in humans and a better understanding of the mechanisms by which latent pain sensitization develops and maintains over long periods of time will be of particular interest to help identifying new therapeutic strategies and targets for chronic pain treatment. The present review aims to recapitulate behavioral expression, potential clinical relevance, cellular mechanisms and intracellular signaling pathways involved so far in latent pain sensitization.
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Affiliation(s)
- Manon Gerum
- Biotechnologie et Signalisation Cellulaire, UMR7242 CNRS, Université de Strasbourg, Institut du Médicament de Strasbourg, Illkirch-Graffenstaden, France
| | - Frédéric Simonin
- Biotechnologie et Signalisation Cellulaire, UMR7242 CNRS, Université de Strasbourg, Institut du Médicament de Strasbourg, Illkirch-Graffenstaden, France.
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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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Gupta S, Gautam M, Prasoon P, Kumar R, Ray SB, Kaler Jhajhria S. Involvement of Neuropeptide Y in Post-Incisional Nociception in Rats. Ann Neurosci 2018; 25:268-276. [PMID: 31000967 PMCID: PMC6470383 DOI: 10.1159/000495130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Accepted: 10/30/2018] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Neuropeptide Y (NPY) is abundantly distributed in the mammalian nervous system. Its role in nociception arising from inflammatory and neuropathic pain conditions has been elucidated. However, its involvement in post-incisional nociception, particularly at the spinal cord level, is relatively unknown. PURPOSE Management of postoperative pain is suboptimal. Evaluation of changes at the spinal level could facilitate better understanding of neural mechanisms underlying this type of pain. METHODS Rats were subjected to hind paw incision and spatiotemporal pattern of NPY expression in the dorsal horn was investigated by immunohistochemistry. Next, rats were implanted with intrathecal catheters using previously standardized procedure. NPY was injected into the intrathecal space by an indwelling catheter and behavioral assessment of nociception was performed. RESULTS Higher expression of NPY was observed in the superficial laminae of the dorsal horn. After incision, specific changes were observed like an abrupt decrease at 3 h after incision, which could be correlated with the intense nociception at this time. In contrast to morphine administration, which attenuated all 3 behavioral parameters of nociception, NPY decreased guarding behavior and thermal hyperalgesia during the acute phase. CONCLUSIONS NPY is extensively expressed in the superficial laminae of the spinal cord and exhibit marked changes after incision. Nociception is also decreased after its administration. Hence, it is likely involved in post-incisional nociception. This information could have clinical relevance.
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Affiliation(s)
| | | | | | | | | | - Saroj Kaler Jhajhria
- Departments of Anatomy, All India Institute of Medical Sciences, New Delhi, India
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Potter LE, Doolen S, Mifflin K, Tenorio G, Baker G, Taylor BK, Kerr BJ. Antinociceptive Effects of the Antidepressant Phenelzine are Mediated by Context-Dependent Inhibition of Neuronal Responses in the Dorsal Horn. Neuroscience 2018; 383:205-215. [PMID: 29752984 DOI: 10.1016/j.neuroscience.2018.04.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 04/23/2018] [Accepted: 04/28/2018] [Indexed: 02/08/2023]
Abstract
The putative strong anti-nociceptive properties of the antidepressant phenelzine (PLZ) have not been widely explored as a treatment for pain. Antinociceptive effects of PLZ were identified in the formalin model of tonic pain (Mifflin et al., 2016) and in allodynia associated with experimental autoimmune encephalomyelitis, (EAE) a mouse model of multiple sclerosis (Potter et al., 2016). Here, we further clarify the specific types of stimuli and contexts in which PLZ modulates nociceptive sensitivity. Our findings indicate that PLZ selectively inhibits ongoing inflammatory pain while sparing transient reflexive and acute nociception. We also investigated the cellular mechanisms of action of PLZ in the dorsal horn, and as expected of a monoamine-oxidase inhibitor, PLZ increased serotonin (5HT) immunoreactivity. We next used two approaches to test the hypothesis that PLZ inhibits the activation of spinal nociresponsive neurons. First, we evaluated the formalin-evoked protein expression of the immediate early gene, c-fos. PLZ reduced Fos expression in the superficial dorsal horn. Second, we evaluated the effects of PLZ on intracellular calcium responses to superfusion of glutamate (0.3-1.0 mM) in an ex vivo lumbar spinal cord slice preparation. Superfusion with PLZ (100-300 μM) reduced 1 mM glutamate-evoked calcium responses. This was blocked by pretreatment with the 5HT1A-receptor antagonist WAY-100,635, but not the alpha-2 adrenergic antagonist idazoxan. We conclude that PLZ exerts antinociceptive effects through a 5-HT/5HT1AR-dependent inhibition of neuronal responses within nociceptive circuits of the dorsal horn.
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Affiliation(s)
- Liam E Potter
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Suzanne Doolen
- Department of Physiology and the Center for Analgesia Research Excellence, University of Kentucky, Lexington, KY 40536, USA
| | - Katherine Mifflin
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Psychology, University of Alberta, Edmonton, AB T6G 2E9, Canada
| | - Gustavo Tenorio
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada
| | - Glen Baker
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Psychiatry (NRU), University of Alberta, Edmonton, AB T6G 2B7, Canada
| | - Bradley K Taylor
- Department of Physiology and the Center for Analgesia Research Excellence, University of Kentucky, Lexington, KY 40536, USA
| | - Bradley J Kerr
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Pharmacology, University of Alberta, Edmonton, AB T6E 2H7, Canada; Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada.
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Ko MH, Yang ML, Youn SC, Lan CT, Tseng TJ. Intact subepidermal nerve fibers mediate mechanical hypersensitivity via the activation of protein kinase C gamma in spared nerve injury. Mol Pain 2016; 12:12/0/1744806916656189. [PMID: 27296621 PMCID: PMC4956387 DOI: 10.1177/1744806916656189] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Spared nerve injury is an important neuropathic pain model for investigating the role of intact primary afferents in the skin on pain hypersensitivity. However, potential cellular mechanisms remain poorly understood. In phosphoinositide-3 kinase pathway, pyruvate dehydrogenase kinase 1 (PDK1) participates in the regulation of neuronal plasticity for central sensitization. The downstream cascades of PDK1 include: (1) protein kinase C gamma (PKCg) controls the trafficking and phosphorylation of ionotropic glutamate receptor; (2) protein kinase B (Akt)/the mammalian target of rapamycin (mTOR) signaling is responsible for local protein synthesis. Under these statements, we therefore hypothesized that an increase of PKCg activation and mTOR-dependent PKCg synthesis in intact primary afferents after SNI might contribute to pain hypersensitivity. RESULTS The variants of spared nerve injury were performed in Sprague-Dawley rats by transecting any two of the three branches of the sciatic nerve, leaving only one branch intact. Following SNIt (spared tibial branch), mechanical hyperalgesia and mechanical allodynia, but not thermal hyperalgesia, were significantly induced. In the first footpad, normal epidermal innervations were verified by the protein gene product 9.5 (PGP9.5)- and growth-associated protein 43 (GAP43)-immunoreactive (IR) intraepidermal nerve fibers (IENFs) densities. Furthermore, the rapid increases of phospho-PKCg- and phosphomTOR-IR subepidermal nerve fibers (SENFs) areas were distinct gathered from the results of PGP9.5-, GAP43-, and neurofilament 200 (NF200)-IR SENFs areas. The efficacy of PKC inhibitor (GF 109203X) or mTOR complex 1 inhibitor (rapamycin) for attenuating mechanical hyperalgesia and mechanical allodynia by intraplantar injection was dose-dependent. CONCLUSIONS From results obtained in this study, we strongly recommend that the intact SENFs persistently increase PKCg activation and mTOR-dependent PKCg synthesis participate in the initiation and maintenance of mechanical hypersensitivity in spared nerve injury, which represents as a novel insight into the therapeutic strategy of pain in the periphery.
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Affiliation(s)
- Miau-Hwa Ko
- Department of Anatomy, College of Medicine, China Medical University, Taichung, Taiwan
| | - Ming-Ling Yang
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Su-Chung Youn
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Chyn-Tair Lan
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
- Chyn-Tair Lan, Department of Anatomy, School of Medicine, Chung Shan Medical University, No. 110, Jian-Guo N. R., Sec. 1, Taichung 40201, Taiwan. To-Jung Tseng, Department of Anatomy, School of Medicine, Chung Shan Medical University, No. 110, Jian-Guo N. R., Sec. 1, Taichung 40201, Taiwan.
| | - To-Jung Tseng
- Department of Anatomy, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung, Taiwan
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Magnussen C, Hung SP, Ribeiro-da-Silva A. Novel expression pattern of neuropeptide Y immunoreactivity in the peripheral nervous system in a rat model of neuropathic pain. Mol Pain 2015; 11:31. [PMID: 26012590 PMCID: PMC4449610 DOI: 10.1186/s12990-015-0029-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 05/20/2015] [Indexed: 12/26/2022] Open
Abstract
Background Neuropeptide Y (NPY) has been implicated in the modulation of pain. Under normal conditions, NPY is found in interneurons in the dorsal horn of the spinal cord and in sympathetic postganglionic neurons but is absent from the cell bodies of sensory neurons. Following peripheral nerve injury NPY is dramatically upregulated in the sensory ganglia. How NPY expression is altered in the peripheral nervous system, distal to a site of nerve lesion, remains unknown. To address this question, NPY expression was investigated using immunohistochemistry at the level of the trigeminal ganglion, the mental nerve and in the skin of the lower lip in relation to markers of sensory and sympathetic fibers in a rat model of trigeminal neuropathic pain. Results At 2 and 6 weeks after chronic constriction injury (CCI) of the mental nerve, de novo expression of NPY was seen in the trigeminal ganglia, in axons in the mental nerve, and in fibers in the upper dermis of the skin. In lesioned animals, NPY immunoreactivity was expressed primarily by large diameter mental nerve sensory neurons retrogradely labelled with Fluorogold. Many axons transported this de novo NPY to the periphery as NPY-immunoreactive (IR) fibers were seen in the mental nerve both proximal and distal to the CCI. Some of these NPY-IR axons co-expressed Neurofilament 200 (NF200), a marker for myelinated sensory fibers, and occasionally colocalization was seen in their terminals in the skin. Peptidergic and non-peptidergic C fibers expressing calcitonin gene-related peptide (CGRP) or binding isolectin B4 (IB4), respectively, never expressed NPY. CCI caused a significant de novo sprouting of sympathetic fibers into the upper dermis of the skin, and most, but not all of these fibers, expressed NPY. Conclusions This is the first study to provide a comprehensive description of changes in NPY expression in the periphery after nerve injury. Novel expression of NPY in the skin comes mostly from sprouted sympathetic fibers. This information is fundamental in order to understand where endogenous NPY is expressed, and how it might be acting to modulate pain in the periphery.
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Affiliation(s)
- Claire Magnussen
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Room 1215, Montreal, Quebec, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, H3A 0G1, Canada.
| | - Shih-Ping Hung
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Room 1215, Montreal, Quebec, H3G 1Y6, Canada.
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building, 3655 Promenade Sir William Osler, Room 1215, Montreal, Quebec, H3G 1Y6, Canada. .,Alan Edwards Centre for Research on Pain, McGill University, Montreal, Quebec, H3A 0G1, Canada. .,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, H3A 0C7, Canada.
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ISSLS Prize winner: Increased innervation and sensory nervous system plasticity in a mouse model of low back pain due to intervertebral disc degeneration. Spine (Phila Pa 1976) 2014; 39:1345-54. [PMID: 24718079 DOI: 10.1097/brs.0000000000000334] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Immunohistochemical and behavioral study using the SPARC (secreted protein, acidic, rich in cysteine)-null mouse model of low back pain (LBP) associated with accelerated intervertebral disc (IVD) degeneration. OBJECTIVE To determine if behavioral signs of LBP in SPARC-null mice are accompanied by sensory nervous system plasticity. SUMMARY OF BACKGROUND DATA IVD pathology is a significant contributor to chronic LBP. In humans and rodents, decreased expression of SPARC is associated with IVD degeneration. We previously reported that SPARC-null mice exhibit age-dependent behavioral signs of chronic axial LBP and radiating leg pain. METHODS SPARC-null and age-matched control young, middle-aged, and old mice (1.5, 6, and 24 mo of age, respectively) were evaluated. Cutaneous hind paw sensitivity to cold, heat, and mechanical stimuli were evaluated as measures of radiating pain. The grip force and tail suspension assays were performed to evaluate axial LBP. Motor impairment was assessed using an accelerating rotarod. IVD innervation was identified by immunohistochemistry targeting the nerve fiber marker PGP9.5 and the sensory neuropeptide calcitonin gene-related peptide (CGRP). Sensory nervous system plasticity was evaluated by quantification of CGRP- and neuropeptide-Y-immunoreactivity (-ir) in dorsal root ganglia neurons and CGRP-ir, GFAP-ir (astrocyte marker), and Iba-1-ir (microglia marker) in the spinal cord. RESULTS SPARC-null mice developed hypersensitivity to cold, axial discomfort, age-dependent motor impairment, age-dependent increases in sensory innervation in and around the IVDs, age-dependent upregulation of CGRP and neuropeptide-Y in dorsal root ganglia, and age-dependent upregulation of CGRP, microglia, and astrocytes in the spinal cord dorsal horn. CONCLUSION Increased innervation of degenerating IVDs by sensory nerve fibers and the neuroplasticity in sensory neurons and spinal cord could contribute to the underlying pathobiology of chronic discogenic LBP. LEVEL OF EVIDENCE N/A.
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Duraku LS, Niehof SP, Misirli Y, Everaers M, Hoendervangers S, Holstege J, Boele HJJ, Koekkoek SKE, Smits ES, Selles RW, Walbeehm ET. Rotterdam Advanced Multiple Plate: a novel method to measure cold hyperalgesia and allodynia in freely behaving rodents. J Neurosci Methods 2013; 224:1-12. [PMID: 24365047 DOI: 10.1016/j.jneumeth.2013.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 12/10/2013] [Accepted: 12/12/2013] [Indexed: 12/17/2022]
Abstract
BACKGROUND To investigate the pathophysiology of temperature hypersensitivity in neuropathic pain rodent models, it is essential to be able to quantify the phenotype as objective as possible. Current temperature sensitivity measuring paradigms are performed during exposure to external factors, i.e. light, sound and smell, which modulate behavior significantly. In addition the present outcome measure for temperature hypersensitivity in rodents is the examination of the hind paw lift upon exposure to a certain temperature, which reflects more a reflex-flexion than an experience of pain. NEW METHOD Therefore the Rotterdam Advanced Multiple Plate (RAMP) was developed to assess cold hyperalgesia and allodynia objectively in freely behaving neuropathic pain rats, which measures the avoidance for certain temperatures and monitoring the location of the rat with an infrared camera while excluding external environmental influences such as light and sound. RESULTS Compared to sham rats, the spared nerve injury (SNI) rats demonstrated a higher preference for the comfortable plate (27 °C) when the other three plates were set at 5 °C, 14 °C, 17 °C and 19 °C. We were unable to detect heat hyperalgesia and allodynia with the RAMP. COMPARISON WITH EXISTING METHOD The paw withdrawal method displays similar results during cold hypersensitivity measurements as observed with the RAMP. The SNI group did display heat hypersensitivity during the paw withdrawal test. CONCLUSIONS The results indicate that the RAMP is able to quantify cold hyperalgesia and allodynia in neuropathic pain rats while resolves some of the problems of conventional temperature sensitivity measuring paradigms in rodents.
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Affiliation(s)
- Liron S Duraku
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, The Netherlands; Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Sjoerd P Niehof
- Pain Treatment Centre, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
| | - Yesim Misirli
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Marco Everaers
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Sieske Hoendervangers
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Joan Holstege
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Henk-Jan J Boele
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Sebastiaan K E Koekkoek
- Department of Neuroscience, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Ernst S Smits
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
| | - Ruud W Selles
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands; Department of Rehabilitation Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
| | - Erik T Walbeehm
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, University Medical Center Rotterdam, The Netherlands.
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Neuropeptide Y is analgesic in rats after plantar incision. Eur J Pharmacol 2012; 698:206-12. [PMID: 23123350 DOI: 10.1016/j.ejphar.2012.10.036] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 10/16/2012] [Accepted: 10/23/2012] [Indexed: 11/22/2022]
Abstract
Previous work has demonstrated that neuropeptide tyrosine (NPY), Y(1) receptor and Y(2) receptor are critical in modulation of pain after nerve injury. We hypothesized that NPY was important for nociception after surgical incision. As a model of postoperative pain, rats underwent a plantar incision in one hindpaw. Western blots were used to quantify changes in protein expression of NPY, Y(1) receptor and Y(2) receptor after incision in skin, muscle, and dorsal root ganglion (DRG). Pain-related behaviors were tested after incision in rats treated with intrathecal NPY, Y(1) receptor antagonist (BIBO3304--Chemical Name: N-[(1R)-1-[[[[4-[[(Aminocarbonyl)amino]methyl]phenyl]methyl]amino]carbonyl]-4-[(aminoiminomethyl)amino]butyl]-α-phenyl-benzeneacetamide ditrifluoroacetate), Y(2) receptor antagonist (BIIE0246--Chemical Name: N-[(1S)-4-[(Aminoiminomethyl)amino]-1-[[[2-(3,5-dioxo-1,2-diphenyl-1,2,4-triazolidin-4-yl)ethyl]amino]carbonyl]butyl]-1-[2-[4-(6,11-dihydro-6-oxo-5H-dibenz[b,e]azepin-11-yl)-1-piperazinyl]-2-oxoethyl]-cyclopentaneacetamide), combined NPY+antagonists, morphine, or vehicle. Pain behaviors were tested after incision in rats treated with locally applied intraplantar injections of NPY, Y(1) receptor and Y(2) receptor antagonists or vehicle. NPY protein expression was significantly downregulated in muscle for two days after incision. In contrast, Y(1) receptor and Y(2) receptor protein expression was upregulated in both skin and muscle. A single intrathecal injection of NPY reduced cumulative guarding pain scores, as did morphine. The intrathecal administration of Y(2) receptor antagonist also reduced pain scores; findings that were not observed when drugs were administered locally. Intrathecal Y(2) receptor antagonists and NPY improved mechanical threshold and heat withdrawal latency 2h after incision. Intrathecal administration of NPY and/or central blockade of Y(2) receptor attenuated pain behaviors early after incision (postoperative day (POD) 1-2). Y(1) receptor antagonist administration blocked the anti-hyperalgesic effect of NPY. Together these data suggest a role for spinal NPY in postoperative pain.
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Abstract
Dramatically up-regulated in the dorsal horn of the mammalian spinal cord following inflammation or nerve injury, neuropeptide Y (NPY) is poised to regulate the transmission of sensory signals. We found that doxycycline-induced conditional in vivo (Npy(tet/tet)) knockdown of NPY produced rapid, reversible, and repeatable increases in the intensity and duration of tactile and thermal hypersensitivity. Remarkably, when allowed to resolve for several weeks, behavioral hypersensitivity could be dramatically reinstated with NPY knockdown or intrathecal administration of Y1 or Y2 receptor antagonists. In addition, Y2 antagonism increased dorsal horn expression of Fos and phosphorylated form of extracellular signal-related kinase. Taken together, these data establish spinal NPY receptor systems as an endogenous braking mechanism that exerts a tonic, long-lasting, broad-spectrum inhibitory control of spinal nociceptive transmission, thus impeding the transition from acute to chronic pain. NPY and its receptors appear to be part of a mechanism whereby mammals naturally recover from the hyperalgesia associated with inflammation or nerve injury.
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Soignier RD, Taylor BK, Baiamonte BA, Lee FA, Paul D, Gould HJ. Measurement of CFA-induced hyperalgesia and morphine-induced analgesia in rats: dorsal vs plantar mechanical stimulation of the hindpaw. PAIN MEDICINE 2011; 12:451-8. [PMID: 21332938 DOI: 10.1111/j.1526-4637.2011.01066.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To compare the sensitivity of stimulating the plantar and dorsal hindpaw surfaces in the detection of mechanical allodynia and morphine analgesia. BACKGROUND Several approaches are used to assess nociceptive reactivity to mechanical stimulation in animal models of pain. Although certain techniques seem to be favored for studying specific nociceptive conditions, the differences between techniques have not been directly compared and characterized. We chose to compare methods employing stimulation applied to the dorsum of the paw with stimulation of the plantar surface to demonstrate the utility of each approach in determining baseline nociceptive thresholds, changes in those thresholds after injury, and analgesic efficacy. METHODS Withdrawal thresholds from mechanical stimulation applied to the dorsal and plantar surface of the hindpaw were measured in rats treated with morphine after receiving subcutaneous injections of complete Freund's adjuvant (CFA) using Semmes-Weinstein (S-W) monofilaments and electro von Frey (EVF) stimulation. RESULTS In contrast to stimulation of the dorsal surface, plantar hindpaw stimulation seldom elicited an aversive withdrawal response. Differences in withdrawal response from baseline were only detectable within the first 5 hours post-CFA and only with EVF stimulation. No significant differences in stimulation techniques were observed after the initial 5-hour window. Effective dose 50 (ED(50)) for analgesic efficacy was consistently lower using dorsal stimulation. CONCLUSIONS Stimulation of the plantar surface of the paw is superior for detecting small changes in paw sensitivity at very low stimulus intensities, whereas stimulation of the dorsal surface is superior for delineating baseline pain thresholds and for detecting robust analgesia. CLINICAL RELEVANCE Reliable and sensitive assessment of animal pain behaviors is critical to translational pain research. This study demonstrates the importance of using proper test protocols in animal studies and its implication in preclinical screening of potential analgesics.
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Affiliation(s)
- R Denis Soignier
- Department of Psychology, University of New Orleans, New Orleans, Louisiana, USA
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