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Wildner F, Neuhäusel TS, Klemz A, Kovács R, Ulmann L, Geiger JRP, Gerevich Z. Extracellular ATP inhibits excitatory synaptic input on parvalbumin positive interneurons and attenuates gamma oscillations via P2X4 receptors. Br J Pharmacol 2024; 181:1635-1653. [PMID: 38073073 DOI: 10.1111/bph.16298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 11/13/2023] [Accepted: 11/16/2023] [Indexed: 02/02/2024] Open
Abstract
BACKGROUND AND PURPOSE P2X4 receptors (P2X4R) are ligand gated cation channels that are activated by extracellular ATP released by neurons and glia. The receptors are widely expressed in the brain and have fractional calcium currents comparable with NMDA receptors. Although P2X4Rs have been reported to modulate synaptic transmission and plasticity, their involvement in shaping neuronal network activity remains to be elucidated. EXPERIMENTAL APPROACH We investigated the effects of P2X receptors at network and synaptic level using local field potential electrophysiology, whole cell patch clamp recordings and calcium imaging in fast spiking parvalbumin positive interneurons (PVINs) in rat and mouse hippocampal slices. The stable ATP analogue ATPγS, selective antagonists and P2X4R knockout mice were used. KEY RESULTS The P2XR agonist ATPγS reversibly decreased the power of gamma oscillations. This inhibition could be antagonized by the selective P2X4R antagonist PSB-12062 and was not observed in P2X4-/- mice. The phasic excitatory inputs of CA3 PVINs were one of the main regulators of the gamma power. Associational fibre compound excitatory postsynaptic currents (cEPSCs) in CA3 PVINs were inhibited by P2X4R activation. This effect was reversible, dependent on intracellular calcium and dynamin-dependent internalization of AMPA receptors. CONCLUSIONS AND IMPLICATIONS The results indicate that P2X4Rs are an important source of dendritic calcium in CA3 PVINs, thereby regulating excitatory synaptic inputs onto the cells and presumably the state of gamma oscillations in the hippocampus. P2X4Rs represent an effective target to modulate hippocampal network activity in pathophysiological conditions such as Alzheimer's disease and schizophrenia.
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Affiliation(s)
- Florian Wildner
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Tim S Neuhäusel
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Alexander Klemz
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Richard Kovács
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Lauriane Ulmann
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Jörg R P Geiger
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Zoltan Gerevich
- Institute of Neurophysiology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
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Qiu X, Yang Y, Da X, Wang Y, Chen Z, Xu C. Satellite glial cells in sensory ganglia play a wider role in chronic pain via multiple mechanisms. Neural Regen Res 2024; 19:1056-1063. [PMID: 37862208 PMCID: PMC10749601 DOI: 10.4103/1673-5374.382986] [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: 02/14/2023] [Revised: 05/26/2023] [Accepted: 07/10/2023] [Indexed: 10/22/2023] Open
Abstract
Satellite glial cells are unique glial cells that surround the cell body of primary sensory neurons. An increasing body of evidence suggests that in the presence of inflammation and nerve damage, a significant number of satellite glial cells become activated, thus triggering a series of functional changes. This suggests that satellite glial cells are closely related to the occurrence of chronic pain. In this review, we first summarize the morphological structure, molecular markers, and physiological functions of satellite glial cells. Then, we clarify the multiple key roles of satellite glial cells in chronic pain, including gap junction hemichannel Cx43, membrane channel Pannexin1, K channel subunit 4.1, ATP, purinergic P2 receptors, and a series of additional factors and their receptors, including tumor necrosis factor, glutamate, endothelin, and bradykinin. Finally, we propose that future research should focus on the specific sorting of satellite glial cells, and identify genomic differences between physiological and pathological conditions. This review provides an important perspective for clarifying mechanisms underlying the peripheral regulation of chronic pain and will facilitate the formulation of new treatment plans for chronic pain.
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Affiliation(s)
- Xiaoyun Qiu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Yuanzhi Yang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Xiaoli Da
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Yi Wang
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Zhong Chen
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
| | - Cenglin Xu
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang Province, China
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Fu GJ, Wang LD, Chi XS, Liang X, Wei JJ, Huang ZH, Shen W, Zhang YL. Research Progress on the Experimental Model and Underlying Mechanistic Studies of Tension-Type Headaches. Curr Pain Headache Rep 2024; 28:439-451. [PMID: 38502437 PMCID: PMC11126509 DOI: 10.1007/s11916-024-01238-2] [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] [Accepted: 03/07/2024] [Indexed: 03/21/2024]
Abstract
PURPOSE OF REVIEW Tension-type headaches (TTH) significantly diminish patients' quality of life and increase absenteeism, thereby imposing a substantial economic burden. Animal models are essential tools for studying disease mechanisms and drug development. However, until now, little focus has been placed on summarizing the animal models of TTH and associated mechanistic studies. This narrative review discusses the current animal models of TTH and related mechanistic studies to provide insights into the pathophysiological mechanisms of and treatments for TTH. RECENT FINDINGS The primary method for constructing an animal model of TTH involves injecting a solution of pain relievers, such as adenosine triphosphate, nerve growth factor, or a high concentration of salt solution, into the neck to initiate harmful cervical muscle responses. This model enables the examination of the interaction between peripheral muscles and central sensitization, which is crucial for understanding the pathophysiology of TTH. Mechanistic studies based on this model have investigated the effect of the P2X receptor antagonist, P2X7 receptor blockade, the P2Y1 receptor agonist 2-MESADP, P2Y1 receptor antagonist MRS2179, nitric oxide synthase inhibitors, and acetylsalicylic acid. Despite notable advancements, the current model of TTH has limitations, including surgical complexity and the inability to replicate chronic tension-type headache (CTTH). To gain a more comprehensive understanding and develop more effective treatment methods, future studies should focus on simplifying surgical procedures, examining other predisposing factors, and establishing a model for chronic TTH. This will offer a deeper insight into the pathophysiological mechanism of TTH and pave the way for improved treatment approaches.
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Affiliation(s)
- Guo-Jing Fu
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China
| | - Liu-Ding Wang
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China
| | - Xian-Su Chi
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China
| | - Xiao Liang
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China
| | - Jing-Jing Wei
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China
| | - Zhi-Hong Huang
- Yidu Central Hospital of Weifang, Weifang, 262,550, China
| | - Wei Shen
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China.
| | - Yun-Ling Zhang
- Xiyuan Hospital of China Academy of Chinese Medical Sciences, Beijing, 100,091, China.
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Salib AMN, Crane MJ, Lee SH, Wainger BJ, Jamieson AM, Lipscombe D. Interleukin-1α links peripheral Ca V2.2 channel activation to rapid adaptive increases in heat sensitivity in skin. Sci Rep 2024; 14:9051. [PMID: 38643253 PMCID: PMC11032389 DOI: 10.1038/s41598-024-59424-6] [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: 12/18/2023] [Accepted: 04/10/2024] [Indexed: 04/22/2024] Open
Abstract
Neurons have the unique capacity to adapt output in response to changes in their environment. Within seconds, sensory nerve endings can become hypersensitive to stimuli in response to potentially damaging events. The underlying behavioral response is well studied, but several of the key signaling molecules that mediate sensory hypersensitivity remain unknown. We previously discovered that peripheral voltage-gated CaV2.2 channels in nerve endings in skin are essential for the rapid, transient increase in sensitivity to heat, but not to mechanical stimuli, that accompanies intradermal capsaicin. Here we report that the cytokine interleukin-1α (IL-1α), an alarmin, is necessary and sufficient to trigger rapid heat and mechanical hypersensitivity in skin. Of 20 cytokines screened, only IL-1α was consistently detected in hind paw interstitial fluid in response to intradermal capsaicin and, similar to behavioral sensitivity to heat, IL-1α levels were also dependent on peripheral CaV2.2 channel activity. Neutralizing IL-1α in skin significantly reduced capsaicin-induced changes in hind paw sensitivity to radiant heat and mechanical stimulation. Intradermal IL-1α enhances behavioral responses to stimuli and, in culture, IL-1α enhances the responsiveness of Trpv1-expressing sensory neurons. Together, our data suggest that IL-1α is the key cytokine that underlies rapid and reversible neuroinflammatory responses in skin.
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Affiliation(s)
- Anne-Mary N Salib
- Department of Neuroscience, Carney Institute for Brain Science, Brown University, Providence, RI, 02912, USA
| | - Meredith J Crane
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912, USA
| | - Sang Hun Lee
- Department of Neurology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Brian J Wainger
- Department of Neurology, Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Amanda M Jamieson
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, 02912, USA
| | - Diane Lipscombe
- Department of Neuroscience, Carney Institute for Brain Science, Brown University, Providence, RI, 02912, USA.
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5
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Hiroshige T, Uemura KI, Nakamura KI, Igawa T. Insights on Platelet-Derived Growth Factor Receptor α-Positive Interstitial Cells in the Male Reproductive Tract. Int J Mol Sci 2024; 25:4128. [PMID: 38612936 PMCID: PMC11012365 DOI: 10.3390/ijms25074128] [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: 03/10/2024] [Revised: 03/31/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024] Open
Abstract
Male infertility is a significant factor in approximately half of all infertility cases and is marked by a decreased sperm count and motility. A decreased sperm count is caused by not only a decreased production of sperm but also decreased numbers successfully passing through the male reproductive tract. Smooth muscle movement may play an important role in sperm transport in the male reproductive tract; thus, understanding the mechanism of this movement is necessary to elucidate the cause of sperm transport disorder. Recent studies have highlighted the presence of platelet-derived growth factor receptor α (PDGFRα)-positive interstitial cells (PICs) in various smooth muscle organs. Although research is ongoing, PICs in the male reproductive tract may be involved in the regulation of smooth muscle movement, as they are in other smooth muscle organs. This review summarizes the findings to date on PICs in male reproductive organs. Further exploration of the structural, functional, and molecular characteristics of PICs could provide valuable insights into the pathogenesis of male infertility and potentially lead to new therapeutic approaches.
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Affiliation(s)
- Tasuku Hiroshige
- Department of Urology, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Kei-Ichiro Uemura
- Department of Urology, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Kei-Ichiro Nakamura
- Cognitive and Molecular Research Institute of Brain Diseases, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Tsukasa Igawa
- Department of Urology, Kurume University School of Medicine, Kurume 830-0011, Japan
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6
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Salib AMN, Crane MJ, Lee SH, Wainger BJ, Jamieson AM, Lipscombe D. Interleukin-1α links peripheral Ca V2.2 channel activation to rapid adaptive increases in heat sensitivity in skin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.17.572072. [PMID: 38585803 PMCID: PMC10996502 DOI: 10.1101/2023.12.17.572072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Neurons have the unique capacity to adapt output in response to changes in their environment. Within seconds, sensory nerve endings can become hypersensitive to stimuli in response to potentially damaging events. The underlying behavioral response is well studied, but several of the key signaling molecules that mediate sensory hypersensitivity remain unknown. We previously discovered that peripheral voltage-gated CaV2.2 channels in nerve endings in skin are essential for the rapid, transient increase in sensitivity to heat, but not to mechanical stimuli, that accompanies intradermal capsaicin. Here we report that the cytokine interleukin-1α (IL-1α), an alarmin, is necessary and sufficient to trigger rapid heat and mechanical hypersensitivity in skin. Of 20 cytokines screened, only IL-1α was consistently detected in hind paw interstitial fluid in response to intradermal capsaicin and, similar to behavioral sensitivity to heat, IL-1α levels were also dependent on peripheral CaV2.2 channel activity. Neutralizing IL-1α in skin significantly reduced capsaicin-induced changes in hind paw sensitivity to radiant heat and mechanical stimulation. Intradermal IL-1α enhances behavioral responses to stimuli and, in culture, IL-1α enhances the responsiveness of Trpv1-expressing sensory neurons. Together, our data suggest that IL-1α is the key cytokine that underlies rapid and reversible neuroinflammatory responses in skin.
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Affiliation(s)
- Anne-Mary N Salib
- Department of Neuroscience, Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
| | - Meredith J Crane
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Sang Hun Lee
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Brian J Wainger
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Amanda M Jamieson
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Diane Lipscombe
- Department of Neuroscience, Carney Institute for Brain Science, Brown University, Providence, RI 02912, USA
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7
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P2Y1 Receptor as a Catalyst of Brain Neurodegeneration. NEUROSCI 2022. [DOI: 10.3390/neurosci3040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Different brain disorders display distinctive etiologies and pathogenic mechanisms. However, they also share pathogenic events. One event systematically occurring in different brain disorders, both acute and chronic, is the increase of the extracellular ATP levels. Accordingly, several P2 (ATP/ADP) and P1 (adenosine) receptors, as well as the ectoenzymes involved in the extracellular catabolism of ATP, have been associated to different brain pathologies, either with a neuroprotective or neurodegenerative action. The P2Y1 receptor (P2Y1R) is one of the purinergic receptors associated to different brain diseases. It has a widespread regional, cellular, and subcellular distribution in the brain, it is capable of modulating synaptic function and neuronal activity, and it is particularly important in the control of astrocytic activity and in astrocyte–neuron communication. In diverse brain pathologies, there is growing evidence of a noxious gain-of-function of P2Y1R favoring neurodegeneration by promoting astrocyte hyperactivity, entraining Ca2+-waves, and inducing the release of glutamate by directly or indirectly recruiting microglia and/or by increasing the susceptibility of neurons to damage. Here, we review the current evidence on the involvement of P2Y1R in different acute and chronic neurodegenerative brain disorders and the underlying mechanisms.
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8
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Mirabelli E, Elkabes S. Neuropathic Pain in Multiple Sclerosis and Its Animal Models: Focus on Mechanisms, Knowledge Gaps and Future Directions. Front Neurol 2022; 12:793745. [PMID: 34975739 PMCID: PMC8716468 DOI: 10.3389/fneur.2021.793745] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/17/2021] [Indexed: 12/22/2022] Open
Abstract
Multiple sclerosis (MS) is a multifaceted, complex and chronic neurological disease that leads to motor, sensory and cognitive deficits. MS symptoms are unpredictable and exceedingly variable. Pain is a frequent symptom of MS and manifests as nociceptive or neuropathic pain, even at early disease stages. Neuropathic pain is one of the most debilitating symptoms that reduces quality of life and interferes with daily activities, particularly because conventional pharmacotherapies do not adequately alleviate neuropathic pain. Despite advances, the mechanisms underlying neuropathic pain in MS remain elusive. The majority of the studies investigating the pathophysiology of MS-associated neuropathic pain have been performed in animal models that replicate some of the clinical and neuropathological features of MS. Experimental autoimmune encephalomyelitis (EAE) is one of the best-characterized and most commonly used animal models of MS. As in the case of individuals with MS, rodents affected by EAE manifest increased sensitivity to pain which can be assessed by well-established assays. Investigations on EAE provided valuable insights into the pathophysiology of neuropathic pain. Nevertheless, additional investigations are warranted to better understand the events that lead to the onset and maintenance of neuropathic pain in order to identify targets that can facilitate the development of more effective therapeutic interventions. The goal of the present review is to provide an overview of several mechanisms implicated in neuropathic pain in EAE by summarizing published reports. We discuss current knowledge gaps and future research directions, especially based on information obtained by use of other animal models of neuropathic pain such as nerve injury.
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Affiliation(s)
- Ersilia Mirabelli
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States.,Department of Biology and Chemistry, School of Health Sciences, Liberty University, Lynchburg, VA, United States
| | - Stella Elkabes
- Reynolds Family Spine Laboratory, Department of Neurosurgery, New Jersey Medical School, Rutgers the State University of New Jersey, Newark, NJ, United States
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Minic Z, O’Leary DS, Reynolds CA. Purinergic receptor antagonism: A viable strategy for the management of autonomic dysreflexia? Auton Neurosci 2021; 230:102741. [PMID: 33220530 PMCID: PMC8855366 DOI: 10.1016/j.autneu.2020.102741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 11/17/2022]
Abstract
The purinergic receptor ligand, ATP, may participate in reflex induced vasoconstriction through sympathetic efferent and sensory afferent mechanisms. However, the role of the purinergic system in contributing to autonomic dysreflexia following spinal cord injury is unclear. The present study investigates the involvement of P2X receptors in contributing to pressor responses during autonomic dysreflexia. Twenty rats were subjected to spinal cord injury and 24 h later hemodynamic responses to colorectal distension were recorded. Animals were randomized to receive intravenous administration of the P2X receptor antagonist, NF023, or vehicle control. The data indicate that NF023 attenuates pressor responses to colorectal distension.
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Affiliation(s)
- Zeljka Minic
- Department of Emergency Medicine, Wayne State University School of Medicine, Detroit, MI, USA; Department of Physiology, Immunology and Pathophysiology, University of Rijeka Medical School, Rijeka, Croatia.
| | - Donal S. O’Leary
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Christian A. Reynolds
- Department of Emergency Medicine, Wayne State University School of Medicine, Detroit, Michigan, USA,Department of Biotechnology, University of Rijeka, Rijeka, Croatia
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Ceruti S. From astrocytes to satellite glial cells and back: A 25 year-long journey through the purinergic modulation of glial functions in pain and more. Biochem Pharmacol 2020; 187:114397. [PMID: 33382970 DOI: 10.1016/j.bcp.2020.114397] [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: 10/22/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 12/16/2022]
Abstract
Fundamental progresses have been made in pain research with a comprehensive understanding of the neuronal pathways which convey painful sensations from the periphery and viscera to the central nervous system and of the descending modulating pathways. Nevertheless, many patients still suffer from various painful conditions, which are often associated to other primary pathologies, and get no or poor relief from available painkillers. Thus, the interest of many researchers has concentrated on new and promising cellular targets and biochemical pathways. This is the case of glia cells, both in the peripheral and in the central nervous system, and of purinergic receptors. Starting from many intuitions and hypotheses raised by Prof. Geoffrey Burnstock, data have accumulated which clearly highlight the fundamental role exerted by several nucleotide and nucleoside receptors in the modulation of glial cell reaction to pain triggers and of their cross-talk with sensory neurons which significantly contributes to the transition from acute to chronic pain. The purinergic system has therefore become an appealing pharmacological target in pain research, also based on the quite unexpected discovery that purines are involved in ancient analgesic techniques such as acupuncture. A more in-depth understanding of the complex and intricated purine-orchestrated scenario in pain conditions will hopefully lead to the identification and clinical development of new and effective analgesics.
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Affiliation(s)
- Stefania Ceruti
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, via Balzaretti, 9, 20133 Milan, Italy.
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Deletion of the Gene Encoding the NMDA Receptor GluN1 Subunit in Schwann Cells Causes Ultrastructural Changes in Remak Bundles and Hypersensitivity in Pain Processing. J Neurosci 2020; 40:9121-9136. [PMID: 33051351 DOI: 10.1523/jneurosci.0663-20.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 09/24/2020] [Accepted: 10/04/2020] [Indexed: 12/19/2022] Open
Abstract
Abnormalities in interactions between sensory neurons and Schwann cells (SCs) may result in heightened pain processing and chronic pain states. We previously reported that SCs express the NMDA receptor (NMDA-R), which activates cell signaling in response to glutamate and specific protein ligands, such as tissue-type plasminogen activator. Herein, we genetically targeted grin1 encoding the essential GluN1 NMDA-R subunit, conditionally in SCs, to create a novel mouse model in which SCs are NMDA-R-deficient (GluN1- mice). These mice demonstrated increased sensitivity to light touch, pinprick, and thermal hyperalgesia in the absence of injury, without associated changes in motor function. Ultrastructural analysis of adult sciatic nerve in GluN1- mice revealed increases in the density of Aδ fibers and Remak bundles and a decrease in the density of Aβ fibers, without altered g-ratios. Abnormalities in adult Remak bundle ultrastructure were also present including aberrant C-fiber ensheathment, distances between axons, and increased poly-axonal pockets. Developmental and post radial sorting defects contributed to altered nerve fiber densities in adult. Uninjured sciatic nerves in GluN1- mice did not demonstrate an increase in neuroinflammatory infiltrates. Transcriptome profiling of dorsal root ganglia (DRGs) revealed 138 differentially regulated genes in GluN1- mice. One third of the regulated genes are known to be involved in pain processing, including sprr1a, npy, fgf3, atf3, and cckbr, which were significantly increased. The intraepidermal nerve fiber density (IENFD) was significantly decreased in the skin of GluN1- mice. Collectively, these findings demonstrate that SC NMDA-R is essential for normal PNS development and for preventing development of pain states.SIGNIFICANCE STATEMENT Chronic unremitting pain is a prevalent medical condition; however, the molecular mechanisms that underlie heightened pain processing remain incompletely understood. Emerging data suggest that abnormalities in Schwann cells (SCs) may cause neuropathic pain. We established a novel mouse model for small fiber neuropathy (SFN) in which grin1, the gene that encodes the NMDA receptor (NMDA-R) GluN1 subunit, is deleted in SCs. These mice demonstrate hypersensitivity in pain processing in the absence of nerve injury. Changes in the density of intraepidermal small fibers, the ultrastructure of Remak bundles, and the transcriptome of dorsal root ganglia (DRGs) provide possible explanations for the increase in pain processing. Our results support the hypothesis that abnormalities in communication between sensory nerve fibers and SCs may result in pain states.
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12
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Behroozi Z, Ramezani F, Janzadeh A, Rahimi B, Nasirinezhad F. Platelet-rich plasma in umbilical cord blood reduces neuropathic pain in spinal cord injury by altering the expression of ATP receptors. Physiol Behav 2020; 228:113186. [PMID: 32980385 DOI: 10.1016/j.physbeh.2020.113186] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 09/21/2020] [Accepted: 09/22/2020] [Indexed: 12/27/2022]
Abstract
BACKGROUND Neuropathic pain following injury or dysfunction of the peripheral or CNS is one of the most important medical challenges to treat. Humane platelet-rich plasma (HPRP), which is a rich source of growth factors, may be able to treat and reduce pain caused by spinal cord injury (SCI). In this study, the effect of HPRP on neuropathic pain caused by SCI was investigated. METHODS Sixty adult male Wistar rats were randomly divided into 6 groups: control, sham, SCI, vehicle (SCI+platelet-poor plasma), SCI+ PRP2day (injection 48 hrs after SCI) and SCI+PRP14day (injection 14 days after SCI). SCI was induced at the T12-T13 level. Behavioral tests were conducted weekly after injury for six weeks. Allodynia and hyperalgesia were assessed using acetone drops, plantar test and von Frey filament. Cavity size and the number of fibroblasts were determined by H&E stain, and the expression of mTOR, p-mTOR, P2×3R and P2Y4R were determined using the western blot technique. Data were analyzed using PRISM & SPSS software. RESULTS PRP injection showed a higher pain threshold in mechanical allodynia (p<0.0001), cold allodynia (p<0.0001) and thermal hyperalgesia (p<0.0001) than those in the spinal. Animals treated with PRP also reduced cavity size, fibroblast number, p-mTOR/mTOR ratio, and P2×3R expression, and increased P2Y4R expression. The difference between the two groups was not statistically significant. CONCLUSIONS The results showed that PRP reduced SCI-induced allodynia and hyperalgesia by regulating ATP signaling. Using HPRP can open a new window in the treatment of pain caused by damage to the nervous system.
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Affiliation(s)
- Zahra Behroozi
- Student research committee, Iran University of Medical Sciences, Tehran, Iran; Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Fatemeh Ramezani
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Atousa Janzadeh
- Radiation Biology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Behnaz Rahimi
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Farinaz Nasirinezhad
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
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He JR, Yu SG, Tang Y, Illes P. Purinergic signaling as a basis of acupuncture-induced analgesia. Purinergic Signal 2020; 16:297-304. [PMID: 32577957 PMCID: PMC7524941 DOI: 10.1007/s11302-020-09708-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
This review summarizes experimental evidence indicating that purinergic mechanisms are causally involved in acupuncture (AP)-induced analgesia. Electroacupuncture (EAP) and manual AP release at pain-relevant acupoints ATP which may activate purinergic P2X receptors (Rs) especially of the P2X3 type situated at local sensory nerve endings (peripheral terminals of dorsal root ganglion [DRG] neurons); the central processes of these neurons are thought to inhibit via collaterals of ascending dorsal horn spinal cord neurons, pain-relevant pathways projecting to higher centers of the brain. In addition, during AP/EAP non-neuronal P2X4 and/or P2X7Rs localized at microglial cells of the CNS become activated at the spinal or supraspinal levels. In consequence, these microglia secrete bioactive compounds such as growth factors, cytokines, chemokines, reactive oxygen, and nitrogen species, which modulate the ascending neuronal pathways conducting painful stimuli. Alternatively, ATP released at acupoints by AP/EAP may be enzymatically degraded to adenosine, stimulating in loco presynaptic A1Rs exerting an inhibitory influence on the primary afferent fibers (the above mentioned pain-sensing peripheral terminals of DRG neurons) which thereby fail to conduct action potentials to the spinal cord dorsal horn. The net effect of the stimulation of P2X3, P2X4, P2X7, and A1Rs by the AP/EAP-induced release of ATP/adenosine at certain acupoints will be analgesia.
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Affiliation(s)
- Jin-Rong He
- International Collaborative Centre on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China
| | - Shu-Guang Yu
- International Collaborative Centre on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.,Acupuncture & Chronobiology Key Laboratory of Sichuan Province, Chengdu, 610075, China
| | - Yong Tang
- International Collaborative Centre on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.,Acupuncture & Chronobiology Key Laboratory of Sichuan Province, Chengdu, 610075, China
| | - Peter Illes
- International Collaborative Centre on Big Science Plan for Purine Signalling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China. .,Rudolf Boehm Institute for Pharmacology and Toxicology, University of Leipzig, 04107, Leipzig, Germany.
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14
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Nociceptor Signalling through ion Channel Regulation via GPCRs. Int J Mol Sci 2019; 20:ijms20102488. [PMID: 31137507 PMCID: PMC6566991 DOI: 10.3390/ijms20102488] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 12/23/2022] Open
Abstract
The prime task of nociceptors is the transformation of noxious stimuli into action potentials that are propagated along the neurites of nociceptive neurons from the periphery to the spinal cord. This function of nociceptors relies on the coordinated operation of a variety of ion channels. In this review, we summarize how members of nine different families of ion channels expressed in sensory neurons contribute to nociception. Furthermore, data on 35 different types of G protein coupled receptors are presented, activation of which controls the gating of the aforementioned ion channels. These receptors are not only targeted by more than 20 separate endogenous modulators, but can also be affected by pharmacotherapeutic agents. Thereby, this review provides information on how ion channel modulation via G protein coupled receptors in nociceptors can be exploited to provide improved analgesic therapy.
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15
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Alves M, Beamer E, Engel T. The Metabotropic Purinergic P2Y Receptor Family as Novel Drug Target in Epilepsy. Front Pharmacol 2018; 9:193. [PMID: 29563872 PMCID: PMC5851315 DOI: 10.3389/fphar.2018.00193] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 02/20/2018] [Indexed: 12/21/2022] Open
Abstract
Epilepsy encompasses a heterogeneous group of neurological syndromes which are characterized by recurrent seizures affecting over 60 million people worldwide. Current anti-epileptic drugs (AEDs) are mainly designed to target ion channels and/or GABA or glutamate receptors. Despite recent advances in drug development, however, pharmacoresistance in epilepsy remains as high as 30%, suggesting the need for the development of new AEDs with a non-classical mechanism of action. Neuroinflammation is increasingly recognized as one of the key players in seizure generation and in the maintenance of the epileptic phenotype. Consequently, targeting signaling molecules involved in inflammatory processes may represent new avenues to improve treatment in epilepsy. Nucleotides such as adenosine-5′-triphosphate (ATP) and uridine-5′-triphosphate (UTP) are released in the brain into the extracellular space during pathological conditions such as increased neuronal firing or cell death. Once released, these nucleotides bind to and activate specific purinergic receptors termed P2 receptors where they mediate the release of gliotransmitters and drive neuronal hyperexcitation and neuroinflammatory processes. This includes the fast acting ionotropic P2X channels and slower-acting G-protein-coupled P2Y receptors. While the expression and function of P2X receptors has been well-established in experimental models of epilepsy, emerging evidence is now also suggesting a prominent role for the P2Y receptor subfamily in seizure generation and the maintenance of epilepsy. In this review we discuss data supporting a role for the P2Y receptor family in epilepsy and the most recent finding demonstrating their involvement during seizure-induced pathology and in epilepsy.
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Affiliation(s)
- Mariana Alves
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Edward Beamer
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tobias Engel
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
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16
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Glutamate-induced and NMDA receptor-mediated neurodegeneration entails P2Y1 receptor activation. Cell Death Dis 2018; 9:297. [PMID: 29463792 PMCID: PMC5833818 DOI: 10.1038/s41419-018-0351-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/28/2017] [Accepted: 01/24/2018] [Indexed: 12/27/2022]
Abstract
Despite the characteristic etiologies and phenotypes, different brain disorders rely on common pathogenic events. Glutamate-induced neurotoxicity is a pathogenic event shared by different brain disorders. Another event occurring in different brain pathological conditions is the increase of the extracellular ATP levels, which is now recognized as a danger and harmful signal in the brain, as heralded by the ability of P2 receptors (P2Rs) to affect a wide range of brain disorders. Yet, how ATP and P2R contribute to neurodegeneration remains poorly defined. For that purpose, we now examined the contribution of extracellular ATP and P2Rs to glutamate-induced neurodegeneration. We found both in vitro and in vivo that ATP/ADP through the activation of P2Y1R contributes to glutamate-induced neuronal death in the rat hippocampus. We found in cultured rat hippocampal neurons that the exposure to glutamate (100 µM) for 30 min triggers a sustained increase of extracellular ATP levels, which contributes to NMDA receptor (NMDAR)-mediated hippocampal neuronal death through the activation of P2Y1R. We also determined that P2Y1R is involved in excitotoxicity in vivo as the blockade of P2Y1R significantly attenuated rat hippocampal neuronal death upon the systemic administration of kainic acid or upon the intrahippocampal injection of quinolinic acid. This contribution of P2Y1R fades with increasing intensity of excitotoxic conditions, which indicates that P2Y1R is not contributing directly to neurodegeneration, rather behaving as a catalyst decreasing the threshold from which glutamate becomes neurotoxic. Moreover, we unraveled that such excitotoxicity process began with an early synaptotoxicity that was also prevented/attenuated by the antagonism of P2Y1R, both in vitro and in vivo. This should rely on the observed glutamate-induced calpain-mediated axonal cytoskeleton damage, most likely favored by a P2Y1R-driven increase of NMDAR-mediated Ca2+ entry selectively in axons. This may constitute a degenerative mechanism shared by different brain diseases, particularly relevant at initial pathogenic stages.
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17
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Gao Y, Manzoor N, Kaltenbach JA. Evidence of activity-dependent plasticity in the dorsal cochlear nucleus, in vivo, induced by brief sound exposure. Hear Res 2016; 341:31-42. [PMID: 27490001 DOI: 10.1016/j.heares.2016.07.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 06/27/2016] [Accepted: 07/24/2016] [Indexed: 10/21/2022]
Abstract
The purpose of the present study was to investigate the immediate effects of acute exposure to intense sound on spontaneous and stimulus-driven activity in the dorsal cochlear nucleus (DCN). We examined the levels of multi- and single-unit spontaneous activity before and immediately following brief exposure (2 min) to tones at levels of either 109 or 85 dB SPL. Exposure frequency was selected to either correspond to the units' best frequency (BF) or fall within the borders of its inhibitory side band. The results demonstrate that these exposure conditions caused significant alterations in spontaneous activity and responses to BF tones. The induced changes have a fast onset (minutes) and are persistent for durations of at least 20 min. The directions of the change were found to depend on the frequency of exposure relative to BF. Transient decreases followed by more sustained increases in spontaneous activity were induced when the exposure frequency was at or near the units' BF, while sustained decreases of activity resulted when the exposure frequency fell inside the inhibitory side band. Follow-up studies at the single unit level revealed that the observed activity changes were found on unit types having properties which have previously been found to represent fusiform cells. The changes in spontaneous activity occurred despite only minor changes in response thresholds. Noteworthy changes also occurred in the strength of responses to BF tones, although these changes tended to be in the direction opposite those of the spontaneous rate changes. We discuss the possible role of activity-dependent plasticity as a mechanism underlying the rapid emergence of increased spontaneous activity after tone exposure and suggest that these changes may represent a neural correlate of acute noise-induced tinnitus.
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Affiliation(s)
- Y Gao
- Department of Neurosciences, Lerner Research Institute, Head and Neck Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - N Manzoor
- Department of Neurosciences, Lerner Research Institute, Head and Neck Institute, The Cleveland Clinic, Cleveland, OH, USA
| | - J A Kaltenbach
- Department of Neurosciences, Lerner Research Institute, Head and Neck Institute, The Cleveland Clinic, Cleveland, OH, USA.
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18
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Zhang PP, Zhang G, Zhou W, Weng SJ, Yang XL, Zhong YM. Signaling mechanism for modulation by ATP of glycine receptors on rat retinal ganglion cells. Sci Rep 2016; 6:28938. [PMID: 27357477 PMCID: PMC4928062 DOI: 10.1038/srep28938] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 06/13/2016] [Indexed: 12/30/2022] Open
Abstract
ATP modulates voltage- and ligand-gated channels in the CNS via the activation of ionotropic P2X and metabotropic P2Y receptors. While P2Y receptors are expressed in retinal neurons, the function of these receptors in the retina is largely unknown. Using whole-cell patch-clamp techniques in rat retinal slice preparations, we demonstrated that ATP suppressed glycine receptor-mediated currents of OFF type ganglion cells (OFF-GCs) dose-dependently, and the effect was in part mediated by P2Y1 and P2Y11, but not by P2X. The ATP effect was abolished by intracellular dialysis of a Gq/11 protein inhibitor and phosphatidylinositol (PI)-phospholipase C (PLC) inhibitor, but not phosphatidylcholine (PC)-PLC inhibitor. The ATP effect was accompanied by an increase in [Ca(2+)]i through the IP3-sensitive pathway and was blocked by intracellular Ca(2+)-free solution. Furthermore, the ATP effect was eliminated in the presence of PKC inhibitors. Neither PKA nor PKG system was involved. These results suggest that the ATP-induced suppression may be mediated by a distinct Gq/11/PI-PLC/IP3/Ca(2+)/PKC signaling pathway, following the activation of P2Y1,11 and other P2Y subtypes. Consistently, ATP suppressed glycine receptor-mediated light-evoked inhibitory postsynaptic currents of OFF-GCs. These results suggest that ATP may modify the ON-to-OFF crossover inhibition, thus changing action potential patterns of OFF-GCs.
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Affiliation(s)
- Ping-Ping Zhang
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Gong Zhang
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Wei Zhou
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Shi-Jun Weng
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Xiong-Li Yang
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - Yong-Mei Zhong
- Institutes of Brain Science, State Key Laboratory of Medical Neurobiology and Collaborative Innovation Center for Brain Science, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
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19
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Tang Y, Yin HY, Rubini P, Illes P. Acupuncture-Induced Analgesia: A Neurobiological Basis in Purinergic Signaling. Neuroscientist 2016; 22:563-578. [PMID: 27343858 DOI: 10.1177/1073858416654453] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Chronic pain is a debilitating and rather common health problem. The present shortage in analgesic drugs with a favorable spectrum but without remarkable side effects furthered the search for alternative therapeutic manipulations. Increasing evidence from both basic and clinical research on acupuncture, a main alternative therapy of traditional Chinese medicine, suggests that chronic pain is sensitive to acupuncture procedures. Clarification of the underlying mechanisms is a challenge of great theoretical and practical significance. The seminal hypothesis of Geoffrey Burnstock and the astounding findings of Maiken Nedergaard on the involvement of purinergic signaling in the beneficial effects of acupuncture fertilized the field and led to an intensification of research on acupurines. In this review, we will summarize the state-of-the-art situation and try to forecast how the field is likely to develop in the future.
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Affiliation(s)
- Yong Tang
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Hai-Yan Yin
- Acupuncture and Tuina School, Chengdu University of Traditional Chinese Medicine, Chengdu, China
| | - Patrizia Rubini
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
| | - Peter Illes
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, Leipzig, Germany
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20
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Membrane coordination of receptors and channels mediating the inhibition of neuronal ion currents by ADP. Purinergic Signal 2016; 12:497-507. [PMID: 27172914 PMCID: PMC5023631 DOI: 10.1007/s11302-016-9516-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 05/02/2016] [Indexed: 12/29/2022] Open
Abstract
ADP and other nucleotides control ion currents in the nervous system via various P2Y receptors. In this respect, Cav2 and Kv7 channels have been investigated most frequently. The fine tuning of neuronal ion channel gating via G protein coupled receptors frequently relies on the formation of higher order protein complexes that are organized by scaffolding proteins and harbor receptors and channels together with interposed signaling components. However, ion channel complexes containing P2Y receptors have not been described. Therefore, the regulation of Cav2.2 and Kv7.2/7.3 channels via P2Y1 and P2Y12 receptors and the coordination of these ion channels and receptors in the plasma membranes of tsA 201 cells have been investigated here. ADP inhibited currents through Cav2.2 channels via both P2Y1 and P2Y12 receptors with phospholipase C and pertussis toxin-sensitive G proteins being involved, respectively. The nucleotide controlled the gating of Kv7 channels only via P2Y1 and phospholipase C. In fluorescence energy transfer assays using conventional as well as total internal reflection (TIRF) microscopy, both P2Y1 and P2Y12 receptors were found juxtaposed to Cav2.2 channels, but only P2Y1, and not P2Y12, was in close proximity to Kv7 channels. Using fluorescence recovery after photobleaching in TIRF microscopy, evidence for a physical interaction was obtained for the pair P2Y12/Cav2.2, but not for any other receptor/channel combination. These results reveal a membrane juxtaposition of P2Y receptors and ion channels in parallel with the control of neuronal ion currents by ADP. This juxtaposition may even result in apparent physical interactions between receptors and channels.
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21
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Rohacs T. Phosphoinositide signaling in somatosensory neurons. Adv Biol Regul 2016; 61:2-16. [PMID: 26724974 PMCID: PMC4884561 DOI: 10.1016/j.jbior.2015.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/06/2015] [Accepted: 11/07/2015] [Indexed: 02/03/2023]
Abstract
Somatosensory neurons of the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are responsible for detecting thermal and tactile stimuli. They are also the primary neurons mediating pain and itch. A large number of cell surface receptors in these neurons couple to phospholipase C (PLC) enzymes leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the generation of downstream signaling molecules. These neurons also express many different ion channels, several of which are regulated by phosphoinositides. This review will summarize the knowledge on phosphoinositide signaling in DRG neurons, with special focus on effects on sensory and other ion channels.
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Affiliation(s)
- Tibor Rohacs
- Rutgers, New Jersey Medical School, Newark, NJ, USA.
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22
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P2Y Receptors in Synaptic Transmission and Plasticity: Therapeutic Potential in Cognitive Dysfunction. Neural Plast 2016; 2016:1207393. [PMID: 27069691 PMCID: PMC4812485 DOI: 10.1155/2016/1207393] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/10/2016] [Indexed: 01/02/2023] Open
Abstract
ATP released from neurons and astrocytes during neuronal activity or under pathophysiological circumstances is able to influence information flow in neuronal circuits by activation of ionotropic P2X and metabotropic P2Y receptors and subsequent modulation of cellular excitability, synaptic strength, and plasticity. In the present paper we review cellular and network effects of P2Y receptors in the brain. We show that P2Y receptors inhibit the release of neurotransmitters, modulate voltage- and ligand-gated ion channels, and differentially influence the induction of synaptic plasticity in the prefrontal cortex, hippocampus, and cerebellum. The findings discussed here may explain how P2Y1 receptor activation during brain injury, hypoxia, inflammation, schizophrenia, or Alzheimer's disease leads to an impairment of cognitive processes. Hence, it is suggested that the blockade of P2Y1 receptors may have therapeutic potential against cognitive disturbances in these states.
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23
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Zhu H, Yu Y, Zheng L, Wang L, Li C, Yu J, Wei J, Wang C, Zhang J, Xu S, Wei X, Cui W, Wang Q, Chen X. Chronic inflammatory pain upregulates expression of P2Y2 receptor in small-diameter sensory neurons. Metab Brain Dis 2015; 30:1349-58. [PMID: 26062804 DOI: 10.1007/s11011-015-9695-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 06/01/2015] [Indexed: 11/28/2022]
Abstract
Roles of ionotropic purinergic (P2X) receptors in chronic pain have been intensively investigated. However, the contribution of metabotropic purinergic (P2Y) receptors to pathological pain is controversial. In the present study, using single cell RT-PCR (reverse transcription-polymerase chain reaction) and single cell nested-PCR techniques, we examined the expression of P2X(2), P2X(3), P2Y(1) and P2Y(2) mRNA transcripts in retrogradely labeled cutaneous sensory neurons from mouse lumber dorsal root ganglia (DRGs) following peripheral inflammation. The percentage of cutaneous sensory neurons expressing P2Y(2) mRNA transcripts increased after complete Freund's adjuvant (CFA) treatment. Particularly, the P2Y(2) mRNA transcripts were more frequently detected in small-diameter cutaneous neurons from CFA-treated mice than those from control mice. Coexpression of P2Y(2) and P2X (P2X(2) or P2X(3)) mRNAs was more frequently observed in cutaneous sensory neurons from CFA-treated mice relative to controls. Pain behavioral tests showed that the blockade of P2Y receptors by suramin attenuated mechanical allodynia evoked either by CFA or uridine triphosphate (UTP), an endogenous P2Y(2) and P2Y(4) agonist. These results suggest that chronic inflammatory pain enhances expression of P2Y(2) receptor in peripheral sensory neurons that innervate the injured tissue and the activation of P2Y receptors contributes to mechanical allodynia following inflammation.
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MESH Headings
- Animals
- Arthritis, Experimental/metabolism
- Arthritis, Experimental/psychology
- Behavior, Animal
- Chronic Pain/etiology
- Chronic Pain/metabolism
- Chronic Pain/psychology
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Hyperalgesia/chemically induced
- Hyperalgesia/metabolism
- Hyperalgesia/psychology
- Inflammation/complications
- Inflammation/metabolism
- Inflammation/psychology
- Mice
- Mice, Inbred ICR
- Nociception
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Purinergic P2Y/biosynthesis
- Receptors, Purinergic P2Y/genetics
- Receptors, Purinergic P2Y2/biosynthesis
- Receptors, Purinergic P2Y2/genetics
- Sensory Receptor Cells/metabolism
- Sensory Receptor Cells/pathology
- Skin/innervation
- Up-Regulation
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Affiliation(s)
- Huiqin Zhu
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Yi Yu
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Lingyan Zheng
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Lu Wang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Chenli Li
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Jiangyuan Yu
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Jing Wei
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Chuang Wang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Junfang Zhang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Shujun Xu
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Xiaofei Wei
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Wei Cui
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Qinwen Wang
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China
| | - Xiaowei Chen
- Ningbo Key Laboratory of Behavioral Neuroscience, Zhejiang Provincial Key Laboratory of Pathophysiology, School of Medicine, Ningbo University, Ningbo, 315211, China.
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24
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Abstract
There is a brief introductory summary of purinergic signaling involving ATP storage, release, and ectoenzymatic breakdown, and the current classification of receptor subtypes for purines and pyrimidines. The review then describes purinergic mechanosensory transduction involved in visceral, cutaneous, and musculoskeletal nociception and on the roles played by receptor subtypes in neuropathic and inflammatory pain. Multiple purinoceptor subtypes are involved in pain pathways both as an initiator and modulator. Activation of homomeric P2X3 receptors contributes to acute nociception and activation of heteromeric P2X2/3 receptors appears to modulate longer-lasting nociceptive sensitivity associated with nerve injury or chronic inflammation. In neuropathic pain activation of P2X4, P2X7, and P2Y12 receptors on microglia may serve to maintain nociceptive sensitivity through complex neural-glial cell interactions and antagonists to these receptors reduce neuropathic pain. Potential therapeutic approaches involving purinergic mechanisms will be discussed.
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25
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Niederberger E, Kuner R, Geißlinger G. [Pharmacological aspects of pain research in Germany]. Schmerz 2015; 29:531-8. [PMID: 26294077 DOI: 10.1007/s00482-015-0042-0] [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] [Indexed: 11/25/2022]
Abstract
In spite of several approved analgesics, the therapy of pain still constitutes a challenge due to the fact that the drugs do not exert sufficient efficacy or are associated with severe side effects. Therefore, the development of new and improved painkillers is still of great importance. A number of highly qualified scientists in Germany are investigating signal transduction pathways in pain, effectivity of new drugs and the so far incompletely investigated mechanisms of well-known analgesics in preclinical and clinical studies. The highlights of pharmacological pain research in Germany are summarized in this article.
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Affiliation(s)
- E Niederberger
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Deutschland
| | - R Kuner
- Pharmakologisches Institut, Universität Heidelberg, Im Neuenheimer Feld 584, 69120, Heidelberg, Deutschland
| | - G Geißlinger
- pharmazentrum frankfurt/ZAFES, Institut für Klinische Pharmakologie, Klinikum der Goethe-Universität Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt am Main, Deutschland.
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26
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Rodrigues RJ, Tomé AR, Cunha RA. ATP as a multi-target danger signal in the brain. Front Neurosci 2015; 9:148. [PMID: 25972780 PMCID: PMC4412015 DOI: 10.3389/fnins.2015.00148] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/10/2015] [Indexed: 12/13/2022] Open
Abstract
ATP is released in an activity-dependent manner from different cell types in the brain, fulfilling different roles as a neurotransmitter, neuromodulator, in astrocyte-to-neuron communication, propagating astrocytic responses and formatting microglia responses. This involves the activation of different ATP P2 receptors (P2R) as well as adenosine receptors upon extracellular ATP catabolism by ecto-nucleotidases. Notably, brain noxious stimuli trigger a sustained increase of extracellular ATP, which plays a key role as danger signal in the brain. This involves a combined action of extracellular ATP in different cell types, namely increasing the susceptibility of neurons to damage, promoting astrogliosis and recruiting and formatting microglia to mount neuroinflammatory responses. Such actions involve the activation of different receptors, as heralded by neuroprotective effects resulting from blockade mainly of P2X7R, P2Y1R and adenosine A2A receptors (A2AR), which hierarchy, cooperation and/or redundancy is still not resolved. These pleiotropic functions of ATP as a danger signal in brain damage prompt a therapeutic interest to multi-target different purinergic receptors to provide maximal opportunities for neuroprotection.
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Affiliation(s)
- Ricardo J Rodrigues
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Institute for Interdisciplinary Research, University of Coimbra Coimbra, Portugal
| | - Angelo R Tomé
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra Coimbra, Portugal
| | - Rodrigo A Cunha
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra Coimbra, Portugal ; Faculty of Medicine, University of Coimbra Coimbra, Portugal
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Magni G, Merli D, Verderio C, Abbracchio MP, Ceruti S. P2Y2 receptor antagonists as anti-allodynic agents in acute and sub-chronic trigeminal sensitization: role of satellite glial cells. Glia 2015; 63:1256-69. [PMID: 25779655 DOI: 10.1002/glia.22819] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/28/2015] [Accepted: 02/27/2015] [Indexed: 12/18/2022]
Abstract
Trigeminal (TG) pain often lacks a satisfactory pharmacological control. A better understanding of the molecular cross-talk between TG neurons and surrounding satellite glial cells (SGCs) could help identifying innovative targets for the development of more effective analgesics. We have previously demonstrated that neuronal pro-algogenic mediators upregulate G protein-coupled nucleotide P2Y receptors (P2YRs) expressed by TG SGCs in vitro. Here, we have identified the specific P2YR subtypes involved (i.e., the ADP-sensitive P2Y1 R and the UTP-responsive P2Y2 R subtypes), and demonstrated the contribution of neuron-derived prostaglandins to their upregulation. Next, we have translated these data to an in vivo model of TG pain (namely, rats injected with Complete Freund's adjuvant in the temporomandibular joint), by demonstrating activation of SGCs and upregulation of P2Y1 R and P2Y2 R in the ipsi-lateral TG. To unequivocally link P2YRs to the development of facial allodynia, we treated animals with various purinergic antagonists. The selective P2Y2 R antagonist AR-C118925 completely inhibited SGCs activation, exerted a potent anti-allodynic effect that lasted over time, and was still effective when administration was started 6-days post induction of allodynia, i.e. under subchronic pain conditions. Conversely, the selective P2Y1 R antagonist MRS2179 was completely ineffective. Moreover, similarly to the anti-inflammatory drug acetylsalicylic acid and the known anti-migraine agent sumatriptan, the P2X/P2Y nonselective antagonist PPADS was only partially effective, and completely lost its activity under sub-chronic conditions. Taken together, our results highlight glial P2Y2 Rs as potential "druggable" targets for the successful management of TG-related pain.
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Affiliation(s)
- Giulia Magni
- Laboratory of Molecular and Cellular Pharmacology of Purinergic Transmission, Department of Pharmacological and Biomolecular Sciences, Università Degli Studi Di Milano, via Balzaretti, 9, Milan, Italy; Department of Drug Discovery and Development, Italian Institute of Technology (IIT), via Morego, 30, Genoa, Italy
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Choi IS, Cho JH, Lee MG, Jang IS. Enzymatic conversion of ATP to adenosine contributes to ATP-induced inhibition of glutamate release in rat medullary dorsal horn neurons. Neuropharmacology 2015; 93:94-102. [PMID: 25656480 DOI: 10.1016/j.neuropharm.2015.01.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 10/24/2022]
Abstract
Purine nucleotides, such as ATP and ADP, activate ionotropic P2X and metabotropic P2Y receptors to regulate neurotransmitter release in the peripheral as well as central nervous system. Here we report another type of ATP-induced presynaptic modulation of glutamate release in rat medullary dorsal horn neurons. Glutamatergic excitatory postsynaptic currents (EPSCs) induced by electrical stimulation of trigeminal tract were recorded from horizontal brain stem slices using a whole-cell patch clamp technique. ATP decreased the amplitude of glutamatergic EPSCs in a reversible and concentration dependent manner and increased the paired-pulse ratio. In addition, ATP reduced the frequency of miniature EPSCs without affecting the current amplitude, suggesting that ATP acts presynaptically to reduce the probability of glutamate release. The ATP-induced decrease in glutamatergic EPSCs was not affected by P2X and P2Y receptor antagonists, but was completely blocked by DPCPX, a selective adenosine A1 receptor antagonist. The ATP-induced decrease in glutamatergic EPSCs was also inhibited by an inhibitor of tissue nonspecific alkaline phosphatase but not by inhibitors of other enzymes such as ecto-nucleoside triphosphate diphosphohydrolases and ecto-5'-nucleotidases. The results suggest that exogenously applied purine nucleotides are rapidly converted to adenosine by specific enzymes, and subsequently act on presynaptic A1 receptors to inhibit glutamate release from primary afferent terminals. This type of modulation mediated by purine nucleotides may play an important role in regulating nociceptive transmission from orofacial tissues.
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Affiliation(s)
- In-Sun Choi
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea
| | - Jin-Hwa Cho
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea
| | - Maan-Gee Lee
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu 700-412, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu 700-412, Republic of Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 700-412, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu 700-412, Republic of Korea.
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29
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Barragán-Iglesias P, Mendoza-Garcés L, Pineda-Farias JB, Solano-Olivares V, Rodríguez-Silverio J, Flores-Murrieta FJ, Granados-Soto V, Rocha-González HI. Participation of peripheral P2Y1, P2Y6 and P2Y11 receptors in formalin-induced inflammatory pain in rats. Pharmacol Biochem Behav 2014; 128:23-32. [PMID: 25449358 DOI: 10.1016/j.pbb.2014.11.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 10/21/2014] [Accepted: 11/01/2014] [Indexed: 12/19/2022]
Abstract
Metabotropic P2Y receptors subfamily consists of eight functional mammalian receptors. Specifically, P2Y1, P2Y6 and P2Y11 receptors have been described in the sensory nervous system, but their participation, at peripheral level, in behavioral pain models is scarcely understood. This study assessed the role of peripheral P2Y1, P2Y6 and P2Y11 receptors in formalin-induced inflammatory pain. Ipsilateral, but not contralateral peripheral pre-treatment with the endogenous P2Y1 (ADP, 100-1000nmol/paw), P2Y6 (UDP, 180-300nmol/paw) and P2Y11 (ATP, 100-1000nmol/paw), or selective P2Y1 (MRS2365, 0.1-10nmol/paw), P2Y6 (PSB0474, 0.1-0.10pmol/paw) and P2Y11 (NF546, 0.3-3nmol/paw) receptor agonists increased 0.5% formalin-induced flinching behavior. Concordantly, peripheral pre-treatment with the selective P2Y1 (MRS2500, 0.01-10pmol/paw), P2Y6 (MRS2578, 3-30nmol/paw) and P2Y11 (NF340, 1-10nmol/paw) receptor antagonists significantly decreased 1% formalin-induced flinching behavior. Furthermore, the pronociceptive effect of ADP (100nmol/paw) or MRS2365 (10nmol/paw), UDP (300nmol/paw) or PSB0474 (10pmol/paw) and ATP (1000nmol/paw) or NF546 (3nmol/paw) was blocked by the selective P2Y1 (MRS2500, 0.01nmol/paw), P2Y6 (MRS2578, 3nmol/paw), and P2Y11 (NF340, 1nmol/paw) receptor antagonists, respectively. Western blot analysis confirmed the presence of P2Y1 (66kDa), P2Y6 (36kDa) and P2Y11 (75kDa) receptors in dorsal root ganglia (DRG) and sciatic nerve. Results suggest that peripheral activation of P2Y1, P2Y6 and P2Y11 receptors plays a pronociceptive role in formalin-induced pain.
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Affiliation(s)
- Paulino Barragán-Iglesias
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav), Sede Sur. Calzada de los Tenorios 235, Col. Granjas Coapa, 14330 México, D.F., Mexico.
| | - Luis Mendoza-Garcés
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Col. Casco de Santo Tomas, Miguel Hidalgo, 11340 México, D.F., Mexico.
| | - Jorge Baruch Pineda-Farias
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav), Sede Sur. Calzada de los Tenorios 235, Col. Granjas Coapa, 14330 México, D.F., Mexico.
| | - Verónica Solano-Olivares
- Unidad de Investigación en Farmacología, Instituto Nacional de Enfermedades Respiratorias, Ismael Cosio Villegas, Secretaría de Salud, Calzada de Tlalpan 4502, Col. Sección XVI, Tlalpan, 14080 México, D.F., Mexico.
| | - Juan Rodríguez-Silverio
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Col. Casco de Santo Tomas, Miguel Hidalgo, 11340 México, D.F., Mexico.
| | - Francisco Javier Flores-Murrieta
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Col. Casco de Santo Tomas, Miguel Hidalgo, 11340 México, D.F., Mexico; Unidad de Investigación en Farmacología, Instituto Nacional de Enfermedades Respiratorias, Ismael Cosio Villegas, Secretaría de Salud, Calzada de Tlalpan 4502, Col. Sección XVI, Tlalpan, 14080 México, D.F., Mexico.
| | - Vinicio Granados-Soto
- Neurobiology of Pain Laboratory, Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados (Cinvestav), Sede Sur. Calzada de los Tenorios 235, Col. Granjas Coapa, 14330 México, D.F., Mexico.
| | - Héctor Isaac Rocha-González
- Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, Col. Casco de Santo Tomas, Miguel Hidalgo, 11340 México, D.F., Mexico.
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Li L, Luo R, Fan P, Guo Y, Wang HS, Ma SJ, Zhao Y. Role of peripheral purinoceptors in the development of bee venom-induced nociception: a behavioural and electrophysiological study in rats. Clin Exp Pharmacol Physiol 2014; 41:902-10. [PMID: 25115823 DOI: 10.1111/1440-1681.12293] [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: 02/21/2014] [Revised: 06/18/2014] [Accepted: 07/29/2014] [Indexed: 11/29/2022]
Abstract
Colocalization of purinergic P2X and P2Y receptors in dorsal root ganglion sensory neurons implies that these receptors play an integrative role in the nociceptive transmission process under inflammatory conditions. In the present study, behavioural and in vivo electrophysiological methods were used to examine the peripheral role of P2 receptors in the persistent nociceptive responses induced by subcutaneous bee venom injection (2 mg/mL) in. Sprague-Dawley rats Local pretreatment with the wide-spectrum P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; 1 mmol/L, 50 μL) 10 min prior to s.c. bee venom injection significantly suppressed the duration of spontaneous nociceptive lifting/licking behaviour, inhibited mechanical hyperalgesia and decreased the firing of spinal dorsal horn wide dynamic range neurons in response to bee venom, without affecting primary thermal and mirror-image hyperalgesia. The localized antinociceptive action of PPADS was not due to a systemic effect, because application of the same dose of PPADS to the contralateral side was not effective. The results suggest that activation of peripheral P2 receptors is involved in the induction of nociceptive responses, mechanical hyperalgesia and the excitation of sensory spinal neurons.
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Affiliation(s)
- Li Li
- Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, China
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Wheeler MA, Heffner DL, Kim S, Espy SM, Spano AJ, Cleland CL, Deppmann CD. TNF-α/TNFR1 signaling is required for the development and function of primary nociceptors. Neuron 2014; 82:587-602. [PMID: 24811380 DOI: 10.1016/j.neuron.2014.04.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2014] [Indexed: 12/19/2022]
Abstract
Primary nociceptors relay painful touch information from the periphery to the spinal cord. Although it is established that signals generated by receptor tyrosine kinases TrkA and Ret coordinate the development of distinct nociceptive circuits, mechanisms modulating TrkA or Ret pathways in developing nociceptors are unknown. We have identified tumor necrosis factor (TNF) receptor 1 (TNFR1) as a critical modifier of TrkA and Ret signaling in peptidergic and nonpeptidergic nociceptors. Specifically, TrkA+ peptidergic nociceptors require TNF-α-TNFR1 forward signaling to suppress nerve growth factor (NGF)-mediated neurite growth, survival, excitability, and differentiation. Conversely, TNFR1-TNF-α reverse signaling augments the neurite growth and excitability of Ret+ nonpeptidergic nociceptors. The developmental and functional nociceptive defects associated with loss of TNFR1 signaling manifest behaviorally as lower pain thresholds caused by increased sensitivity to NGF. Thus, TNFR1 exerts a dual role in nociceptor information processing by suppressing TrkA and enhancing Ret signaling in peptidergic and nonpeptidergic nociceptors, respectively.
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Affiliation(s)
- Michael A Wheeler
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Danielle L Heffner
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Suemin Kim
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Sarah M Espy
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Anthony J Spano
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Corey L Cleland
- Department of Biology, James Madison University, Harrisonburg, VA 22807, USA
| | - Christopher D Deppmann
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, USA; Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22903, USA.
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Stotz SC, Scott LO, Drummond-Main C, Avchalumov Y, Girotto F, Davidsen J, Gómez-Gárcia MR, Rho JM, Pavlov EV, Colicos MA. Inorganic polyphosphate regulates neuronal excitability through modulation of voltage-gated channels. Mol Brain 2014; 7:42. [PMID: 24886461 PMCID: PMC4061113 DOI: 10.1186/1756-6606-7-42] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 05/26/2014] [Indexed: 01/06/2023] Open
Abstract
Background Inorganic polyphosphate (polyP) is a highly charged polyanion capable of interacting with a number of molecular targets. This signaling molecule is released into the extracellular matrix by central astrocytes and by peripheral platelets during inflammation. While the release of polyP is associated with both induction of blood coagulation and astrocyte extracellular signaling, the role of secreted polyP in regulation of neuronal activity remains undefined. Here we test the hypothesis that polyP is an important participant in neuronal signaling. Specifically, we investigate the ability of neurons to release polyP and to induce neuronal firing, and clarify the underlying molecular mechanisms of this process by studying the action of polyP on voltage gated channels. Results Using patch clamp techniques, and primary hippocampal and dorsal root ganglion cell cultures, we demonstrate that polyP directly influences neuronal activity, inducing action potential generation in both PNS and CNS neurons. Mechanistically, this is accomplished by shifting the voltage sensitivity of NaV channel activation toward the neuronal resting membrane potential, the block KV channels, and the activation of CaV channels. Next, using calcium imaging we found that polyP stimulates an increase in neuronal network activity and induces calcium influx in glial cells. Using in situ DAPI localization and live imaging, we demonstrate that polyP is naturally present in synaptic regions and is released from the neurons upon depolarization. Finally, using a biochemical assay we demonstrate that polyP is present in synaptosomes and can be released upon their membrane depolarization by the addition of potassium chloride. Conclusions We conclude that polyP release leads to increased excitability of the neuronal membrane through the modulation of voltage gated ion channels. Together, our data establishes that polyP could function as excitatory neuromodulator in both the PNS and CNS.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Michael A Colicos
- Department of Physiology & Pharmacology and the Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
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Purinergic neuron-glia interactions in sensory systems. Pflugers Arch 2014; 466:1859-72. [DOI: 10.1007/s00424-014-1510-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 03/26/2014] [Accepted: 03/26/2014] [Indexed: 02/06/2023]
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Kwon SG, Roh DH, Yoon SY, Moon JY, Choi SR, Choi HS, Kang SY, Han HJ, Beitz AJ, Oh SB, Lee JH. Acid evoked thermal hyperalgesia involves peripheral P2Y1 receptor mediated TRPV1 phosphorylation in a rodent model of thrombus induced ischemic pain. Mol Pain 2014; 10:2. [PMID: 24401144 PMCID: PMC3895685 DOI: 10.1186/1744-8069-10-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 12/30/2013] [Indexed: 01/04/2023] Open
Abstract
Background We previously developed a thrombus-induced ischemic pain (TIIP) animal model, which was characterized by chronic bilateral mechanical allodynia without thermal hyperalgesia (TH). On the other hand we had shown that intraplantar injection of acidic saline facilitated ATP-induced pain, which did result in the induction of TH in normal rats. Because acidic pH and increased ATP are closely associated with ischemic conditions, this study is designed to: (1) examine whether acidic saline injection into the hind paw causes the development of TH in TIIP, but not control, animals; and (2) determine which peripheral mechanisms are involved in the development of this TH. Results Repeated intraplantar injection of pH 4.0 saline, but not pH 5.5 and 7.0 saline, for 3 days following TIIP surgery resulted in the development of TH. After pH 4.0 saline injections, protein levels of hypoxia inducible factor-1α (HIF-1α) and carbonic anhydrase II (CA II) were elevated in the plantar muscle indicating that acidic stimulation intensified ischemic insults with decreased tissue acidity. At the same time point, there were no changes in the expression of TRPV1 in hind paw skin, whereas a significant increase in TRPV1 phosphorylation (pTRPV1) was shown in acidic saline (pH 4.0) injected TIIP (AS-TIIP) animals. Moreover, intraplantar injection of chelerythrine (a PKC inhibitor) and AMG9810 (a TRPV1 antagonist) effectively alleviated the established TH. In order to investigate which proton- or ATP-sensing receptors contributed to the development of TH, amiloride (an ASICs blocker), AMG9810, TNP-ATP (a P2Xs antagonist) or MRS2179 (a P2Y1 antagonist) were pre-injected before the pH 4.0 saline. Only MRS2179 significantly prevented the induction of TH, and the increased pTRPV1 ratio was also blocked in MRS2179 injected animals. Conclusion Collectively these data show that maintenance of an acidic environment in the ischemic hind paw of TIIP rats results in the phosphorylation of TRPV1 receptors via a PKC-dependent pathway, which leads to the development of TH mimicking what occurs in chronic ischemic patients with severe acidosis. More importantly, peripheral P2Y1 receptors play a pivotal role in this process, suggesting a novel peripheral mechanism underlying the development of TH in these patients.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Jang-Hern Lee
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea.
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Kwon SG, Roh DH, Yoon SY, Moon JY, Choi SR, Choi HS, Kang SY, Han HJ, Beitz AJ, Lee JH. Blockade of peripheral P2Y1 receptors prevents the induction of thermal hyperalgesia via modulation of TRPV1 expression in carrageenan-induced inflammatory pain rats: involvement of p38 MAPK phosphorylation in DRGs. Neuropharmacology 2013; 79:368-79. [PMID: 24333674 DOI: 10.1016/j.neuropharm.2013.12.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 11/18/2013] [Accepted: 12/04/2013] [Indexed: 01/01/2023]
Abstract
Although previous reports have suggested that P2Y1 receptors (P2Y1Rs) are involved in cutaneous nociceptive signaling, it remains unclear how P2Y1Rs contribute to peripheral sensitization. The current study was designed to delineate the role of peripheral P2Y1Rs in pain and to investigate potential linkages to mitogen-activated protein kinase (MAPK) in DRGs and Transient Receptor Potential Vanilloid 1 (TRPV1) expression in a rodent inflammatory pain model. Following injection of 2% carrageenan into the hind paw, expressions of P2Y1 and TRPV1 and the phosphorylation rates of both p38 MAPK and ERK but not JNK were increased and peaked at day 2 post-injection. Blockade of peripheral P2Y1Rs by the P2Y1R antagonist, MRS2500 injection (i.pl, D0 to D2) significantly reduced the induction of thermal hyperalgesia, but not mechanical allodynia. Simultaneously, MRS2500 injections suppressed upregulated TRPV1 expression and DRG p38 phosphorylation, while pERK signaling was not affected. Furthermore, inhibition of p38 activation in the DRGs by SB203580 (a p38 inhibitor, i.t, D0 to D2) prevented the upregulation of TRPV1 and a single i.t injection of SB203580 reversed the established thermal hyperalgesia, but not mechanical allodynia. Lastly, to identify the mechanism of action of P2Y1Rs, we repeatedly injected the P2Y1 agonist, MRS2365 into the naïve rat's hind paw and observed a dose-dependent increase in TRPV1 expression and p38 MAPK phosphorylation. These data demonstrate a sequential role for P2Y1R, p38 MAPK and TRPV1 in inflammation-induced thermal hyperalgesia; thus, peripheral P2Y1Rs activation modulates p38 MAPK signaling and TRPV1 expression, which ultimately leads to the induction of thermal hyperalgesia.
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Affiliation(s)
- Soon-Gu Kwon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Dae-Hyun Roh
- Department of Maxillofacial Tissue Regeneration, School of Dentistry, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Seo-Yeon Yoon
- Laboratory of Molecular Signal Transduction, Center for Neural Science, Korea Institute of Science and Technology (KIST), Seoul 136-791, Republic of Korea
| | - Ji-Young Moon
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Sheu-Ran Choi
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Hoon-Seong Choi
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Suk-Yun Kang
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Ho-Jae Han
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Alvin J Beitz
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA
| | - Jang-Hern Lee
- Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea.
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Carmo MRS, Simões AP, Fonteles AA, Souza CM, Cunha RA, Andrade GM. ATP P2Y1 receptors control cognitive deficits and neurotoxicity but not glial modifications induced by brain ischemia in mice. Eur J Neurosci 2013; 39:614-22. [PMID: 24304101 DOI: 10.1111/ejn.12435] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 10/21/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
Abstract
ATP is a pleiotropic cell-to-cell signaling molecule in the brain that functions through activation of the P2 receptors (P2R), encompassing ionotropic P2XR or metabotropic P2YR. Noxious brain insults increase the extracellular levels of ATP and previous studies have implicated different P2R, namely P2Y1R, in the control of ischemic brain damage, but it remains to be defined if P2Y1R antagonists also alleviate the behavioral impairments associated with brain ischemia. Furthermore, as P2Y1R can control neuronal and glial functions, we explored if P2Y1R antagonist-mediated protection would mainly involve neuronal and/or glial processes. Adult male mice subject to permanent middle cerebral artery occlusion (pMCAO) displayed an infarcted cortical area (2,3,5-triphenyltetrazolium chloride staining), decreased neurological score with decreased working and reference memory performance (Y-maze, object recognition and aversive memory), accompanied by neuronal damage (FluoroJade C), astrogliosis (glial fibrillary acidic protein) and microgliosis (CD11b). All of these changes were attenuated by intracerebroventricular pre-treatment (10 min before pMCAO) with the generic P2R antagonist 4-[(E)-{4-formyl-5-hydroxy-6-methyl-3-[(phosphono-oxy)methyl]pyridin-2-yl}diazenyl]benzene-1,3-disulfonic acid (PPADS, 0.5-1.0 nmol/μL). In contrast, the selective P2Y1R antagonist (1R*,2S*)-4-[2-Iodo-6-(methylamino)-9H-purin-9-yl]-2-(phosphono-oxy)bicycle[3.1.0] hexane-1-methanol dihydrogen phosphate ester (MRS2500, 1.0-2.0 nmol/μL) afforded equivalent behavioral benefits but only prevented neuronal damage but not astrogliosis or microgliosis upon pMCAO. These results indicated that P2Y1R-associated neuroprotection mainly occurred through neuronal mechanisms, whereas other P2R were also involved in the control of astrocytic reactivity upon brain injury.
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Affiliation(s)
- Marta R S Carmo
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
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Del Puerto A, Wandosell F, Garrido JJ. Neuronal and glial purinergic receptors functions in neuron development and brain disease. Front Cell Neurosci 2013; 7:197. [PMID: 24191147 PMCID: PMC3808753 DOI: 10.3389/fncel.2013.00197] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Accepted: 10/10/2013] [Indexed: 11/23/2022] Open
Abstract
Brain development requires the interaction of complex signaling pathways, involving different cell types and molecules. For a long time, most attention has focused on neurons in a neuronocentric conceptualization of central nervous system development, these cells fulfilling an intrinsic program that establishes the brain’s morphology and function. By contrast, glia have mainly been studied as support cells, offering guidance or as the cells that react to brain injury. However, new evidence is appearing that demonstrates a more fundamental role of glial cells in the control of different aspects of neuronal development and function, events in which the influence of neurons is at best weak. Moreover, it is becoming clear that the function and organization of the nervous system depends heavily on reciprocal neuron–glia interactions. During development, neurons are often generated far from their final destination and while intrinsic mechanisms are responsible for neuronal migration and growth, they need support and regulatory influences from glial cells in order to migrate correctly. Similarly, the axons emitted by neurons often have to reach faraway targets and in this sense, glia help define the way that axons grow. Moreover, oligodendrocytes and Schwann cells ultimately envelop axons, contributing to the generation of nodes of Ranvier. Finally, recent publications show that astrocytes contribute to the modulation of synaptic transmission. In this sense, purinergic receptors are expressed widely by glial cells and neurons, and recent evidence points to multiple roles of purines and purinergic receptors in neuronal development and function, from neurogenesis to axon growth and functional axonal maturation, as well as in pathological conditions in the brain. This review will focus on the role of glial and neuronal secreted purines, and on the purinergic receptors, fundamentally in the control of neuronal development and function, as well as in diseases of the nervous system.
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Affiliation(s)
- Ana Del Puerto
- Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Consejo Superior de Investigaciones Científicas Madrid, Spain ; Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas Madrid, Spain
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Chen KH, Lin CR, Cheng JT, Cheng JK, Liao WT, Yang CH. Altered mitochondrial ATP synthase expression in the rat dorsal root ganglion after sciatic nerve injury and analgesic effects of intrathecal ATP. Cell Mol Neurobiol 2013; 34:51-9. [PMID: 24048632 DOI: 10.1007/s10571-013-9986-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 09/06/2013] [Indexed: 11/29/2022]
Abstract
Mitochondrial ATP synthase has multiple interdependent biological functions in neurons. Among them, ATP generation and regulation are the most important. The present study investigated whether the expression of mitochondrial ATP synthase correlates with symptoms of neuropathic pain in adult rats after axotomy, and whether intrathecal ATP administration is therapeutic in these neuropathic rats. Male Sprague-Dawley rats received left sciatic nerve transection (axotomy) and were randomly designated to a control (sham-operated) group, a neuropathic pain group (axotomy), a neuropathic pain and intrathecal sterile saline group, and a neuropathic pain and intrathecal ATP group. The thermal and mechanical sensitivity tests were performed at 1, 3, 5, and 7 days after axotomy. Left L4-L5 dorsal root ganglions (DRGs) were harvested to assess mitochondrial ATP synthase by immunoblotting and immunohistochemistry. After nerve injury, the expression of mitochondrial ATP synthase was decreased in protein extracts and was found mainly in C-fiber and A-δ fiber neurons of the DRGs. The decreased expression of mitochondrial ATP synthase and its subcellular localization were related to thermal and mechanical hyperalgesia. Administration of intrathecal ATP significantly attenuated thermal and mechanical hypersensitivity throughout the experimental period, which suggests its potential role in the treatment of neuropathic pain.
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Affiliation(s)
- Kuan-Hung Chen
- Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, No. 123 Dapi Rd., Niaosong District, Kaohsiung, 833, Taiwan (R.O.C.)
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Huang LYM, Gu Y, Chen Y. Communication between neuronal somata and satellite glial cells in sensory ganglia. Glia 2013; 61:1571-81. [PMID: 23918214 DOI: 10.1002/glia.22541] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 04/15/2013] [Accepted: 05/17/2013] [Indexed: 01/08/2023]
Abstract
Studies of the structural organization and functions of the cell body of a neuron (soma) and its surrounding satellite glial cells (SGCs) in sensory ganglia have led to the realization that SGCs actively participate in the information processing of sensory signals from afferent terminals to the spinal cord. SGCs use a variety ways to communicate with each other and with their enwrapped soma. Changes in this communication under injurious conditions often lead to abnormal pain conditions. "What are the mechanisms underlying the neuronal soma and SGC communication in sensory ganglia?" and "how do tissue or nerve injuries affect the communication?" are the main questions addressed in this review.
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Affiliation(s)
- Li-Yen M Huang
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas 77555-1069, USA.
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Ramachandra R, Hassan B, McGrew SG, Dompor J, Farrag M, Ruiz-Velasco V, Elmslie KS. Identification of CaV channel types expressed in muscle afferent neurons. J Neurophysiol 2013; 110:1535-43. [PMID: 23843437 DOI: 10.1152/jn.00069.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cardiovascular adjustments to exercise are partially mediated by group III/IV (small to medium) muscle afferents comprising the exercise pressor reflex (EPR). However, this reflex can be inappropriately activated in disease states (e.g., peripheral vascular disease), leading to increased risk of myocardial infarction. Here we investigate the voltage-dependent calcium (CaV) channels expressed in small to medium muscle afferent neurons as a first step toward determining their potential role in controlling the EPR. Using specific blockers and 5 mM Ba(2+) as the charge carrier, we found the major calcium channel types to be CaV2.2 (N-type) > CaV2.1 (P/Q-type) > CaV1.2 (L-type). Surprisingly, the CaV2.3 channel (R-type) blocker SNX482 was without effect. However, R-type currents are more prominent when recorded in Ca(2+) (Liang and Elmslie 2001). We reexamined the channel types using 10 mM Ca(2+) as the charge carrier, but results were similar to those in Ba(2+). SNX482 was without effect even though ∼27% of the current was blocker insensitive. Using multiple methods, we demonstrate that CaV2.3 channels are functionally expressed in muscle afferent neurons. Finally, ATP is an important modulator of the EPR, and we examined the effect on CaV currents. ATP reduced CaV current primarily via G protein βγ-mediated inhibition of CaV2.2 channels. We conclude that small to medium muscle afferent neurons primarily express CaV2.2 > CaV2.1 ≥ CaV2.3 > CaV1.2 channels. As with chronic pain, CaV2.2 channel blockers may be useful in controlling inappropriate activation of the EPR.
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Affiliation(s)
- Renuka Ramachandra
- The Baker Laboratory of Pharmacology, Department of Pharmacology, AT Still University of Health Sciences, Kirksville, Missouri
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Magni G, Ceruti S. P2Y purinergic receptors: new targets for analgesic and antimigraine drugs. Biochem Pharmacol 2012; 85:466-77. [PMID: 23146663 DOI: 10.1016/j.bcp.2012.10.027] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/12/2012] [Accepted: 10/12/2012] [Indexed: 10/27/2022]
Abstract
Millions of individuals worldwide suffer from acute and, more severely, chronic pain conditions (e.g., neuropathic pain, and migraine). The latter bear tremendous personal, familial, and social costs, since sufferers and their relatives undergo a complete turnaround of their lives with the search of relief from pain becoming their pivotal thought. Sadly, to date no effective pharmacological approaches are available which can alleviate chronic pain significantly or in the long run in all patients. The current central strategy for the development of new and effective painkillers lies in the hypothesis that cellular and/or molecular players in nociception must exists that are not targeted by "classical" analgesics, and therefore researchers have put tremendous efforts into the in-depth analysis of the pathways leading to pain development and maintenance over time. In this complex scenario, two outsiders are now taking the center stage: glial cells in sensory ganglia and in the central nervous system, thanks to their ability to communicate with neurons and to modulate their firing, and the purinergic system. Extracellular purine and pyrimidine nucleotides are involved in the physiology of virtually every body district, and their extracellular concentrations massively increase under pathological situations, suggesting that they might represent potential targets for the modulation of disease-associated symptoms, like pain. Here, we provide an overview of the present knowledge of the role of nucleotides in nociception, with a particular emphasis on G protein-coupled P2Y receptors and their involvement in the communication between first- and second-order neurons in sensory nerve pathways and surrounding glial cells.
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Affiliation(s)
- Giulia Magni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy
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Klaft ZJ, Schulz SB, Maslarova A, Gabriel S, Heinemann U, Gerevich Z. Extracellular ATP differentially affects epileptiform activity via purinergic P2X7 and adenosine A1 receptors in naive and chronic epileptic rats. Epilepsia 2012; 53:1978-86. [PMID: 23106524 DOI: 10.1111/j.1528-1167.2012.03724.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE Adenosine is considered an endogenous anticonvulsant. However, much less is known about the putative effects of its precursor, ATP, on epilepsy. Therefore, we tested whether ATP and its receptors are able to modulate epileptiform activity in the medial entorhinal cortex of the rat. METHODS Recurrent epileptiform discharges (REDs) were induced by elevating extracellular potassium concentration combined with application of bicuculline in brain slices from naive and pilocarpine-treated chronic epileptic rats. Field potentials were recorded from layer V/VI of the medial entorhinal cortex. KEY FINDINGS REDs in slices from naive animals had a higher incidence and a shorter duration than in slices from chronic epileptic animals. Exogenous application of ATP reversibly reduced the incidence of REDs in naive and chronic epileptic slices via activation of adenosine A(1) receptors without discernible P2 receptor effects. This effect was stronger in slices from chronic epileptic rats. In slices from naive rats, the P2X7 receptor antagonist A 740003 slightly but significantly reduced the amplitude of slow field potentials of REDs. In slices from chronic epileptic rats, none of the P2 receptor antagonists affected the parameters of REDs. SIGNIFICANCE Our results suggest that endogenously released ATP differentially modulates REDs by activation of A(1) and P2X7 receptors. Although it has a minor proepileptic effect by direct activation of P2X7 receptors, its metabolite adenosine reduces the epileptiform activity via activation of A(1) receptors. The exact effect of ATP on neural activity depends on the actual activity of ectonucleotidases and the expression level of the purinergic receptors, which both alter during epileptogenesis. In addition, our data suggest that P2X7 receptor antagonists have a minor antiepileptic effect.
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Affiliation(s)
- Zin-Juan Klaft
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, Charitplatz 1, Berlin, Germany
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Kabanova NV, Vassilevski AA, Rogachevskaja OA, Bystrova MF, Korolkova YV, Pluzhnikov KA, Romanov RA, Grishin EV, Kolesnikov SS. Modulation of P2X3 receptors by spider toxins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2868-75. [PMID: 22842000 DOI: 10.1016/j.bbamem.2012.07.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 07/18/2012] [Accepted: 07/20/2012] [Indexed: 12/17/2022]
Abstract
Recently, the novel peptide named purotoxin-1 (PT1) has been identified in the venom of the spider Geolycosa sp. and shown to exert marked modulatory effects on P2X3 receptors in rat sensory neurons. Here we studied another polypeptide from the same spider venom, purotoxin-2 (PT2), and demonstrated that it also affected activity of mammalian P2X3 receptors. The murine and human P2X3 receptors were heterologously expressed in cells of the CHO line, and nucleotide-gated currents were stimulated by CTP and ATP, respectively. Both PT1 and PT2 negligibly affected P2X3-mediated currents elicited by brief pulses of the particular nucleotide. When subthreshold CTP or ATP was added to the bath to exert the high-affinity desensitization of P2X3 receptors, both spider toxins strongly enhanced the desensitizing action of the ambient nucleotides. At the concentration of 50nM, PT1 and PT2 elicited 3-4-fold decrease in the IC(50) dose of ambient CTP or ATP. In contrast, 100nM PT1 and PT2 negligibly affected nucleotide-gated currents mediated by mP2X2 receptors or mP2X2/mP2X3 heteromers. Altogether, our data point out that the PT1 and PT2 toxins specifically target the fast-desensitizing P2X3 receptor, thus representing a unique tool to manipulate its activity.
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Affiliation(s)
- Natalia V Kabanova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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Zhang PP, Yang XL, Zhong YM. Cellular localization of P2Y₆ receptor in rat retina. Neuroscience 2012; 220:62-9. [PMID: 22728100 DOI: 10.1016/j.neuroscience.2012.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 06/08/2012] [Accepted: 06/13/2012] [Indexed: 12/23/2022]
Abstract
Extracellular nucleotides exert their actions via two subfamilies of purinoceptors: P2X and P2Y. Eight mammalian P2Y receptor subtypes (P2Y(1,2,4,6,11,12,13,14)) have been identified. In this work, the localization of P2Y(6) was studied in rat retina using double immunofluorescence labeling and confocal scanning microscopy. Immunostaining for P2Y(6) was strong in the outer plexiform layer and was diffusely distributed throughout the full thickness of the inner plexiform layer. In addition, P2Y(6) immunoreactivity was clearly observed in many cells in the inner nuclear layer and the ganglion cell layer. In the outer retina photoreceptor terminals, labeled by VGluT1, and horizontal cells, labeled by calbindin, were P2Y(6)-positive. However, no P2Y(6) immunostaining was detected in bipolar cells, labeled by homeobox protein Chx10. In the inner retina P2Y(6) was localized to most of GABAergic amacrine cells, including dopaminergic and cholinergic ones, stained by tyrosine hydroxylase (TH) and choline acetyltransferase (ChAT) respectively. Some of glycinergic amacrine cells, but not glycinergic AII amacrine cells, were also labeled by P2Y(6). Moreover, P2Y(6) immunoreactivity was seen in almost all ganglion cells, labeled by Brn3a. In Müller glial cells, stained by cellular retinaldehyde binding protein (CRALBP), however, no P2Y(6) expression was found in both somata and processes. We speculate that P2Y(6) may be involved in retinal information processing in different ways, probably by regulating the release of transmitters and/or modulating the radial flow of visual signals and lateral interaction mediated by horizontal and amacrine cells.
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Affiliation(s)
- P P Zhang
- Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, 138 Yixueyuan Road, Shanghai 200032, PR China
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Chandaka GK, Salzer I, Drobny H, Boehm S, Schicker KW. Facilitation of transmitter release from rat sympathetic neurons via presynaptic P2Y(1) receptors. Br J Pharmacol 2012; 164:1522-33. [PMID: 21557728 PMCID: PMC3221105 DOI: 10.1111/j.1476-5381.2011.01466.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE P2Y(1) , P2Y(2) , P2Y(4) , P2Y(12) and P2Y(13) receptors for nucleotides have been reported to mediate presynaptic inhibition, but unequivocal evidence for facilitatory presynaptic P2Y receptors is not available. The search for such receptors was the purpose of this study. EXPERIMENTAL APPROACH In primary cultures of rat superior cervical ganglion neurons and in PC12 cell cultures, currents were recorded via the perforated patch clamp technique, and the release of [(3) H]-noradrenaline was determined. KEY RESULTS ADP, 2-methylthio-ATP and ATP enhanced stimulation-evoked (3) H overflow from superior cervical ganglion neurons, treated with pertussis toxin to prevent the signalling of inhibitory G proteins. This effect was abolished by P2Y(1) antagonists and by inhibition of phospholipase C, but not by inhibition of protein kinase C or depletion of intracellular Ca(2+) stores. ADP and a specific P2Y(1) agonist caused inhibition of Kv7 channels, and this was prevented by a respective antagonist. In neurons not treated with pertussis toxin, (3) H overflow was also enhanced by a specific P2Y(1) agonist and by ADP, but only when the P2Y(12) receptors were blocked. ADP also enhanced K(+) -evoked (3) H overflow from PC12 cells treated with pertussis toxin, but only in a clone expressing recombinant P2Y(1) receptors. CONCLUSIONS AND IMPLICATIONS These results demonstrate that presynaptic P2Y(1) receptors mediate facilitation of transmitter release from sympathetic neurons most likely through inhibition of Kv7 channels.
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Affiliation(s)
- Giri K Chandaka
- Department of Neurophysiology and Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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Abstract
Previous studies of NMDA receptor (NMDAR) expression on axons of cerebellar molecular layer interneurons have produced conflicting results. We made use of the calcium sensitivity of vesicular release machinery to test for NMDAR activity in basket cell axons. Iontophoresis of l-aspartate, an NMDAR agonist, onto basket cell axon collaterals had no effect on evoked IPSCs measured in synaptically coupled Purkinje cells. Furthermore, calcium indicators in basket cell varicosities did not report any change in intracellular calcium following iontophoresis of l-aspartate or two-photon uncaging of glutamate. In contrast, activation of presynaptic purinergic receptors by iontophoresis of ATP decreased evoked IPSC amplitudes and action potential-evoked calcium transients in axonal varicosities, demonstrating the effectiveness of activating presynaptic receptors by iontophoresis. We find no evidence for functional NMDARs in basket cell varicosities.
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Jankowski MP, Rau KK, Soneji DJ, Ekmann KM, Anderson CE, Molliver DC, Koerber RH. Purinergic receptor P2Y1 regulates polymodal C-fiber thermal thresholds and sensory neuron phenotypic switching during peripheral inflammation. Pain 2011; 153:410-419. [PMID: 22137295 DOI: 10.1016/j.pain.2011.10.042] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 10/28/2011] [Accepted: 10/28/2011] [Indexed: 11/30/2022]
Abstract
We have recently found that, following complete Freund's adjuvant (CFA)-induced inflammation, cutaneous polymodal nociceptors (CPM) lacking the transient receptor potential vanilloid 1 (TRPV1) are sensitized to heat stimuli. In order to determine possible mechanisms playing a role in this change, we examined gene expression in the L2/L3 sensory ganglia following CFA injection into the hairy hind paw skin and found that G-protein-coupled purinoreceptor P2Y1 expression was increased. This receptor is of particular interest, as most CPMs innervating mouse hairy skin bind isolectin B4, which co-localizes with P2Y1. Additionally, our recent findings have shown that cutaneous CPMs in P2Y1-/- mice displayed significantly reduced thermal sensitivity. Together, these findings suggested a possible role for P2Y1 in inflammation-induced heat sensitization in these fibers. To test this hypothesis, we utilized our in vivo small interfering RNA technique to knock down the inflammation-induced increase in P2Y1 expression and then examined the functional effects using ex vivo recording. We found that the normal reduction of heat thresholds in CPM fibers induced by CFA was completely blocked by inhibition of P2Y1. Surprisingly, inhibition of P2Y1 during inflammation also significantly increased the number of CPM neurons expressing TRPV1 without a change in the total number of TRPV1-positive cells in the L2 and L3 dorsal root ganglia. These results show that the inflammation-induced enhanced expression of P2Y1 is required for normal heat sensitization of cutaneous CPM fibers. They also suggest that P2Y1 plays a role in the maintenance of phenotype in cutaneous afferent fibers containing TRPV1.
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Affiliation(s)
- Michael P Jankowski
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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Targeting the visceral purinergic system for pain control. Curr Opin Pharmacol 2011; 12:80-6. [PMID: 22036885 DOI: 10.1016/j.coph.2011.10.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Accepted: 10/06/2011] [Indexed: 11/24/2022]
Abstract
Experimental evidence is presented to support the hypothesis that purinergic mechanosensory transduction can initiate visceral pain in urinary bladder, ureter, gut and uterus. In general, physiological reflexes are mediated via P2X3 and P2X2/3 receptors on low threshold sensory fibres, while these receptors on high threshold sensory fibres mediate pain. Potential therapeutic strategies are considered for the treatment of visceral pain in such conditions as renal colic, interstitial cystitis and inflammatory bowel disease by purinergic agents, including P2X3 and P2X2/3 receptor antagonists that are orally bioavailable and stable in vivo and agents that modulate ATP release and breakdown.
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Purinergic P2X, P2Y and adenosine receptors differentially modulate hippocampal gamma oscillations. Neuropharmacology 2011; 62:914-24. [PMID: 22001427 DOI: 10.1016/j.neuropharm.2011.09.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 09/20/2011] [Accepted: 09/22/2011] [Indexed: 01/02/2023]
Abstract
The present study was designed to investigate the role of extracellular ATP and its receptors on neuronal network activity. Gamma oscillations (30-50 Hz) were induced in the CA3 region of acute rat hippocampal slices by either acetylcholine (ACh) or kainic acid (KA). ATP reduced the power of KA-induced gamma oscillations exclusively by activation of adenosine receptors after its degradation to adenosine. In contrast, ATP suppressed ACh-induced oscillations through both adenosine and ATP receptors. Activation of adenosine receptors accounts for about 55%, activation of P2 receptors for ∼45% of suppression. Monitoring the ATP degradation by ATP biosensors revealed that bath-applied ATP reaches ∼300 times lower concentrations within the slice. P2 receptors were also activated by endogenous ATP since inhibition of ATP-hydrolyzing enzymes had an inhibitory effect on ACh-induced gamma oscillations. More specific antagonists revealed that ionotropic P2X2 and/or P2X4 receptors reduced the power of ACh-induced gamma oscillations whereas metabotropic P2Y(1) receptor increased it. Intracellular recordings from CA3 pyramidal cells suggest that adenosine receptors reduce the spiking rate and the synchrony of action potentials during gamma oscillations whereas P2 receptors only modulate the firing rate of the cells. In conclusion, our results suggest that endogenously released ATP differentially modulates the power of ACh- or KA-induced gamma oscillations in the CA3 region of the hippocampus by interacting with P2X, P2Y and adenosine receptors. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.
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Lechner SG, Boehm S. Regulation of neuronal ion channels via P2Y receptors. Purinergic Signal 2011; 1:31-41. [PMID: 18404398 PMCID: PMC2096562 DOI: 10.1007/s11302-004-4746-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 10/11/2004] [Accepted: 10/12/2004] [Indexed: 11/25/2022] Open
Abstract
Within the last 15 years, at least 8 different G protein-coupled P2Y receptors have been characterized. These mediate slow metabotropic effects of nucleotides in neurons as well as non-neural cells, as opposed to the fast ionotropic effects which are mediated by P2X receptors. One class of effector systems regulated by various G protein-coupled receptors are voltage-gated and ligand-gated ion channels. This review summarizes the current knowledge about the modulation of such neuronal ion channels via P2Y receptors. The regulated proteins include voltage-gated Ca2+ and K+ channels, as well as N-methyl-d-aspartate, vanilloid, and P2X receptors, and the regulating entities include most of the known P2Y receptor subtypes. The functional consequences of the modulation of ion channels by nucleotides acting at pre- or postsynaptic P2Y receptors are changes in the strength of synaptic transmission. Accordingly, ATP and related nucleotides may act not only as fast transmitters (via P2X receptors) in the nervous system, but also as neuromodulators (via P2Y receptors). Hence, nucleotides are as universal transmitters as, for instance, acetylcholine, glutamate, or γ-aminobutyric acid.
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Affiliation(s)
- Stefan G Lechner
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
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