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Waltz TB, Chao D, Prodoehl EK, Enders JD, Ehlers VL, Dharanikota BS, Dahms NM, Isaeva E, Hogan QH, Pan B, Stucky CL. Fabry disease Schwann cells release p11 to induce sensory neuron hyperactivity. JCI Insight 2024; 9:e172869. [PMID: 38646936 PMCID: PMC11141882 DOI: 10.1172/jci.insight.172869] [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: 06/06/2023] [Accepted: 03/05/2024] [Indexed: 04/25/2024] Open
Abstract
Patients with Fabry disease suffer from chronic debilitating pain and peripheral sensory neuropathy with minimal treatment options, but the cellular drivers of this pain are unknown. Here, we propose a mechanism we believe to be novel in which altered signaling between Schwann cells and sensory neurons underlies the peripheral sensory nerve dysfunction we observed in a genetic rat model of Fabry disease. Using in vivo and in vitro electrophysiological recordings, we demonstrated that Fabry rat sensory neurons exhibited pronounced hyperexcitability. Schwann cells probably contributed to this finding because application of mediators released from cultured Fabry Schwann cells induced spontaneous activity and hyperexcitability in naive sensory neurons. We examined putative algogenic mediators using proteomic analysis and found that Fabry Schwann cells released elevated levels of the protein p11 (S100A10), which induced sensory neuron hyperexcitability. Removal of p11 from Fabry Schwann cell media caused hyperpolarization of neuronal resting membrane potentials, indicating that p11 may contribute to the excessive neuronal excitability caused by Fabry Schwann cells. These findings demonstrate that sensory neurons from rats with Fabry disease exhibit hyperactivity caused in part by Schwann cell release of the protein p11.
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Affiliation(s)
| | | | | | | | | | | | - Nancy M. Dahms
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Elena Isaeva
- Department of Cell Biology, Neurobiology & Anatomy
| | | | - Bin Pan
- Department of Anesthesiology; and
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2
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Doucette A, Johnson K, Hulke S, Mujteba S, Miller E, Meyer B, Dosa PI, Klein AH. K ATP Channel Prodrugs Reduce Inflammatory and Neuropathic Hypersensitivity, Morphine-Induced Hypersensitivity, and Precipitated Withdrawal in Mice. J Pharmacol Exp Ther 2023; 387:18-26. [PMID: 36931644 PMCID: PMC10519579 DOI: 10.1124/jpet.122.001522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/14/2023] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
Previous studies show ATP-sensitive potassium (KATP) channel openers can reduce hypersensitivity associated with chronic pain models in rodents, and reduce morphine tolerance. Many agonists of KATP channels are not soluble in physiologically relevant vehicles, requiring adaptation for clinical use. This study compared the antinociceptive activity of novel KATP channel targeting prodrugs, CKLP1, CKLP2, and CF3-CKLP. These prodrugs are activated by endogenous alkaline phosphatase enzymes present in the peripheral and central nervous systems. Analgesic capabilities of intrathecally injected prodrugs were tested in rodent models of spinal nerve ligation (SNL) and complete Freund's adjuvant (CFA) as models for neuropathic and inflammatory pain, respectively. CKLP1 and CKLP2 significantly increased mechanical paw withdrawal thresholds 1-2 hours after intrathecal administration in the SNL model, but all three prodrugs were able to attenuate hypersensitivity up to 7 days after CFA treatment. The reduction of opioid tolerance and opioid-induced hypersensitivity in mice treated chronically with morphine was significantly reduced in CKLP1 and CKLP2 treated animals. Prodrug cleavage was confirmed in mouse spinal cords using liquid chromatography. These studies may aid in the further development of KATP channel prodrugs for use in treatments of chronic pain, opioid tolerance, and withdrawal. SIGNIFICANCE STATEMENT: The cromakalim prodrugs, CKLP1, CKLP2, and CF3-CKLP1 reduced hypersensitivity in inflammatory and neuropathic pain models in male and female mice. CKLP1 and CKLP2 also reduced morphine-induced hypersensitivity in a mouse model of chronic morphine exposure. CKLP2 reduced jumping and rearing behaviors after naloxone-induced precipitated morphine withdrawal. Taken together, CKLP2 demonstrates the potential for development as a non-opioid analgesic drug.
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Affiliation(s)
- Alexis Doucette
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Kayla Johnson
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Shelby Hulke
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Sunna Mujteba
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Elena Miller
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Belle Meyer
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Peter I Dosa
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, Minnesota (A.D., K.J., S.H., S.M., E.M., B.M., A.H.K.) and Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, Minneapolis, Minnesota (P.I.D.)
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3
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Zambelli VO, Gross ER. Fixing a Broken Heart Opens the Door to Developing K ATP Channel Agonists as Pain Relievers. J Pharmacol Exp Ther 2023; 387:15-17. [PMID: 37714690 DOI: 10.1124/jpet.123.001716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/25/2023] [Indexed: 09/17/2023] Open
Affiliation(s)
- Vanessa O Zambelli
- Laboratory of Pain and Signaling, Butantan Institute, Sāo Paulo, Brazil (V.O.Z.) and Department of Anesthesiology, Perioperative and Pain Medicine, School of Medicine, Stanford University, Stanford, California (E.R.G.)
| | - Eric R Gross
- Laboratory of Pain and Signaling, Butantan Institute, Sāo Paulo, Brazil (V.O.Z.) and Department of Anesthesiology, Perioperative and Pain Medicine, School of Medicine, Stanford University, Stanford, California (E.R.G.)
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4
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Fisher C, Johnson K, Moore M, Sadrati A, Janecek JL, Graham ML, Klein AH. Loss of ATP-sensitive channel expression and function decreases opioid sensitivity in a mouse model of type 2 diabetes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.06.556526. [PMID: 37732180 PMCID: PMC10508758 DOI: 10.1101/2023.09.06.556526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
During diabetes, β-cell dysfunction due to loss of potassium channels sensitive to ATP, known as KATP channels occurs progressively over time contributing to hyperglycemia. KATP channels are additionally present in the central and peripheral nervous systems and are downstream targets of opioid receptor signaling. The aim of this study is to investigate if KATP channel expression or activity in the nervous system changes in diabetic mice and if morphine antinociception changes in mice fed a high fat diet (HFD) for 16 weeks compared to controls. Mechanical thresholds were also monitored before and after administration of glyburide or nateglinide, KATP channel antagonists, for four weeks. HFD mice have decreased antinociception to systemic morphine, which is exacerbated after systemic treatment with glyburide or nateglinide. HFD mice also have lower rotarod scores, decreased mobility in an open field test, and lower burrowing behavior compared to their control diet counterparts, which is unaffected by KATP channel antagonist delivery. Expression of KATP channel subunits, Kcnj11 (Kir6.2) and Abcc8 (SUR1), were decreased in the peripheral and central nervous system in HFD mice, which is significantly correlated with baseline paw withdrawal thresholds. Upregulation of SUR1 through an adenovirus delivered intrathecally increased morphine antinociception in HFD mice, whereas Kir6.2 upregulation improved morphine antinociception only marginally. Perspective: This article presents the potential link between KATP channel function and neuropathy during diabetes. There is a need for increased knowledge in how diabetes affects structural and molecular changes in the nervous system to lead to the progression of chronic pain and sensory issues.
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Affiliation(s)
- Cole Fisher
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
| | - Kayla Johnson
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
| | - Madelyn Moore
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
| | - Amir Sadrati
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
| | - Jody L. Janecek
- Department of Surgery, University of Minnesota, St. Paul, MN, USA
| | | | - Amanda H. Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, USA
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Waltz TB, Chao D, Prodoehl EK, Ehlers VL, Dharanikota BS, Dahms NM, Isaeva E, Hogan QH, Pan B, Stucky CL. Schwann cell release of p11 induces sensory neuron hyperactivity in Fabry disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542493. [PMID: 37292928 PMCID: PMC10245981 DOI: 10.1101/2023.05.26.542493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Patients with Fabry disease suffer from chronic debilitating pain and peripheral sensory neuropathy with minimal treatment options, but the cellular drivers of this pain are unknown. Here, we propose a novel mechanism by which altered signaling between Schwann cells and sensory neurons underlies the peripheral sensory nerve dysfunction we observe in a genetic rat model of Fabry disease. Using in vivo and in vitro electrophysiological recordings, we demonstrate that Fabry rat sensory neurons exhibit pronounced hyperexcitability. Schwann cells likely contribute to this finding as application of mediators released from cultured Fabry Schwann cells induces spontaneous activity and hyperexcitability in naïve sensory neurons. We examined putative algogenic mediators using proteomic analysis and found that Fabry Schwann cells release elevated levels of the protein p11 (S100-A10) which induces sensory neuron hyperexcitability. Removal of p11 from Fabry Schwann cell media causes hyperpolarization of neuronal resting membrane potential, indicating that p11 contributes to the excessive neuronal excitability caused by Fabry Schwann cells. These findings demonstrate that rats with Fabry disease exhibit sensory neuron hyperexcitability caused in part by Schwann cell release of the protein p11.
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Nakai-Shimoda H, Himeno T, Okawa T, Miura-Yura E, Sasajima S, Kato M, Yamada Y, Morishita Y, Tsunekawa S, Kato Y, Seino Y, Inoue R, Kondo M, Seino S, Naruse K, Kato K, Mizukami H, Nakamura J, Kamiya H. Kir6.2-deficient mice develop somatosensory dysfunction and axonal loss in the peripheral nerves. iScience 2022; 25:103609. [PMID: 35005553 PMCID: PMC8719014 DOI: 10.1016/j.isci.2021.103609] [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: 08/11/2021] [Revised: 11/27/2021] [Accepted: 12/08/2021] [Indexed: 10/26/2022] Open
Abstract
Glucose-responsive ATP-sensitive potassium channels (KATP) are expressed in a variety of tissues including nervous systems. The depolarization of the membrane potential induced by glucose may lead to hyperexcitability of neurons and induce excitotoxicity. However, the roles of KATP in the peripheral nervous system (PNS) are poorly understood. Here, we determine the roles of KATP in the PNS using KATP-deficient (Kir6.2-deficient) mice. We demonstrate that neurite outgrowth of dorsal root ganglion (DRG) neurons was reduced by channel closers sulfonylureas. However, a channel opener diazoxide elongated the neurite. KATP subunits were expressed in mouse DRG, and expression of certain subunits including Kir6.2 was increased in diabetic mice. In Kir6.2-deficient mice, the current perception threshold, thermal perception threshold, and sensory nerve conduction velocity were impaired. Electron microscopy revealed a reduction of unmyelinated and small myelinated fibers in the sural nerves. In conclusion, KATP may contribute to the development of peripheral neuropathy.
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Affiliation(s)
- Hiromi Nakai-Shimoda
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Tatsuhito Himeno
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan.,Department of Innovative Diabetes Therapy, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Tetsuji Okawa
- Department of Endocrinology, Gifu Prefectural Tajimi Hospital, Tajimi 507-8522, Japan
| | - Emiri Miura-Yura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Sachiko Sasajima
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Makoto Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yuichiro Yamada
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yoshiaki Morishita
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Shin Tsunekawa
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yoshiro Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yusuke Seino
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake 470-1192, Aichi, Japan
| | - Rieko Inoue
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Masaki Kondo
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
| | - Keiko Naruse
- Department of Internal Medicine, Aichi Gakuin University School of Dentistry, Nagoya 464-0821, Japan
| | - Koichi Kato
- Department of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya 464-8650, Japan
| | - Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan
| | - Jiro Nakamura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan.,Department of Innovative Diabetes Therapy, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Hideki Kamiya
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
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Avraham O, Deng PY, Maschi D, Klyachko VA, Cavalli V. Disrupted Association of Sensory Neurons With Enveloping Satellite Glial Cells in Fragile X Mouse Model. Front Mol Neurosci 2022; 14:796070. [PMID: 35058748 PMCID: PMC8763968 DOI: 10.3389/fnmol.2021.796070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/17/2021] [Indexed: 11/24/2022] Open
Abstract
Among most prevalent deficits in individuals with Fragile X syndrome (FXS) is hypersensitivity to sensory stimuli and somatosensory alterations. Whether dysfunction in peripheral sensory system contributes to these deficits remains poorly understood. Satellite glial cells (SGCs), which envelop sensory neuron soma, play critical roles in regulating neuronal function and excitability. The potential contributions of SGCs to sensory deficits in FXS remain unexplored. Here we found major structural defects in sensory neuron-SGC association in the dorsal root ganglia (DRG), manifested by aberrant covering of the neuron and gaps between SGCs and the neuron along their contact surface. Single-cell RNAseq analyses demonstrated transcriptional changes in both neurons and SGCs, indicative of defects in neuronal maturation and altered SGC vesicular secretion. We validated these changes using fluorescence microscopy, qPCR, and high-resolution transmission electron microscopy (TEM) in combination with computational analyses using deep learning networks. These results revealed a disrupted neuron-glia association at the structural and functional levels. Given the well-established role for SGCs in regulating sensory neuron function, altered neuron-glia association may contribute to sensory deficits in FXS.
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Affiliation(s)
- Oshri Avraham
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
| | - Pan-Yue Deng
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Dario Maschi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
| | - Vitaly A. Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, United States
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States
| | - Valeria Cavalli
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, United States
- Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, United States
- Center of Regenerative Medicine, Washington University School of Medicine, St. Louis, MO, United States
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Sakamaki G, Johnson K, Mensinger M, Hmu E, Klein AH. Loss of SUR1 subtype K ATP channels alters antinociception and locomotor activity after opioid administration. Behav Brain Res 2021; 414:113467. [PMID: 34274374 PMCID: PMC11019344 DOI: 10.1016/j.bbr.2021.113467] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 06/07/2021] [Accepted: 07/13/2021] [Indexed: 11/30/2022]
Abstract
Opioid signaling can occur through several downstream mediators and influence analgesia as well as reward mechanisms in the nervous system. KATP channels are downstream targets of the μ opioid receptor and contribute to morphine-induced antinociception. The aim of the present work was to assess the role of SUR1-subtype KATP channels in antinociception and hyperlocomotion of synthetic and semi-synthetic opioids. Adult male and female mice wild-type (WT) and SUR1 deficient (KO) mice were assessed for mechanical and thermal antinociception after administration of either buprenorphine, fentanyl, or DAMGO. Potassium flux was assessed in the dorsal root ganglia and superficial dorsal horn cells in WT and KO mice. Hyperlocomotion was also assessed in WT and KO animals after buprenorphine, fentanyl, or DAMGO administration. SUR1 KO mice had attenuated mechanical antinociception after systemic administration of buprenorphine, fentanyl, and DAMGO. Potassium flux was also attenuated in the dorsal root ganglia and spinal cord dorsal horn cells after acute administration of buprenorphine and fentanyl. Hyperlocomotion after administration of morphine and buprenorphine was potentiated in SUR1 KO mice, but was not seen after administration of fentanyl or DAMGO. These results suggest SUR1-subtype KATP channels mediate the antinociceptive response of several classes of opioids (alkaloid and synthetic/semi-synthetic), but may not contribute to the "drug-seeking" behaviors of all classes of opioids.
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Affiliation(s)
- Gerald Sakamaki
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States
| | - Kayla Johnson
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States
| | - Megan Mensinger
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States
| | - Eindray Hmu
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States.
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Possible Participation of Ionotropic Glutamate Receptors and l-Arginine-Nitric Oxide-Cyclic Guanosine Monophosphate-ATP-Sensitive K + Channel Pathway in the Antinociceptive Activity of Cardamonin in Acute Pain Animal Models. Molecules 2020; 25:molecules25225385. [PMID: 33217904 PMCID: PMC7698774 DOI: 10.3390/molecules25225385] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/06/2020] [Accepted: 10/08/2020] [Indexed: 01/16/2023] Open
Abstract
The perception of pain caused by inflammation serves as a warning sign to avoid further injury. The generation and transmission of pain impulses involves various pathways and receptors. Cardamonin isolated from Boesenbergia rotunda (L.) Mansf. has been reported to exert antinociceptive effects in thermal and mechanical pain models; however, the precise mechanism has yet to be examined. The present study investigated the possible mechanisms involved in the antinociceptive activity of cardamonin on protein kinase C, N-methyl-d-aspartate (NMDA) and non-NMDA glutamate receptors, l-arginine/cyclic guanosine monophosphate (cGMP) mechanism, as well as the ATP-sensitive potassium (K+) channel. Cardamonin was administered to the animals intra-peritoneally. Present findings showed that cardamonin significantly inhibited pain elicited by intraplantar injection of phorbol 12-myristate 13-acetate (PMA, a protein kinase C activator) with calculated mean ED50 of 2.0 mg/kg (0.9–4.5 mg/kg). The study presented that pre-treatment with MK-801 (NMDA receptor antagonist) and NBQX (non-NMDA receptor antagonist) significantly modulates the antinociceptive activity of cardamonin at 3 mg/kg when tested with glutamate-induced paw licking test. Pre-treatment with l-arginine (a nitric oxide precursor), ODQ (selective inhibitor of soluble guanylyl cyclase) and glibenclamide (ATP-sensitive K+ channel inhibitor) significantly enhanced the antinociception produced by cardamonin. In conclusion, the present findings showed that the antinociceptive activity of cardamonin might involve the modulation of PKC activity, NMDA and non-NMDA glutamate receptors, l-arginine/nitric oxide/cGMP pathway and ATP-sensitive K+ channel.
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10
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Fisher C, Johnson K, Okerman T, Jurgenson T, Nickell A, Salo E, Moore M, Doucette A, Bjork J, Klein AH. Morphine Efficacy, Tolerance, and Hypersensitivity Are Altered After Modulation of SUR1 Subtype K ATP Channel Activity in Mice. Front Neurosci 2019; 13:1122. [PMID: 31695594 PMCID: PMC6817471 DOI: 10.3389/fnins.2019.01122] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 10/04/2019] [Indexed: 01/26/2023] Open
Abstract
ATP-sensitive potassium (KATP) channels are found in the nervous system and are downstream targets of opioid receptors. KATP channel activity can effect morphine efficacy and may beneficial for relieving chronic pain in the peripheral and central nervous system. Unfortunately, the KATP channels exists as a heterooctomers, and the exact subtypes responsible for the contribution to chronic pain and opioid signaling in either dorsal root ganglia (DRG) or the spinal cord are yet unknown. Chronic opioid exposure (15 mg/kg morphine, s.c., twice daily) over 5 days produces significant downregulation of Kir6.2 and SUR1 in the spinal cord and DRG of mice. In vitro studies also conclude potassium flux after KATP channel agonist stimulation is decreased in neuroblastoma cells treated with morphine for several days. Mice lacking the KATP channel SUR1 subunit have reduced opioid efficacy in mechanical paw withdrawal behavioral responses compared to wild-type and heterozygous littermates (5 and 15 mg/kg, s.c., morphine). Using either short hairpin RNA (shRNA) or SUR1 cre-lox strategies, downregulation of SUR1 subtype KATP channels in the spinal cord and DRG of mice potentiated the development of morphine tolerance and withdrawal. Opioid tolerance was attenuated with intraplantar injection of SUR1 agonists, such as diazoxide and NN-414 (100 μM, 10 μL) compared to vehicle treated animals. These studies are an important first step in determining the role of KATP channel subunits in antinociception, opioid signaling, and the development of opioid tolerance, and shed light on the potential translational ability of KATP channel targeting pharmaceuticals and their possible future clinical utilization. These data suggest that increasing neuronal KATP channel activity in the peripheral nervous system may be a viable option to alleviate opioid tolerance and withdrawal.
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Affiliation(s)
- Cole Fisher
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Kayla Johnson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Travis Okerman
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Taylor Jurgenson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Austin Nickell
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Erin Salo
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Madelyn Moore
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - Alexis Doucette
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
| | - James Bjork
- Department of Biomedical Sciences, Medical School Duluth, Duluth, MN, United States
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota, Duluth, MN, United States
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11
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Islam S, Shajib MS, Rashid RB, Khan MF, Al-Mansur MA, Datta BK, Rashid MA. Antinociceptive activities of Artocarpus lacucha Buch-ham (Moraceae) and its isolated phenolic compound, catechin, in mice. Altern Ther Health Med 2019; 19:214. [PMID: 31412852 PMCID: PMC6694492 DOI: 10.1186/s12906-019-2565-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/17/2019] [Indexed: 12/13/2022]
Abstract
Background The present study evaluated the antinociceptive effect of the bark of Artocarpus lacucha, which is used for the treatment of stomachache, headache and boils in the traditional system of medicine. Methods The antinociceptive activity was investigated by the tail immersion, hot plate, acetic acid- & formalin-induced nociception and carrageenan-induced paw edema tests using a hydro-methanolic extract of A. lacucha bark. The plant extract was found to contain a substantial amount of phenolic compounds according to the total phenolic and flavonoid content assay. A phenolic metabolite, (+)-catechin, has been isolated using different chromatographic techniques. The compound was characterized with 1D and 2D NMR spectroscopic data. (+)-catechin, isolated from A. lacucha was assessed for antinociceptive effects swiss albino mice. Furthermore, the possible involvement of opioid receptors and ATP-sensitive K+ channel for the effect of the plant extract and (+)-catechin has been justified using naloxone and glibenclamide, respectively. Results Oral administration (p.o) of the plant extract (50–200 mg/Kg b.w.) resulted in significant thermal pain protection in the hot plate and tail immersion tests. The action of the plant extract was significantly antagonized by naloxone, a non-selective opioid antagonist, in the hot plate and tail immersion tests, which supports the involvement of opioid receptors. Both the plant extract and (+)-catechin, (50–200 mg/Kg b.w., p.o.) significantly diminished the acetic acid- & formalin-induced nociception, and carrageenan-induced paw edema. Glibenclamide, an ATP-sensitive K+ channel blocker, significantly reversed their effect in the acetic acid-induced writhing test which indicates the participation of ATP-sensitive K+ channel system. Conclusions The investigation revealed potential central and peripheral antinociceptive effects of A. lacucha bark supports its applications in the traditional system of medicine. Electronic supplementary material The online version of this article (10.1186/s12906-019-2565-x) contains supplementary material, which is available to authorized users.
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Luu W, Bjork J, Salo E, Entenmann N, Jurgenson T, Fisher C, Klein AH. Modulation of SUR1 K ATP Channel Subunit Activity in the Peripheral Nervous System Reduces Mechanical Hyperalgesia after Nerve Injury in Mice. Int J Mol Sci 2019; 20:E2251. [PMID: 31067750 PMCID: PMC6539735 DOI: 10.3390/ijms20092251] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/26/2019] [Accepted: 05/03/2019] [Indexed: 01/23/2023] Open
Abstract
The ATP-sensitive K+ channel (KATP) is involved in hypersensitivity during chronic pain and is presumed to be a downstream target of mu opioid receptors. Multiple subtypes of KATP channels exist in the peripheral and central nervous system and their activity may be inversely correlated to chronic pain phenotypes in rodents. In this study, we investigated the different KATP channel subunits that could be involved in neuropathic pain in mice. In chronic pain models utilizing spinal nerve ligation, SUR1 and Kir6.2 subunits were found to be significantly downregulated in dorsal root ganglia and the spinal cord. Local or intrathecal administration of SUR1-KATP channel subtype agonists resulted in analgesia after spinal nerve ligation but not SUR2 agonists. In ex-vivo nerve recordings, administration of the SUR1 agonist diazoxide to peripheral nerve terminals decreased mechanically evoked potentials. Genetic knockdown of SUR1 through an associated adenoviral strategy resulted in mechanical hyperalgesia but not thermal hyperalgesia compared to control mice. Behavioral data from neuropathic mice indicate that local reductions in SUR1-subtype KATP channel activity can exacerbate neuropathic pain symptoms. Since neuropathic pain is of major clinical relevance, potassium channels present a target for analgesic therapies, especially since they are expressed in nociceptors and could play an essential role in regulating the excitability of neurons involved in pain-transmission.
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Affiliation(s)
- Wing Luu
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
| | - James Bjork
- Department of Biomedical Sciences, Medical School Duluth, Duluth, MN 55812, USA.
| | - Erin Salo
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
| | - Nicole Entenmann
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
| | - Taylor Jurgenson
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
| | - Cole Fisher
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
| | - Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN 55812, USA.
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Ali Khan MS, Misbah, Ahmed N, Arifuddin M, Rehman A, Ling MP. Indole alkaloids and anti-nociceptive mechanisms of Tabernaemontana divaricata (L.) R. Br. flower methanolic extract. Food Chem Toxicol 2018; 118:953-962. [DOI: 10.1016/j.fct.2018.06.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/30/2018] [Accepted: 06/04/2018] [Indexed: 11/26/2022]
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14
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Koh WU, Shin JW, Bang JY, Kim SG, Song JG. The Antiallodynic Effects of Nefopam Are Mediated by the Adenosine Triphosphate-Sensitive Potassium Channel in a Neuropathic Pain Model. Anesth Analg 2017; 123:762-70. [PMID: 27224932 DOI: 10.1213/ane.0000000000001411] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Nefopam hydrochloride is a centrally acting compound that induces antinociceptive and antihyperalgesic properties in neuropathic pain models. Previous reports have shown that activation of adenosine triphosphate (ATP)-sensitive and calcium-activated potassium (KATP and KCa2+) channels has antiallodynic effects in neuropathic pain. In the present study, we evaluated the relationship between potassium channels and nefopam to determine whether the antiallodynic effects of nefopam are mediated by potassium channels in a neuropathic pain model. METHODS Mechanical allodynia was induced by spinal nerve ligation (SNL) in rats, and the paw withdrawal threshold (PWT) was evaluated by the use of von Frey filaments. Nefopam was administered intraperitoneally before or after SNL. We assessed the relationship between nefopam and intrathecal injection of the KCa2+ channel antagonists apamin and charybdotoxin, and the KATP channel blocker glibenclamide to assess their abilities to reverse the antiallodynic effects of nefopam. In addition, we evaluated whether the KATP channel opener pinacidil had antiallodynic effects and promoted the antiallodynic effects of nefopam. RESULTS Administration of nefopam before and after SNL induced significant antiallodynic effects (P < .01, respectively), which were significantly reduced by glibenclamide (P < .01). Pinacidil improved the antiallodynic effects of nefopam (P < .01); however, apamin and charybdotoxin had little effects on the antiallodynic properties of nefopam. CONCLUSIONS The antiallodynic effects of nefopam are increased by a KATP channel agonist and reversed by a KATP channel antagonist. These data suggest that the KATP channel is involved in the antiallodynic effects of nefopam in a neuropathic pain model.
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Affiliation(s)
- Won Uk Koh
- From the Department of Anesthesiology and Pain Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
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15
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François A, Scherrer G. Delta Opioid Receptor Expression and Function in Primary Afferent Somatosensory Neurons. Handb Exp Pharmacol 2017; 247:87-114. [PMID: 28993838 DOI: 10.1007/164_2017_58] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The functional diversity of primary afferent neurons of the dorsal root ganglia (DRG) generates a variety of qualitatively and quantitatively distinct somatosensory experiences, from shooting pain to pleasant touch. In recent years, the identification of dozens of genetic markers specifically expressed by subpopulations of DRG neurons has dramatically improved our understanding of this diversity and provided the tools to manipulate their activity and uncover their molecular identity and function. Opioid receptors have long been known to be expressed by discrete populations of DRG neurons, in which they regulate cell excitability and neurotransmitter release. We review recent insights into the identity of the DRG neurons that express the delta opioid receptor (DOR) and the ion channel mechanisms that DOR engages in these cells to regulate sensory input. We highlight recent findings derived from DORGFP reporter mice and from in situ hybridization and RNA sequencing studies in wild-type mice that revealed DOR presence in cutaneous mechanosensory afferents eliciting touch and implicated in tactile allodynia. Mechanistically, we describe how DOR modulates opening of voltage-gated calcium channels (VGCCs) to control glutamatergic neurotransmission between somatosensory neurons and postsynaptic neurons in the spinal cord dorsal horn. We additionally discuss other potential signaling mechanisms, including those involving potassium channels, which DOR may engage to fine tune somatosensation. We conclude by discussing how this knowledge may explain the analgesic properties of DOR agonists against mechanical pain and uncovers an unanticipated specialized function for DOR in cutaneous mechanosensation.
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Affiliation(s)
- Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.,Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.,Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA. .,Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA. .,Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
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16
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Landa-Juárez AY, Ortiz MI, Castañeda-Hernández G, Chávez-Piña AE. Participation of potassium channels in the antinociceptive effect of docosahexaenoic acid in the rat formalin test. Eur J Pharmacol 2016; 793:95-100. [DOI: 10.1016/j.ejphar.2016.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 01/25/2023]
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17
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Smith-Edwards KM, DeBerry JJ, Saloman JL, Davis BM, Woodbury CJ. Profound alteration in cutaneous primary afferent activity produced by inflammatory mediators. eLife 2016; 5. [PMID: 27805567 PMCID: PMC5117853 DOI: 10.7554/elife.20527] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/01/2016] [Indexed: 12/13/2022] Open
Abstract
Inflammatory pain is thought to arise from increased transmission from nociceptors and recruitment of 'silent' afferents. To evaluate inflammation-induced changes, mice expressing GCaMP3 in cutaneous sensory neurons were generated and neuronal responses to mechanical stimulation in vivo before and after subcutaneous infusion of an 'inflammatory soup' (IS) were imaged in an unanesthetized preparation. Infusion of IS rapidly altered mechanical responsiveness in the majority of neurons. Surprisingly, more cells lost, rather than gained, sensitivity and 'silent' afferents that were mechanically insensitive and gained mechanosensitivity after IS exposure were rare. However, the number of formerly 'silent' afferents that became mechanosensitive was increased five fold when the skin was heated briefly prior to infusion of IS. These findings suggest that pain arising from inflamed skin reflects a dramatic shift in the balance of sensory input, where gains and losses in neuronal populations results in novel output that is ultimately interpreted by the CNS as pain.
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Affiliation(s)
- Kristen M Smith-Edwards
- Department of Zoology and Physiology, University of Wyoming, Laramie, United States.,University of Wyoming Graduate Program in Neuroscience, Laramie, United States
| | - Jennifer J DeBerry
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - Jami L Saloman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - C Jeffery Woodbury
- Department of Zoology and Physiology, University of Wyoming, Laramie, United States
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18
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Qian LP, Shen SR, Chen JJ, Ji LL, Cao S. Peripheral KATP activation inhibits pain sensitization induced by skin/muscle incision and retraction via the nuclear factor-κB/c-Jun N-terminal kinase signaling pathway. Mol Med Rep 2016; 14:2632-8. [PMID: 27484116 DOI: 10.3892/mmr.2016.5546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 02/15/2016] [Indexed: 11/05/2022] Open
Abstract
The aim of the current study was to assess the effect of pinacidil activation of ATP‑sensitive potassium (KATP) channels prior to skin/muscle incision and retraction (SMIR) surgery on peripheral and central sensitization, and investigate molecular interferential targets for preventive analgesia. Male Sprague-Dawley rats were randomly assigned to one of the following five groups: Control, incision (sham surgery), incision plus retraction (SMIR) group, SMIR plus pinacidil (pinacidil) group and the SMIR plus pyrrolidine dithiocarbamate (PDTC) group. The rats in the pinacidil and PDTC groups were intraperitoneally injected with pinacidil or PDTC, respectively, prior to the SMIR procedure. The mechanical withdrawal threshold (MWT) was determined. Western blotting was performed to detect the alterations in the subunits of the KATP channels, Kir6.1 and SUR2, levels of nuclear factor‑κB (NF‑κB) in the tissue around the incision and c‑Jun N‑terminal kinase (JNK) in the spinal cord. There was a significant increase observed in the levels of NF‑κB and JNK following SMIR surgery compared with the control group, and a significant reduction in MWT and the levels of Kir6.1 and SUR2. Additionally, intraperitoneal administration of pinacidil inhibited the reduction in MWT, and Kir6.1 and SUR2 levels. SMIR was observed to result in increases in the levels of NF‑κB and JNK. In addition, in the PDTC group, the alterations in MWT, NF‑κB, JNK, Kir6.1 and SUR2 resulting from SMIR were blocked. The results of the current study suggest that the deteriorations in the microenvironment resulting from the SMIR procedure can induce peripheral and central sensitization, and that the activation of peripheral KATP by pinacidil prior to SMIR is able to inhibit peripheral and central sensitization via the NF‑κB/JNK signaling pathway, thus resulting in preventive analgesia.
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Affiliation(s)
- Li-Ping Qian
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Shi-Ren Shen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Jun-Jie Chen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Lu-Lu Ji
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Su Cao
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
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Ji J, Yan H, Chen ZZ, Zhao Z, Yang DD, Sun XL, Shi YP. Iptakalim protects against ischemic injury by improving neurovascular unit function in the mouse brain. Clin Exp Pharmacol Physiol 2015; 42:766-71. [DOI: 10.1111/1440-1681.12426] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/12/2015] [Accepted: 05/13/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Juan Ji
- Department of Pharmacology; Nanjing Medical University; Nanjing China
| | - Hui Yan
- Department of Pharmacology; Nanjing Medical University; Nanjing China
| | - Zheng-Zhen Chen
- Department of Pharmacology; Nanjing Medical University; Nanjing China
| | - Zhan Zhao
- Department of Pharmacology; Nanjing Medical University; Nanjing China
| | - Dan-Dan Yang
- Department of Pharmacology; Nanjing Medical University; Nanjing China
| | - Xiu-Lan Sun
- Department of Pharmacology; Nanjing Medical University; Nanjing China
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20
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Zhu X, Liu J, Gao Y, Cao S, Shen S. ATP-sensitive potassium channels alleviate postoperative pain through JNK-dependent MCP-1 expression in spinal cord. Int J Mol Med 2015; 35:1257-65. [PMID: 25812598 PMCID: PMC4380206 DOI: 10.3892/ijmm.2015.2143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 03/09/2015] [Indexed: 12/24/2022] Open
Abstract
Although adenosine triphosphate-sensitive potassium (KATP) channels have been proven to be involved in regulating postoperative pain, the underlying mechanism remains to be investigated. In this study, we aimed to determine the role of spinal KATP channels in the control of mechanical hypersensitivity in a rat pain model, in which rats were subjected to skin/muscle incision and retraction (SMIR) surgery, as well as in LPS-stimulated astrocytes. The results showed that KATP channel subunits Kir6.1, SUR1 and SUR2 were normally expressed in the spinal cord and significantly downregulated after SMIR. SMIR caused a marked increase in monocyte chemoattractant protein-1 (MCP-1) mRNA expression and in the protein level of p-JNK in the spinal cord. Intrathecal administration of a KATP channel opener pinacidil (Pina) suppressed mechanical allodynia after SMIR and significantly downregulated the MCP-1 mRNA expression and the protein level of p-JNK induced by SMIR. Inverted fluorescence microscopy showed that Kir6.1 was co-localized with astrocytes only and SUR2 was co-localized primarily with neurons, in a small amount with astrocytes. Furthermore, in vitro studies showed that following incubation with LPS, the astrocytic MCP-1 mRNA expression and p-JNK content were markedly increased, whereas the mRNA levels of Kir6.1 and SUR2 were significantly downregulated in astrocytes. KATP channel opener pinacidil inhibited the LPS-triggered MCP-1 and p-JNK elevation in rat primary astrocytes. The results suggested that KATP channel opener treatment is an effective therapy for postoperative pain in animals, through the activation of the JNK/MCP-1 pathway in astrocytes.
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Affiliation(s)
- Xiang Zhu
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Jinqian Liu
- Department of Anesthesiology, Binzhou Medical University Hospital, Binzhou, Shandong 256603, P.R. China
| | - Yongjing Gao
- Institute of Nautical Medicine, Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Su Cao
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Shiren Shen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
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21
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Cao S, Qin Y, Chen J, Shen S. Effects of pinacidil on changes to the microenvironment around the incision site, of a skin/muscle incision and retraction, in a rat model of postoperative pain. Mol Med Rep 2015; 12:829-36. [PMID: 25760986 PMCID: PMC4438946 DOI: 10.3892/mmr.2015.3465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 07/23/2014] [Indexed: 12/18/2022] Open
Abstract
The aim of the present study was to evaluate the influence of the microenvironment around an incision site, on peripheral and central sensitization. The effects of pinacidil activation of ATP-sensitive potassium (KATP) channels prior to skin/muscle incision and retraction (SMIR) surgery were assessed. A total of 24 male Sprague Dawley rats were randomly assigned to four groups: Control, sham (incision operation), SMIR (incision plus retraction 1 h after the skin/muscle incision) and pinacidil (SMIR plus pinacidil). The rats in the pinacidil group were intraperitoneally injected with pinacidil prior to the SMIR procedure. The mechanical withdrawal threshold (MWT) was determined at each time point. The microvessel density (MVD) value was determined by immunohistochemistry, and western blotting was performed to analyze the relative protein expression levels of nerve growth factor (NGF), glucose transporter protein-1 (GLUT1) and C-jun N-terminal kinases. There was a significant reduction in the levels of MVD, GLUT1 and MWT following SMIR surgery as compared with the incision alone, and a significant increase in the NGF protein expression levels. In the SMIR group, the MVD value was significantly increased seven days after surgery, as compared with three days after surgery. Additionally, intraperitoneal administration of pinacidil prior to the SMIR surgery inhibited the SMIR-induced reduction in MWT and MVD and attenuated the SMIR-induced GLUT1 reduction. The results of the present study suggest that the microenvironment around an incision site may affect the development of peripheral and central sensitization. In addition, pinacidil had an inhibitory effect on the formation of the inflammatory microenvironment around the incision site through activation of KATP channels, thereby inhibiting peripheral and central sensitization.
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Affiliation(s)
- Su Cao
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Yinbin Qin
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Junjie Chen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Shiren Shen
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, Jiangsu 226001, P.R. China
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22
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Gamper N, Ooi L. Redox and nitric oxide-mediated regulation of sensory neuron ion channel function. Antioxid Redox Signal 2015; 22:486-504. [PMID: 24735331 PMCID: PMC4323017 DOI: 10.1089/ars.2014.5884] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
SIGNIFICANCE Reactive oxygen and nitrogen species (ROS and RNS, respectively) can intimately control neuronal excitability and synaptic strength by regulating the function of many ion channels. In peripheral sensory neurons, such regulation contributes towards the control of somatosensory processing; therefore, understanding the mechanisms of such regulation is necessary for the development of new therapeutic strategies and for the treatment of sensory dysfunctions, such as chronic pain. RECENT ADVANCES Tremendous progress in deciphering nitric oxide (NO) and ROS signaling in the nervous system has been made in recent decades. This includes the recognition of these molecules as important second messengers and the elucidation of their metabolic pathways and cellular targets. Mounting evidence suggests that these targets include many ion channels which can be directly or indirectly modulated by ROS and NO. However, the mechanisms specific to sensory neurons are still poorly understood. This review will therefore summarize recent findings that highlight the complex nature of the signaling pathways involved in redox/NO regulation of sensory neuron ion channels and excitability; references to redox mechanisms described in other neuron types will be made where necessary. CRITICAL ISSUES The complexity and interplay within the redox, NO, and other gasotransmitter modulation of protein function are still largely unresolved. Issues of specificity and intracellular localization of these signaling cascades will also be addressed. FUTURE DIRECTIONS Since our understanding of ROS and RNS signaling in sensory neurons is limited, there is a multitude of future directions; one of the most important issues for further study is the establishment of the exact roles that these signaling pathways play in pain processing and the translation of this understanding into new therapeutics.
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Affiliation(s)
- Nikita Gamper
- 1 Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds , Leeds, United Kingdom
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Du X, Hao H, Gigout S, Huang D, Yang Y, Li L, Wang C, Sundt D, Jaffe DB, Zhang H, Gamper N. Control of somatic membrane potential in nociceptive neurons and its implications for peripheral nociceptive transmission. Pain 2014; 155:2306-22. [PMID: 25168672 PMCID: PMC4247381 DOI: 10.1016/j.pain.2014.08.025] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 08/02/2014] [Accepted: 08/19/2014] [Indexed: 01/10/2023]
Abstract
Peripheral sensory ganglia contain somata of afferent fibres conveying somatosensory inputs to the central nervous system. Growing evidence suggests that the somatic/perisomatic region of sensory neurons can influence peripheral sensory transmission. Control of resting membrane potential (Erest) is an important mechanism regulating excitability, but surprisingly little is known about how Erest is regulated in sensory neuron somata or how changes in somatic/perisomatic Erest affect peripheral sensory transmission. We first evaluated the influence of several major ion channels on Erest in cultured small-diameter, mostly capsaicin-sensitive (presumed nociceptive) dorsal root ganglion (DRG) neurons. The strongest and most prevalent effect on Erest was achieved by modulating M channels, K2P and 4-aminopiridine-sensitive KV channels, while hyperpolarization-activated cyclic nucleotide-gated, voltage-gated Na+, and T-type Ca2+ channels to a lesser extent also contributed to Erest. Second, we investigated how varying somatic/perisomatic membrane potential, by manipulating ion channels of sensory neurons within the DRG, affected peripheral nociceptive transmission in vivo. Acute focal application of M or KATP channel enhancers or a hyperpolarization-activated cyclic nucleotide-gated channel blocker to L5 DRG in vivo significantly alleviated pain induced by hind paw injection of bradykinin. Finally, we show with computational modelling how somatic/perisomatic hyperpolarization, in concert with the low-pass filtering properties of the t-junction within the DRG, can interfere with action potential propagation. Our study deciphers a complement of ion channels that sets the somatic Erest of nociceptive neurons and provides strong evidence for a robust filtering role of the somatic and perisomatic compartments of peripheral nociceptive neuron.
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Affiliation(s)
- Xiaona Du
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China.
| | - Han Hao
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Sylvain Gigout
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, UK
| | - Dongyang Huang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Yuehui Yang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Li Li
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Caixue Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Danielle Sundt
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - David B Jaffe
- Department of Biology, University of Texas at San Antonio, San Antonio, TX, USA
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China
| | - Nikita Gamper
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, PR China; Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, UK.
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Pandurangan K, Krishnappan V, Subramanian V, Subramanyan R. Antinociceptive effect of certain dimethoxy flavones in mice. Eur J Pharmacol 2014; 727:148-57. [PMID: 24486704 DOI: 10.1016/j.ejphar.2014.01.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 01/21/2014] [Accepted: 01/22/2014] [Indexed: 10/25/2022]
Abstract
The aim of the present study was to evaluate the antinociceptive action of certain dimethoxy flavones (DMF, (7,2׳-dimethoxy flavone, 7,3׳-dimethoxy flavone, 7,4׳-dimethoxy flavone and 7,8,-dimethoxy flavone) and the possible mechanisms involved. The antinociceptive effect of dimethoxy flavones was investigated in mice employing acetic acid-induced abdominal writhings, formalin-induced nociception and hot water tail immersion assay procedures. To identify the possible mechanisms involved in the antinociceptive action of these compounds, acetic acid-induced abdominal constriction assay alone was employed. Mice were pretreated with naloxone, yohimbine, ondansetron, haloperidol, bicuculline or glibenclamide before dimethoxy flavone treatment to identify the role of opioid, adrenergic, 5HT3-serotonergic, dopaminergic, gamma-amino butyric acid (GABA) receptor or potassium channels, respectively. The investigated dimethoxy flavones produced a significant reduction in the number of abdominal constrictions in acetic acid assay. A dose dependent decrease in paw-licking response time was evident in both the early and late phases of formalin induced nociception. A significant increase in reaction time was also evident after treatment with various dimethoxy flavones in hot water tail immersion assay. Pretreatment with naloxone, ondansetron or glibenclamide significantly attenuated the antinociceptive effect of all the four dimethoxy flavones. Yohimbine pretreatment attenuated the antinociceptive response of 7,3׳-dimethoxy flavone, 7,4׳-dimethoxy flavone and 7,8-dimethoxy flavone. Pretreatment with haloperidol potentiated the antinociceptive response of all the tested dimethoxy flavones. The antinociceptive effect of 7,2׳-dimethoxy flavone and 7,3׳-dimethoxy flavone was annulled by bicuculline pretreatment. The results of the present study reveal the antinociceptive effect of dimethoxy flavones involving multiple pathways.
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Affiliation(s)
- Kamalakannan Pandurangan
- Department of Pharmacology, Meenakshi Medical College & Research Institute, Meenakshi Academy of Higher Education and Research, Kanchipuram 631 552, Tamilnadu, India.
| | | | - Viswanathan Subramanian
- Department of Pharmacology, Meenakshi Medical College & Research Institute, Meenakshi Academy of Higher Education and Research, Kanchipuram 631 552, Tamilnadu, India.
| | - Ramaswamy Subramanyan
- Department of Pharmacology, Sri Lakshminarayana Institute of Medical Sciences, Pondicherry 605 502, India.
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Opening paths to novel analgesics: the role of potassium channels in chronic pain. Trends Neurosci 2014; 37:146-58. [PMID: 24461875 PMCID: PMC3945816 DOI: 10.1016/j.tins.2013.12.002] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/13/2013] [Accepted: 12/17/2013] [Indexed: 01/02/2023]
Abstract
Potassium (K+) channels are crucial determinants of neuronal excitability. Nerve injury or inflammation alters K+ channel activity in neurons of the pain pathway. These changes can render neurons hyperexcitable and cause chronic pain. Therapies targeting K+ channels may provide improved pain relief in these states.
Chronic pain is associated with abnormal excitability of the somatosensory system and remains poorly treated in the clinic. Potassium (K+) channels are crucial determinants of neuronal activity throughout the nervous system. Opening of these channels facilitates a hyperpolarizing K+ efflux across the plasma membrane that counteracts inward ion conductance and therefore limits neuronal excitability. Accumulating research has highlighted a prominent involvement of K+ channels in nociceptive processing, particularly in determining peripheral hyperexcitability. We review salient findings from expression, pharmacological, and genetic studies that have untangled a hitherto undervalued contribution of K+ channels in maladaptive pain signaling. These emerging data provide a framework to explain enigmatic pain syndromes and to design novel pharmacological treatments for these debilitating states.
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Du X, Gamper N. Potassium channels in peripheral pain pathways: expression, function and therapeutic potential. Curr Neuropharmacol 2013; 11:621-40. [PMID: 24396338 PMCID: PMC3849788 DOI: 10.2174/1570159x113119990042] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Electrical excitation of peripheral somatosensory nerves is a first step in generation of most pain signals in mammalian nervous system. Such excitation is controlled by an intricate set of ion channels that are coordinated to produce a degree of excitation that is proportional to the strength of the external stimulation. However, in many disease states this coordination is disrupted resulting in deregulated peripheral excitability which, in turn, may underpin pathological pain states (i.e. migraine, neuralgia, neuropathic and inflammatory pains). One of the major groups of ion channels that are essential for controlling neuronal excitability is potassium channel family and, hereby, the focus of this review is on the K+ channels in peripheral pain pathways. The aim of the review is threefold. First, we will discuss current evidence for the expression and functional role of various K+ channels in peripheral nociceptive fibres. Second, we will consider a hypothesis suggesting that reduced functional activity of K+ channels within peripheral nociceptive pathways is a general feature of many types of pain. Third, we will evaluate the perspectives of pharmacological enhancement of K+ channels in nociceptive pathways as a strategy for new analgesic drug design.
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Affiliation(s)
- Xiaona Du
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Nikita Gamper
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
- Faculty of Biological Sciences, University of Leeds, Leeds, UK
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Triple cysteine module within M-type K+ channels mediates reciprocal channel modulation by nitric oxide and reactive oxygen species. J Neurosci 2013; 33:6041-6. [PMID: 23554485 DOI: 10.1523/jneurosci.4275-12.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We have identified a new signaling role for nitric oxide (NO) in neurons from the trigeminal ganglia (TG). We show that in rat sensory neurons from the TG the NO donor, S-nitroso-N-acetyl-dl-penicillamine, inhibited M-current. This inhibitory effect was blocked by NO scavenging, while inhibition of NO synthases increased M-current, suggesting that tonic NO levels inhibit M-current in TG neurons. Moreover NO increased neuronal excitability and calcitonin gene-related peptide (CGRP) release and these effects could be prevented by perturbing M-channel function. First, NO-induced depolarization was prevented by pre-application of the M-channel blocker XE991 and second, NO-induced increase in CGRP release was prevented by incubation with the M-channel opener retigabine. We investigated the mechanism of the effects of NO on M-channels and identified a site of action of NO to be the redox modulatory site at the triplet of cysteines within the cytosolic linker between transmembrane domains 2 and 3, which is also a site of oxidative modification of M-channels by reactive oxygen species (ROS). NO and oxidative modifications have opposing effects on M-current, suggesting that a tightly controlled local redox and NO environment will exert fine control over M-channel activity and thus neuronal excitability. Together our data have identified a dynamic redox sensor within neuronal M-channels, which mediates reciprocal regulation of channel activity by NO and ROS. This sensor may play an important role in mediating excitatory effects of NO in such trigeminal disorders as headache and migraine.
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Babes A, Fischer MJ, Filipovic M, Engel MA, Flonta ML, Reeh PW. The anti-diabetic drug glibenclamide is an agonist of the transient receptor potential Ankyrin 1 (TRPA1) ion channel. Eur J Pharmacol 2013; 704:15-22. [DOI: 10.1016/j.ejphar.2013.02.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/01/2013] [Accepted: 02/07/2013] [Indexed: 12/16/2022]
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De Paz-Campos MA, Chávez-Piña AE, Ortiz MI, Castañeda-Hernández G. Evidence for the Participation of ATP-sensitive Potassium Channels in the Antinociceptive Effect of Curcumin. Korean J Pain 2012; 25:221-7. [PMID: 23091682 PMCID: PMC3468798 DOI: 10.3344/kjp.2012.25.4.221] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Revised: 08/31/2012] [Accepted: 09/04/2012] [Indexed: 12/27/2022] Open
Abstract
Background It has been reported that curcumin, the main active compound of Curcuma longa, also known as turmeric, exhibits antinociceptive properties. The aim of this study was to examine the participation of ATP-sensitive potassium channels (KATP channels) and, in particular, that of the L-arginine-nitric oxide-cyclic GMP-KATP channel pathway, in the antinociceptive effect of curcumin. Methods Pain was induced by the intraplantar injection of 1% formalin in the right hind paw of Wistar rats. Formalin-induced flinching behavior was interpreted as an expression of nociception. The antinociceptive effect of oral curcumin was explored in the presence and absence of local pretreatment with L-NAME, an inhibitor of nitric oxide synthase, ODQ, an inhibitor of soluble guanylyl cyclase, and glibenclamide, a blocker of KATP channels. Results Oral curcumin produced a dose-dependent antinociceptive effect in the 1% formalin test. Curcumin-induced antinociception was not altered by local L-NAME or ODQ, but was significantly impaired by glibenclamide. Conclusions Our results confirm that curcumin is an effective antinociceptive agent. Curcumin-induced antinociception appears to involve the participation of KATP channels at the peripheral level, as local injection of glibenclamide prevented its effect. Activation of KATP channels, however, does not occur by activation of the L-arginine-nitric oxide-cGMP-KATP channel pathway.
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Affiliation(s)
- Marco Antonio De Paz-Campos
- Department of Pharmacology, Center for Research and Advanced Studies of the National Polytechnic Institute, Mexico, DF, Mexico
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Chen YF, Zhang JY, Zhao MH, Yan M, Zhao QC, Wu Q, Jin H, Shi GB. The analgesic activity and possible mechanisms of deacetyl asperulosidic acid methyl ester from Ji shi teng in mice. Pharmacol Biochem Behav 2012; 102:585-92. [DOI: 10.1016/j.pbb.2012.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 07/02/2012] [Accepted: 07/11/2012] [Indexed: 11/29/2022]
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Iwase T, Takebayashi T, Tanimoto K, Terashima Y, Miyakawa T, Kobayashi T, Tohse N, Yamashita T. Sympathectomy attenuates excitability of dorsal root ganglion neurons and pain behaviour in a lumbar radiculopathy model. Bone Joint Res 2012; 1:198-204. [PMID: 23610691 PMCID: PMC3626214 DOI: 10.1302/2046-3758.19.2000073] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/03/2012] [Indexed: 01/19/2023] Open
Abstract
Objectives In order to elucidate the influence of sympathetic nerves on
lumbar radiculopathy, we investigated whether sympathectomy attenuated
pain behaviour and altered the electrical properties of the dorsal
root ganglion (DRG) neurons in a rat model of lumbar root constriction. Methods Sprague-Dawley rats were divided into three experimental groups.
In the root constriction group, the left L5 spinal nerve root was
ligated proximal to the DRG as a lumbar radiculopathy model. In
the root constriction + sympathectomy group, sympathectomy was performed
after the root constriction procedure. In the control group, no
procedures were performed. In order to evaluate the pain relief
effect of sympathectomy, behavioural analysis using mechanical and
thermal stimulation was performed. In order to evaluate the excitability
of the DRG neurons, we recorded action potentials of the isolated
single DRG neuron by the whole-cell patch-clamp method. Results In behavioural analysis, sympathectomy attenuated the mechanical
allodynia and thermal hyperalgesia caused by lumbar root constriction.
In electrophysiological analysis, single isolated DRG neurons with
root constriction exhibited lower threshold current, more depolarised
resting membrane potential, prolonged action potential duration,
and more depolarisation frequency. These hyperexcitable alterations
caused by root constriction were significantly attenuated in rats
treated with surgical sympathectomy. Conclusion The present results suggest that sympathectomy attenuates lumbar
radicular pain resulting from root constriction by altering the
electrical property of the DRG neuron itself. Thus, the sympathetic
nervous system was closely associated with lumbar radicular pain,
and suppressing the activity of the sympathetic nervous system may therefore
lead to pain relief.
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Affiliation(s)
- T Iwase
- Sapporo Medical University School of Medicine, Department of Orthopaedic Surgery, South 1, West 16, Chuo-ku, Sapporo 060-8543, Japan
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