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Norris MR, Kuo CC, Dunn SS, Kim JR, Becker LJ, Borges G, Thang LV, Parker KE, McCall JG. Mu opioid receptors gate the locus coeruleus pain generator. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.20.562785. [PMID: 37961541 PMCID: PMC10634678 DOI: 10.1101/2023.10.20.562785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The locus coeruleus (LC) plays a paradoxical role in chronic pain. Although largely known as a potent source of endogenous analgesia, increasing evidence suggests injury can transform the LC into a chronic pain generator. We sought to clarify the role of this system in pain. Here, we show optogenetic inhibition of LC activity is acutely antinociceptive. Following long-term spared nerve injury, the same LC inhibition is analgesic - further supporting its pain generator function. To identify inhibitory substrates that may naturally serve this function, we turned to endogenous LC mu opioid receptors (LC-MOR). These receptors provide powerful LC inhibition and exogenous activation of LC-MOR is antinociceptive. We therefore hypothesized that endogenous LC-MOR-mediated inhibition is critical to how the LC modulates pain. Using cell type-selective conditional knockout and rescue of LC-MOR receptor signaling, we show these receptors bidirectionally regulate thermal and mechanical hyperalgesia - providing a functional gate on the LC pain generator.
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Affiliation(s)
- Makenzie R. Norris
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Chao-Cheng Kuo
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Samantha S. Dunn
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Jenny R. Kim
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Léa J. Becker
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Gustavo Borges
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Loc V. Thang
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Kyle E. Parker
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Jordan G. McCall
- Department of Anesthesiology, Washington University in St. Louis, St. Louis, MO, USA; Department of Pharmaceutical and Administrative Sciences, University of Health Sciences and Pharmacy in St. Louis, St. Louis, MO, USA; Center for Clinical Pharmacology, University of Health Sciences and Pharmacy in St. Louis and Washington University School of Medicine, St. Louis, MO, USA; Washington University Pain Center, Washington University in St. Louis, St. Louis, MO, USA
- Division of Biology and Biomedical Sciences, Washington University School of Medicine, St. Louis, MO, USA
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Yildiz Pehlivan D, Kara AY, Koyu A, Simsek F. Enhancing fentanyl antinociception and preventing tolerance with α-2 adrenoceptor agonists in rats. Behav Brain Res 2024; 457:114726. [PMID: 37865211 DOI: 10.1016/j.bbr.2023.114726] [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: 08/08/2023] [Revised: 10/06/2023] [Accepted: 10/17/2023] [Indexed: 10/23/2023]
Abstract
Fentanyl (FEN) is a potent opioid analgesic used for pain management. Opioid analgesic tolerance poses a significant challenge to the clinical utility of opioid agonists. Preventing the development of tolerance to opioid analgesia is crucial for improving its efficacy and safety. The noradrenergic system is involved in pain regulation. This study examined the effects of α-2 adrenoceptor (AR) agonists, dexmedetomidine (DEX), and xylazine (XYL) on FEN tolerance and antinociception, and their impact on μ-opioid receptor (MOR) expression in the posterior horn of the spinal cord (SC). Male rats were divided into six groups and treated with different drug combinations for three consecutive days. Analgesia tests and motor performance assessments were conducted, followed by SC analysis using immunohistochemistry (IHC). Analgesia tests revealed the development of FEN tolerance on the second day, but the groups receiving combined drugs did not develop tolerance. Instead, FEN antinociception was enhanced, with a prolonged duration of its effects. None of the drugs caused sedation or motor impairment, and SC morphology appeared normal. MOR expression levels did not differ significantly between the groups based on IHC analysis. These findings suggest that changes in the secondary messenger system may play a role in the early development of FEN tolerance. Combining drugs can prevent tolerance, while enhancing FEN's antinociceptive effects. These results have promising implications for chronic pain management; however, further research is needed to explore the molecular effects of α-2 AR agonists on FEN tolerance. Overall, this study sheds light on the mechanism of FEN tolerance and identifies potential avenues for future research.
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Affiliation(s)
- Deniz Yildiz Pehlivan
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey
| | - Ali Yucel Kara
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey.
| | - Ahmet Koyu
- Izmir Katip Celebi University, Faculty of Medicine, Department of Physiology, Izmir, Turkey
| | - Fatma Simsek
- Izmir Katip Celebi University, Faculty of Medicine, Department of Histology and Embryology, Izmir, Turkey
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Harbour K, Cappel Z, Baccei ML. Effects of Corticosterone on the Excitability of Glutamatergic and GABAergic Neurons of the Adolescent Mouse Superficial Dorsal Horn. Neuroscience 2023; 526:290-304. [PMID: 37437798 PMCID: PMC10530204 DOI: 10.1016/j.neuroscience.2023.07.009] [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: 04/04/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 07/14/2023]
Abstract
Stress evokes age-dependent effects on pain sensitivity and commonly occurs during adolescence. However, the mechanisms linking adolescent stress and pain remain poorly understood, in part due to a lack of information regarding how stress hormones modulate the function of nociceptive circuits in the adolescent CNS. Here we investigate the short- and long-term effects of corticosterone (CORT) on the excitability of GABAergic and presumed glutamatergic neurons of the spinal superficial dorsal horn (SDH) in Gad1-GFP mice at postnatal days (P)21-P34. In situ hybridization revealed that glutamatergic SDH neurons expressed significantly higher mRNA levels of both glucocorticoid receptors (GR) and mineralocorticoid receptors (MR) compared to adjacent GABAergic neurons. The incubation of spinal cord slices with CORT (90 min) evoked select long-term changes in spontaneous synaptic transmission across both cell types in a sex-dependent manner, without altering the intrinsic firing of either Gad1-GFP+ or GFP- neurons. Meanwhile, the acute bath application of CORT significantly decreased the frequency and amplitude of miniature excitatory postsynaptic currents (mEPSCs), as well as the frequency of miniature inhibitory postsynaptic currents (mIPSCs), in both cell types leading to a net reduction in the balance of spontaneous excitation vs. inhibition (E:I ratio). This CORT-induced reduction in the E:I ratio was not prevented by selective antagonists of either GR (mifepristone) or MR (eplerenone), although eplerenone blocked the effect on mEPSC amplitude. Collectively, these data suggest that corticosterone modulates synaptic function within the adolescent SDH which could influence the overall excitability and output of the spinal nociceptive network.
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Affiliation(s)
- Kyle Harbour
- Molecular, Cellular and Biochemical Pharmacology Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Zoe Cappel
- Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; American Society for Pharmacology and Experimental Therapeutics Summer Research Program, Department of Pharmacology and Systems Physiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA
| | - Mark L Baccei
- Molecular, Cellular and Biochemical Pharmacology Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Pain Research Center, Department of Anesthesiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; Neuroscience Graduate Program, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45267, USA; American Society for Pharmacology and Experimental Therapeutics Summer Research Program, Department of Pharmacology and Systems Physiology, University of Cincinnati Medical Center, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
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Huang Y, Chen H, Chen SR, Pan HL. Duloxetine and Amitriptyline Reduce Neuropathic Pain by Inhibiting Primary Sensory Input to Spinal Dorsal Horn Neurons via α1- and α2-Adrenergic Receptors. ACS Chem Neurosci 2023; 14:1261-1277. [PMID: 36930958 DOI: 10.1021/acschemneuro.2c00780] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
Abstract
Antidepressants, such as duloxetine and amitriptyline, are effective for treating patients with chronic neuropathic pain. Inhibiting norepinephrine and serotonin transporters at presynaptic terminals raises extracellular concentrations of norepinephrine. The α1- and α2-adrenergic receptor agonists inhibit glutamatergic input from primary afferent nerves to the spinal dorsal horn. However, the contribution of spinal α1- and α2-adrenergic receptors to the analgesic effect of antidepressants and associated synaptic plasticity remains uncertain. In this study, we showed that systemic administration of duloxetine or amitriptyline acutely reduced tactile allodynia and mechanical and thermal hyperalgesia caused by spinal nerve ligation in rats. In contrast, duloxetine or amitriptyline had no effect on nociception in sham rats. Blocking α1-adrenergic receptors with WB-4101 or α2-adrenergic receptors with yohimbine at the spinal level diminished the analgesic effect of systemically administered duloxetine and amitriptyline. Furthermore, intrathecal injection of duloxetine or amitriptyline similarly attenuated pain hypersensitivity in nerve-injured rats; the analgesic effect was abolished by intrathecal pretreatment with both WB-4101 and yohimbine. In addition, whole-cell patch-clamp recordings in spinal cord slices showed that duloxetine or amitriptyline rapidly inhibited dorsal root-evoked excitatory postsynaptic currents in dorsal horn neurons in nerve-injured rats but had no such effect in sham rats. The inhibitory effect of duloxetine and amitriptyline was abolished by the WB-4101 and yohimbine combination. Therefore, antidepressants attenuate neuropathic pain predominantly by inhibiting primary afferent input to the spinal cord via activating both α1- and α2-adrenergic receptors. This information helps the design of new strategies to improve the treatment of neuropathic pain.
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Affiliation(s)
- Yuying Huang
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Hong Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Shao-Rui Chen
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
| | - Hui-Lin Pan
- Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, United States
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Ishibashi T, Sueto D, Yoshikawa Y, Koga K, Yamaura K, Tsuda M. Identification of Spinal Inhibitory Interneurons Required for Attenuating Effect of Duloxetine on Neuropathic Allodynia-like Signs in Rats. Cells 2022; 11:cells11244051. [PMID: 36552814 PMCID: PMC9777279 DOI: 10.3390/cells11244051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Neuropathic pain is a chronic pain condition that occurs after nerve damage; allodynia, which refers to pain caused by generally innocuous stimuli, is a hallmark symptom. Although allodynia is often resistant to analgesics, the antidepressant duloxetine has been used as an effective therapeutic option. Duloxetine increases spinal noradrenaline (NA) levels by inhibiting its transporter at NAergic terminals in the spinal dorsal horn (SDH), which has been proposed to contribute to its pain-relieving effect. However, the mechanism through which duloxetine suppresses neuropathic allodynia remains unclear. Here, we identified an SDH inhibitory interneuron subset (captured by adeno-associated viral (AAV) vectors incorporating a rat neuropeptide Y promoter; AAV-NpyP+ neurons) that is mostly depolarized by NA. Furthermore, this excitatory effect was suppressed by pharmacological blockade or genetic knockdown of α1B-adrenoceptors (ARs) in AAV-NpyP+ SDH neurons. We found that duloxetine suppressed Aβ fiber-mediated allodynia-like behavioral responses after nerve injury and that this effect was not observed in AAV-NpyP+ SDH neuron-selective α1B-AR-knockdown. These results indicate that α1B-AR and AAV-NpyP+ neurons are critical targets for spinal NA and are necessary for the therapeutic effect of duloxetine on neuropathic pain, which can support the development of novel analgesics.
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Affiliation(s)
- Tadayuki Ishibashi
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
- Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Daichi Sueto
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Yu Yoshikawa
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Keisuke Koga
- Department of Neurophysiology, Hyogo College of Medicine, Nishinomiya 663-8501, Japan
| | - Ken Yamaura
- Department of Anesthesiology and Critical Care Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka 812-8582, Japan
- Kyushu University Institute for Advanced Study, Fukuoka 819-0395, Japan
- Correspondence:
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Irvine KA, Peters CM, Vazey EM, Ferguson AR, Clark JD. Activation of the Locus Coeruleus Mediated by Designer Receptor Exclusively Activated by Designer Drug Restores Descending Nociceptive Inhibition after Traumatic Brain Injury in Rats. J Neurotrauma 2022; 39:964-978. [PMID: 35412843 PMCID: PMC9467637 DOI: 10.1089/neu.2021.0485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Disruption of endogenous pain control mechanisms including descending pain inhibition has been linked to several forms of pain including chronic pain after traumatic brain injury (TBI). The locus coeruleus (LC) is the principal noradrenergic (NA) nucleus participating in descending pain inhibition. We therefore hypothesized that selectively stimulating LC neurons would reduce nociception after TBI. All experiments used a well-characterized rat lateral fluid percussion model of TBI. NA neurons were stimulated by administering clozapine N-oxide (CNO) to rats selectively expressing a designer receptor exclusively activated by designer drug (DREADD) viral construct in their LC's. Mechanical nociceptive thresholds were measured using von Frey fibers. The efficacy of diffuse noxious inhibitory control (DNIC), a critical endogenous pain control mechanism, was assessed using the hindpaw administration of capsaicin. Immunohistochemical analyses demonstrated the selective expression of the DREADD construct in LC neurons after stereotactic injection. During the 1st week after TBI, when rats demonstrated hindlimb (HL) nociceptive sensitization, CNO administration provided transient anti-allodynia in DREADD-expressing rats but not in rats injected with control virus. Seven weeks after TBI we observed a complete loss of DNIC in response to capsaicin. However, CNO administration largely restored DNIC in TBI DREADD-expressing rats but not those injected with control virus. Unexpectedly, the effects of LC activation in the DREADD-expressing rats were blocked by the α-1 adrenergic receptor antagonist prazosin, but not the α-2 adrenergic receptor antagonist atipamezole. These results suggest that directly stimulating the LC after TBI can reduce both early and late manifestations of dysfunctional endogenous pain regulation. Clinical approaches to activating descending pain circuits may reduce suffering in those with pain after TBI.
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Affiliation(s)
- Karen-Amanda Irvine
- Department of Anesthesiology, Perioperative and Pain Medicine; Stanford University, School of Medicine, Stanford, California, USA.,Anesthesiology Service; Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA.,Address correspondence to: Karen-Amanda Irvine, PhD, Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, School of Medicine, Stanford, CA 94305, USA
| | - Christopher M. Peters
- Department of Anesthesiology, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina, USA
| | - Elena M. Vazey
- Department of Biology, University of Massachusetts Amherst, Amherst Massachusetts, USA
| | - Adam R. Ferguson
- University of California San Francisco, Brain and Spinal Injury Center, Department of Neurosurgery, San Francisco, California, USA
| | - J. David Clark
- Department of Anesthesiology, Perioperative and Pain Medicine; Stanford University, School of Medicine, Stanford, California, USA.,Anesthesiology Service; Veterans Affairs Palo Alto Health Care System, Palo Alto, California, USA
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Ohashi N, Uta D, Ohashi M, Baba H. Norepinephrine restores inhibitory tone of spinal lamina X circuitry, thus contributing to analgesia against inflammatory pain. Neuroscience 2022; 490:224-235. [DOI: 10.1016/j.neuroscience.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/12/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
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Oliva V, Hartley-Davies R, Moran R, Pickering AE, Brooks JC. Simultaneous brain, brainstem and spinal cord pharmacological-fMRI reveals involvement of an endogenous opioid network in attentional analgesia. eLife 2022; 11:71877. [PMID: 35080494 PMCID: PMC8843089 DOI: 10.7554/elife.71877] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
Pain perception is decreased by shifting attentional focus away from a threatening event. This attentional analgesia engages parallel descending control pathways from anterior cingulate (ACC) to locus coeruleus, and ACC to periaqueductal grey (PAG) – rostral ventromedial medulla (RVM), indicating possible roles for noradrenergic or opioidergic neuromodulators. To determine which pathway modulates nociceptive activity in humans, we used simultaneous whole brain-spinal cord pharmacological-fMRI (N = 39) across three sessions. Noxious thermal forearm stimulation generated somatotopic-activation of dorsal horn (DH) whose activity correlated with pain report and mirrored attentional pain modulation. Activity in an adjacent cluster reported the interaction between task and noxious stimulus. Effective connectivity analysis revealed that ACC interacts with PAG and RVM to modulate spinal cord activity. Blocking endogenous opioids with Naltrexone impairs attentional analgesia and disrupts RVM-spinal and ACC-PAG connectivity. Noradrenergic augmentation with Reboxetine did not alter attentional analgesia. Cognitive pain modulation involves opioidergic ACC-PAG-RVM descending control which suppresses spinal nociceptive activity.
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Affiliation(s)
- Valeria Oliva
- Department of Anesthesiology, University of California, San Diego, La Jolla, United States
| | - Ron Hartley-Davies
- School of Psychological Science, University of Bristol, Bristol, United Kingdom
| | - Rosalyn Moran
- Department of Neuroimaging, King's College London, London, United Kingdom
| | - Anthony E Pickering
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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Murtazina AR, Bondarenko NS, Pronina TS, Chandran KI, Bogdanov VV, Dilmukhametova LK, Ugrumov MV. A Comparative Analysis of CSF and the Blood Levels of Monoamines As Neurohormones in Rats during Ontogenesis. Acta Naturae 2021; 13:89-97. [PMID: 35127152 PMCID: PMC8807534 DOI: 10.32607/actanaturae.11516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 09/15/2021] [Indexed: 11/20/2022] Open
Abstract
According to the literature, the cerebrospinal fluid (CSF) in the cerebral ventricles contains numerous neuron-derived physiologically active substances that can function as neurohormones and contribute to volume neurotransmission in the periventricular region of the brain. This study was aimed at carrying out a comparative analysis of CSF and the blood levels of monoamines in rats during ontogenesis as an indicator of age-related characteristics of monoamine transport to body fluids and their function as neurohormones in volume neurotransmission in the periventricular region of the brain. We have shown that CSF in the perinatal period and adulthood contains the most functionally significant monoamines: dopamine, noradrenaline, and serotonin. A comparison of the monoamine levels in the CSF and blood of animals of different age groups revealed that CSF contains monoamines of predominantly neuronal (cerebral) origin and almost no monoamines derived from the general circulation. We also established that monoamines are found in the CSF at physiologically active levels that allow them to act as neurohormones in both reversible volume neurotransmission in the adult brain and irreversible regulation of brain development in the perinatal period.
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Affiliation(s)
- A. R. Murtazina
- Institute of Developmental Biology RAS, Moscow, 119334 Russia
| | | | - T. S. Pronina
- Institute of Developmental Biology RAS, Moscow, 119334 Russia
| | - K. I. Chandran
- Institute of Developmental Biology RAS, Moscow, 119334 Russia
| | - V. V. Bogdanov
- Institute of Developmental Biology RAS, Moscow, 119334 Russia
| | | | - M. V. Ugrumov
- Institute of Developmental Biology RAS, Moscow, 119334 Russia
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5-HT 1A Serotonergic, α-Adrenergic and Opioidergic Receptors Mediate the Analgesic Efficacy of Vortioxetine in Mice. Molecules 2021; 26:molecules26113242. [PMID: 34071269 PMCID: PMC8199248 DOI: 10.3390/molecules26113242] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/22/2021] [Accepted: 05/25/2021] [Indexed: 01/09/2023] Open
Abstract
Vortioxetine is a multimodal antidepressant drug that affects several brain neurochemicals and has the potential to induce various pharmacological effects on the central nervous system. Therefore, we investigated the centrally mediated analgesic efficacy of this drug and the mechanisms underlying this effect. Analgesic activity of vortioxetine (5, 10 and 20 mg/kg, p.o.) was examined by tail-clip, tail-immersion and hot-plate tests. Motor performance of animals was evaluated using Rota-rod device. Time course measurements (30-180 min) showed that vortioxetine (10 and 20 mg/kg) administrations significantly increased the response latency, percent maximum possible effect and area under the curve values in all of the nociceptive tests. These data pointed out the analgesic effect of vortioxetine on central pathways carrying acute thermal and mechanical nociceptive stimuli. Vortioxetine did not alter the motor coordination of mice indicating that the analgesic activity of this drug was specific. In mechanistic studies, pre-treatments with p-chlorophenylalanine (serotonin-synthesis inhibitor), NAN-190 (serotonin 5-HT1A receptor antagonist), α-methyl-para-tyrosine (catecholamine-synthesis inhibitor), phentolamine (non-selective α-adrenoceptor blocker), and naloxone (non-selective opioid receptor blocker) antagonised the vortioxetine-induced analgesia. Obtained findings indicated that vortioxetine-induced analgesia is mediated by 5-HT1A serotonergic, α-adrenergic and opioidergic receptors, and contributions of central serotonergic and catecholaminergic neurotransmissions are critical for this effect.
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Huang CT, Chen SH, Chang CF, Lin SC, Lue JH, Tsai YJ. Melatonin reduces neuropathic pain behavior and glial activation through MT 2 melatonin receptor modulation in a rat model of lysophosphatidylcholine-induced demyelination neuropathy. Neurochem Int 2020; 140:104827. [PMID: 32853748 DOI: 10.1016/j.neuint.2020.104827] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 07/28/2020] [Accepted: 08/07/2020] [Indexed: 12/17/2022]
Abstract
In this study, we investigated whether melatonin treatment prevents development of neuropathic pain via suppression of glial mitogen-activated protein kinases (MAPKs) activation in the cuneate nucleus (CN) in a lysophosphatidylcholine (LPC)-induced median nerve demyelination neuropathy model. Rats were fed orally with melatonin once a day at a dose of 37.5, 75, or 150 mg/kg 30 min before until 3 days after LPC treatment. Subsequently, behavioral tests were conducted on these animals, and immunohistochemistry and immunoblotting were used for qualitative and quantitative analysis of glia and MAPKs, including ERK, JNK, and p38, activation. Enzyme-linked immunosorbent assays were applied to measure pro-inflammatory cytokine responses. Furthermore, intra-CN microinjection of S26131 (MT1 receptor antagonist), 4P-PDOT (MT2 receptor antagonist), or prazosin (MT3 receptor antagonist) were performed to investigate the association between melatonin receptor subtypes and effects of melatonin on demyelination neuropathy. LPC treatment of the median nerve induced a significant increase in glial fibrillary acidic protein (GFAP; an astrocyte marker) and ED1 (an activated microglia marker) immunoreactivity in the ipsilateral CN and led to development of neuropathic pain behavior. Inspection of GFAP-immunoreactive astrocytes revealed that astrocytic hypertrophy, but not proliferation, contributed to increased GFAP immunoreactivity. Double immunofluorescence showed that both GFAP-immunoreactive astrocytes and ED1-immunoreactive microglia co-expressed p-ERK, p-JNK, and p-p38 immunoreactivity. Melatonin administration dose-dependently reduced neuropathic pain behavior, decreased glial and MAPKs activation, and diminished the release of pro-inflammatory cytokines in the ipsilateral CN after LPC treatment. Furthermore, 4P-PDOT, but not S26131 or prazosin, antagonized the therapeutic effects of melatonin. In conclusion, administration of melatonin, via its cognate MT2 receptor, inhibited activation of glial MAPKs, production of pro-inflammatory cytokines, and development of demyelination-induced neuropathic pain behavior.
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Affiliation(s)
- Chun-Ta Huang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Seu-Hwa Chen
- Department of Anatomy, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University, Taichung, Taiwan
| | - Shih-Chang Lin
- Division of Allergy and Immunology, Department of Internal Medicine, Cathay General Hospital, Taipei, Taiwan
| | - June-Horng Lue
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Ju Tsai
- Graduate Institute of Biomedical and Pharmaceutical Science, College of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.
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12
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Cellular Mechanisms for Antinociception Produced by Oxytocin and Orexins in the Rat Spinal Lamina II-Comparison with Those of Other Endogenous Pain Modulators. Pharmaceuticals (Basel) 2019; 12:ph12030136. [PMID: 31527474 PMCID: PMC6789548 DOI: 10.3390/ph12030136] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 08/31/2019] [Accepted: 09/12/2019] [Indexed: 01/23/2023] Open
Abstract
Much evidence indicates that hypothalamus-derived neuropeptides, oxytocin, orexins A and B, inhibit nociceptive transmission in the rat spinal dorsal horn. In order to unveil cellular mechanisms for this antinociception, the effects of the neuropeptides on synaptic transmission were examined in spinal lamina II neurons that play a crucial role in antinociception produced by various analgesics by using the whole-cell patch-clamp technique and adult rat spinal cord slices. Oxytocin had no effect on glutamatergic excitatory transmission while producing a membrane depolarization, γ-aminobutyric acid (GABA)-ergic and glycinergic spontaneous inhibitory transmission enhancement. On the other hand, orexins A and B produced a membrane depolarization and/or a presynaptic spontaneous excitatory transmission enhancement. Like oxytocin, orexin A enhanced both GABAergic and glycinergic transmission, whereas orexin B facilitated glycinergic but not GABAergic transmission. These inhibitory transmission enhancements were due to action potential production. Oxytocin, orexins A and B activities were mediated by oxytocin, orexin-1 and orexin-2 receptors, respectively. This review article will mention cellular mechanisms for antinociception produced by oxytocin, orexins A and B, and discuss similarity and difference in antinociceptive mechanisms among the hypothalamic neuropeptides and other endogenous pain modulators (opioids, nociceptin, adenosine, adenosine 5’-triphosphate (ATP), noradrenaline, serotonin, dopamine, somatostatin, cannabinoids, galanin, substance P, bradykinin, neuropeptide Y and acetylcholine) exhibiting a change in membrane potential, excitatory or inhibitory transmission in the spinal lamina II neurons.
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13
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Caraci F, Merlo S, Drago F, Caruso G, Parenti C, Sortino MA. Rescue of Noradrenergic System as a Novel Pharmacological Strategy in the Treatment of Chronic Pain: Focus on Microglia Activation. Front Pharmacol 2019; 10:1024. [PMID: 31572196 PMCID: PMC6751320 DOI: 10.3389/fphar.2019.01024] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 08/12/2019] [Indexed: 12/11/2022] Open
Abstract
Different types of pain can evolve toward a chronic condition characterized by hyperalgesia and allodynia, with an abnormal response to normal or even innocuous stimuli, respectively. A key role in endogenous analgesia is recognized to descending noradrenergic pathways that originate from the locus coeruleus and project to the dorsal horn of the spinal cord. Impairment of this system is associated with pain chronicization. More recently, activation of glial cells, in particular microglia, toward a pro-inflammatory state has also been implicated in the transition from acute to chronic pain. Both α2- and β2-adrenergic receptors are expressed in microglia, and their activation leads to acquisition of an anti-inflammatory phenotype. This review analyses in more detail the interconnection between descending noradrenergic system and neuroinflammation, focusing on drugs that, by rescuing the noradrenergic control, exert also an anti-inflammatory effect, ultimately leading to analgesia. More specifically, the potential efficacy in the treatment of neuropathic pain of different drugs will be analyzed. On one side, drugs acting as inhibitors of the reuptake of serotonin and noradrenaline, such as duloxetine and venlafaxine, and on the other, tapentadol, inhibitor of the reuptake of noradrenaline, and agonist of the µ-opioid receptor.
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Affiliation(s)
- Filippo Caraci
- Department of Drug Sciences, Section of Pharmacology and Toxicology, University of Catania, Catania, Italy.,Oasi Research Institute-IRCCS, Troina, Italy
| | - Sara Merlo
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Filippo Drago
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | | | - Carmela Parenti
- Department of Drug Sciences, Section of Pharmacology and Toxicology, University of Catania, Catania, Italy
| | - Maria Angela Sortino
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
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14
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High-resolution detection of ATP release from single cultured mouse dorsal horn spinal cord glial cells and its modulation by noradrenaline. Purinergic Signal 2019; 15:403-420. [PMID: 31444738 DOI: 10.1007/s11302-019-09673-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Accepted: 07/12/2019] [Indexed: 12/30/2022] Open
Abstract
Human embryonic kidney 293 (HEK293) cells stably transfected with the rat P2X2 receptor subunit were preincubated with 200 nM progesterone (HEK293-P2X2-PROG), a potent positive allosteric modulator of homomeric P2X2 receptors, and used to detect low nanomolar concentrations of extracellular ATP. Fura-2-loaded HEK293-P2X2-PROG cells were acutely plated on top of cultured DH glial cells to quantify ATP release from single DH glial cells. Application of the α1 adrenoceptor agonist phenylephrine (PHE, 20 μM) or of a low K+ (0.2 mM) solution evoked reversible increases in the intracellular calcium concentration ([Ca2+]i) in the biosensor cells. A reversible increase in [Ca2+]i was also detected in half of the biosensor cells following the interruption of general extracellular perfusion. All increases in [Ca2+]i were blocked in the presence of the P2X2 antagonist PPADS or after preloading the glial cells with the calcium chelator BAPTA, indicating that they were due to calcium-dependent ATP release from the glial cells. ATP release induced by PHE was blocked by -L-phenylalanine 2-naphtylamide (GPN) that permeabilizes secretory lysosomes and bafilomycin A1 (Baf A1), an inhibitor of the H+-pump of acidic secretory vesicles. By contrast, ATP release induced by application of a low-K+ solution was abolished by Baf A1 but not by GPN. Finally, spontaneous ATP release observed after interrupting general perfusion was insensitive to both GPN and Baf A1 pretreatment. Our results indicate that ATP is released in a calcium-dependent manner from two distinct vesicular pools and one non-vesicular pool coexisting in DH glial cells and that noradrenaline and PHE selectively target the secretory lysosome pool.
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15
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Caylor J, Reddy R, Yin S, Cui C, Huang M, Huang C, Rao R, Baker DG, Simmons A, Souza D, Narouze S, Vallejo R, Lerman I. Spinal cord stimulation in chronic pain: evidence and theory for mechanisms of action. Bioelectron Med 2019; 5:12. [PMID: 31435499 PMCID: PMC6703564 DOI: 10.1186/s42234-019-0023-1] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 05/30/2019] [Indexed: 12/30/2022] Open
Abstract
Well-established in the field of bioelectronic medicine, Spinal Cord Stimulation (SCS) offers an implantable, non-pharmacologic treatment for patients with intractable chronic pain conditions. Chronic pain is a widely heterogenous syndrome with regard to both pathophysiology and the resultant phenotype. Despite advances in our understanding of SCS-mediated antinociception, there still exists limited evidence clarifying the pathways recruited when patterned electric pulses are applied to the epidural space. The rapid clinical implementation of novel SCS methods including burst, high frequency and dorsal root ganglion SCS has provided the clinician with multiple options to treat refractory chronic pain. While compelling evidence for safety and efficacy exists in support of these novel paradigms, our understanding of their mechanisms of action (MOA) dramatically lags behind clinical data. In this review, we reconstruct the available basic science and clinical literature that offers support for mechanisms of both paresthesia spinal cord stimulation (P-SCS) and paresthesia-free spinal cord stimulation (PF-SCS). While P-SCS has been heavily examined since its inception, PF-SCS paradigms have recently been clinically approved with the support of limited preclinical research. Thus, wide knowledge gaps exist between their clinical efficacy and MOA. To close this gap, many rich investigative avenues for both P-SCS and PF-SCS are underway, which will further open the door for paradigm optimization, adjunctive therapies and new indications for SCS. As our understanding of these mechanisms evolves, clinicians will be empowered with the possibility of improving patient care using SCS to selectively target specific pathophysiological processes in chronic pain.
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Affiliation(s)
- Jacob Caylor
- Department of Anesthesiology, Center for Pain Medicine, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Rajiv Reddy
- Department of Anesthesiology, Center for Pain Medicine, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Sopyda Yin
- Department of Anesthesiology, Center for Pain Medicine, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Christina Cui
- Department of Anesthesiology, Center for Pain Medicine, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Mingxiong Huang
- Department of Radiology, University of California San Diego School of Medicine, La Jolla, CA USA
- Department of Radiology, VA San Diego Healthcare System, La Jolla, CA USA
| | - Charles Huang
- Department of Radiology, VA San Diego Healthcare System, La Jolla, CA USA
- Department of Bioengineering, Stanford University, Palo Alto, CA USA
| | - Ramesh Rao
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA USA
| | - Dewleen G. Baker
- VA Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA USA
- Department of Psychiatry, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Alan Simmons
- VA Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA USA
- Department of Psychiatry, University of California San Diego School of Medicine, La Jolla, CA USA
| | - Dmitri Souza
- Center for Pain Medicine, Western Reserve Hospital. Department of Surgery, Northeast Ohio Medical School (NEOMED), Athens, OH USA
| | - Samer Narouze
- Center for Pain Medicine, Western Reserve Hospital. Department of Surgery, Northeast Ohio Medical School (NEOMED), Athens, OH USA
| | - Ricardo Vallejo
- Basic Science Research, Millennium Pain Center, Bloomington, IL USA
- School of Biological Sciences, Illinois State University, Normal, IL USA
- Department of Psychology, Illinois Wesleyan University, Bloomington, IL USA
| | - Imanuel Lerman
- Department of Anesthesiology, Center for Pain Medicine, University of California San Diego School of Medicine, La Jolla, CA USA
- VA Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, La Jolla, CA USA
- Department of Radiology, VA San Diego Healthcare System, La Jolla, CA USA
- Department of Electrical and Computer Engineering, University of California San Diego, La Jolla, CA USA
- Present Address: VA San Diego, 3350 La Jolla Village Dr, (MC116A), San Diego, CA 92161 USA
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16
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Sonohata M, Doi A, Yasaka T, Uta D, Mawatari M, Yoshimura M. Noradrenaline modulates mechanically evoked responses in the rat spinal dorsal horn: an in vivo patch-clamp study. J Pain Res 2019; 12:1269-1278. [PMID: 31114307 PMCID: PMC6489873 DOI: 10.2147/jpr.s181210] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 02/14/2019] [Indexed: 12/16/2022] Open
Abstract
Purpose: We investigated the effects of noradrenaline (NA) on physiologically evoked synaptic responses of substantia gelatinosa (SG) neurons using anesthetized animals. Methods: Male Sprague–Dawley rats (6–8 weeks, 200–300 g, n=21) were anesthetized. The lumbar spinal cord was exposed from L3 to L5; subsequently, the rats were fixed to a stereotaxic apparatus. The electrode was advanced at an angle of 30–45 degrees into the SG using a micromanipulator. We recorded excitatory post-synaptic currents (EPSC). Under these conditions, innocuous or noxious mechanical stimuli were applied to the receptive field of the ipsilateral hindlimb with or without NA, respectively. Results: NA (50 μM) pre-application induced three types of responses for pinch-evoked EPSCs. The number of neurons showing inhibition, facilitation, and no-effect was 15 (71.4%), 2 (9.5%), and 4 (19%), respectively (n=21). Pre-treatment with NA also induced three different types of responses for puff-evoked EPSC (n=21). The number of neurons showing inhibition, facilitation, and no-effect was 9 (42.9%), 9 (42.9%), and 3 (14.2%), respectively. Further, there was a significant difference in the rate distribution (inhibition, facilitation, and no change) between puff- and pinch-evoked responses. Conclusion: Our present data indicate that NA acts on noxious and innocuous mechanical transmission in the SG. Considering the distinct sensory inputs to the SG, the different actions of NA on the transmission of sensory information imply that NA exerts its analgesic effects in a manner more complicated than previously believed.
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Affiliation(s)
- Motoki Sonohata
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Atsushi Doi
- Department of Physical Therapy, Kumamoto Health Science University, Kumamoto, Japan
| | - Toshiharu Yasaka
- Department of Immunology, Graduate School of Medical and Dental SciencesKagoshima University, Kagoshima, Japan
| | - Daisuke Uta
- Department of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Masaaki Mawatari
- Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Megumu Yoshimura
- Department of Integrative Physiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Nakamura Hospital, Nogata, Fukuoka, Japan
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17
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Ohashi N, Ohashi M, Baba H. Action of Norepinephrine on Lamina X of the Spinal Cord. Neuroscience 2019; 408:214-225. [PMID: 30981866 DOI: 10.1016/j.neuroscience.2019.04.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 03/28/2019] [Accepted: 04/02/2019] [Indexed: 11/30/2022]
Abstract
Lamina X is localized in the spinal cord within the region surrounding the central canal and receives descending projections from the supraspinal nuclei. Norepinephrine (NE) is a neurotransmitter in descending pathways emanating from the brain stem; NE-containing fibers terminate in the spinal dorsal cord, particularly in the substantia gelatinosa (SG). NE enhances inhibitory synaptic transmission in SG neurons by activating presynaptic α1-receptors and hyperpolarizes the membranes of SG neurons by acting on α2-receptors; NE may thus act directly on SG neurons of the dorsal spinal cord and inhibit nociceptive transmission at the spinal level. NE-containing fibers also reportedly terminate in lamina X, suggesting that NE also modulates synaptic transmission in lamina X. However, the cellular mechanisms underlying such action have not been investigated. We hypothesized that NE might directly act on lamina X and enhance inhibitory synaptic transmission therein. Using rat spinal cord slices and in vitro whole-cell patch-clamps, we found that the bath-application of NE to lamina X does not affect the excitatory interneurons but enhances GABAergic and glycinergic miniature inhibitory postsynaptic currents (mIPSCs) and induces an outward current. NE-induced enhancement of mIPSCs was blocked by α1A-receptor antagonists, and NE-induced outward current was blocked by α2-receptor antagonists. NE did not affect GABA- or glycine- induced outward currents. These findings are similar to those obtained from SG neurons: NE may act at presynaptic terminals of GABAergic and glycinergic interneurons on lamina X to facilitate inhibitory-transmitter release through α1A-receptor activation and directly induce inhibitory interneuron membrane hyperpolarization through α2-receptors activation.
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Affiliation(s)
- Nobuko Ohashi
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City, Niigata 951-8510, Japan.
| | - Masayuki Ohashi
- Division of Orthopedic Surgery, Department of Regenerative and Transplant Medicine, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City, Niigata 951-8510, Japan
| | - Hiroshi Baba
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City, Niigata 951-8510, Japan
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18
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Vuilleumier PH, Fritsche R, Schliessbach J, Schmitt B, Arendt-Nielsen L, Zeilhofer HU, Curatolo M. Mutations affecting glycinergic neurotransmission in hyperekplexia increase pain sensitivity. Brain 2019; 141:63-71. [PMID: 29149236 DOI: 10.1093/brain/awx289] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 09/19/2017] [Indexed: 11/14/2022] Open
Abstract
See Dickenson (doi:10.1093/brain/awx334) for a scientific commentary on this article.Inhibitory interneurons in the spinal cord use glycine and GABA for fast inhibitory neurotransmission. While there is abundant research on these inhibitory pain pathways in animal models, their relevance in humans remains unclear, largely due to the limited possibility to manipulate selectively these pathways in humans. Hyperekplexia is a rare human disease that is caused by loss-of-function mutations in genes encoding for glycine receptors and glycine transporters. In the present study, we tested whether hyperekplexia patients display altered pain perception or central pain modulation compared with healthy subjects. Seven patients with genetically and clinically confirmed hyperekplexia were compared to 14 healthy age- and sex-matched controls. The following quantitative sensory tests were performed: pressure pain detection threshold (primary outcome), ice water tolerance, single and repeated electrical pain detection thresholds, nociceptive withdrawal reflex threshold, and conditioned pain modulation. Statistical analysis was performed using linear mixed models. Hyperekplexia patients displayed lower pain thresholds than healthy controls for all of the quantitative sensory tests [mean (standard deviation)]: pressure pain detection threshold [273 (170) versus 475 (115) kPa, P = 0.003], ice water tolerance [49.2 (36.5) versus 85.7 (35.0) s, P = 0.015], electrical single pain detection threshold [5.42 (2.64) versus 7.47 (2.62) mA, P = 0.012], electrical repeated pain detection threshold [3.76 (1.41) versus 5.8 (1.73) mA, P = 0.003], and nociceptive withdrawal reflex [7.42 (3.63) versus 14.1 (6.9) mA, P = 0.015]. Conditioned pain modulation was significantly reduced in hyperekplexia [increase to baseline: 53.2 (63.7) versus 105 (57) kPa, P = 0.030]. Our data demonstrate increased pain sensitivity and impaired central pain modulation in hyperekplexia patients, supporting the importance of glycinergic neurotransmission for central pain modulation in humans.
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Affiliation(s)
- Pascal Henri Vuilleumier
- Department of Anaesthesiology and Pain Medicine, Bern University Hospital, University of Bern, Switzerland
| | - Raphael Fritsche
- Department of Ophthalmology, Canton Hospital of Lucerne, Switzerland
| | - Jürg Schliessbach
- Department of Anaesthesiology and Pain Medicine, Bern University Hospital, University of Bern, Switzerland
| | - Bernhard Schmitt
- Department of Child Neurology, Children's Hospital, University of Zurich, Switzerland
| | - Lars Arendt-Nielsen
- Center for Sensory-Motor Interaction, School of Medicine, University of Aalborg, Denmark
| | - Hanns Ulrich Zeilhofer
- Institute of Pharmacology and Toxicology, University of Zurich, and Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zurich, Switzerland
| | - Michele Curatolo
- Center for Sensory-Motor Interaction, School of Medicine, University of Aalborg, Denmark.,Department of Anaesthesiology and Pain Medicine, University of Washington, Seattle, USA
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Bahari Z, Meftahi GH. Spinal α 2 -adrenoceptors and neuropathic pain modulation; therapeutic target. Br J Pharmacol 2019; 176:2366-2381. [PMID: 30657594 DOI: 10.1111/bph.14580] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 11/23/2018] [Accepted: 12/04/2018] [Indexed: 12/22/2022] Open
Abstract
Neuropathic pain can arise from disease or damage to the nervous system. The most common symptoms of neuropathic pain include spontaneous pain, allodynia, and hyperalgesia. There is still limited knowledge about the factors that initiate and maintain neuropathic pain. However, ample evidence has proved the antinociceptive role of spinal α-adrenoceptors following nerve injury. It is well-documented that noradrenergic descending pathways from supraspinal loci exert an inhibitory influence on the spinal cord nociceptive neurons, mostly through the activation of spinal α2 -adrenoceptors. This, in turn, suppresses transmission of pain input and the hyperexcitability of spinal dorsal horn neurons. There is considerable evidence demonstrating that spinal application of α2 -adrenoceptor agonists leads to analgesic effects in animal models of neuropathic pain. Today, despite the recent rapid development of neuroscience and drug discovery, effective drugs with clear basic mechanisms have remained a mystery. Here, we give an overview of the cellular mechanisms through which brainstem adrenergic descending inhibitory processing can alter spinal pain transmission to the higher centres, and how these pathways change in neuropathic pain conditions focusing on the role of spinal α2 -adrenoceptors in the spinal dorsal horn. We then suggest that α2 -adrenoceptor agonist may be useful to treat neuropathic pain. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.
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Affiliation(s)
- Zahra Bahari
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.,Department of Physiology and Medical Physics, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
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Selective deficiencies in descending inhibitory modulation in neuropathic rats: implications for enhancing noradrenergic tone. Pain 2019; 159:1887-1899. [PMID: 29863529 PMCID: PMC6095727 DOI: 10.1097/j.pain.0000000000001300] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Supplemental Digital Content is Available in the Text. Descending noradrenergic pathways modulate spontaneous but not evoked thalamic neuronal hyperexcitability in neuropathic pain states. Spinal clonidine inhibits evoked and spontaneous firing, whereas reboxetine selectively inhibits evoked firing. Pontine noradrenergic neurones form part of a descending inhibitory system that influences spinal nociceptive processing. Weak or absent descending inhibition is a common feature of chronic pain patients. We examined the extent to which the descending noradrenergic system is tonically active, how control of spinal neuronal excitability is integrated into thalamic relays within sensory-discriminative projection pathways, and how this inhibitory control is altered after nerve injury. In vivo electrophysiology was performed in anaesthetised spinal nerve–ligated (SNL) and sham-operated rats to record from wide dynamic range neurones in the ventral posterolateral thalamus (VPL). In sham rats, spinal block of α2-adrenoceptors with atipamezole resulted in enhanced stimulus-evoked and spontaneous firing in the VPL, and produced conditioned place avoidance. However, in SNL rats, these conditioned avoidance behaviours were absent. Furthermore, inhibitory control of evoked neuronal responses was lost, but spinal atipamezole markedly increased spontaneous firing. Augmenting spinal noradrenergic tone in neuropathic rats with reboxetine, a selective noradrenergic reuptake inhibitor, modestly reinstated inhibitory control of evoked responses in the VPL but had no effect on spontaneous firing. By contrast, clonidine, an α2 agonist, inhibited both evoked and spontaneous firing, and exhibited increased potency in SNL rats compared with sham controls. These data suggest descending noradrenergic inhibitory pathways are tonically active in sham rats. Moreover, in neuropathic states, descending inhibitory control is diminished, but not completely absent, and distinguishes between spontaneous and evoked neuronal activity. These observations may have implications for how analgesics targeting the noradrenergic system provide relief.
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López-Álvarez VM, Cobianchi S, Navarro X. Chronic electrical stimulation reduces hyperalgesia and associated spinal changes induced by peripheral nerve injury. Neuromodulation 2019; 22:509-518. [PMID: 30786105 DOI: 10.1111/ner.12927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/05/2018] [Accepted: 01/02/2019] [Indexed: 12/23/2022]
Abstract
OBJECTIVES We aimed to investigate if different protocols of electrical stimulation following nerve injury might improve neuropathic pain outcomes and modify associated plastic changes at the spinal cord level. MATERIALS AND METHODS Adult rats were subjected to sciatic nerve transection and repair, and distributed in four groups: untreated (SNTR, n = 12), repeated acute electrical stimulation (rAES, 50 Hz, one hour, n = 12), chronic electrical stimulation (CES, 50 Hz, one hour, n = 12), and increasing-frequency chronic electrical stimulation (iCES, one hour, n = 12) delivered during two weeks following the lesion. The threshold of nociceptive withdrawal to mechanical stimuli was evaluated by means of a Von Frey algesimeter during three weeks postlesion. Spinal cord samples were processed by immunohistochemistry for labeling glial cells, adrenergic receptors, K+ -Cl- cotransporter 2 (KCC2) and GABA. RESULTS Acute electrical stimulation (50 Hz, one hour) delivered at 3, 7, and 14 days induced an immediate increase of mechanical pain threshold that disappeared after a few days. Chronic electrical stimulation given daily reduced mechanical hyperalgesia until the end of follow-up, being more sustained with the iCES than with constant 50 Hz stimulation (CES). Chronic stimulation protocols restored the expression of β2 adrenergic receptor and of KCC2 in the dorsal horn, which were significantly reduced by nerve injury. These treatments decreased also the activation of microglia and astrocytes in the dorsal horn. CONCLUSION Daily electrical stimulation, especially if frequency-patterned, was effective in ameliorating hyperalgesia after nerve injury, and partially preventing the proinflammatory and hyperalgesic changes in the dorsal horn associated to neuropathic pain.
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Affiliation(s)
- Víctor M López-Álvarez
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Stefano Cobianchi
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
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22
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In vivo electrophysiological analysis of mechanisms of monoaminergic pain inhibitory systems. Pain 2018; 158 Suppl 1:S85-S91. [PMID: 28240646 DOI: 10.1097/j.pain.0000000000000844] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Kawatani M, Akimoto N, Yamada A, Furue H, Kawatani M. Noradrenergic effects in rat sacral autonomic nucleus using in vitro slice patch-clamp recordings. Biomed Res 2018; 38:359-369. [PMID: 29225214 DOI: 10.2220/biomedres.38.359] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Noradrenergic modulation has been frequently discussed in the context of neural activities that are related to pelvic organs. The sacral preganglionic nucleus (SPN) is a spinal nucleus containing parasympathetic preganglionic neurons that send fibers to pelvic nerves. In spite of the abundant presence of noradrenergic fibers around the SPN, the effects of noradrenaline (NA) remain obscure. To explore this issue, NA (50 μM) was applied to parasympathetic preganglionic neurons in the SPN during whole-cell patch clamp recording. The SPN was labeled with the retrograde tracer, DiI. These neurons demonstrated two classes of firing patterns (delayed and regular) in terms of initiation of firing. Independent of these firing patterns, NA induced inward (56%) or outward (32%) currents in labeled SPN neurons. Phenylephrine, an α1 receptor agonist, induced an inward current, and clonidine, an α2 receptor agonist, induced an outward current, indicating the existence of both α1 and α2 adrenoreceptors in DiI-labeled SPN neurons. NA also modulated synaptic currents according to the firing patterns. In delayed firing neurons, NA inhibited both spontaneous excitatory post-synaptic currents (sEPSCs) and spontaneous inhibitory post-synaptic currents (sIPSCs). Hence, NA facilitated sEPSCs and sIPSCs in about a half of regular firing neurons. Bath application of phenylephrine facilitated sEPSCs and sIPSCs, and clonidine inhibited them. These results support the hypothesis of multiple effects of NA in the SPN, and may suggest functional differences among SPN neurons.
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Affiliation(s)
| | - Nozomi Akimoto
- Department of Information Physiology, National Institute for Physiological Sciences
| | - Akihiro Yamada
- Department of Information Physiology, National Institute for Physiological Sciences
| | - Hidemasa Furue
- Department of Information Physiology, National Institute for Physiological Sciences
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Merighi A. The histology, physiology, neurochemistry and circuitry of the substantia gelatinosa Rolandi (lamina II) in mammalian spinal cord. Prog Neurobiol 2018; 169:91-134. [PMID: 29981393 DOI: 10.1016/j.pneurobio.2018.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 06/07/2018] [Accepted: 06/30/2018] [Indexed: 02/06/2023]
Abstract
The substantia gelatinosa Rolandi (SGR) was first described about two centuries ago. In the following decades an enormous amount of information has permitted us to understand - at least in part - its role in the initial processing of pain and itch. Here, I will first provide a comprehensive picture of the histology, physiology, and neurochemistry of the normal SGR. Then, I will analytically discuss the SGR circuits that have been directly demonstrated or deductively envisaged in the course of the intensive research on this area of the spinal cord, with particular emphasis on the pathways connecting the primary afferent fibers and the intrinsic neurons. The perspective existence of neurochemically-defined sets of primary afferent neurons giving rise to these circuits will be also discussed, with the proposition that a cross-talk between different subsets of peptidergic fibers may be the structural and functional substrate of additional gating mechanisms in SGR. Finally, I highlight the role played by slow acting high molecular weight modulators in these gating mechanisms.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095 Grugliasco (TO), Italy.
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Wang C, Fujita T, Kumamoto E. Orexin B Modulates Spontaneous Excitatory and Inhibitory Transmission in Lamina II Neurons of Adult Rat Spinal Cord. Neuroscience 2018; 383:114-128. [PMID: 29752983 DOI: 10.1016/j.neuroscience.2018.04.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/13/2018] [Accepted: 04/30/2018] [Indexed: 01/23/2023]
Abstract
Cellular mechanisms underlying the antinociceptive properties of orexins, a group of neuropeptides produced by the hypothalamus, in the spinal dorsal horn have not been thoroughly investigated. We examined how orexin B affects spontaneous synaptic transmission in lamina II neurons, which play a pivotal role in regulating nociceptive transmission, by applying a whole-cell patch-clamp technique to lamina II neurons in adult rat spinal cord slices. In 66% of neurons tested, bath-applied orexin B concentration dependently produced an inward current at -70 mV and/or increased the frequency of glutamatergic spontaneous excitatory postsynaptic current (sEPSC) without changing its amplitude, in a manner resistant to the voltage-gated Na+-channel blocker tetrodotoxin (TTX). Glycinergic spontaneous inhibitory transmission was enhanced by orexin B in a TTX-sensitive manner in 71% of neurons examined, whereas GABAergic transmission was unaffected in the majority of these neurons. These activities were inhibited by an orexin-2 receptor antagonist (JNJ10397049) but not an orexin-1 receptor antagonist (SB334867). While the effects of orexin B in orexin B-sensitive neurons were mimicked by orexin A, another hypothalamic neuropeptide, oxytocin, produced an inward current but no increase in sEPSC frequency. These results indicate that orexin B produces membrane depolarization and/or increased spontaneous l-glutamate release in lamina II neurons by activating orexin-2 receptors, leading to increased excitability of these neurons. Such increases potentially produce an action potential, resulting in enhancement of glycinergic transmission in lamina II neurons. This activity of orexin B, and possibly orexin A, may contribute to its antinociceptive effects, which are partly shared by oxytocin.
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Affiliation(s)
- Chong Wang
- Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan
| | - Tsugumi Fujita
- Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan
| | - Eiichi Kumamoto
- Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
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Effects of naftopidil on inhibitory transmission in substantia gelatinosa neurons of the rat spinal dorsal horn in vitro. J Neurol Sci 2017; 380:205-211. [DOI: 10.1016/j.jns.2017.07.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 07/07/2017] [Accepted: 07/22/2017] [Indexed: 01/14/2023]
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Noradrenaline, Serotonin, GABA, and Glycine in Cerebrospinal Fluid during Labor Pain: A Cross-Sectional Prospective Study. Pain Res Manag 2017; 2017:2752658. [PMID: 28701860 PMCID: PMC5494104 DOI: 10.1155/2017/2752658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/04/2017] [Accepted: 05/24/2017] [Indexed: 11/17/2022]
Abstract
Background and Aims The inhibitory pathways that play a role in spinal modulation include local interneurons and descending control. Clinical data regarding the role of these pathways in acute pain is lacking. Accordingly, the aim of this study was to evaluate cerebrospinal fluid (CSF) levels of noradrenaline, serotonin, gamma-aminobutyric acid (GABA), and glycine in parturients with labor pain compared to those without labor pain. Methods One hundred term uncomplicated pregnant women receiving spinal anesthesia for cesarean section were enrolled in this prospective cross-sectional study. CSF noradrenaline, serotonin, GABA, and glycine levels were analyzed by enzyme-linked immunosorbent assay. Labor pain score was assessed by numerical rating scale. Results Median CSF serotonin concentration in parturients with labor pain was significantly lower than in those without pain (p < 0.001). Median CSF glycine level in the labor pain group was significantly higher than in the control group (p < 0.001). There were no significant differences in median CSF level of noradrenaline or GABA between parturients with and without labor pain. Subsequent analysis showed labor pain scores to be negatively correlated with CSF serotonin (r = −0.217, p = 0.04) but positively correlated with CSF glycine (r = 0.415, p < 0.001). Conclusion CSF serotonin and glycine were significantly correlated with labor pain scores. These findings suggest that the serotonergic and glycinergic systems may play a role in spinal modulation of visceral pain.
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Zhang FF, Morioka N, Abe H, Fujii S, Miyauchi K, Nakamura Y, Hisaoka-Nakashima K, Nakata Y. Stimulation of spinal dorsal horn β2-adrenergic receptor ameliorates neuropathic mechanical hypersensitivity through a reduction of phosphorylation of microglial p38 MAP kinase and astrocytic c-jun N-terminal kinase. Neurochem Int 2016; 101:144-155. [PMID: 27840124 DOI: 10.1016/j.neuint.2016.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 10/21/2016] [Accepted: 11/01/2016] [Indexed: 12/22/2022]
Abstract
The noradrenaline-adrenergic system has a crucial role in controlling nociceptive transduction at the spinal level. While α-adrenergic receptors are known to regulate nociceptive neurotransmitter release at the spinal presynaptic level, it is not entirely clear whether β-adrenergic receptors are involved in controlling pain transduction at the spinal level as well. The current study elucidated a role of β-adrenergic receptors in neuropathic pain in mice following a partial sciatic nerve ligation (PSNL). In addition, the cellular and intracellular signaling cascade induced by β-adrenergic receptors in neuropathic mice was elaborated. Intrathecal injection of isoproterenol (1 nmol), a nonselective β-adrenergic receptor agonist, briefly ameliorated hind paw mechanical hypersensitivity of PSNL mice. Isoproterenol's antinociceptive effect was mediated through β2-adrenergic receptors since pretreatment with ICI118551, a selective β2-adrenergic receptor antagonist, but not with CGP20712A, a selective β1-adrenergic receptor antagonist, significantly attenuated isoproterenol's effect. Furthermore, intrathecal treatment with a selective β2-adrenergic receptor agonist, terbutaline, but not a selective β1-adrenergic receptor agonist, dobutamine, also significantly ameliorated neuropathic pain. Fourteen days after PSNL, increased phosphorylation of both p38 Mitogen-activated protein kinase (MAPK) in microglia and c-jun N-terminal kinase (JNK) in astrocytes of ipsilateral spinal dorsal horn were observed. Phosphorylation of both microglial p38 MAPK and astrocytic JNK were downregulated by stimulation of the β2-adrenergic receptor. Together, these results suggest that spinal β2-adrenergic receptor have an inhibitory role in neuropathic nociceptive transduction at the spinal level through a downregulation of glial activity, perhaps through modulation of MAP kinases phosphorylation. Thus, targeting of β2-adrenergic receptors could be an effective therapeutic strategy in treating neuropathic pain.
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Affiliation(s)
- Fang Fang Zhang
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan; Institute of Pharmacology, Taishan Medical University, 619 Changcheng Road, Taian, Shandong, 271016, China
| | - Norimitsu Morioka
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan.
| | - Hiromi Abe
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Shiori Fujii
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Kazuki Miyauchi
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Yoki Nakamura
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Kazue Hisaoka-Nakashima
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
| | - Yoshihiro Nakata
- Department of Pharmacology, Hiroshima University Graduate School of Biomedical & Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan
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Taylor BK, Westlund KN. The noradrenergic locus coeruleus as a chronic pain generator. J Neurosci Res 2016; 95:1336-1346. [PMID: 27685982 DOI: 10.1002/jnr.23956] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/25/2016] [Accepted: 09/07/2016] [Indexed: 12/17/2022]
Abstract
Central noradrenergic centers such as the locus coeruleus (LC) are traditionally viewed as pain inhibitory; however, complex interactions among brainstem pathways and their receptors modulate both inhibition and facilitation of pain. In addition to the well-described role of descending pontospinal pathways that inhibit spinal nociceptive transmission, an emerging body of research now indicates that noradrenergic neurons in the LC and their terminals in the dorsal reticular nucleus (DRt), medial prefrontal cortex (mPFC), spinal dorsal horn, and spinal trigeminal nucleus caudalis participate in the development and maintenance of allodynia and hyperalgesia after nerve injury. With time after injury, we argue that the balance of LC function shifts from pain inhibition to pain facilitation. Thus, the pain-inhibitory actions of antidepressant drugs achieved with elevated noradrenaline concentrations in the dorsal horn may be countered or even superseded by simultaneous activation of supraspinal facilitating systems dependent on α1 -adrenoreceptors in the DRt and mPFC as well as α2 -adrenoreceptors in the LC. Indeed, these opposing actions may account in part for the limited treatment efficacy of tricyclic antidepressants and noradrenaline reuptake inhibitors such as duloxetine for the treatment of chronic pain. We propose that the traditional view of the LC as a pain-inhibitory structure be modified to account for its capacity as a pain facilitator. Future studies are needed to determine the neurobiology of ascending and descending pathways and the pharmacology of receptors underlying LC-mediated pain inhibition and facilitation. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Bradley K Taylor
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, Kentucky
| | - Karin N Westlund
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, Kentucky
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30
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Hydrogen peroxide modulates neuronal excitability and membrane properties in ventral horn neurons of the rat spinal cord. Neuroscience 2016; 331:206-20. [DOI: 10.1016/j.neuroscience.2016.06.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 05/27/2016] [Accepted: 06/17/2016] [Indexed: 01/29/2023]
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Kozuka Y, Kawamata M, Furue H, Ishida T, Tanaka S, Namiki A, Yamakage M. Changes in synaptic transmission of substantia gelatinosa neurons after spinal cord hemisection revealed by analysis using in vivo patch-clamp recording. Mol Pain 2016; 12:1744806916665827. [PMID: 27573517 PMCID: PMC5006296 DOI: 10.1177/1744806916665827] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND After spinal cord injury, central neuropathic pain develops in the majority of spinal cord injury patients. Spinal hemisection in rats, which has been developed as an animal model of spinal cord injury in humans, results in hyperexcitation of spinal dorsal horn neurons soon after the hemisection and thereafter. The hyperexcitation is likely caused by permanent elimination of the descending pain systems. We examined the change in synaptic transmission of substantia gelatinosa neurons following acute spinal hemisection by using an in vivo whole-cell patch-clamp technique. RESULTS An increased spontaneous action potential firings of substantia gelatinosa neurons was detected in hemisected rats compared with that in control animals. The frequencies and amplitudes of spontaneous excitatory postsynaptic currents and of evoked excitatory postsynaptic currentss in response to non-noxious and noxious stimuli were not different between hemisected and control animals. On the contrary, the amplitude and frequency of spontaneous inhibitory postsynaptic currents of substantia gelatinosa neurons in hemisected animals were significantly smaller and lower, respectively, than those in control animals (P < 0.01). Large amplitude and high-frequency spontaneous inhibitory postsynaptic currents, which could not be elicited by mechanical stimuli, were seen in 44% of substantia gelatinosa neurons in control animals but only in 17% of substantia gelatinosa neurons in hemisected animals. In control animals, such large amplitude spontaneous inhibitory postsynaptic currents were suppressed by spinal application of tetrodotoxin (1 µM). Cervical application of lidocaine (2%, 10 µl) also inhibited such large amplitude of inhibitory postsynaptic currents. The proportion of multi-receptive substantia gelatinosa neurons, which exhibit action potential firing in response to non-noxious and noxious stimuli, was much larger in hemisected animals than in control animals. CONCLUSIONS These suggest that substantia gelatinosa neurons receive tonic inhibition by spinal inhibitory interneurons which generate persistent action potentials. Spinal hemisection results in hyperexcitation of substantia gelatinosa neurons at least in part by eliminating the tonic descending control of spinal inhibitory interneurons from supraspinal levels.
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Affiliation(s)
- Yuji Kozuka
- Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Mikito Kawamata
- Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Hidemasa Furue
- Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan
| | - Takashi Ishida
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Satoshi Tanaka
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Matsumoto, Japan
| | - Akiyoshi Namiki
- Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan
| | - Michiaki Yamakage
- Department of Anesthesiology, Sapporo Medical University School of Medicine, Sapporo, Japan
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Differential Activation of TRP Channels in the Adult Rat Spinal Substantia Gelatinosa by Stereoisomers of Plant-Derived Chemicals. Pharmaceuticals (Basel) 2016; 9:ph9030046. [PMID: 27483289 PMCID: PMC5039499 DOI: 10.3390/ph9030046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 06/19/2016] [Accepted: 07/25/2016] [Indexed: 02/07/2023] Open
Abstract
Activation of TRPV1, TRPA1 or TRPM8 channel expressed in the central terminal of dorsal root ganglion (DRG) neuron increases the spontaneous release of l-glutamate onto spinal dorsal horn lamina II (substantia gelatinosa; SG) neurons which play a pivotal role in regulating nociceptive transmission. The TRP channels are activated by various plant-derived chemicals. Although stereoisomers activate or modulate ion channels in a distinct manner, this phenomenon is not fully addressed for TRP channels. By applying the whole-cell patch-clamp technique to SG neurons of adult rat spinal cord slices, we found out that all of plant-derived chemicals, carvacrol, thymol, carvone and cineole, increase the frequency of spontaneous excitatory postsynaptic current, a measure of the spontaneous release of l-glutamate from nerve terminals, by activating TRP channels. The presynaptic activities were different between stereoisomers (carvacrol and thymol; (-)-carvone and (+)-carvone; 1,8-cineole and 1,4-cineole) in the extent or the types of TRP channels activated, indicating that TRP channels in the SG are activated by stereoisomers in a distinct manner. This result could serve to know the properties of the central terminal TRP channels that are targets of drugs for alleviating pain.
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Wei L, Zhu YM, Zhang YX, Liang F, Jia H, Qu CL, Wang J, Tang JS, Lu SM, Huo FQ, Yan CX. Activation of α1 adrenoceptors in ventrolateral orbital cortex attenuates allodynia induced by spared nerve injury in rats. Neurochem Int 2016; 99:85-93. [PMID: 27296114 DOI: 10.1016/j.neuint.2016.06.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/05/2016] [Accepted: 06/09/2016] [Indexed: 01/27/2023]
Abstract
Recent studies have demonstrated that noradrenaline acting in the ventrolateral orbital cortex (VLO) can potentially reduce allodynia induced by spared nerve injury (SNI), and this effect is mediated by α2 adrenoceptor. The present study examined the effect of the α1 adrenoceptors in the VLO on allodynia induced by SNI in the rats. The mechanical paw withdrawal threshold (PWT) was measured using von-Frey filaments. Microinjection of selective α1 adrenoceptor agonist methoxamine (20, 50, 100 μg in 0.5 μl) into the VLO, contralateral to the site of nerve injury, increased PWT in a dose-dependent manner. This effect was antagonized by pre-microinjection of the selective α1 adrenoceptor antagonist benoxathian into the same VLO site, and blocked by electrolytic lesion of the ventrolateral periaqueductal gray (PAG). Furthermore, pre-administration of non-selective glutamate receptor antagonist kynurenic acid, phospholipase C (PLC) inhibitor U73122, and protein kinase C (PKC) inhibitor chelerythrine to the VLO also blocked methoxamine-induced inhibition of allodynia. These results suggest that activation of α1 adrenoceptors in the VLO can potentially reduce allodynia induced by SNI. This effect may be direct excitation of the VLO neurons, via PLC-PKC signaling pathway, projecting to the PAG or facilitating glutamate release and then indirectly exciting the VLO output neurons projecting to the PAG, leading to activation of the PAG-brainstem descending inhibitory system which depresses the nociceptive transmission at the spinal cord level.
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Affiliation(s)
- Lai Wei
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Division of Forensic Medicine, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, China
| | - Yuan-Mei Zhu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Yu-Xiang Zhang
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Feng Liang
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China
| | - Hong Jia
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China
| | - Chao-Ling Qu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China
| | - Jing Wang
- Key Laboratory of Orthopedics of Gansu Province, The Second Hospital of Lanzhou University, Lanzhou, Gansu 730030, China
| | - Jing-Shi Tang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China
| | - She-Min Lu
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China
| | - Fu-Quan Huo
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China.
| | - Chun-Xia Yan
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China.
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Sex differences in hypothalamic-mediated tonic norepinephrine release for thermal hyperalgesia in rats. Neuroscience 2016; 324:420-9. [DOI: 10.1016/j.neuroscience.2016.03.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/31/2022]
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Kurabe M, Furue H, Kohno T. Intravenous administration of lidocaine directly acts on spinal dorsal horn and produces analgesic effect: An in vivo patch-clamp analysis. Sci Rep 2016; 6:26253. [PMID: 27188335 PMCID: PMC4870564 DOI: 10.1038/srep26253] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 04/28/2016] [Indexed: 02/01/2023] Open
Abstract
Intravenous lidocaine administration produces an analgesic effect in various pain states, such as neuropathic and acute pain, although the underlying mechanisms remains unclear. Here, we hypothesized that intravenous lidocaine acts on spinal cord neurons and induces analgesia in acute pain. We therefore examined the action of intravenous lidocaine in the spinal cord using the in vivo patch-clamp technique. We first investigated the effects of intravenous lidocaine using behavioural measures in rats. We then performed in vivo patch-clamp recording from spinal substantia gelatinosa (SG) neurons. Intravenous lidocaine had a dose-dependent analgesic effect on the withdrawal response to noxious mechanical stimuli. In the electrophysiological experiments, intravenous lidocaine inhibited the excitatory postsynaptic currents (EPSCs) evoked by noxious pinch stimuli. Intravenous lidocaine also decreased the frequency, but did not change the amplitude, of both spontaneous and miniature EPSCs. However, it did not affect inhibitory postsynaptic currents. Furthermore, intravenous lidocaine induced outward currents in SG neurons. Intravenous lidocaine inhibits glutamate release from presynaptic terminals in spinal SG neurons. Concomitantly, it hyperpolarizes postsynaptic neurons by shifting the membrane potential. This decrease in the excitability of spinal dorsal horn neurons may be a possible mechanism for the analgesic action of intravenous lidocaine in acute pain.
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Affiliation(s)
- Miyuki Kurabe
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City, 951-8510 Japan
| | - Hidemasa Furue
- Department of Information Physiology, National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan
| | - Tatsuro Kohno
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi Dori, Chuo-Ku, Niigata City, 951-8510 Japan
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Spinal histamine in attenuation of mechanical hypersensitivity in the spinal nerve ligation-induced model of experimental neuropathy. Eur J Pharmacol 2016; 772:1-10. [DOI: 10.1016/j.ejphar.2015.12.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/17/2015] [Accepted: 12/22/2015] [Indexed: 12/20/2022]
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Seibt F, Schlichter R. Noradrenaline-mediated facilitation of inhibitory synaptic transmission in the dorsal horn of the rat spinal cord involves interlaminar communications. Eur J Neurosci 2015; 42:2654-65. [PMID: 26370319 DOI: 10.1111/ejn.13077] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/31/2015] [Accepted: 09/07/2015] [Indexed: 12/20/2022]
Abstract
In the dorsal horn of the spinal cord (DH), noradrenaline (NA) is released by axons originating from the locus coeruleus and induces spinal analgesia, the mechanisms of which are poorly understood. Here, the effects of NA on synaptic transmission in the deep laminae (III-V) of the DH were characterized. It was shown that exogenously applied, as well as endogenously released, NA facilitated inhibitory [γ-aminobutyric acid (GABA)ergic and glycinergic] synaptic transmission in laminae III-IV of the DH by activating α1-, α2- and β-adrenoceptors (ARs). In contrast, NA had no effect on excitatory (glutamatergic) synaptic transmission. Physical interruption of communications between deep and more superficial laminae (by a mechanical transection between laminae IV and V) totally blocked the effects of α2-AR agonists and strongly reduced the effects of α1-AR agonists on inhibitory synaptic transmission in laminae III-IV without directly impairing synaptic release of GABA or glycine from neurons. Short-term pretreatment of intact spinal cord slices with the glial cell metabolism inhibitor fluorocitrate or pharmacological blockade of ionotropic glutamate and ATP receptors mimicked the consequences of a mechanical transection between laminae IV and V. Taken together, the current results indicate that the facilitation of inhibitory synaptic transmission in laminae III-IV of the DH by NA requires functional interlaminar connections between deep and more superficial laminae, and might strongly depend on glia to neuron interactions. These interlaminar connections and glia to neuron interactions could represent interesting targets for analgesic strategies.
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Affiliation(s)
- Frederik Seibt
- Centre National de la Recherche Scientifique (CNRS UPR 3212), Institut des Neurosciences Cellulaires et Intégratives, 5 rue Blaise Pascal, 67084, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
| | - Rémy Schlichter
- Centre National de la Recherche Scientifique (CNRS UPR 3212), Institut des Neurosciences Cellulaires et Intégratives, 5 rue Blaise Pascal, 67084, Strasbourg, France.,Université de Strasbourg, Strasbourg, France
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Abstract
Chronic abdominal pain in irritable bowel syndrome (IBS) usually appears in combination with disturbed bowel habits, but the etiological relationship between these symptoms remains unclear. Noradrenaline is a major neurotransmitter controlling pain sensation in the spinal cord. To test the hypothesis that the descending noradrenergic pathway from the brain stem moderates gut motility, we examined effects of intrathecal application of noradrenaline to the spinal defecation center on colorectal motility. Colorectal intraluminal pressure and expelled volume were recorded in vivo in anesthetized rats. Intrathecal application of noradrenaline into the L6-S1 spinal cord, where the lumbosacral defecation center is located, caused propulsive contractions of the colorectum. Inactivation of spinal neurons by tetrodotoxin blocked the effect of noradrenaline. Pharmacological experiments showed that the effect of noradrenaline is mediated primarily by alpha-1 adrenoceptors. The enhancement of colorectal motility by intrathecal noradrenaline was abolished by severing of the pelvic nerves. Our results demonstrate that noradrenaline acting on sacral parasympathetic preganglionic neurons through alpha-1 adrenoceptors causes propulsive motility of the colorectum in rats. Considering that visceral pain activates the descending inhibitory pathways including noradrenergic neurons, our results provide a rational explanation of the concurrent appearance of chronic abdominal pain and colonic motility disorders in IBS patients.
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Abstract
Chronic postsurgical pain is a serious issue in clinical practice. After surgery, patients experience ongoing pain or become sensitive to incident, normally nonpainful stimulation. The intensity and duration of postsurgical pain vary. However, it is unclear how the transition from acute to chronic pain occurs. Here we showed that social defeat stress enhanced plantar incision-induced AMPA receptor GluA1 phosphorylation at the Ser831 site in the spinal cord and greatly prolonged plantar incision-induced pain. Interestingly, targeted mutation of the GluA1 phosphorylation site Ser831 significantly inhibited stress-induced prolongation of incisional pain. In addition, stress hormones enhanced GluA1 phosphorylation and AMPA receptor-mediated electrical activity in the spinal cord. Subthreshold stimulation induced spinal long-term potentiation in GluA1 phosphomimetic mutant mice, but not in wild-type mice. Therefore, spinal AMPA receptor phosphorylation contributes to the mechanisms underlying stress-induced pain transition.
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Hou PW, Fu PK, Hsu HC, Hsieh CL. Traditional Chinese medicine in patients with osteoarthritis of the knee. J Tradit Complement Med 2015; 5:182-96. [PMID: 26587390 PMCID: PMC4624358 DOI: 10.1016/j.jtcme.2015.06.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/14/2015] [Accepted: 06/04/2015] [Indexed: 11/20/2022] Open
Abstract
To evaluate whether the use of traditional Chinese medicine (TCM; 中醫 zhōng yī) influences symptoms or functional outcomes in patients with osteoarthritis (OA) of the knee (膝關節炎 xī guān jié yán). A systematic review of randomized control trials was conducted. Searches for studies in PubMed that were performed between 1965 and August 2013, and retrieved studies were subjected to reference screening. The types of studies included in our review were 1) placebo-based or comparative studies; 2) open label, single-blinded or double-blinded studies; 3) studies evaluating the efficacy of TCM for treating OA of the knee; and 4) studies evaluating only TCM or combination preparations. Trials were conducted with participants over 18 years of age with knee pain and at least three of the following characteristics: 1) an age greater than 50 years; 2) morning stiffness lasting for fewer than 30 min; 3) a crackling or grating sensation; 4) bony tenderness of the knee; 5) bony enlargement of the knee; or 6) no detectable warmth of the joint to the touch. Studies were rated for risk of bias and graded for quality. After screening, 104 studies that satisfied the eligibility requirements were identified, and only 18 randomized control trials were included in the quantitative and qualitative synthesis. Upon review, we found “moderate-quality” evidence of effects from acupuncture (針灸 zhēn jiǔ) on pain, which was measured using a visual analogue scale, and physical function, which was measured using qigong (氣功 qì gōng) with motion. “Low-quality” evidence was found regarding the effects of acupuncture on physical function, and no evidence was found regarding the effects of herbal medicine on pain or physical function. Herbal patches (藥布 yào bù) appeared to affect pain and physical and function, but these effects were not found to be significant. The initial findings included in this review suggest that acupuncture is a promising intervention according to the primary outcome measure, pain, and qigong with motion is an effective method for treating physical function. However, according to the Grades of Recommendation, Assessment, Development, and Evaluation criteria, only moderate-quality evidence was found in these studies. Further rigorous studies are warranted to investigate the application of TCM in treating OA of knee.
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Affiliation(s)
- Pu-Wei Hou
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Pin-Kuei Fu
- Division of Critical Care and Respiratory Therapy, Department of Internal Medicine, Taichung Veterans General Hospital, Taichung 40705, Taiwan
| | - Hsin-Cheng Hsu
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan
| | - Ching-Liang Hsieh
- Department of Chinese Medicine, China Medical University Hospital, Taichung 40447, Taiwan
- Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung 40402, Taiwan
- Corresponding author. Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, 91 Hsueh-Shih Road, Taichung 40402, Taiwan. Tel.: +886 4 22053366x3500; fax: +886 4 22037690.
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Abstract
Inhibition of both itching and scratching is important in the treatment of chronic pruritic diseases, because itching has a negative impact on quality of life and vigorous scratching worsens skin conditions. Pharmacological modulation of itch transmission in the dorsal horn is an effective way to inhibit both itching and scratching in pruritic diseases. Pruriceptive transmission in the spinal dorsal horn undergoes inhibitory modulation by the descending noradrenergic system. The noradrenergic inhibition is mediated by excitatory α₁-adrenoceptors located on inhibitory interneurons and inhibitory α₂-adrenoceptors located on central terminals of primary sensory neurons. The descending noradrenergic system and α-adrenoceptors in the dorsal horn are potential targets for antipruritic drugs.
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Affiliation(s)
- Yasushi Kuraishi
- Laboratory of Applied Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan,
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Wei H, Jin CY, Viisanen H, You HJ, Pertovaara A. Histamine in the locus coeruleus promotes descending noradrenergic inhibition of neuropathic hypersensitivity. Pharmacol Res 2014; 90:58-66. [DOI: 10.1016/j.phrs.2014.09.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/25/2014] [Accepted: 09/26/2014] [Indexed: 11/28/2022]
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Oginsky MF, Cui N, Zhong W, Johnson CM, Jiang C. Alterations in the cholinergic system of brain stem neurons in a mouse model of Rett syndrome. Am J Physiol Cell Physiol 2014; 307:C508-20. [PMID: 25009110 DOI: 10.1152/ajpcell.00035.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Rett syndrome is an autism-spectrum disorder resulting from mutations to the X-linked gene, methyl-CpG binding protein 2 (MeCP2), which causes abnormalities in many systems. It is possible that the body may develop certain compensatory mechanisms to alleviate the abnormalities. The norepinephrine system originating mainly in the locus coeruleus (LC) is defective in Rett syndrome and Mecp2-null mice. LC neurons are subject to modulation by GABA, glutamate, and acetylcholine (ACh), providing an ideal system to test the compensatory hypothesis. Here we show evidence for potential compensatory modulation of LC neurons by post- and presynaptic ACh inputs. We found that the postsynaptic currents of nicotinic ACh receptors (nAChR) were smaller in amplitude and longer in decay time in the Mecp2-null mice than in the wild type. Single-cell PCR analysis showed a decrease in the expression of α3-, α4-, α7-, and β3-subunits and an increase in the α5- and α6-subunits in the mutant mice. The α5-subunit was present in many of the LC neurons with slow-decay nAChR currents. The nicotinic modulation of spontaneous GABAA-ergic inhibitory postsynaptic currents in LC neurons was enhanced in Mecp2-null mice. In contrast, the nAChR manipulation of glutamatergic input to LC neurons was unaffected in both groups of mice. Our current-clamp studies showed that the modulation of LC neurons by ACh input was reduced moderately in Mecp2-null mice, despite the major decrease in nAChR currents, suggesting possible compensatory processes may take place, thus reducing the defects to a lesser extent in LC neurons.
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Affiliation(s)
- Max F Oginsky
- Department of Biology, Georgia State University, Atlanta, Georgia
| | - Ningren Cui
- Department of Biology, Georgia State University, Atlanta, Georgia
| | - Weiwei Zhong
- Department of Biology, Georgia State University, Atlanta, Georgia
| | | | - Chun Jiang
- Department of Biology, Georgia State University, Atlanta, Georgia
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Sokolov AY, Lyubashina OA, Amelin AV, Panteleev SS. The role of gamma-aminobutyric acid in migraine pathogenesis. NEUROCHEM J+ 2014. [DOI: 10.1134/s1819712414020093] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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45
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Vidal-Torres A, Fernández-Pastor B, Carceller A, Vela JM, Merlos M, Zamanillo D. Effects of the selective sigma-1 receptor antagonist S1RA on formalin-induced pain behavior and neurotransmitter release in the spinal cord in rats. J Neurochem 2014; 129:484-94. [PMID: 24384038 DOI: 10.1111/jnc.12648] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 12/03/2013] [Accepted: 12/30/2013] [Indexed: 12/21/2022]
Abstract
We have previously shown that the selective sigma-1 receptor (σ1 R) antagonist S1RA (E-52862) inhibits neuropathic pain and activity-induced spinal sensitization in various pre-clinical pain models. In this study we characterized both the behavioral and the spinal neurochemical effects of S1RA in the rat formalin test. Systemic administration of S1RA produced a dose-related attenuation of flinching and lifting/licking behaviors in the formalin test. Neurochemical studies using concentric microdialysis in the ipsilateral dorsal horn of awake, freely moving rats revealed that the systemic S1RA-induced antinociceptive effect occurs concomitantly with an enhancement of noradrenaline levels and an attenuation of formalin-evoked glutamate release in the spinal dorsal horn. Intrathecal pre-treatment with idazoxan prevented the systemic S1RA antinociceptive effect, suggesting that the S1RA antinociception depends on the activation of spinal α2 -adrenoceptors which, in turn, could induce an inhibition of formalin-evoked glutamate release. When administered locally, intrathecal S1RA inhibited only the flinching behavior, whereas intracerebroventricularly or intraplantarly injected also attenuated the lifting/licking behavior. These results suggest that S1RA supraspinally activates the descending noradrenergic pain inhibitory system, which may explain part of its antinociceptive properties in the formalin test; however, effects at other central and peripheral sites also account for the overall effect. Formalin-induced nociceptive effect occurs concomitantly with an enhancement of glutamate (Glu) level in the dorsal horn spinal cord. The selective σ1 receptor antagonist S1RA results in inhibition of formalin-evoked Glu release, no modification of GABA levels, and enhancement of noradrenaline (NA) levels. This increased spinal NA activates spinal α2-adrenoceptors producing the attenuation of the formalin-induced pain behaviour.
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Affiliation(s)
- Alba Vidal-Torres
- Drug Discovery and Preclinical Development, Laboratorios Esteve. Parc Científic Barcelona, Barcelona, Spain
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TRP Channels Involved in Spontaneous L-Glutamate Release Enhancement in the Adult Rat Spinal Substantia Gelatinosa. Cells 2014; 3:331-62. [PMID: 24785347 PMCID: PMC4092856 DOI: 10.3390/cells3020331] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 04/10/2014] [Accepted: 04/18/2014] [Indexed: 12/31/2022] Open
Abstract
The spinal substantia gelatinosa (SG) plays a pivotal role in modulating nociceptive transmission through dorsal root ganglion (DRG) neurons from the periphery. TRP channels such as TRPV1 and TRPA1 channels expressed in the SG are involved in the regulation of the nociceptive transmission. On the other hand, the TRP channels located in the peripheral terminals of the DRG neurons are activated by nociceptive stimuli given to the periphery and also by plant-derived chemicals, which generates a membrane depolarization. The chemicals also activate the TRP channels in the SG. In this review, we introduce how synaptic transmissions in the SG neurons are affected by various plant-derived chemicals and suggest that the peripheral and central TRP channels may differ in property from each other.
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47
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Jiang CY, Fujita T, Kumamoto E. Synaptic modulation and inward current produced by oxytocin in substantia gelatinosa neurons of adult rat spinal cord slices. J Neurophysiol 2014; 111:991-1007. [DOI: 10.1152/jn.00609.2013] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cellular mechanisms for antinociception produced by oxytocin in the spinal dorsal horn have not yet been investigated thoroughly. We examined how oxytocin affects synaptic transmission in substantia gelatinosa neurons, which play a pivotal role in regulating nociceptive transmission, by applying the whole-cell patch-clamp technique to the substantia gelatinosa neurons of adult rat spinal cord slices. Bath-applied oxytocin did not affect glutamatergic spontaneous, monosynaptically-evoked primary-afferent Aδ-fiber and C-fiber excitatory transmissions. On the other hand, oxytocin produced an inward current at −70 mV and enhanced GABAergic and glycinergic spontaneous inhibitory transmissions. These activities were repeated with a slow recovery from desensitization, concentration-dependent and mimicked by oxytocin-receptor agonist. The oxytocin current was inhibited by oxytocin-receptor antagonist, intracellular GDPβS, U-73122, 2-aminoethoxydiphenyl borate, but not dantrolene, chelerythrine, dibutyryl cyclic-AMP, CNQX, Ca2+-free and tetrodotoxin, while the spontaneous inhibitory transmission enhancements were depressed by tetrodotoxin. Current-voltage relation for the oxytocin current reversed at negative potentials more than the equilibrium potential for K+, or around 0 mV. The oxytocin current was depressed in high-K+, low-Na+ or Ba2+-containing solution. Vasopressin V1A-receptor antagonist inhibited the oxytocin current, but there was no correlation in amplitude between a vasopressin-receptor agonist [Arg8]vasopressin and oxytocin responses. It is concluded that oxytocin produces a membrane depolarization mediated by oxytocin but not vasopressin-V1A receptors, which increases neuronal activity, resulting in the enhancement of inhibitory transmission, a possible mechanism for antinociception. This depolarization is due to a change in membrane permeabilities to K+ and/or Na+, which is possibly mediated by phospholipase C and inositol 1,4,5-triphosphate-induced Ca2+-release.
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Affiliation(s)
- Chang-Yu Jiang
- Department of Physiology, Saga Medical School, Saga, Japan
| | - Tsugumi Fujita
- Department of Physiology, Saga Medical School, Saga, Japan
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48
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Petrenko AB, Yamakura T, Sakimura K, Baba H. Defining the role of NMDA receptors in anesthesia: Are we there yet? Eur J Pharmacol 2014; 723:29-37. [DOI: 10.1016/j.ejphar.2013.11.039] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 11/05/2013] [Accepted: 11/24/2013] [Indexed: 12/26/2022]
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49
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Funai Y, Pickering AE, Uta D, Nishikawa K, Mori T, Asada A, Imoto K, Furue H. Systemic dexmedetomidine augments inhibitory synaptic transmission in the superficial dorsal horn through activation of descending noradrenergic control: an in vivo patch-clamp analysis of analgesic mechanisms. Pain 2013; 155:617-628. [PMID: 24355412 DOI: 10.1016/j.pain.2013.12.018] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/26/2013] [Accepted: 12/10/2013] [Indexed: 12/19/2022]
Abstract
α2-Adrenoceptors are widely distributed throughout the central nervous system (CNS) and the systemic administration of α2-agonists such as dexmedetomidine produces clinically useful, centrally mediated sedation and analgesia; however, these same actions also limit the utility of these agents (ie, unwanted sedative actions). Despite a wealth of data on cellular and synaptic actions of α2-agonists in vitro, it is not known which neuronal circuits are modulated in vivo to produce the analgesic effect. To address this issue, we made in vivo recordings of membrane currents and synaptic activities in superficial spinal dorsal horn neurons and examined their responses to systemic dexmedetomidine. We found that dexmedetomidine at doses that produce analgesia (<10 μg/kg) enhanced inhibitory postsynaptic transmission within the superficial dorsal horn without altering excitatory synaptic transmission or evoking direct postsynaptic membrane currents. In contrast, higher doses of dexmedetomidine (>10 μg/kg) induced outward currents by a direct postsynaptic action. The dexmedetomidine-mediated inhibitory postsynaptic current facilitation was not mimicked by spinal application of dexmedetomidine and was absent in spinalized rats, suggesting that it acts at a supraspinal site. Furthermore, it was inhibited by spinal application of the α1-antagonist prazosin. In the brainstem, low doses of systemic dexmedetomidine produced an excitation of locus coeruleus neurons. These results suggest that systemic α2-adrenoceptor stimulation may facilitate inhibitory synaptic responses in the superficial dorsal horn to produce analgesia mediated by activation of the pontospinal noradrenergic inhibitory system. This novel mechanism may provide new targets for intervention, perhaps allowing analgesic actions to be dissociated from excessive sedation.
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Affiliation(s)
- Yusuke Funai
- Department of Information Physiology, National Institutes for Physiological Sciences, Okazaki, Japan Department of Anesthesiology, Osaka City University Graduate School of Medicine, Osaka, Japan School of Physiology and Pharmacology, University of Bristol, Bristol, UK School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
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Sokolov AY, Lyubashina OA, Amelin AV, Panteleev SS. The role of noradrenalin in the pathogenesis of primary headaches. NEUROCHEM J+ 2013. [DOI: 10.1134/s1819712413040090] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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