1
|
Patel R, Taylor JL, Dickenson AH, McMahon SB, Bannister K. A back-translational study of descending interactions with the induction of hyperalgesia by high-frequency electrical stimulation in rat and human. Pain 2024:00006396-990000000-00493. [PMID: 38198231 DOI: 10.1097/j.pain.0000000000003166] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/29/2023] [Indexed: 01/12/2024]
Abstract
ABSTRACT In humans and animals, high-frequency electrocutaneous stimulation (HFS) induces an "early long-term potentiation-like" sensitisation, where synaptic plasticity is underpinned by an ill-defined interaction between peripheral input and central modulatory processes. The relative contributions of these processes to the initial pain or nociceptive response likely differ from those that underpin development of the heightened response. To investigate the impact of HFS-induced hyperalgesia on pain and nociception in perception and neural terms, respectively, and to explore the impact of descending inhibitory pathway activation on the development of HFS-induced hyperalgesia, we performed parallel studies utilising identical stimuli to apply HFS concurrent to (1) a conditioned pain modulation paradigm during psychophysical testing in healthy humans or (2) a diffuse noxious inhibitory controls paradigm during in vivo electrophysiological recording of spinal neurones in healthy anaesthetised rats. High-frequency electrocutaneous stimulation alone induced enhanced perceptual responses to pinprick stimuli in cutaneous areas secondary to the area of electrical stimulation in humans and increased the excitability of spinal neurones which exhibited stimulus intensity-dependent coded responses to pinprick stimulation in a manner that tracked with human psychophysics, supporting their translational validity. Application of a distant noxious conditioning stimulus during HFS did not alter perceived primary or secondary hyperalgesia in humans or the development of primary or secondary neuronal hyperexcitability in rats compared with HFS alone, suggesting that, upon HFS-response initiation in a healthy nervous system, excitatory signalling escapes inhibitory control. Therefore, in this model, dampening facilitatory mechanisms rather than augmenting top-down inhibitions could prevent pain development.
Collapse
Affiliation(s)
- Ryan Patel
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Joseph L Taylor
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Anthony H Dickenson
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, United Kingdom
| | - Stephen B McMahon
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| | - Kirsty Bannister
- King's College London, Wolfson Centre, Guy's Campus, London, United Kingdom
| |
Collapse
|
2
|
Kozar-Gillan N, Velichkova A, Kanatouris G, Eshed-Eisenbach Y, Steel G, Jaegle M, Aunin E, Peles E, Torsney C, Meijer DN. LGI3/2-ADAM23 interactions cluster Kv1 channels in myelinated axons to regulate refractory period. J Cell Biol 2023; 222:e202211031. [PMID: 36828548 PMCID: PMC9997507 DOI: 10.1083/jcb.202211031] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/18/2022] [Accepted: 01/17/2023] [Indexed: 02/26/2023] Open
Abstract
Along myelinated axons, Shaker-type potassium channels (Kv1) accumulate at high density in the juxtaparanodal region, directly adjacent to the paranodal axon-glia junctions that flank the nodes of Ranvier. However, the mechanisms that control the clustering of Kv1 channels, as well as their function at this site, are still poorly understood. Here we demonstrate that axonal ADAM23 is essential for both the accumulation and stability of juxtaparanodal Kv1 complexes. The function of ADAM23 is critically dependent on its interaction with its extracellular ligands LGI2 and LGI3. Furthermore, we demonstrate that juxtaparanodal Kv1 complexes affect the refractory period, thus enabling high-frequency burst firing of action potentials. Our findings not only reveal a previously unknown molecular pathway that regulates Kv1 channel clustering, but they also demonstrate that the juxtaparanodal Kv1 channels that are concealed below the myelin sheath, play a significant role in modifying axonal physiology.
Collapse
Affiliation(s)
- Nina Kozar-Gillan
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | | | - George Kanatouris
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology and Molecular Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Gavin Steel
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
| | | | - Eerik Aunin
- Biomedical Sciences, ErasmusMC, Rotterdam, Netherlands
| | - Elior Peles
- Department of Molecular Cell Biology and Molecular Neurobiology, Weizmann Institute of Science, Rehovot, Israel
| | - Carole Torsney
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh. UK
| | - Dies N. Meijer
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh. UK
- Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
3
|
Pre-Synaptic GABAA in NaV1.8+ Primary Afferents Is Required for the Development of Punctate but Not Dynamic Mechanical Allodynia following CFA Inflammation. Cells 2022; 11:cells11152390. [PMID: 35954234 PMCID: PMC9368720 DOI: 10.3390/cells11152390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 01/27/2023] Open
Abstract
Hypersensitivity to mechanical stimuli is a cardinal symptom of neuropathic and inflammatory pain. A reduction in spinal inhibition is generally considered a causal factor in the development of mechanical hypersensitivity after injury. However, the extent to which presynaptic inhibition contributes to altered spinal inhibition is less well established. Here, we used conditional deletion of GABAA in NaV1.8-positive sensory neurons (Scn10aCre;Gabrb3fl/fl) to manipulate selectively presynaptic GABAergic inhibition. Behavioral testing showed that the development of inflammatory punctate allodynia was mitigated in mice lacking pre-synaptic GABAA. Dorsal horn cellular circuits were visualized in single slices using stimulus-tractable dual-labelling of c-fos mRNA for punctate and the cognate c-Fos protein for dynamic mechanical stimulation. This revealed a substantial reduction in the number of cells activated by punctate stimulation in mice lacking presynaptic GABAA and an approximate 50% overlap of the punctate with the dynamic circuit, the relative percentage of which did not change following inflammation. The reduction in dorsal horn cells activated by punctate stimuli was equally prevalent in parvalbumin- and calretinin-positive cells and across all laminae I–V, indicating a generalized reduction in spinal input. In peripheral DRG neurons, inflammation following complete Freund’s adjuvant (CFA) led to an increase in axonal excitability responses to GABA, suggesting that presynaptic GABA effects in NaV1.8+ afferents switch from inhibition to excitation after CFA. In the days after inflammation, presynaptic GABAA in NaV1.8+ nociceptors constitutes an “open gate” pathway allowing mechanoreceptors responding to punctate mechanical stimulation access to nociceptive dorsal horn circuits.
Collapse
|
4
|
Velichkova AN, Coleman SE, Torsney C. Postoperative pain facilitates rat C-fibre activity-dependent slowing and induces thermal hypersensitivity in a sex-dependent manner. Br J Anaesth 2022; 128:718-733. [DOI: 10.1016/j.bja.2021.10.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/05/2021] [Accepted: 10/26/2021] [Indexed: 11/02/2022] Open
|
5
|
Rat dorsal horn neurons primed by stress develop a long-lasting manifest sensitization after a short-lasting nociceptive low back input. Pain Rep 2021; 6:e904. [PMID: 33688602 PMCID: PMC7935483 DOI: 10.1097/pr9.0000000000000904] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/29/2020] [Accepted: 01/15/2021] [Indexed: 11/26/2022] Open
Abstract
Background A single injection of nerve growth factor (NGF) into a low back muscle induces a latent sensitization of rat dorsal horn neurons (DHNs) that primes for a manifest sensitization by a subsequent second NGF injection. Repeated restraint stress also causes a latent DHN sensitization. Objective In this study, we investigated whether repeated restraint stress followed by a single NGF injection causes a manifest sensitization of DHNs. Methods Rats were stressed repeatedly in a narrow plastic restrainer (1 hour on 12 consecutive days). Control animals were handled but not restrained. Two days after stress paradigm, behavioral tests and electrophysiological in vivo recordings from single DHNs were performed. Mild nociceptive low back input was induced by a single NGF injection into the lumbar multifidus muscle just before the recording started. Results Restraint stress slightly lowered the low back pressure pain threshold (Cohen d = 0.83). Subsequent NGF injection increased the proportion of neurons responsive to deep low back input (control + NGF: 14%, stress + NGF: 39%; P = 0.041), mostly for neurons with input from outside the low back (7% vs 26%; P = 0.081). There was an increased proportion of neurons with resting activity (28% vs 55%; P = 0.039), especially in neurons having deep input (0% vs 26%; P = 0.004). Conclusions The results indicate that stress followed by a short-lasting nociceptive input causes manifest sensitization of DHNs to deep input, mainly from tissue outside the low back associated with an increased resting activity. These findings on neuronal mechanisms in our rodent model suggest how stress might predispose to radiating pain in patients.
Collapse
|
6
|
Torsney C. Inflammatory pain neural plasticity. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
van den Broeke EN, Gousset S, Bouvy J, Stouffs A, Lebrun L, van Neerven SGA, Mouraux A. Heterosynaptic facilitation of mechanical nociceptive input is dependent on the frequency of conditioning stimulation. J Neurophysiol 2019; 122:994-1001. [PMID: 31291140 PMCID: PMC6766737 DOI: 10.1152/jn.00274.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/10/2019] [Accepted: 07/09/2019] [Indexed: 11/22/2022] Open
Abstract
High-frequency burstlike electrical conditioning stimulation (HFS) applied to human skin induces an increase in mechanical pinprick sensitivity of the surrounding unconditioned skin (a phenomenon known as secondary hyperalgesia). The present study assessed the effect of frequency of conditioning stimulation on the development of this increased pinprick sensitivity in humans. In a first experiment, we compared the increase in pinprick sensitivity induced by HFS, using monophasic non-charge-compensated pulses and biphasic charge-compensated pulses. High-frequency stimulation, traditionally delivered with non-charge-compensated square-wave pulses, may induce a cumulative depolarization of primary afferents and/or changes in pH at the electrode-tissue interface due to the accumulation of a net residue charge after each pulse. Both could contribute to the development of the increased pinprick sensitivity in a frequency-dependent fashion. We found no significant difference in the increase in pinprick sensitivity between HFS delivered with charge-compensated and non-charge-compensated pulses, indicating that the possible contribution of charge accumulation when non-charge-compensated pulses are used is negligible. In a second experiment, we assessed the effect of different frequencies of conditioning stimulation (5, 20, 42, and 100 Hz) using charge-compensated pulses on the development of increased pinprick sensitivity. The maximal increase in pinprick sensitivity was observed at intermediate frequencies of stimulation (20 and 42 Hz). It is hypothesized that the stronger increase in pinprick sensitivity at intermediate frequencies may be related to the stronger release of substance P and/or neurokinin-1 receptor activation expressed at lamina I neurons after C-fiber stimulation.NEW & NOTEWORTHY Burstlike electrical conditioning stimulation applied to human skin induces an increase in pinprick sensitivity in the surrounding unconditioned skin (a phenomenon referred to as secondary hyperalgesia). Here we show that the development of the increase in pinprick sensitivity is dependent on the frequency of the burstlike electrical conditioning stimulation.
Collapse
Affiliation(s)
- E N van den Broeke
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - S Gousset
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - J Bouvy
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - A Stouffs
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - L Lebrun
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - S G A van Neerven
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - A Mouraux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| |
Collapse
|
8
|
Hoheisel U, Chacur M, Treede RD, Mense S. Action potentials and subthreshold potentials of dorsal horn neurons in a rat model of myositis: a study employing intracellular recordings in vivo. J Neurophysiol 2019; 122:632-643. [PMID: 31166805 DOI: 10.1152/jn.00338.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Intracellular in vivo recordings from rat dorsal horn neurons were made to study the contribution of microglia to the central sensitization of spinal synapses induced by a chronic muscle inflammation. To block microglia activation, minocycline was continuously administered intrathecally during development of the inflammation. The aim was to test whether an inflammation-induced sensitization of dorsal horn neurons is mediated by changes in synaptic strength or other synaptic changes and how activated microglia influence these processes. Intracellular recordings were used to measure subthreshold excitatory postsynaptic potentials (EPSPs) and suprathreshold action potentials (APs). The muscle inflammation significantly increased the proportion of dorsal horn neurons responding with APs or EPSPs to electrical stimulation of the muscle nerve from 27 to 56% (P < 0.01) and to noxious muscle stimulation (3 vs. 44%, P < 0.01). Neurons showing spontaneous ongoing AP or EPSP activity increased from 28 to 74% (P < 0.01). Generally, the increases in suprathreshold AP responses did not occur at the expense of subthreshold EPSPs, because EPSP-only responses also increased. Intrathecal minocycline prevented the inflammation-induced increase in responsiveness to electrical (24%, P < 0.02) and mechanical stimulation (14%, P < 0.02); the effect was stronger on suprathreshold APs than on subthreshold EPSPs. The increase in ongoing activity was only partly suppressed. These data suggest that the myositis-induced hypersensitivity of the dorsal horn neurons to peripheral input and its prevention by intrathecal minocycline treatment were due to both an increase in the number of active synapses and an increased synaptic strength.NEW & NOTEWORTHY During a chronic muscle inflammation (myositis), activated microglia controls both the increase in the number of active synapses and the increase in synaptic strength.
Collapse
Affiliation(s)
- Ulrich Hoheisel
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Marucia Chacur
- Department of Anatomy, Institute of Biomedical Science-ICB III, University of São Paulo, São Paulo, Brazil
| | - Rolf-Detlef Treede
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Siegfried Mense
- Department of Neurophysiology, Center for Biomedicine and Medical Technology Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| |
Collapse
|
9
|
Huang Y, Chen SR, Chen H, Pan HL. Endogenous transient receptor potential ankyrin 1 and vanilloid 1 activity potentiates glutamatergic input to spinal lamina I neurons in inflammatory pain. J Neurochem 2019; 149:381-398. [PMID: 30716174 DOI: 10.1111/jnc.14677] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/31/2018] [Accepted: 01/30/2019] [Indexed: 01/21/2023]
Abstract
Inflammatory pain is associated with peripheral and central sensitization, but the underlying synaptic plasticity at the spinal cord level is poorly understood. Transient receptor potential (TRP) channels expressed at peripheral nerve endings, including TRP subtypes ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1), can detect nociceptive stimuli. In this study, we determined the contribution of presynaptic TRPA1 and TRPV1 at the spinal cord level to regulating nociceptive drive in chronic inflammatory pain induced by complete Freund's adjuvant (CFA) in rats. CFA treatment caused a large increase in the frequency of spontaneous excitatory postsynaptic currents (EPSCs) in lamina I, but not lamina II outer zone, dorsal horn neurons. However, blocking NMDA receptors had no effect on spontaneous EPSCs in lamina I neurons of CFA-treated rats. Application of a specific TRPA1 antagonist, AM-0902, or of a specific TRPV1 antagonist, 5'-iodoresiniferatoxin, significantly attenuated the elevated frequency of spontaneous EPSCs and miniature EPSCs, the amplitude of monosynaptic EPSCs evoked from the dorsal root in lamina I neurons of CFA-treated rats. AM-0902 and 5'-iodoresiniferatoxin had no effect on evoked or miniature EPSCs in lamina I neurons of vehicle-treated rats. In addition, intrathecal injection of AM-0902 or 5'-iodoresiniferatoxin significantly reduced pain hypersensitivity in CFA-treated rats but had no effect on acute nociception in vehicle-treated rats. Therefore, unlike neuropathic pain, chronic inflammatory pain is associated with NMDA receptor-independent potentiation in glutamatergic drive to spinal lamina I neurons. Endogenous presynaptic TRPA1 and TRPV1 activity at the spinal level contributes to increased nociceptive input from primary sensory nerves to dorsal horn neurons in inflammatory pain. OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
Collapse
Affiliation(s)
- Yuying Huang
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience and Pain Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Shao-Rui Chen
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience and Pain Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Hong Chen
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience and Pain Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Hui-Lin Pan
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience and Pain Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| |
Collapse
|
10
|
Presynaptic Inhibition of Primary Nociceptive Signals to Dorsal Horn Lamina I Neurons by Dopamine. J Neurosci 2018; 38:8809-8821. [PMID: 30143577 DOI: 10.1523/jneurosci.0323-18.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/18/2018] [Accepted: 08/09/2018] [Indexed: 01/10/2023] Open
Abstract
The dorsal horn of the spinal cord represents the first relay station in the pain pathway where primary nociceptive inputs are modulated by local circuits and by descending signals before being relayed to supraspinal nuclei. To determine whether dopamine can modulate primary nociceptive Aδ- and C-fiber signals, the effects of dopamine were tested on the excitatory postsynaptic currents (EPSCs) recorded from large lamina I neurons and from retrograde-labeled spinoparabrachial lamina I neurons upon stimulation of the L4/L5 dorsal root in horizontal spinal cord slices in vitro Dopamine inhibited the EPSCs in a dose-dependent manner, with substantial inhibition (33%) at 1 μm and maximum inhibition (∼70%) at 10-20 μm Dopamine reduced the frequency of miniature EPSCs recorded from large lamina I neurons, increased the paired pulse depression ratio of paired EPSCs, and induced similar inhibition of EPSCs after dialysis of large lamina I neurons with GDP-β-S, consistent with actions at presynaptic sites. Pharmacological experiments suggested that the inhibitory effects of dopamine were largely mediated by D4 receptors (53%). Similar inhibition (66%) by dopamine was observed on EPSCs recorded from ipsilateral large lamina I neurons 6 d after injection of complete Freund's adjuvant in the hindpaw, suggesting that dopamine downregulates primary nociceptive inputs to lamina I neurons during chronic inflammatory pain. We propose that presynaptic inhibition of primary nociceptive inputs to lamina I projection neurons is a mechanism whereby dopamine can inhibit incoming noxious stimuli to the dorsal horn of the spinal cord.SIGNIFICANCE STATEMENT Lamina I projection neurons represent the main output for the pain signals from the dorsal horn of the spinal cord to brainstem and thalamic nuclei. We found that dopamine inhibits the nociceptive Aδ- and C-fiber synaptic inputs to lamina I projection neurons via presynaptic actions. Similar inhibitory effects of dopamine on the EPSCs were observed in rats subjected to complete Freund's adjuvant to induce peripheral inflammation, suggesting that dopamine inhibits the synaptic inputs to lamina I neurons in the setting of injury. A better understanding of how primary nociceptive inputs to the dorsal horn of the spinal cord are modulated by descending monoaminergic signals may help in the development of new pharmacological strategies to selectively downregulate the output from lamina I projection neurons.
Collapse
|
11
|
Maiarù M, Leese C, Certo M, Echeverria-Altuna I, Mangione AS, Arsenault J, Davletov B, Hunt SP. Selective neuronal silencing using synthetic botulinum molecules alleviates chronic pain in mice. Sci Transl Med 2018; 10:10/450/eaar7384. [DOI: 10.1126/scitranslmed.aar7384] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/20/2018] [Accepted: 06/28/2018] [Indexed: 12/16/2022]
|
12
|
|
13
|
Galley HF, McCormick B, Wilson KL, Lowes DA, Colvin L, Torsney C. Melatonin limits paclitaxel-induced mitochondrial dysfunction in vitro and protects against paclitaxel-induced neuropathic pain in the rat. J Pineal Res 2017; 63:e12444. [PMID: 28833461 PMCID: PMC5656911 DOI: 10.1111/jpi.12444] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 08/18/2017] [Indexed: 12/29/2022]
Abstract
Chemotherapy-induced neuropathic pain is a debilitating and common side effect of cancer treatment. Mitochondrial dysfunction associated with oxidative stress in peripheral nerves has been implicated in the underlying mechanism. We investigated the potential of melatonin, a potent antioxidant that preferentially acts within mitochondria, to reduce mitochondrial damage and neuropathic pain resulting from the chemotherapeutic drug paclitaxel. In vitro, paclitaxel caused a 50% reduction in mitochondrial membrane potential and metabolic rate, independent of concentration (20-100 μmol/L). Mitochondrial volume was increased dose-dependently by paclitaxel (200% increase at 100 μmol/L). These effects were prevented by co-treatment with 1 μmol/L melatonin. Paclitaxel cytotoxicity against cancer cells was not affected by co-exposure to 1 μmol/L melatonin of either the breast cancer cell line MCF-7 or the ovarian carcinoma cell line A2780. In a rat model of paclitaxel-induced painful peripheral neuropathy, pretreatment with oral melatonin (5/10/50 mg/kg), given as a daily bolus dose, was protective, dose-dependently limiting development of mechanical hypersensitivity (19/43/47% difference from paclitaxel control, respectively). Melatonin (10 mg/kg/day) was similarly effective when administered continuously in drinking water (39% difference). Melatonin also reduced paclitaxel-induced elevated 8-isoprostane F2 α levels in peripheral nerves (by 22% in sciatic; 41% in saphenous) and limited paclitaxel-induced reduction in C-fibre activity-dependent slowing (by 64%). Notably, melatonin limited the development of mechanical hypersensitivity in both male and female animals (by 50/41%, respectively), and an additive effect was found when melatonin was given with the current treatment, duloxetine (75/62% difference, respectively). Melatonin is therefore a potential treatment to limit the development of painful neuropathy resulting from chemotherapy treatment.
Collapse
Affiliation(s)
- Helen F. Galley
- Institute of Medical SciencesUniversity of AberdeenAberdeenUK
| | - Barry McCormick
- Institute of Medical SciencesUniversity of AberdeenAberdeenUK
- Centre for Integrative PhysiologyEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Kirsten L. Wilson
- Centre for Integrative PhysiologyEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| | - Damon A. Lowes
- Institute of Medical SciencesUniversity of AberdeenAberdeenUK
| | - Lesley Colvin
- Department of Anaesthesia, Critical Care and Pain MedicineUniversity of EdinburghEdinburghUK
| | - Carole Torsney
- Centre for Integrative PhysiologyEdinburgh Medical School: Biomedical SciencesUniversity of EdinburghEdinburghUK
| |
Collapse
|
14
|
Altered intrinsic and synaptic properties of lumbosacral dorsal horn neurons in a mouse model of colitis. Neuroscience 2017; 362:152-167. [DOI: 10.1016/j.neuroscience.2017.08.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 07/19/2017] [Accepted: 08/14/2017] [Indexed: 12/30/2022]
|
15
|
Inflammatory Pain Reduces C Fiber Activity-Dependent Slowing in a Sex-Dependent Manner, Amplifying Nociceptive Input to the Spinal Cord. J Neurosci 2017; 37:6488-6502. [PMID: 28576935 PMCID: PMC5511880 DOI: 10.1523/jneurosci.3816-16.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/10/2017] [Accepted: 05/13/2017] [Indexed: 11/21/2022] Open
Abstract
C fibers display activity-dependent slowing (ADS), whereby repetitive stimulation (≥1 Hz) results in a progressive slowing of action potential conduction velocity, which manifests as a progressive increase in response latency. However, the impact of ADS on spinal pain processing has not been explored, nor whether ADS is altered in inflammatory pain conditions. To investigate, compound action potentials were made, from dorsal roots isolated from rats with or without complete Freund's adjuvant (CFA) hindpaw inflammation, in response to electrical stimulus trains. CFA inflammation significantly reduced C fiber ADS at 1 and 2 Hz stimulation rates. Whole-cell patch-clamp recordings in the spinal cord slice preparation with attached dorsal roots also demonstrated that CFA inflammation reduced ADS in the monosynaptic C fiber input to lamina I neurokinin 1 receptor-expressing neurons (1–10 Hz stimulus trains) without altering the incidence of synaptic response failures. When analyzed by sex, it was revealed that females display a more pronounced ADS that is reduced by CFA inflammation to a level comparable with males. Cumulative ventral root potentials evoked by long and short dorsal root stimulation lengths, to maximize and minimize the impact of ADS, respectively, demonstrated that reducing ADS facilitates spinal summation, and this was also sex dependent. This finding correlated with the behavioral observation of increased noxious thermal thresholds and enhanced inflammatory thermal hypersensitivity in females. We propose that sex/inflammation-dependent regulation of C fiber ADS can, by controlling the temporal relay of nociceptive inputs, influence the spinal summation of nociceptive signals contributing to sex/inflammation-dependent differences in pain sensitivity. SIGNIFICANCE STATEMENT The intensity of a noxious stimulus is encoded by the frequency of action potentials relayed by nociceptive C fibers to the spinal cord. C fibers conduct successive action potentials at progressively slower speeds, but the impact of this activity-dependent slowing (ADS) is unknown. Here we demonstrate that ADS is more prevalent in females than males and is reduced in an inflammatory pain model in females only. We also demonstrate a progressive delay of C fiber monosynaptic transmission to the spinal cord that is similarly sex and inflammation dependent. Experimentally manipulating ADS strongly influences spinal summation consistent with sex differences in behavioral pain thresholds. This suggests that ADS provides a peripheral mechanism that can regulate spinal nociceptive processing and pain sensation.
Collapse
|
16
|
Ke C, Gao F, Tian X, Li C, Shi D, He W, Tian Y. Slit2/Robo1 Mediation of Synaptic Plasticity Contributes to Bone Cancer Pain. Mol Neurobiol 2017; 54:295-307. [PMID: 26738857 DOI: 10.1007/s12035-015-9564-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/29/2015] [Indexed: 12/11/2022]
Abstract
Synaptic plasticity is fundamental to spinal sensitivity of bone cancer pain. Here, we have shown that excitatory synaptogenesis contributes to bone cancer pain. New synapse formation requires neurite outgrowth and an interaction between axons and dendrites, accompanied by the appositional organization of presynaptic and postsynaptic specializations. We have shown that Slit2, Robo1, and RhoA act as such cues that promote neurite outgrowth and guide the axon for synapse formation. Sarcoma inoculation induces excitatory synaptogenesis and bone cancer pain which are reversed by Slit2 knockdown but aggravated by Robo1 knockdown. Synaptogenesis of cultured neurons are inhibited by Slit2 knockdown but enhanced by Robo1 knockdown. Sarcoma implantation induces an increase in Slit2 and decreases Robo1 and RhoA, while Slit2 knockdown results in an increase of Robo1 and RhoA. These results have demonstrated a molecular mechanism of synaptogenesis in bone cancer pain.
Collapse
Affiliation(s)
- Changbin Ke
- Institute of Anesthesiology and Pain (IAP) and Department of Anesthesiology, Taihe Hospital, Hubei University of Medicine, Shiyan City, 442000, Hubei Province, China
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Feng Gao
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xuebi Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Caijuan Li
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Dai Shi
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wensheng He
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yuke Tian
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| |
Collapse
|
17
|
Zhuo M. Ionotropic glutamate receptors contribute to pain transmission and chronic pain. Neuropharmacology 2017; 112:228-234. [DOI: 10.1016/j.neuropharm.2016.08.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 12/31/2022]
|
18
|
A combined electrophysiological and morphological study of neuropeptide Y-expressing inhibitory interneurons in the spinal dorsal horn of the mouse. Pain 2016; 157:598-612. [PMID: 26882346 PMCID: PMC4751741 DOI: 10.1097/j.pain.0000000000000407] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The spinal dorsal horn contains numerous inhibitory interneurons that control transmission of somatosensory information. Although these cells have important roles in modulating pain, we still have limited information about how they are incorporated into neuronal circuits, and this is partly due to difficulty in assigning them to functional populations. Around 15% of inhibitory interneurons in laminae I-III express neuropeptide Y (NPY), but little is known about this population. We therefore used a combined electrophysiological/morphological approach to investigate these cells in mice that express green fluorescent protein (GFP) under control of the NPY promoter. We show that GFP is largely restricted to NPY-immunoreactive cells, although it is only expressed by a third of those in lamina I-II. Reconstructions of recorded neurons revealed that they were morphologically heterogeneous, but never islet cells. Many NPY-GFP cells (including cells in lamina III) appeared to be innervated by C fibres that lack transient receptor potential vanilloid-1, and consistent with this, we found that some lamina III NPY-immunoreactive cells were activated by mechanical noxious stimuli. Projection neurons in lamina III are densely innervated by NPY-containing axons. Our results suggest that this input originates from a small subset of NPY-expressing interneurons, with the projection cells representing only a minority of their output. Taken together with results of previous studies, our findings indicate that somatodendritic morphology is of limited value in classifying functional populations among inhibitory interneurons in the dorsal horn. Because many NPY-expressing cells respond to noxious stimuli, these are likely to have a role in attenuating pain and limiting its spread.
Collapse
|
19
|
Gastrodin protects against chronic inflammatory pain by inhibiting spinal synaptic potentiation. Sci Rep 2016; 6:37251. [PMID: 27853254 PMCID: PMC5112517 DOI: 10.1038/srep37251] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 10/26/2016] [Indexed: 12/15/2022] Open
Abstract
Tissue injury is known to produce inflammation and pain. Synaptic potentiation between peripheral nociceptors and spinal lamina I neurons has been proposed to serve as a trigger for chronic inflammatory pain. Gastrodin is a main bioactive constituent of the traditional Chinese herbal medicine Gastrodia elata Blume, which has been widely used as an analgesic since ancient times. However, its underlying cellular mechanisms have remained elusive. The present study demonstrated for the first time that gastrodin exhibits an analgesic effect at the spinal level on spontaneous pain, mechanical and thermal pain hypersensitivity induced by peripheral inflammation, which is not dependent on opioid receptors and without tolerance. This analgesia by gastrodin is at least in part mediated by depressing spinal synaptic potentiation via blockade of acid-sensing ion channels. Further studies with miniature EPSCs and paired-pulse ratio analysis revealed the presynaptic origin of the action of gastrodin, which involves a decrease in transmitter release probability. In contrast, neither basal nociception nor basal synaptic transmission was altered. This study revealed a dramatic analgesic action of gastrodin on inflammatory pain and uncovered a novel spinal mechanism that could underlie the analgesia by gastrodin, pointing the way to a new analgesic for treating chronic inflammatory pain.
Collapse
|
20
|
Hulse RP, Drake RAR, Bates DO, Donaldson LF. The control of alternative splicing by SRSF1 in myelinated afferents contributes to the development of neuropathic pain. Neurobiol Dis 2016; 96:186-200. [PMID: 27616424 PMCID: PMC5113660 DOI: 10.1016/j.nbd.2016.09.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/24/2016] [Accepted: 09/06/2016] [Indexed: 02/07/2023] Open
Abstract
Neuropathic pain results from neuroplasticity in nociceptive neuronal networks. Here we demonstrate that control of alternative pre-mRNA splicing, through the splice factor serine-arginine splice factor 1 (SRSF1), is integral to the processing of nociceptive information in the spinal cord. Neuropathic pain develops following a partial saphenous nerve ligation injury, at which time SRSF1 is activated in damaged myelinated primary afferent neurons, with minimal found in small diameter (IB4 positive) dorsal root ganglia neurons. Serine arginine protein kinase 1 (SRPK1) is the principal route of SRSF1 activation. Spinal SRPK1 inhibition attenuated SRSF1 activity, abolished neuropathic pain behaviors and suppressed central sensitization. SRSF1 was principally expressed in large diameter myelinated (NF200-rich) dorsal root ganglia sensory neurons and their excitatory central terminals (vGLUT1+ve) within the dorsal horn of the lumbar spinal cord. Expression of pro-nociceptive VEGF-Axxxa within the spinal cord was increased after nerve injury, and this was prevented by SRPK1 inhibition. Additionally, expression of anti-nociceptive VEGF-Axxxb isoforms was elevated, and this was associated with reduced neuropathic pain behaviors. Inhibition of VEGF receptor-2 signaling in the spinal cord attenuated behavioral nociceptive responses to mechanical, heat and formalin stimuli, indicating that spinal VEGF receptor-2 activation has potent pro-nociceptive actions. Furthermore, intrathecal VEGF-A165a resulted in mechanical and heat hyperalgesia, whereas the sister inhibitory isoform VEGF-A165b resulted in anti-nociception. These results support a role for myelinated fiber pathways, and alternative pre-mRNA splicing of factors such as VEGF-A in the spinal processing of neuropathic pain. They also indicate that targeting pre-mRNA splicing at the spinal level could lead to a novel target for analgesic development.
Collapse
Affiliation(s)
- Richard P Hulse
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham, NG7 7UH, United Kingdom; School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom.
| | - Robert A R Drake
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - David O Bates
- Cancer Biology, School of Medicine, University of Nottingham, Nottingham, NG7 7UH, United Kingdom; School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Lucy F Donaldson
- School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom; School of Life Sciences and Arthritis Research UK Pain Centre, University of Nottingham, Nottingham NG7 7UH, United Kingdom.
| |
Collapse
|
21
|
Neuronal networks and nociceptive processing in the dorsal horn of the spinal cord. Neuroscience 2016; 338:230-247. [PMID: 27595888 DOI: 10.1016/j.neuroscience.2016.08.048] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/23/2016] [Accepted: 08/28/2016] [Indexed: 12/31/2022]
Abstract
The dorsal horn (DH) of the spinal cord receives a variety of sensory information arising from the inner and outer environment, as well as modulatory inputs from supraspinal centers. This information is integrated by the DH before being forwarded to brain areas where it may lead to pain perception. Spinal integration of this information relies on the interplay between different DH neurons forming complex and plastic neuronal networks. Elements of these networks are therefore potential targets for new analgesics and pain-relieving strategies. The present review aims at providing an overview of the current knowledge on these networks, with a special emphasis on those involving interlaminar communication in both physiological and pathological conditions.
Collapse
|
22
|
Protein Kinase C γ Interneurons Mediate C-fiber–induced Orofacial Secondary Static Mechanical Allodynia, but Not C-fiber–induced Nociceptive Behavior. Anesthesiology 2016; 124:1136-52. [DOI: 10.1097/aln.0000000000001000] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Abstract
Background
Tissue injury enhances pain sensitivity both at the site of tissue damage and in surrounding uninjured skin (secondary hyperalgesia). Secondary hyperalgesia encompasses several pain symptoms including pain to innocuous punctate stimuli or static mechanical allodynia. How injury-induced barrage from C-fiber nociceptors produces secondary static mechanical allodynia has not been elucidated.
Methods
Combining behavioral, immunohistochemical, and Western blot analysis, the authors investigated the cell and molecular mechanisms underlying the secondary static mechanical allodynia in the rat medullary dorsal horn (MDH) using the capsaicin model (n = 4 to 5 per group).
Results
Intradermal injection of capsaicin (25 μg) into the vibrissa pad produces a spontaneous pain and a secondary static mechanical allodynia. This allodynia is associated with the activation of a neuronal network encompassing lamina I–outer lamina III, including interneurons expressing the γ isoform of protein kinase C (PKCγ) within inner lamina II (IIi) of MDH. PKCγ is concomitantly phosphorylated (+351.4 ± 79.2%, mean ± SD; P = 0.0003). Mechanical allodynia and innocuous punctate stimulus–evoked laminae I to III neuronal activation can be replicated after intracisternally applied γ-aminobutyric acid receptor type A (GABAA) antagonist (bicuculline: 0.05 μg) or reactive oxygen species (ROS) donor (tert-butyl hydroperoxide: 50 to 250 ng). Conversely, intracisternal PKCγ antagonist, GABAA receptor agonist, or ROS scavenger prevent capsaicin-induced static mechanical allodynia and neuronal activation.
Conclusions
Sensitization of lamina IIi PKCγ interneurons is required for the manifestation of secondary static mechanical allodynia but not for spontaneous pain. Such sensitization is driven by ROS and GABAAergic disinhibition. ROS released during intense C-fiber nociceptor activation might produce a GABAAergic disinhibition of PKCγ interneurons. Innocuous punctate inputs carried by Aδ low-threshold mechanoreceptors onto PKCγ interneurons can then gain access to the pain transmission circuitry of superficial MDH, producing pain.
Collapse
|
23
|
Betelli C, MacDermott AB, Bardoni R. Transient, activity dependent inhibition of transmitter release from low threshold afferents mediated by GABAA receptors in spinal cord lamina III/IV. Mol Pain 2015; 11:64. [PMID: 26463733 PMCID: PMC4605127 DOI: 10.1186/s12990-015-0067-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Background Presynaptic GABAA receptors (GABAARs) located on central terminals of low threshold afferent fibers are thought to be involved in the processing of touch and possibly in the generation of tactile allodynia in chronic pain. These GABAARs mediate primary afferent depolarization (PAD) and modulate transmitter release. The objective of this study was to expand our understanding of the presynaptic inhibitory action of GABA released onto primary afferent central terminals following afferent stimulation. Results We recorded evoked postsynaptic excitatory responses (eEPSCs and eEPSPs) from lamina III/IV neurons in spinal cord slices from juvenile rats (P17–P23, either sex), while stimulating dorsal roots. We investigated time and activity dependent changes in glutamate release from low threshold A fibers and the impact of these changes on excitatory drive. Blockade of GABAARs by gabazine potentiated the second eEPSC during a train of four afferent stimuli in a large subset of synapses. This resulted in a corresponding increase of action potential firing after the second stimulus. The potentiating effect of gabazine was due to inhibition of endogenously activated presynaptic GABAARs, because it was not prevented by the blockade of postsynaptic GABAARs through intracellular perfusion of CsF. Exogenous activation of presynaptic GABAARs by muscimol depressed evoked glutamate release at all synapses and increased paired pulse ratio (PPR). Conclusions These observations suggest that afferent driven release of GABA onto low threshold afferent terminals is most effective following the first action potential in a train and serves to suppress the initial strong excitatory drive onto dorsal horn circuitry.
Collapse
Affiliation(s)
- Chiara Betelli
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi, 287, 41125, Modena, Italy.
| | - Amy B MacDermott
- Departments of Physiology and Cellular Biophysics, Neuroscience, Columbia University, 630 W. 168th Street, New York, NY, 10032, USA.
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Campi, 287, 41125, Modena, Italy.
| |
Collapse
|
24
|
Walker SM, Beggs S, Baccei ML. Persistent changes in peripheral and spinal nociceptive processing after early tissue injury. Exp Neurol 2015; 275 Pt 2:253-60. [PMID: 26103453 DOI: 10.1016/j.expneurol.2015.06.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 06/16/2015] [Accepted: 06/18/2015] [Indexed: 12/11/2022]
Abstract
It has become clear that tissue damage during a critical period of early life can result in long-term changes in pain sensitivity, but the underlying mechanisms remain to be fully elucidated. Here we review the clinical and preclinical evidence for persistent alterations in nociceptive processing following neonatal tissue injury, which collectively point to the existence of both a widespread hypoalgesia at baseline as well as an exacerbated degree of hyperalgesia following a subsequent insult to the same somatotopic region. We also highlight recent work investigating the effects of early trauma on the organization and function of ascending pain pathways at a cellular and molecular level. These effects of neonatal injury include altered ion channel expression in both primary afferent and spinal cord neurons, shifts in the balance between synaptic excitation and inhibition within the superficial dorsal horn (SDH) network, and a 'priming' of microglial responses in the adult SDH. A better understanding of how early tissue damage influences the maturation of nociceptive circuits could yield new insight into strategies to minimize the long-term consequences of essential, but invasive, medical procedures on the developing somatosensory system.
Collapse
Affiliation(s)
- Suellen M Walker
- Pain Research (Respiratory Critical Care and Anaesthesia), UCL Institute of Child Health, Department of Anaesthesia and Pain Medicine, Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom; Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Simon Beggs
- Program in Neurosciences and Mental Health, The Hospital for Sick Children and Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Mark L Baccei
- Pain Research Center, Dept. of Anesthesiology, University of Cincinnati, Cincinnati, OH USA.
| |
Collapse
|
25
|
Ganley RP, Iwagaki N, del Rio P, Baseer N, Dickie AC, Boyle KA, Polgár E, Watanabe M, Abraira VE, Zimmerman A, Riddell JS, Todd AJ. Inhibitory Interneurons That Express GFP in the PrP-GFP Mouse Spinal Cord Are Morphologically Heterogeneous, Innervated by Several Classes of Primary Afferent and Include Lamina I Projection Neurons among Their Postsynaptic Targets. J Neurosci 2015; 35:7626-42. [PMID: 25972186 PMCID: PMC4429159 DOI: 10.1523/jneurosci.0406-15.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/18/2015] [Accepted: 04/03/2015] [Indexed: 01/09/2023] Open
Abstract
The superficial dorsal horn of the spinal cord contains numerous inhibitory interneurons, which regulate the transmission of information perceived as touch, pain, or itch. Despite the importance of these cells, our understanding of their roles in the neuronal circuitry is limited by the difficulty in identifying functional populations. One group that has been identified and characterized consists of cells in the mouse that express green fluorescent protein (GFP) under control of the prion protein (PrP) promoter. Previous reports suggested that PrP-GFP cells belonged to a single morphological class (central cells), received inputs exclusively from unmyelinated primary afferents, and had axons that remained in lamina II. However, we recently reported that the PrP-GFP cells expressed neuronal nitric oxide synthase (nNOS) and/or galanin, and it has been shown that nNOS-expressing cells are more diverse in their morphology and synaptic connections. We therefore used a combined electrophysiological, pharmacological, and anatomical approach to reexamine the PrP-GFP cells. We provide evidence that they are morphologically diverse (corresponding to "unclassified" cells) and receive synaptic input from a variety of primary afferents, with convergence onto individual cells. We also show that their axons project into adjacent laminae and that they target putative projection neurons in lamina I. This indicates that the neuronal circuitry involving PrP-GFP cells is more complex than previously recognized, and suggests that they are likely to have several distinct roles in regulating the flow of somatosensory information through the dorsal horn.
Collapse
Affiliation(s)
- Robert P Ganley
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Noboru Iwagaki
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Patricia del Rio
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Najma Baseer
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Allen C Dickie
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Kieran A Boyle
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Erika Polgár
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo 060-8638, Japan, and
| | - Victoria E Abraira
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Amanda Zimmerman
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - John S Riddell
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom,
| | - Andrew J Todd
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, United Kingdom,
| |
Collapse
|
26
|
Henrich F, Magerl W, Klein T, Greffrath W, Treede RD. Capsaicin-sensitive C- and A-fibre nociceptors control long-term potentiation-like pain amplification in humans. Brain 2015; 138:2505-20. [DOI: 10.1093/brain/awv108] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Accepted: 02/24/2015] [Indexed: 01/08/2023] Open
|
27
|
Synaptic GluN2A and GluN2B containing NMDA receptors within the superficial dorsal horn activated following primary afferent stimulation. J Neurosci 2014; 34:10808-20. [PMID: 25122884 DOI: 10.1523/jneurosci.0145-14.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
NMDA receptors are important elements in pain signaling in the spinal cord dorsal horn. They are heterotetramers, typically composed of two GluN1 and two of four GluN2 subunits: GluN2A-2D. Mice lacking some of the GluN2 subunits show deficits in pain transmission yet functional synaptic localization of these receptor subtypes in the dorsal horn has not been fully resolved. In this study, we have investigated the composition of synaptic NMDA receptors expressed in monosynaptic and polysynaptic pathways from peripheral sensory fibers to lamina I neurons in rats. We focused on substance P receptor-expressing (NK1R+) projection neurons, critical for expression of hyperalgesia and allodynia. EAB-318 and (R)-CPP, GluN2A/B antagonists, blocked both monosynaptic and polysynaptic NMDA EPSCs initiated by primary afferent activation by ∼90%. Physiological measurements exploiting the voltage dependence of monosynaptic EPSCs similarly indicated dominant expression of GluN2A/B types of synaptic NMDA receptors. In addition, at synapses between C fibers and NK1R+ neurons, NMDA receptor activation initiated a secondary, depolarizing current. Ifenprodil, a GluN2B antagonist, caused modest suppression of monosynaptic NMDA EPSC amplitudes, but had a widely variable, sometimes powerful, effect on polysynaptic responses following primary afferent stimulation when inhibitory inputs were blocked to mimic neuropathic pain. We conclude that GluN2B subunits are moderately expressed at primary afferent synapses on lamina I NK1R+ neurons, but play more important roles for polysynaptic NMDA EPSCs driven by primary afferents following disinhibition, supporting the view that the analgesic effect of the GluN2B antagonist on neuropathic pain is at least in part, within the spinal cord.
Collapse
|
28
|
Chen BN, Sharrad DF, Hibberd TJ, Zagorodnyuk VP, Costa M, Brookes SJ. Neurochemical characterization of extrinsic nerves in myenteric ganglia of the guinea pig distal colon. J Comp Neurol 2014; 523:742-56. [DOI: 10.1002/cne.23704] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 10/24/2014] [Accepted: 10/29/2014] [Indexed: 12/18/2022]
Affiliation(s)
- Bao Nan Chen
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| | - Dale F. Sharrad
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| | - Timothy J. Hibberd
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| | - Vladimir P. Zagorodnyuk
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| | - Marcello Costa
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| | - Simon J.H. Brookes
- Department of Human Physiology and Centre for Neuroscience; Flinders Medical Science and Technology, School of Medicine, Flinders University; Bedford Park South Australia Australia
| |
Collapse
|
29
|
Taylor BK, Corder G. Endogenous analgesia, dependence, and latent pain sensitization. Curr Top Behav Neurosci 2014; 20:283-325. [PMID: 25227929 PMCID: PMC4464817 DOI: 10.1007/7854_2014_351] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Endogenous activation of µ-opioid receptors (MORs) provides relief from acute pain. Recent studies have established that tissue inflammation produces latent pain sensitization (LS) that is masked by spinal MOR signaling for months, even after complete recovery from injury and re-establishment of normal pain thresholds. Disruption with MOR inverse agonists reinstates pain and precipitates cellular, somatic, and aversive signs of physical withdrawal; this phenomenon requires N-methyl-D-aspartate receptor-mediated activation of calcium-sensitive adenylyl cyclase type 1 (AC1). In this review, we present a new conceptual model of the transition from acute to chronic pain, based on the delicate balance between LS and endogenous analgesia that develops after painful tissue injury. First, injury activates pain pathways. Second, the spinal cord establishes MOR constitutive activity (MORCA) as it attempts to control pain. Third, over time, the body becomes dependent on MORCA, which paradoxically sensitizes pain pathways. Stress or injury escalates opposing inhibitory and excitatory influences on nociceptive processing as a pathological consequence of increased endogenous opioid tone. Pain begets MORCA begets pain vulnerability in a vicious cycle. The final result is a silent insidious state characterized by the escalation of two opposing excitatory and inhibitory influences on pain transmission: LS mediated by AC1 (which maintains the accelerator) and pain inhibition mediated by MORCA (which maintains the brake). This raises the prospect that opposing homeostatic interactions between MORCA analgesia and latent NMDAR-AC1-mediated pain sensitization creates a lasting vulnerability to develop chronic pain. Thus, chronic pain syndromes may result from a failure in constitutive signaling of spinal MORs and a loss of endogenous analgesic control. An overarching long-term therapeutic goal of future research is to alleviate chronic pain by either (a) facilitating endogenous opioid analgesia, thus restricting LS within a state of remission, or (b) extinguishing LS altogether.
Collapse
Affiliation(s)
- Bradley K Taylor
- Department of Physiology, School of Medicine, University of Kentucky Medical Center, Lexington, KY, 40536-0298, USA,
| | | |
Collapse
|
30
|
Baseer N, Al-Baloushi AS, Watanabe M, Shehab SAS, Todd AJ. Selective innervation of NK1 receptor-lacking lamina I spinoparabrachial neurons by presumed nonpeptidergic Aδ nociceptors in the rat. Pain 2014; 155:2291-300. [PMID: 25168670 PMCID: PMC4247378 DOI: 10.1016/j.pain.2014.08.023] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/20/2014] [Accepted: 08/19/2014] [Indexed: 11/30/2022]
Abstract
Fine myelinated (Aδ) nociceptors are responsible for fast, well-localised pain, but relatively little is known about their postsynaptic targets in the spinal cord, and therefore about their roles in the neuronal circuits that process nociceptive information. Here we show that transganglionically transported cholera toxin B subunit (CTb) labels a distinct set of afferents in lamina I that are likely to correspond to Aδ nociceptors, and that most of these lack neuropeptides. The vast majority of lamina I projection neurons can be retrogradely labelled from the lateral parabrachial area, and these can be divided into 2 major groups based on expression of the neurokinin 1 receptor (NK1r). We show that CTb-labelled afferents form contacts on 43% of the spinoparabrachial lamina I neurons that lack the NK1r, but on a significantly smaller proportion (26%) of those that express the receptor. We also confirm with electron microscopy that these contacts are associated with synapses. Among the spinoparabrachial neurons that received contacts from CTb-labelled axons, contact density was considerably higher on NK1r-lacking cells than on those with the NK1r. By comparing the density of CTb contacts with those from other types of glutamatergic bouton, we estimate that nonpeptidergic Aδ nociceptors may provide over half of the excitatory synapses on some NK1r-lacking spinoparabrachial cells. These results provide further evidence that synaptic inputs to dorsal horn projection neurons are organised in a specific way. Taken together with previous studies, they suggest that both NK1r(+) and NK1r-lacking lamina I projection neurons are directly innervated by Aδ nociceptive afferents.
Collapse
Affiliation(s)
- Najma Baseer
- Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK
| | - Abdullah S Al-Baloushi
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - Safa A S Shehab
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates.
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, UK.
| |
Collapse
|
31
|
Zhang TC, Janik JJ, Grill WM. Modeling effects of spinal cord stimulation on wide-dynamic range dorsal horn neurons: influence of stimulation frequency and GABAergic inhibition. J Neurophysiol 2014; 112:552-67. [DOI: 10.1152/jn.00254.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Spinal cord stimulation (SCS) is a clinical therapy for chronic, neuropathic pain, but an incomplete understanding of the mechanisms underlying SCS contributes to the lack of improvement in SCS efficacy over time. To study the mechanisms underlying SCS, we constructed a biophysically based network model of the dorsal horn circuit consisting of interconnected dorsal horn interneurons and a wide-dynamic range (WDR) projection neuron and representations of both local and surround receptive field inhibition. We validated the network model by reproducing cellular and network responses relevant to pain processing including wind-up, A fiber-mediated inhibition, and surround receptive field inhibition. We then simulated the effects of SCS on the activity of the WDR projection neuron and found that the response of the model WDR neuron to SCS depends on the SCS frequency; SCS frequencies of 30–100 Hz maximally inhibited the model WDR neuron, while frequencies under 30 Hz and over 100 Hz excited the model WDR neuron. We also studied the impacts on the effects of SCS of loss of inhibition due to the loss of either GABA or KCC2 function. Reducing the influence of local and surround GABAergic interneurons by weakening their inputs or their connections to the WDR neuron and shifting the anionic reversal potential of the WDR neurons upward each reduced the range of optimal SCS frequencies and changed the frequency at which SCS had a maximal effect. The results of this study provide insights into the mechanisms of SCS and pave the way for improved SCS parameter selection.
Collapse
Affiliation(s)
- Tianhe C. Zhang
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
| | | | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, North Carolina
- Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina
- Department of Neurobiology, Duke University, Durham, North Carolina
- Department of Surgery, Duke University, Durham, North Carolina; and
| |
Collapse
|
32
|
Zhang TC, Janik JJ, Grill WM. Mechanisms and models of spinal cord stimulation for the treatment of neuropathic pain. Brain Res 2014; 1569:19-31. [PMID: 24802658 DOI: 10.1016/j.brainres.2014.04.039] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 04/25/2014] [Accepted: 04/27/2014] [Indexed: 12/23/2022]
Abstract
Spinal cord stimulation (SCS) is an established and cost-effective therapy for treating severe chronic pain. However, despite over 40 years of clinical practice and the development of novel electrode designs and treatment protocols, increases in clinical success, defined as the proportion of patients that experience 50% or greater self-reported pain relief, have stalled. An incomplete knowledge of the neural circuits and systems underlying chronic pain and the interaction of SCS with these circuits may underlie this plateau in clinical efficacy. This review summarizes prior work and identifies gaps in our knowledge regarding the neural circuits related to pain and SCS in the dorsal horn, supraspinal structures, and the Pain Matrix. In addition, this review discusses and critiques current experimental and computational models used to investigate and optimize SCS. Further research into the interactions between SCS and pain pathways in the nervous system using animal and computational models is a fruitful approach to improve this promising therapy.
Collapse
Affiliation(s)
- Tianhe C Zhang
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | | | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, USA; Department of Electrical and Computer Engineering, Duke University, Durham, NC, USA; Department of Neurobiology, Duke University, Durham, NC, USA; Department of Surgery, Duke University, Durham, NC, USA.
| |
Collapse
|
33
|
Dickie AC, Torsney C. The chemerin receptor 23 agonist, chemerin, attenuates monosynaptic C-fibre input to lamina I neurokinin 1 receptor expressing rat spinal cord neurons in inflammatory pain. Mol Pain 2014; 10:24. [PMID: 24716552 PMCID: PMC4023702 DOI: 10.1186/1744-8069-10-24] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 04/01/2014] [Indexed: 11/10/2022] Open
Abstract
Background Recent evidence has shown that the chemerin receptor 23 (ChemR23) represents a novel inflammatory pain target, whereby the ChemR23 agonists, resolvin E1 and chemerin, can inhibit inflammatory pain hypersensitivity, by a mechanism that involves normalisation of potentiated spinal cord responses. This study has examined the ability of the ChemR23 agonist, chemerin, to modulate synaptic input to lamina I neurokinin 1 receptor expressing (NK1R+) dorsal horn neurons, which are known to be crucial for the manifestation of inflammatory pain. Results Whole-cell patch-clamp recordings from pre-identified lamina I NK1R+ neurons, in rat spinal cord slices, revealed that chemerin significantly attenuates capsaicin potentiation of miniature excitatory postsynaptic current (mEPSC) frequency, but is without effect in non-potentiated conditions. In tissue isolated from complete Freund’s adjuvant (CFA) treated rats, chemerin significantly reduced the peak amplitude of monosynaptic C-fibre evoked excitatory postsynaptic currents (eEPSCs) in a subset of lamina I NK1R+ neurons, termed chemerin responders. However, chemerin did not alter the peak amplitude of monosynaptic C-fibre eEPSCs in control tissue. Furthermore, paired-pulse recordings in CFA tissue demonstrated that chemerin significantly reduced paired-pulse depression in the subset of neurons classified as chemerin responders, but was without effect in non-responders, indicating that chemerin acts presynaptically to attenuate monosynaptic C-fibre input to a subset of lamina I NK1R+ neurons. Conclusions These results suggest that the reported ability of ChemR23 agonists to attenuate inflammatory pain hypersensitivity may in part be due to a presynaptic inhibition of monosynaptic C-fibre input to lamina I NK1R+ neurons and provides further evidence that ChemR23 represents a promising inflammatory pain target.
Collapse
Affiliation(s)
| | - Carole Torsney
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
34
|
Bardoni R, Tawfik VL, Wang D, François A, Solorzano C, Shuster SA, Choudhury P, Betelli C, Cassidy C, Smith K, de Nooij JC, Mennicken F, O'Donnell D, Kieffer BL, Woodbury CJ, Basbaum AI, MacDermott AB, Scherrer G. Delta opioid receptors presynaptically regulate cutaneous mechanosensory neuron input to the spinal cord dorsal horn. Neuron 2014; 81:1312-1327. [PMID: 24583022 DOI: 10.1016/j.neuron.2014.01.044] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2014] [Indexed: 11/24/2022]
Abstract
Cutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity.
Collapse
Affiliation(s)
- Rita Bardoni
- Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, 41100 Modena, Italy
| | - Vivianne L Tawfik
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Dong Wang
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Carlos Solorzano
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Scott A Shuster
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Papiya Choudhury
- Department of Physiology and Cellular Biophysics, Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Chiara Betelli
- Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, 41100 Modena, Italy
| | - Colleen Cassidy
- Graduate Program in Neuroscience, University of Wyoming, Laramie, WY 82071, USA; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Kristen Smith
- Graduate Program in Neuroscience, University of Wyoming, Laramie, WY 82071, USA; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Joriene C de Nooij
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Françoise Mennicken
- AstraZeneca R&D Montreal, Department of Translational Science, Montreal, QC H4S 1Z9, Canada
| | - Dajan O'Donnell
- AstraZeneca R&D Montreal, Department of Translational Science, Montreal, QC H4S 1Z9, Canada
| | - Brigitte L Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR7104 CNRS/Université de Strasbourg, U964 INSERM, 67400 Illkirch, France
| | - C Jeffrey Woodbury
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Amy B MacDermott
- Department of Physiology and Cellular Biophysics, Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA.
| |
Collapse
|
35
|
Mitchell K, Lebovitz EE, Keller JM, Mannes AJ, Nemenov MI, Iadarola MJ. Nociception and inflammatory hyperalgesia evaluated in rodents using infrared laser stimulation after Trpv1 gene knockout or resiniferatoxin lesion. Pain 2014; 155:733-745. [PMID: 24434730 DOI: 10.1016/j.pain.2014.01.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Revised: 12/19/2013] [Accepted: 01/10/2014] [Indexed: 01/23/2023]
Abstract
TRPV1 is expressed in a subpopulation of myelinated Aδ and unmyelinated C-fibers. TRPV1+ fibers are essential for the transmission of nociceptive thermal stimuli and for the establishment and maintenance of inflammatory hyperalgesia. We have previously shown that high-power, short-duration pulses from an infrared diode laser are capable of predominantly activating cutaneous TRPV1+ Aδ-fibers. Here we show that stimulating either subtype of TRPV1+ fiber in the paw during carrageenan-induced inflammation or following hind-paw incision elicits pronounced hyperalgesic responses, including prolonged paw guarding. The ultrapotent TRPV1 agonist resiniferatoxin (RTX) dose-dependently deactivates TRPV1+ fibers and blocks thermal nociceptive responses in baseline or inflamed conditions. Injecting sufficient doses of RTX peripherally renders animals unresponsive to laser stimulation even at the point of acute thermal skin damage. In contrast, Trpv1-/- mice, which are generally unresponsive to noxious thermal stimuli at lower power settings, exhibit withdrawal responses and inflammation-induced sensitization using high-power, short duration Aδ stimuli. In rats, systemic morphine suppresses paw withdrawal, inflammatory guarding, and hyperalgesia in a dose-dependent fashion using the same Aδ stimuli. The qualitative intensity of Aδ responses, the leftward shift of the stimulus-response curve, the increased guarding behaviors during carrageenan inflammation or after incision, and the reduction of Aδ responses with morphine suggest multiple roles for TRPV1+ Aδ fibers in nociceptive processes and their modulation of pathological pain conditions.
Collapse
Affiliation(s)
- Kendall Mitchell
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, USA Department of Anesthesia, Stanford University, Palo Alto, CA, USA Lasmed LLC, Mountain View, CA, USA Neurobiology and Pain Therapeutics Section, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | | |
Collapse
|
36
|
Hanse E, Seth H, Riebe I. AMPA-silent synapses in brain development and pathology. Nat Rev Neurosci 2013; 14:839-50. [DOI: 10.1038/nrn3642] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
37
|
Vo L, Drummond PD. Coexistence of ipsilateral pain-inhibitory and facilitatory processes after high-frequency electrical stimulation. Eur J Pain 2013; 18:376-85. [PMID: 23868187 DOI: 10.1002/j.1532-2149.2013.00370.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND High-frequency electrical stimulation (HFS) of the human forearm evokes analgesia to blunt pressure in the ipsilateral forehead, consistent with descending ipsilateral inhibitory pain modulation. The aim of the current study was to further delineate pain modulation processes evoked by HFS by examining sensory changes in the arm and forehead; investigating the effects of HFS on nociceptive blink reflexes elicited by supraorbital electrical stimulation; and assessing effects of counter-irritation (electrically evoked pain at the HFS-conditioned site in the forearm) on nociceptive blink reflexes before and after HFS. METHODS Before and after HFS conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the conditioned site in the forearm and on each side of the forehead. Nociceptive blink reflexes were also assessed before and after HFS with and without counter-irritation of the forearm. RESULTS HFS triggered secondary hyperalgesia in the forearm (a sign of central sensitization) and analgesia to blunt pressure in the ipsilateral forehead. Under most conditions, both HFS conditioning and counter-irritation of the forearm suppressed electrically evoked pain in the forehead, and the amplitude of the blink reflex to supraorbital stimuli decreased. Importantly, however, in the absence of forearm counter-irritation, HFS conditioning facilitated ipsilateral blink reflex amplitude to supraorbital stimuli delivered ipsilateral to the HFS-conditioned site. CONCLUSIONS These findings suggest that HFS concurrently triggers hemilateral inhibitory and facilitatory influences on nociceptive processing over and above more general effects of counter-irritation. The inhibitory influence may help limit the spread of sensitization in central nociceptive pathways.
Collapse
Affiliation(s)
- L Vo
- Centre for Research on Chronic Pain and Inflammatory Diseases, School of Psychology and Exercise Science, Murdoch University, Perth, WA, Australia
| | | |
Collapse
|
38
|
Cleary DR, Heinricher MM. Adaptations in responsiveness of brainstem pain-modulating neurons in acute compared with chronic inflammation. Pain 2013; 154:845-55. [PMID: 23588008 PMCID: PMC3661698 DOI: 10.1016/j.pain.2013.02.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 01/15/2013] [Accepted: 02/19/2013] [Indexed: 12/23/2022]
Abstract
Despite similar behavioral hypersensitivity, acute and chronic pain have distinct neural bases. We used intraplantar injection of complete Freund's adjuvant to directly compare activity of pain-modulating neurons in the rostral ventromedial medulla (RVM) in acute vs chronic inflammation. Heat-evoked and von Frey-evoked withdrawal reflexes and corresponding RVM neuronal activity were recorded in lightly anesthetized animals either during the first hour after complete Freund's adjuvant injection (acute) or 3 to 10 days later (chronic). Thermal and modest mechanical hyperalgesia during acute inflammation were associated with increases in the spontaneous activity of pain-facilitating ON-cells and suppression of pain-inhibiting OFF-cells. Acute hyperalgesia was reversed by RVM block, showing that the increased activity of RVM ON-cells is necessary for acute behavioral hypersensitivity. In chronic inflammation, thermal hyperalgesia had resolved but mechanical hyperalgesia had become pronounced. The spontaneous discharges of ON- and OFF-cells were not different from those in control subjects, but the mechanical response thresholds for both cell classes were reduced into the innocuous range. RVM block in the chronic condition worsened mechanical hyperalgesia. These studies identify distinct contributions of RVM ON- and OFF-cells to acute and chronic inflammatory hyperalgesia. During early immune-mediated inflammation, ON-cell spontaneous activity promotes hyperalgesia. After inflammation is established, the antinociceptive influence of OFF-cells is dominant, yet the lowered threshold for the OFF-cell pause allows behavioral responses to stimuli that would normally be considered innocuous. The efficacy of OFF-cells in counteracting sensitization of ascending transmission pathways could therefore be an important determining factor in development of chronic inflammatory pain.
Collapse
Affiliation(s)
- Daniel R Cleary
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, USA.
| | | |
Collapse
|
39
|
Jarcho JM, Feier NA, Bert A, Labus JA, Lee M, Stains J, Ebrat B, Groman SM, Tillisch K, Brody AL, London ED, Mandelkern MA, Mayer EA. Diminished neurokinin-1 receptor availability in patients with two forms of chronic visceral pain. Pain 2013; 154:987-96. [PMID: 23582152 DOI: 10.1016/j.pain.2013.02.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 02/08/2013] [Accepted: 02/22/2013] [Indexed: 12/29/2022]
Abstract
Central sensitization and dysregulation of peripheral substance P and neurokinin-1 receptor (NK-1R) signaling are associated with chronic abdominal pain in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS). Although positron emission tomography (PET) has demonstrated that patients with injury-related chronic pain have diminished NK-1R availability in the brain, it is unknown whether these deficits are present in IBD and IBS patients, who have etiologically distinct forms of non-injury-related chronic pain. This study's aim was to determine if patients with IBD or IBS exhibit deficits in brain expression of NK-1Rs relative to healthy controls (HCs), the extent to which expression patterns differ across patient populations, and if these patterns differentially relate to clinical parameters. PET with [(18)F]SPA-RQ was used to measure NK-1R availability by quantifying binding potential (BP) in the 3 groups. Exploratory correlation analyses were performed to detect associations between NK-1R BP and physical symptoms. Compared to HCs, IBD patients had NK-1R BP deficits across a widespread network of cortical and subcortical regions. IBS patients had similar, but less pronounced deficits. BP in a subset of these regions was robustly related to discrete clinical parameters in each patient population. Widespread deficits in NK-1R BP occur in IBD and, to a lesser extent, IBS; however, discrete clinical parameters relate to NK-1R BP in each patient population. This suggests that potential pharmacological interventions that target NK-1R signaling may be most effective for treating distinct symptoms in IBD and IBS.
Collapse
Affiliation(s)
- Johanna M Jarcho
- Section on Developmental and Affective Neuroscience, National Institute of Mental Health, Bethesda, MD, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Vo L, Drummond PD. High frequency electrical stimulation concurrently induces central sensitization and ipsilateral inhibitory pain modulation. Eur J Pain 2012; 17:357-68. [PMID: 22893547 DOI: 10.1002/j.1532-2149.2012.00208.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2012] [Indexed: 12/18/2022]
Abstract
BACKGROUND In healthy humans, analgesia to blunt pressure develops in the ipsilateral forehead during various forms of limb pain. The aim of the current study was to determine whether this analgesic response is induced by ultraviolet B radiation (UVB), which evokes signs of peripheral sensitization, or by high-frequency electrical stimulation (HFS), which triggers signs of central sensitization. METHODS Before and after HFS and UVB conditioning, sensitivity to heat and to blunt and sharp stimuli was assessed at and adjacent to the treated site in the forearm. In addition, sensitivity to blunt pressure was measured bilaterally in the forehead. The effect of ipsilateral versus contralateral temple cooling on electrically evoked pain in the forearm was then examined, to determine whether HFS or UVB conditioning altered inhibitory pain modulation. RESULTS UVB conditioning triggered signs of peripheral sensitization, whereas HFS conditioning triggered signs of central sensitization. Importantly, ipsilateral forehead analgesia developed after HFS but not UVB conditioning. In addition, decreases in electrically evoked pain at the HFS-treated site were greater during ipsilateral than contralateral temple cooling, whereas decreases at the UVB-treated site were similar during both procedures. CONCLUSIONS HFS conditioning induced signs of central sensitization in the forearm and analgesia both in the ipsilateral forehead and the HFS-treated site. This ipsilateral analgesia was not due to peripheral sensitization or other non-specific effects, as it failed to develop after UVB conditioning. Thus, the supra-spinal mechanisms that evoke central sensitization might also trigger a hemilateral inhibitory pain modulation process. This inhibitory process could sharpen the boundaries of central sensitization or limit its spread.
Collapse
Affiliation(s)
- L Vo
- School of Psychology, Murdoch University, Perth, WA, Australia
| | | |
Collapse
|
41
|
Li J, Baccei ML. Developmental regulation of membrane excitability in rat spinal lamina I projection neurons. J Neurophysiol 2012; 107:2604-14. [PMID: 22338021 DOI: 10.1152/jn.00899.2011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is now universally recognized that neonates can experience considerable pain. While spinal lamina I neurons projecting to the brain contribute to the generation of hyperalgesia, nothing is known about their electrophysiological properties during early life. Here we have used in vitro whole cell patch-clamp recordings in rat spinal cord slices to determine whether the intrinsic membrane properties of lamina I projection neurons, as well as their synaptic inputs, are developmentally regulated during the early postnatal period. Projection neurons were identified via retrograde transport of DiI injected into the parabrachial nucleus (PB) or periaqueductal gray (PAG) and characterized at postnatal days (P)2-5, P10-12, P19-23, and P30-32. Both spino-PB and spino-PAG neurons demonstrated an age-dependent reduction in spike threshold and duration at room temperature, which was accompanied by a developmental increase in the frequency of miniature excitatory and inhibitory postsynaptic currents. Notably, in both groups, age-dependent changes in the passive membrane properties or rheobase only occurred after the third postnatal week. However, spontaneous activity was significantly more prevalent within the developing spino-PB population and was dominated by an irregular pattern of discharge. In addition, while the instantaneous firing frequency remained unaltered in spino-PB neurons during the first weeks of life, spino-PAG cells fired at a higher rate at P19-23 compared with younger groups, suggesting that the gain of parallel ascending nociceptive pathways may be independently regulated during development. Overall, these results demonstrate that intrinsic membrane excitability is modulated in a cell type-specific manner within developing spinal nociceptive circuits.
Collapse
Affiliation(s)
- Jie Li
- Pain Research Center, Dept. of Anesthesiology, Univ. of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | | |
Collapse
|
42
|
Abstract
Transient receptor potential A1 (TRPA1) is a calcium permeable non-selective cation channel that is selectively localized to peptidergic C-fibres in the pain pathway. TRPA1 is highly conserved across the animal kingdom and it is able to detect a wide range of potentially toxic environmental chemicals. An unusual mechanism of TRPA1 activation was recently elucidated in which reactive agonists bind covalently to cysteines and lysine in the intracellular N-terminus. Despite a covalent activation mechanism, only transient TRPA1 activation is seen in the maintained presence of reactive agonists in whole-cell patch clamp experiments. I suggest that previous patch clamp studies are performed under conditions that do not fully mimic all aspects of TRPA1 activation. Here, I argue that compelling evidence exists for sustained TRPA1 activation in several chronic (neuropathic) pain-related pathophysiological conditions in vivo. I discuss briefly putative mechanisms that are likely to contribute to and maintain sustained TRPA1 agonist levels through increased production and/or decreased metabolism and inactivation. Chronic pain can be understood as a false alarm evoked by sustained and increased levels of endogenous TRPA1 agonists in various pathophysiological conditions.
Collapse
Affiliation(s)
- A Koivisto
- In Vitro Pharmacology, Orion Pharma Orion Corporation, Turku, Finland.
| |
Collapse
|
43
|
Sandkühler J, Gruber-Schoffnegger D. Hyperalgesia by synaptic long-term potentiation (LTP): an update. Curr Opin Pharmacol 2011; 12:18-27. [PMID: 22078436 PMCID: PMC3315008 DOI: 10.1016/j.coph.2011.10.018] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 10/17/2011] [Indexed: 11/17/2022]
Abstract
Long-term potentiation of synaptic strength (LTP) in nociceptive pathways shares principle features with hyperalgesia including induction protocols, pharmacological profile, neuronal and glial cell types involved and means for prevention. LTP at synapses of nociceptive nerve fibres constitutes a contemporary cellular model for pain amplification following trauma, inflammation, nerve injury or withdrawal from opioids. It provides a novel target for pain therapy. This review summarizes recent progress which has been made in unravelling the properties and functions of LTP in the nociceptive system and in identifying means for its prevention and reversal.
Collapse
Affiliation(s)
- Jürgen Sandkühler
- Medical University of Vienna, Center for Brain Research, Department of Neurophysiology, Spitalgasse 4, A-1090 Vienna, Austria.
| | | |
Collapse
|
44
|
Jang JH, Liang D, Kido K, Sun Y, Clark DJ, Brennan TJ. Increased local concentration of complement C5a contributes to incisional pain in mice. J Neuroinflammation 2011; 8:80. [PMID: 21736743 PMCID: PMC3141504 DOI: 10.1186/1742-2094-8-80] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 07/07/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In our previous study, we demonstrated that local injection of complement C5a and C3a produce mechanical and heat hyperalgesia, and that C5a and C3a activate and sensitize cutaneous nociceptors in normal skin, suggesting a contribution of complement fragments to acute pain. Other studies also have shown that the complement system can be activated by surgical incision, and the systemic blockade of C5a receptor (C5aR) reduces incision-induced pain and inflammation. In this study, we further examined the possible contribution of wound area C5a to incisional pain. METHODS Using of a hind paw incisional model, the effects of a selective C5aR antagonist, PMX53, on nociceptive behaviors were measured after incision in vivo. mRNA levels of C5 and C5aR in skin, dorsal root ganglia (DRG) and spinal cord, and C5a protein levels in the skin were quantified after incision. The responses of nociceptors to C5a were also evaluated using the in vitro skin-nerve preparation. RESULTS Local administration of PMX53 suppressed heat hyperalgesia and mechanical allodynia induced by C5a injection or after hind paw incision in vivo. mRNA levels of C5 and C5aR in the skin, but not DRG and spinal cord, were dramatically increased after incision. C5a protein in the skin was also increased after incision. In vitro C5a did not increase the prevalence of fibers with ongoing activity in afferents from incised versus control, unincised skin. C5a sensitized C-fiber afferent responses to heat; however, this was less evident in afferents adjacent to the incision. PMX53 blocked sensitization of C-fiber afferents to heat by C5a but did not by itself influence ongoing activity or heat sensitivity in afferents innervating control or incised skin. The magnitude of mechanical responses was also not affected by C5a in any nociceptive fibers innervating incised or unincised skin. CONCLUSIONS This study demonstrates that high locally generated C5a levels are present in wounds for at least 72 hours after incision. In skin, C5a contributes to hypersensitivity after incision, but increased responsiveness of cutaneous nociceptors to C5a was not evident in incised skin. Thus, high local concentrations of C5a produced in wounds likely contribute to postoperative pain.
Collapse
Affiliation(s)
- Jun H Jang
- Department of Anesthesia, University of Iowa Hospitals and Clinics, Iowa City, Iowa, USA
| | | | | | | | | | | |
Collapse
|