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Belay S, Belay G, Nigussie H, Ahbara AM, Tijjani A, Dessie T, Tarekegn GM, Jian-Lin H, Mor S, Woldekiros HS, Dobney K, Lebrasseur O, Hanotte O, Mwacharo JM. Anthropogenic events and responses to environmental stress are shaping the genomes of Ethiopian indigenous goats. Sci Rep 2024; 14:14908. [PMID: 38942813 PMCID: PMC11213886 DOI: 10.1038/s41598-024-65303-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/19/2024] [Indexed: 06/30/2024] Open
Abstract
Anthropological and biophysical processes have shaped livestock genomes over Millenia and can explain their current geographic distribution and genetic divergence. We analyzed 57 Ethiopian indigenous domestic goat genomes alongside 67 equivalents of east, west, and north-west African, European, South Asian, Middle East, and wild Bezoar goats. Cluster, ADMIXTURE (K = 4) and phylogenetic analysis revealed four genetic groups comprising African, European, South Asian, and wild Bezoar goats. The Middle Eastern goats had an admixed genome of these four genetic groups. At K = 5, the West African Dwarf and Moroccan goats were separated from East African goats demonstrating a likely historical legacy of goat arrival and dispersal into Africa via the coastal Mediterranean Sea and the Horn of Africa. FST, XP-EHH, and Hp analysis revealed signatures of selection in Ethiopian goats overlaying genes for thermo-sensitivity, oxidative stress response, high-altitude hypoxic adaptation, reproductive fitness, pathogen defence, immunity, pigmentation, DNA repair, modulation of renal function and integrated fluid and electrolyte homeostasis. Notable examples include TRPV1 (a nociception gene); PTPMT1 (a critical hypoxia survival gene); RETREG (a regulator of reticulophagy during starvation), and WNK4 (a molecular switch for osmoregulation). These results suggest that human-mediated translocations and adaptation to contrasting environments are shaping indigenous African goat genomes.
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Affiliation(s)
- Shumuye Belay
- Tigray Agricultural Research Institute, Mekelle, Ethiopia.
- Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia.
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia.
| | - Gurja Belay
- Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Helen Nigussie
- Department of Microbial, Cellular and Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Abulgasim M Ahbara
- Animal and Veterinary Sciences, Scotland's Rural College (SRUC), Roslin Institute Building, Midlothian, UK
- Department of Zoology, Misurata University, Misurata, Libya
| | - Abdulfatai Tijjani
- The Jackson Laboratory, Bar Harbor, ME, 04609, USA
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
| | - Tadelle Dessie
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
| | - Getinet M Tarekegn
- Animal and Veterinary Sciences, Scotland's Rural College (SRUC), Roslin Institute Building, Midlothian, UK
- Institute of Biotechnology (IoB), Addis Ababa University, Addis Ababa, Ethiopia
| | - Han Jian-Lin
- CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Beijing, China
- Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, China
| | - Siobhan Mor
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - Helina S Woldekiros
- Department of Anthropology, Washington University in St. Louis, St. Louis, USA
| | - Keith Dobney
- Department of Archaeology, Classics and Egyptology, University of Liverpool, Liverpool, UK
- University of Sydney, Sydney, Australia
| | - Ophelie Lebrasseur
- Palaeogenomics and Bioarchaeology Research Network, School of Archaeology, University of Oxford, Oxford, UK
| | - Olivier Hanotte
- International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Joram M Mwacharo
- Animal and Veterinary Sciences, Scotland's Rural College (SRUC), Roslin Institute Building, Midlothian, UK.
- Small Ruminant Genomics, International Centre for Agricultural Research in the Dry Areas (ICARDA), Addis Ababa, Ethiopia.
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Pang JJ. The Variety of Mechanosensitive Ion Channels in Retinal Neurons. Int J Mol Sci 2024; 25:4877. [PMID: 38732096 PMCID: PMC11084373 DOI: 10.3390/ijms25094877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
Alterations in intraocular and external pressure critically involve the pathogenesis of glaucoma, traumatic retinal injury (TRI), and other retinal disorders, and retinal neurons have been reported to express multiple mechanical-sensitive channels (MSCs) in recent decades. However, the role of MSCs in visual functions and pressure-related retinal conditions has been unclear. This review will focus on the variety and functional significance of the MSCs permeable to K+, Na+, and Ca2+, primarily including the big potassium channel (BK); the two-pore domain potassium channels TRAAK and TREK; Piezo; the epithelial sodium channel (ENaC); and the transient receptor potential channels vanilloid TRPV1, TRPV2, and TRPV4 in retinal photoreceptors, bipolar cells, horizontal cells, amacrine cells, and ganglion cells. Most MSCs do not directly mediate visual signals in vertebrate retinas. On the other hand, some studies have shown that MSCs can open in physiological conditions and regulate the activities of retinal neurons. While these data reasonably predict the crossing of visual and mechanical signals, how retinal light pathways deal with endogenous and exogenous mechanical stimulation is uncertain.
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Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
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Wang B, Liang Y, Bekker A, Hu H, Tao YX. Sensory neuron-specific long noncoding RNA in small non-peptidergic dorsal root ganglion neurons selectively impairs nerve injury-induced mechanical hypersensitivity. Life Sci 2023; 332:122120. [PMID: 37741322 PMCID: PMC10591916 DOI: 10.1016/j.lfs.2023.122120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/16/2023] [Accepted: 09/20/2023] [Indexed: 09/25/2023]
Abstract
AIMS Nerve injury-induced mechanical hypersensitivity is one of major clinical symptoms in neuropathic pain patients. Understanding molecular mechanisms underlying this symptom is crucial for developing effective therapies. The present study was to investigate whether sensory neuron-specific long noncoding RNA (SS-lncRNA) predominantly expressed in small non-peptidergic dorsal root ganglion (DRG) neurons repaired nerve injury-induced mechanical hypersensitivity. MATERIALS AND METHODS SS-lncRNA downregulation in the mas-related G protein-coupled receptor member D (Mrgprd)-expressed DRG neurons was rescued and mimicked by crossbreeding MrgprdCreERT2/+ lines with Rosa26SS-lncRNA knock-in mice and SS-lncRNAfl/fl mice, respectively, followed by tamoxifen injection. KEY FINDINGS Rescuing SS-lncRNA downregulation in the Mrgprd-expressed DRG neurons significantly reversed the spinal nerve ligation (SNL)-induced reduction of the calcium-activated potassium channel subfamily N member 1 (KCNN1) in these DRG neurons and alleviated the SNL-induced mechanical hypersensitivity, without affecting the SNL-induced heat and cold nociceptive hypersensitivities, on the ipsilateral side. Conversely, mimicking SS-lncRNA downregulation in the Mrgprd-expressed DRG neurons reduced basal KCNN1 expression in these DRG neurons and produced the enhanced response to mechanical stimulation, but not thermal and cold stimuli, on bilateral sides. Mechanistically, SS-lncRNA downregulation caused a reduction in its binding to lysine-specific demethylase 6B (KDM6B) and consequent recruitment of less KDM6B to Kcnn1 promoter and an increase of H3K27me3 enrichment in this promoter in injured DRG. SIGNIFICANCE Our findings suggest that SS-lncRNA downregulation in small non-peptidergic sensory neurons is required specifically for nerve injury-induced mechanical hypersensitivity likely through silencing KCNN1 expression caused by KDM6B-gated increase of H3K27me3 enrichment in Kcnn1 promoter in these neurons.
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Affiliation(s)
- Bing Wang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Yingping Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Huijuan Hu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Physiology, Pharmacology & Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA; Department of Cell Biology & Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA.
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Yajima T, Sato T, Hosokawa H, Kondo T, Ichikawa H. Transient receptor potential melastatin-7 in the rat dorsal root ganglion. J Chem Neuroanat 2022; 125:102163. [PMID: 36122679 DOI: 10.1016/j.jchemneu.2022.102163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 09/08/2022] [Accepted: 09/15/2022] [Indexed: 11/30/2022]
Abstract
AIMS Transient receptor potential melastatin-7 (TRPM7) is a selective cation permeable channel which plays important roles in cellular and developmental biology such as cell proliferation, survival, differentiation and migration. This channel is also known to be necessary for transmitter release in the peripheral nervous system. In this study, immunohistochemistry for TRPM7 was conducted in the rat lumbar dorsal root ganglion (DRG). METHODS Triple immunofluorescence methods were used to demonstrate distribution of TRPM7 and its relationship to other TRP channels in the DRG. Retrograde tracing and double immunofluorescence methods were also performed to know peripheral targets of DRG neurons containing TRPM7 and TRP vanilloid 1 (TRPV1). In addition, transection of the sciatic nerve was conducted to demonstrate an effect of the nerve injury on TRPM7expression in the DRG. RESULTS TRPM7-immunoreactivity was expressed by 53.9% of sensory neurons in the 4th lumbar DRG. TRPM7-immunoreactive (-IR) DRG neurons mostly had small (<600 µm²) and medium-sized (600-1200 µm²) cell bodies. By triple and double immunofluorescence methods, approximately 70% of TRPM7-IR DRG neurons contained TRPV1-immunoreactivity. Although the number of DRG neurons co-expressing TRPM7 and TRPM8 was small in the DRG, almost all of TRPM8-IR DRG neurons co-expressed TRPM7-immunoreactivity. By combination of retrograde tracing method and immunohistochemistry, TRPM7 was expressed by half of DRG neurons innervating the plantar skin (61.9%) and gastrocnemius muscle (51.2%), and 79.6% of DRG neurons innervating the periosteum. Co-expression of TRPM7 and TRPV1 among periosteum DRG neurons (75.7%) was more abundant than among cutaneous (53.2%) and muscular (40.4%) DRG neurons. DRG neurons which co-expressed these ion channels in the periosteum had smaller cell bodies compared to the skin and muscle. In addition, the sciatic nerve transection decreased the number of TRPM7-IR neurons in the DRG (approximately 60% reduction). The RT-qPCR analysis also demonstrated reduction of TRPM7 mRNA in the injured DRG. CONCLUSION The present study suggests that TRPM7 is mainly located in small nociceptors in the DRG. The content of TRPM7 in DRG neurons is probably different among their peripheral targets. TRPM7 in DRG neurons may be able to respond to noxious stimulation from their peripheral tissues. The nerve injury can decrease the level of TRPM7 mRNA and protein in DRG neurons.
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Affiliation(s)
- Takehiro Yajima
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Tadasu Sato
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan.
| | - Hiroshi Hosokawa
- Department of Intelligence Science and Technology, Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan
| | - Teruyoshi Kondo
- Department of Animal Pharmaceutical Sciences, School of Pharmaceutical Sciences, Kyushu University of Health and Welfare, Nobeoka 882-8508, Japan
| | - Hiroyuki Ichikawa
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
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Eller OC, Stair RN, Neal C, Rowe PS, Nelson-Brantley J, Young EE, Baumbauer KM. Comprehensive phenotyping of cutaneous afferents reveals early-onset alterations in nociceptor response properties, release of CGRP, and hindpaw edema following spinal cord injury. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2022; 12:100097. [PMID: 35756343 PMCID: PMC9218836 DOI: 10.1016/j.ynpai.2022.100097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 06/09/2022] [Accepted: 06/10/2022] [Indexed: 11/30/2022]
Abstract
Spinal cord injury (SCI) is a complex syndrome that has profound effects on patient well-being, including the development of medically-resistant chronic pain. The mechanisms underlying SCI pain have been the subject of thorough investigation but remain poorly understood. While the majority of the research has focused on changes occurring within and surrounding the site of injury in the spinal cord, there is now a consensus that alterations within the peripheral nervous system, namely sensitization of nociceptors, contribute to the development and maintenance of chronic SCI pain. Using an ex vivo skin/nerve/DRG/spinal cord preparation to characterize afferent response properties following SCI, we found that SCI increased mechanical and thermal responding, as well as the incidence of spontaneous activity (SA) and afterdischarge (AD), in below-level C-fiber nociceptors 24 hr following injury relative to naïve controls. Interestingly, the distribution of nociceptors that exhibit SA and AD are not identical, and the development of SA was observed more frequently in nociceptors with low heat thresholds, while AD was found more frequently in nociceptors with high heat thresholds. We also found that SCI resulted in hindpaw edema and elevated cutaneous calcitonin gene-related peptide (CGRP) concentration that were not observed in naïve mice. These results suggest that SCI causes a rapidly developing nociceptor sensitization and peripheral inflammation that may contribute to the early emergence and persistence of chronic SCI pain.
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Affiliation(s)
- Olivia C. Eller
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Rena N. Stair
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Christopher Neal
- Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS, United States
| | - Peter S.N. Rowe
- Department of Internal Medicine, University of Kansas Medical Center, Kansas City, KS, United States
- The Kidney Institute & Division of Nephrology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Jennifer Nelson-Brantley
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Erin E. Young
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, United States
- Center for Advancement in Managing Pain, School of Nursing, University of Connecticut, Storrs, CT, United States
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, United States
- Department of Neuroscience, UConn Health, Farmington, CT, United States
| | - Kyle M. Baumbauer
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, KS, United States
- Department of Anesthesiology, University of Kansas Medical Center, Kansas City, KS, United States
- Center for Advancement in Managing Pain, School of Nursing, University of Connecticut, Storrs, CT, United States
- Department of Neuroscience, UConn Health, Farmington, CT, United States
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Wank I, Kutsche L, Kreitz S, Reeh P, Hess A. Imaging the influence of peripheral TRPV1-signaling on cerebral nociceptive processing applying fMRI-based graph theory in a resiniferatoxin rat model. PLoS One 2022; 17:e0266669. [PMID: 35482725 PMCID: PMC9049522 DOI: 10.1371/journal.pone.0266669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 03/24/2022] [Indexed: 11/19/2022] Open
Abstract
Resiniferatoxin (RTX), an extract from the spurge plant Euphorbia resinifera, is a potent agonist of the transient receptor potential cation channel subfamily V member 1 (TRPV1), mainly expressed on peripheral nociceptors-a prerequisite for nociceptive heat perception. Systemic overdosing of RTX can be used to desensitize specifically TRPV1-expressing neurons, and was therefore utilized here to selectively characterize the influence of TRPV1-signaling on central nervous system (CNS) temperature processing. Resting state and CNS temperature processing of male rats were assessed via functional magnetic resonance imaging before and after RTX injection. General linear model-based and graph-theoretical network analyses disentangled the underlying distinct CNS circuitries. At baseline, rats displayed an increase of nociception-related response amplitude and activated brain volume that correlated highly with increasing stimulation temperatures. In contrast, RTX-treated rats showed a clear disruption of thermal nociception, reflected in a missing increase of CNS responses to temperatures above 48°C. Graph-theoretical analyses revealed two distinct brain subnetworks affected by RTX: one subcortical (brainstem, lateral and medial thalamus, hippocampus, basal ganglia and amygdala), and one cortical (primary sensory, motor and association cortices). Resting state analysis revealed first, that peripheral desensitization of TRPV1-expressing neurons did not disrupt the basic resting-state-network of the brain. Second, only at baseline, but not after RTX, noxious stimulation modulated the RS-network in regions associated with memory formation (e.g. hippocampus). Altogether, the combination of whole-brain functional magnetic resonance imaging and RTX-mediated desensitization of TRPV1-signaling provided further detailed insight into cerebral processing of noxious temperatures.
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Affiliation(s)
- Isabel Wank
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Lisa Kutsche
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Silke Kreitz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Peter Reeh
- Institute of Physiology and Pathophysiology, Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas Hess
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
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Warwick C, Cassidy C, Hachisuka J, Wright MC, Baumbauer KM, Adelman PC, Lee KH, Smith KM, Sheahan TD, Ross SE, Koerber HR. MrgprdCre lineage neurons mediate optogenetic allodynia through an emergent polysynaptic circuit. Pain 2021; 162:2120-2131. [PMID: 34130311 PMCID: PMC8206522 DOI: 10.1097/j.pain.0000000000002227] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/07/2021] [Accepted: 01/13/2021] [Indexed: 12/14/2022]
Abstract
ABSTRACT Most cutaneous C fibers, including both peptidergic and nonpeptidergic subtypes, are presumed to be nociceptors and respond to noxious input in a graded manner. However, mechanically sensitive, nonpeptidergic C fibers also respond to mechanical input in the innocuous range, so the degree to which they contribute to nociception remains unclear. To address this gap, we investigated the function of nonpeptidergic afferents using the MrgprdCre allele. In real-time place aversion studies, we found that low-frequency optogenetic activation of MrgrpdCre lineage neurons was not aversive in naive mice but became aversive after spared nerve injury (SNI). To address the underlying mechanisms of this allodynia, we recorded responses from lamina I spinoparabrachial (SPB) neurons using the semi-intact ex vivo preparation. After SNI, innocuous brushing of the skin gave rise to abnormal activity in lamina I SPB neurons, consisting of an increase in the proportion of recorded neurons that responded with excitatory postsynaptic potentials or action potentials. This increase was likely due, at least in part, to an increase in the proportion of lamina I SPB neurons that received input on optogenetic activation of MrgprdCre lineage neurons. Intriguingly, in SPB neurons, there was a significant increase in the excitatory postsynaptic current latency from MrgprdCre lineage input after SNI, consistent with the possibility that the greater activation post-SNI could be due to the recruitment of a new polysynaptic circuit. Together, our findings suggest that MrgprdCre lineage neurons can provide mechanical input to the dorsal horn that is nonnoxious before injury but becomes noxious afterwards because of the engagement of a previously silent polysynaptic circuit in the dorsal horn.
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Affiliation(s)
- Charles Warwick
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Colleen Cassidy
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Junichi Hachisuka
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
- Spinal Cord Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, United Kingdom
| | - Margaret C. Wright
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kyle M. Baumbauer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO, United States
| | - Peter C. Adelman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kuan H. Lee
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kelly M. Smith
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Tayler D. Sheahan
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - Sarah E. Ross
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
| | - H. Richard Koerber
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, PA, United States
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Mizuno M, Hotta N, Ishizawa R, Kim HK, Iwamoto G, Vongpatanasin W, Mitchell JH, Smith SA. The Impact of Insulin Resistance on Cardiovascular Control During Exercise in Diabetes. Exerc Sport Sci Rev 2021; 49:157-167. [PMID: 33965976 PMCID: PMC8195845 DOI: 10.1249/jes.0000000000000259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Patients with diabetes display heightened blood pressure response to exercise, but the underlying mechanism remains to be elucidated. There is no direct evidence that insulin resistance (hyperinsulinemia or hyperglycemia) impacts neural cardiovascular control during exercise. We propose a novel paradigm in which hyperinsulinemia or hyperglycemia significantly influences neural regulatory pathways controlling the circulation during exercise in diabetes.
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Affiliation(s)
- Masaki Mizuno
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Norio Hotta
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- College of Life and Health Sciences, Chubu University, Kasugai 487-850, Japan
| | - Rie Ishizawa
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Gary Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Jere H. Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
| | - Scott A. Smith
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA
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9
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Sato T, Yajima T, Saijyo S, Shimazaki K, Nishitani T, Hoshika T, Nishitani Y, Ichikawa H, Mizoguchi I, Fukunaga T. Distribution of alpha-synuclein in the rat cranial sensory ganglia, and oro-cervical regions. Ann Anat 2021; 238:151776. [PMID: 34082081 DOI: 10.1016/j.aanat.2021.151776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/24/2021] [Accepted: 05/07/2021] [Indexed: 12/27/2022]
Abstract
BACKGROUND Alpha-synuclein (Syn), an unfolded soluble cytosolic protein, is known as a disease-associated protein in the brain. However, little is known about distribution of this protein in the peripheral nervous system. In this study, expression of Syn was investigated in the sensory ganglia of the cranial nerves V, IX and X. METHODS To analyze distribution of Syn and its co-expression with calcitonin gene-related peptide (CGRP) or the transient receptor potential cation channel subfamily V member 1 (TRPV1), immunohistochemical techniques were used in the rat cranial sensory ganglia and their peripheral tissues. RESULTS Syn-immunoreactive (-ir) neurons were abundant in the sensory ganglia of the petrosal (56.7%), jugular (28.3%) and nodose ganglia (82.5%). These neurons had small to medium-sized cell bodies (petrosal, mean ± S.D. = 667.4 ± 310.8 μ m2; jugular, 625.1 ± 318.4 μ m2; nodose, 708.3 ± 248.3 μ m2), and were distributed throughout the ganglia. However, the trigeminal ganglion was mostly free of Syn-ir neurons. By double and triple immunofluorescence staining, Syn-ir neurons co-expressed CGRP and TRPV1 in the petrosal and jugular ganglia. Syn-immunoreactivity was expressed by nerve fibers in the epithelium and taste bud of oral and cervical viscerae. These nerve fibers were abundant in the naso-pharynx, epiglottis and laryngeal vestibule. Some taste bud cells were also immunoreactive for Syn. In addition, Syn-ir nerve fibers were detected in the vicinity of macrophages, dendritic cells and Langerhans cells. CONCLUSIONS Syn was abundant in the visceral sensory neurons but not in somatic sensory neurons. This protein may play a role in nociceptive and chemosensory transduction in the glossopharyngeal and vagal sensory ganglia. It is possible that Syn has a function about the immune mechanism of the upper air way.
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Affiliation(s)
- Tadasu Sato
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan.
| | - Takehiro Yajima
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Shiori Saijyo
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Kenichiro Shimazaki
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Tomiko Nishitani
- Department of Restorative Dentistry and Endodontology, Research Field in Dentistry, Medical and Dental Sciences Area, Research and Education Assembly, Kagoshima University, Kagoshima 890-8544, Japan
| | - Tomohiro Hoshika
- Department of Restorative Dentistry and Endodontology, Research Field in Dentistry, Medical and Dental Sciences Area, Research and Education Assembly, Kagoshima University, Kagoshima 890-8544, Japan
| | - Yoshihiro Nishitani
- Department of Restorative Dentistry and Endodontology, Research Field in Dentistry, Medical and Dental Sciences Area, Research and Education Assembly, Kagoshima University, Kagoshima 890-8544, Japan
| | - Hiroyuki Ichikawa
- Division of Oral and Craniofacial Anatomy, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Itaru Mizoguchi
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
| | - Tomohiro Fukunaga
- Division of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Tohoku University, Sendai 980-8575, Japan
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10
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Functional expression of glycine receptors in DRG neurons of mice. Eur J Pharmacol 2021; 899:174034. [PMID: 33727056 DOI: 10.1016/j.ejphar.2021.174034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 02/25/2021] [Accepted: 03/11/2021] [Indexed: 11/20/2022]
Abstract
Glycine receptor is one of the chloride-permeable ion channels composed of combinations of four α subunits and one β subunit. In adult spinal cord, the glycine receptor α1 subunit is crucial for the generation of inhibitory neurotransmission. The reduced glycinergic inhibition is regarded as one of the key spinal mechanisms underlying pathological pain symptoms. However, the expression and function of glycine receptors in the peripheral system are largely unknown as yet. Here we found that glycine receptor α1 subunit was prevalent in the dorsal root ganglia (DRG) neurons as well as in the sciatic nerves of adult mice. Intraganglionar or intraplantar injection of glycine receptor antagonist strychnine caused the hypersensitivity to mechanical, thermal and cold stimuli, suggesting the functional importance of peripheral glycine receptors in the control of nociceptive signal transmission. Our data showed that peripheral inflammation induced by formalin decreased the expression of glycine receptor α1 subunit on the plasma membrane of DRG neurons, which was attributed to the activation of protein kinase C signaling. Intraplantar application of glycine receptor agonist glycine or positive modulator divalent zinc ion alleviated the first-phase painful behaviors induced by formalin. These data suggested that peripheral glycine receptor might serve as an effective target for pain therapy.
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11
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Adelman PC, Baumbauer KM, Friedman R, Shah M, Wright M, Young E, Jankowski MP, Albers KM, Koerber HR. Single-cell q-PCR derived expression profiles of identified sensory neurons. Mol Pain 2020; 15:1744806919884496. [PMID: 31588843 PMCID: PMC6820183 DOI: 10.1177/1744806919884496] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sensory neurons are chemically and functionally heterogeneous, and this heterogeneity has been examined extensively over the last several decades. These studies have employed a variety of different methodologies, including anatomical, electrophysiological, and molecular approaches. Recent studies using next-generation sequencing techniques have examined the transcriptome of single sensory neurons. Although these reports have provided a wealth of exciting new information on the heterogeneity of sensory neurons, correlation with functional types is lacking. Here, we employed retrograde tracing of cutaneous and muscle afferents to examine the variety of mRNA expression profiles of individual, target-specific sensory neurons. In addition, we used an ex vivo skin/nerve/dorsal root ganglion/spinal cord preparation to record and characterize the functional response properties of individual cutaneous sensory neurons that were then intracellularly labeled with fluorescent dyes, recovered from dissociated cultures, and analyzed for gene expression. We found that by using single-cell quantitative polymerase chain reaction techniques and a set of 28 genes, we can identify transcriptionally distinct groups. We have also used calcium imaging and single-cell quantitative polymerase chain reaction to determine the correlation between levels of mRNA expression and functional protein expression and how functional properties correlated with the different transcriptional groups. These studies show that although transcriptomics does map to functional types, within any one functional subgroup, there are highly variable patterns of gene expression. Thus, studies that rely on the expression pattern of one or a few genes as a stand in for physiological experiments, runs a high risk of data misinterpretation with respect to function.
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Affiliation(s)
- Peter C Adelman
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Kyle M Baumbauer
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Robert Friedman
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Mansi Shah
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Margaret Wright
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Erin Young
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Michael P Jankowski
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - Kathryn M Albers
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
| | - H Richard Koerber
- Department of Neurobiology, School of Medicine, University of Pittsburgh, PA, USA
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12
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Neurochemical and Ultrastructural Characterization of Unmyelinated Non-peptidergic C-Nociceptors and C-Low Threshold Mechanoreceptors Projecting to Lamina II of the Mouse Spinal Cord. Cell Mol Neurobiol 2020; 41:247-262. [PMID: 32306148 DOI: 10.1007/s10571-020-00847-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/09/2020] [Indexed: 12/19/2022]
Abstract
C-nociceptors (C-Ncs) and non-nociceptive C-low threshold mechanoreceptors (C-LTMRs) are two subpopulations of small unmyelinated non-peptidergic C-type neurons of the dorsal root ganglia (DRGs) with central projections displaying a specific pattern of termination in the spinal cord dorsal horn. Although these two subpopulations exist in several animals, remarkable neurochemical differences occur between mammals, particularly rat/humans from one side and mouse from the other. Mouse is widely investigated by transcriptomics. Therefore, we here studied the immunocytochemistry of murine C-type DRG neurons and their central terminals in spinal lamina II at light and electron microscopic levels. We used a panel of markers for peptidergic (CGRP), non-peptidergic (IB4), nociceptive (TRPV1), non-nociceptive (VGLUT3) C-type neurons and two strains of transgenic mice: the TAFA4Venus knock-in mouse to localize the TAFA4+ C-LTMRs, and a genetically engineered ginip mouse that allows an inducible and tissue-specific ablation of the DRG neurons expressing GINIP, a key modulator of GABABR-mediated analgesia. We confirmed that IB4 and TAFA4 did not coexist in small non-peptidergic C-type DRG neurons and separately tagged the C-Ncs and the C-LTMRs. We then showed that TRPV1 was expressed in only about 7% of the IB4+ non-peptidergic C-Ncs and their type Ia glomerular terminals within lamina II. Notably, the selective ablation of GINIP did not affect these neurons, whereas it reduced IB4 labeling in the medial part of lamina II and the density of C-LTMRs glomerular terminals to about one half throughout the entire lamina. We discuss the significance of these findings for interspecies differences and functional relevance.
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13
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Knight BE, Kozlowski N, Havelin J, King T, Crocker SJ, Young EE, Baumbauer KM. TIMP-1 Attenuates the Development of Inflammatory Pain Through MMP-Dependent and Receptor-Mediated Cell Signaling Mechanisms. Front Mol Neurosci 2019. [PMID: 31616247 DOI: 10.3389/fnmol.2019.00220/bibtex] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Unresolved inflammation is a significant predictor for developing chronic pain, and targeting the mechanisms underlying inflammation offers opportunities for therapeutic intervention. During inflammation, matrix metalloproteinase (MMP) activity contributes to tissue remodeling and inflammatory signaling, and is regulated by tissue inhibitors of metalloproteinases (TIMPs). TIMP-1 and -2 have known roles in pain, but only in the context of MMP inhibition. However, TIMP-1 also has receptor-mediated cell signaling functions that are not well understood. Here, we examined how TIMP-1-dependent cell signaling impacts inflammatory hypersensitivity and ongoing pain. We found that hindpaw injection of complete Freund's adjuvant (CFA) increased cutaneous TIMP-1 expression that peaked prior to development of mechanical hypersensitivity, suggesting that TIMP-1 inhibits the development of inflammatory hypersensitivity. To examine this possibility, we injected TIMP-1 knockout (T1KO) mice with CFA and found that T1KO mice exhibited rapid onset thermal and mechanical hypersensitivity at the site of inflammation that was absent or attenuated in WT controls. We also found that T1KO mice exhibited hypersensitivity in adjacent tissues innervated by different sets of afferents, as well as skin contralateral to the site of inflammation. Replacement of recombinant murine (rm)TIMP-1 alleviated hypersensitivity when administered at the site and time of inflammation. Administration of either the MMP inhibiting N-terminal or the cell signaling C-terminal domains recapitulated the antinociceptive effect of full-length rmTIMP-1, suggesting that rmTIMP-1inhibits hypersensitivity through MMP inhibition and receptor-mediated cell signaling. We also found that hypersensitivity was not due to genotype-specific differences in MMP-9 activity or expression, nor to differences in cytokine expression. Administration of rmTIMP-1 prevented mechanical hypersensitivity and ongoing pain in WT mice, collectively suggesting a novel role for TIMP-1 in the attenuation of inflammatory pain.
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Affiliation(s)
- Brittany E Knight
- Department of Neuroscience, UConn Health, Farmington, CT, United States
| | - Nathan Kozlowski
- School of Nursing, University of Connecticut, Storrs, CT, United States
| | - Joshua Havelin
- Center for Excellence in the Neurosciences, University of New England, Biddeford, ME, United States.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States
| | - Tamara King
- Center for Excellence in the Neurosciences, University of New England, Biddeford, ME, United States.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States.,College of Osteopathic Medicine, University of New England, Biddeford, ME, United States
| | - Stephen J Crocker
- Department of Neuroscience, UConn Health, Farmington, CT, United States.,Institute for Systems Genomics, UConn Health, Farmington, CT, United States
| | - Erin E Young
- School of Nursing, University of Connecticut, Storrs, CT, United States.,Institute for Systems Genomics, UConn Health, Farmington, CT, United States.,The Center for Advancement in Managing Pain, School of Nursing, University of Connecticut, Storrs, CT, United States.,Genetics and Genome Sciences, UConn Health, Farmington, CT, United States
| | - Kyle M Baumbauer
- School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States
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14
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Lawson SN, Fang X, Djouhri L. Nociceptor subtypes and their incidence in rat lumbar dorsal root ganglia (DRGs): focussing on C-polymodal nociceptors, Aβ-nociceptors, moderate pressure receptors and their receptive field depths. CURRENT OPINION IN PHYSIOLOGY 2019; 11:125-146. [PMID: 31956744 PMCID: PMC6959836 DOI: 10.1016/j.cophys.2019.10.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A recent study with Ca++-sensitive-dyes in neurons in whole DRGs (Table 5) found that much lower percentages of nociceptors were polymodal-nociceptors (PMNs) (Emery et al., 2016), than the 50-80% values in many electrophysiological fiber studies. This conflict highlighted the lack of knowledge about percentages of nociceptor-subtypes in the DRG. This was analysed from intracellularly-recorded neurons in rat lumbar DRGs stimulated from outside the skin. Polymodal nociceptors (PMNs) were 11% of all neurons and 19% of all nociceptors. Most PMNs had C-fibers (CPMNs). Percentages of C-nociceptors that were CPMNs varied with receptive field (RF) depths, whether superficial (∼80%), dermal (25%), deep (0%) or cutaneous (superficial + dermal) (40%). This explains CPMN percentages 40-90%, being highest, in electrophysiological studies using cutaneous nerves, and lowest in studies that also include deep RFs, including ours, and the recent Ca++-imaging studies in whole DRGs. Despite having been originally described in 1967 (Burgess and Perl), both Aβ-nociceptors and Aβ-moderate pressure receptors (MPRs) remain overlooked. Most A-fiber nociceptors in rodents have Aβ-fibers. Of rat lumbar Aβ-nociceptors with superficial RFs, 50% were MPRs with variable medium-low trkA-expression. Despite having conduction velocities at the two extremes for nociceptors, both CPMNs and MPRs have relatively low thresholds, superficial/epidermal RFs and low trkA-expression. For abbreviations used see Table 5.
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Affiliation(s)
- Sally N Lawson
- The Physiology Department, University of Bristol, Bristol BS8 1TD, UK
| | - Xin Fang
- Qihan BioTech Co. Ltd, Hangzhou, China
| | - Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
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15
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Knight BE, Kozlowski N, Havelin J, King T, Crocker SJ, Young EE, Baumbauer KM. TIMP-1 Attenuates the Development of Inflammatory Pain Through MMP-Dependent and Receptor-Mediated Cell Signaling Mechanisms. Front Mol Neurosci 2019; 12:220. [PMID: 31616247 PMCID: PMC6764257 DOI: 10.3389/fnmol.2019.00220] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 08/30/2019] [Indexed: 12/12/2022] Open
Abstract
Unresolved inflammation is a significant predictor for developing chronic pain, and targeting the mechanisms underlying inflammation offers opportunities for therapeutic intervention. During inflammation, matrix metalloproteinase (MMP) activity contributes to tissue remodeling and inflammatory signaling, and is regulated by tissue inhibitors of metalloproteinases (TIMPs). TIMP-1 and -2 have known roles in pain, but only in the context of MMP inhibition. However, TIMP-1 also has receptor-mediated cell signaling functions that are not well understood. Here, we examined how TIMP-1-dependent cell signaling impacts inflammatory hypersensitivity and ongoing pain. We found that hindpaw injection of complete Freund’s adjuvant (CFA) increased cutaneous TIMP-1 expression that peaked prior to development of mechanical hypersensitivity, suggesting that TIMP-1 inhibits the development of inflammatory hypersensitivity. To examine this possibility, we injected TIMP-1 knockout (T1KO) mice with CFA and found that T1KO mice exhibited rapid onset thermal and mechanical hypersensitivity at the site of inflammation that was absent or attenuated in WT controls. We also found that T1KO mice exhibited hypersensitivity in adjacent tissues innervated by different sets of afferents, as well as skin contralateral to the site of inflammation. Replacement of recombinant murine (rm)TIMP-1 alleviated hypersensitivity when administered at the site and time of inflammation. Administration of either the MMP inhibiting N-terminal or the cell signaling C-terminal domains recapitulated the antinociceptive effect of full-length rmTIMP-1, suggesting that rmTIMP-1inhibits hypersensitivity through MMP inhibition and receptor-mediated cell signaling. We also found that hypersensitivity was not due to genotype-specific differences in MMP-9 activity or expression, nor to differences in cytokine expression. Administration of rmTIMP-1 prevented mechanical hypersensitivity and ongoing pain in WT mice, collectively suggesting a novel role for TIMP-1 in the attenuation of inflammatory pain.
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Affiliation(s)
- Brittany E Knight
- Department of Neuroscience, UConn Health, Farmington, CT, United States
| | - Nathan Kozlowski
- School of Nursing, University of Connecticut, Storrs, CT, United States
| | - Joshua Havelin
- Center for Excellence in the Neurosciences, University of New England, Biddeford, ME, United States.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States
| | - Tamara King
- Center for Excellence in the Neurosciences, University of New England, Biddeford, ME, United States.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States.,College of Osteopathic Medicine, University of New England, Biddeford, ME, United States
| | - Stephen J Crocker
- Department of Neuroscience, UConn Health, Farmington, CT, United States.,Institute for Systems Genomics, UConn Health, Farmington, CT, United States
| | - Erin E Young
- School of Nursing, University of Connecticut, Storrs, CT, United States.,Institute for Systems Genomics, UConn Health, Farmington, CT, United States.,The Center for Advancement in Managing Pain, School of Nursing, University of Connecticut, Storrs, CT, United States.,Genetics and Genome Sciences, UConn Health, Farmington, CT, United States
| | - Kyle M Baumbauer
- School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States.,School of Nursing, University of Connecticut, Storrs, CT, United States
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16
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Abstract
Our understanding of how peripheral damage-sensing neurons (nociceptors) respond to noxious stimuli is fundamental to the development of effective analgesics. To date, numerous studies have presented diverging hypotheses on how nociceptors encode modality-specific stimuli, including labelled-line, intensity dependence or pattern theory. In this short review, we appraise data from electrophysiological, behavioural, imaging and molecular expression studies from the last 60 years, in order to obtain a coherent view of modality-specific sensing in peripheral sensory neurons. We propose a mechanistic explanation for the broad range of values obtained for the incidence of polymodal nociceptors that reconciles apparently contradictory data.
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17
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Kim HK, Hotta N, Ishizawa R, Iwamoto GA, Vongpatanasin W, Mitchell JH, Smith SA, Mizuno M. Exaggerated pressor and sympathetic responses to stimulation of the mesencephalic locomotor region and exercise pressor reflex in type 2 diabetic rats. Am J Physiol Regul Integr Comp Physiol 2019; 317:R270-R279. [PMID: 31091155 DOI: 10.1152/ajpregu.00061.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The cardiovascular responses to exercise are potentiated in patients with type 2 diabetes mellitus (T2DM). However, the underlying mechanisms causing this abnormality remain unknown. Central command (CC) and the exercise pressor reflex (EPR) are known to contribute significantly to cardiovascular control during exercise. Thus these neural signals are viable candidates for the generation of the abnormal circulatory regulation in this disease. We hypothesized that augmentations in CC as well as EPR function contribute to the heightened cardiovascular responses during exercise in T2DM. To test this hypothesis, changes in mean arterial pressure (MAP) and renal sympathetic nerve activity (RSNA) in response to electrical stimulation of mesencephalic locomotor region (MLR), a putative component of the central command pathway, and activation of the EPR, evoked by electrically induced hindlimb muscle contraction, were examined in decerebrate animals. Sprague-Dawley rats were given either a normal diet (control) or a high-fat diet (14-16 wk) in combination with two low doses (35 mg/kg week 1, 25 mg/kg week 2) of streptozotocin (T2DM). The changes in MAP and RSNA responses to MLR stimulation were significantly greater in T2DM compared with control (2,739 ± 123 vs. 1,298 ± 371 mmHg/s, 6,326 ± 1,621 vs. 1,390 ± 277%/s, respectively, P < 0.05). Similarly, pressor and sympathetic responses to activation of the EPR in diabetic animals were significantly augmented compared with control animals (436 ± 74 vs. 134 ± 44 mmHg/s, 645 ± 135 vs. 139 ± 65%/s, respectively, P < 0.05). These findings provide the first evidence that CC and the EPR may generate the exaggerated rise in sympathetic activity and blood pressure during exercise in T2DM.
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Affiliation(s)
- Han-Kyul Kim
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Norio Hotta
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.,College of Life and Health Sciences, Chubu University, Kasugai, Japan
| | - Rie Ishizawa
- Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Gary A Iwamoto
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Wanpen Vongpatanasin
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jere H Mitchell
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Scott A Smith
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Masaki Mizuno
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.,Department of Health Care Sciences, University of Texas Southwestern Medical Center, Dallas, Texas
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18
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Djouhri L, Malki MI, Zeidan A, Nagi K, Smith T. Activation of Kv7 channels with the anticonvulsant retigabine alleviates neuropathic pain behaviour in the streptozotocin rat model of diabetic neuropathy. J Drug Target 2019; 27:1118-1126. [DOI: 10.1080/1061186x.2019.1608552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Laiche Djouhri
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Mohammed Imad Malki
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Asad Zeidan
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Karim Nagi
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Trevor Smith
- Department of Medical Physics & Biomedical Engineering, University College London, London, UK
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19
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Peripheral afferents and spinal inhibitory system in dynamic and static mechanical allodynia. Pain 2019; 158:2285-2289. [PMID: 28885453 DOI: 10.1097/j.pain.0000000000001055] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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20
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Yamamoto K, Tanaka S, Fuseya S, Ishida T, Zhang H, Kawamata T, Kawamata M. Knockdown of TRPV2 channels in sensory neurons increases limb use and weight bearing but does not affect spontaneous flinching behavior in a mouse model of bone cancer. Mol Pain 2018. [PMCID: PMC6305955 DOI: 10.1177/1744806918819942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Bone cancer pain is a complex pain state involving ongoing pain and movement-related pain, which are thought to be caused by different mechanisms. Transient receptor potential vanilloid subfamily 1 (TRPV1) is involved in ongoing pain but not movement-related pain. The purpose of this study was to investigate the role of transient receptor potential vanilloid subfamily 2 (TRPV2) in bone cancer pain. Proportions of TRPV1- and TRPV2-immunoreactive neurons in lumbar dorsal root ganglia innervating the femurs of male mice were examined by using Fluoro-Gold. Mice were intrathecally injected with small interfering RNA (siRNA) against TRPV2 or scrambled siRNA for three consecutive days from day 14 after sarcoma injection into the left femur. In the mice with bone cancer, the number of spontaneous flinches was quantified for assessment of ongoing pain, and limb use and weight bearing were assessed as indications of movement-related pain. Changes in TRPV2 protein levels in dorsal root ganglion were evaluated by Western blotting. We also examined the effects of intrathecal administration of siRNA against TRPV2 or scrambled siRNA on thermal and mechanical sensitivities in normal mice without tumors. The proportions of TRPV1-immunoreactive and TRPV2-immunoreactive neurons were 21% and 22% of neurons in dorsal root ganglia innervating the femur, respectively. Tumor-bearing mice exhibited an increased number of spontaneous flinches and impaired limb use and weight bearing at day 13 after sarcoma injection. TRPV2 protein level in dorsal root ganglia at day 13 was comparable to that at baseline. siRNA against TRPV2 significantly improved limb use and weight bearing but did not affect the number of spontaneous flinches compared to those in the group treated with scrambled siRNA. siRNA against TRPV2 did not affect thermal or mechanical sensitivity in normal mice. The results suggest that TRPV2 is involved in movement-related pain but not ongoing pain in mice with bone cancer.
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Affiliation(s)
- Katsumi Yamamoto
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Satoshi Tanaka
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Satoshi Fuseya
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Takashi Ishida
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Hao Zhang
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
| | - Tomoyuki Kawamata
- Department of Anesthesiology, Wakayama Medical University, Wakayama City, Japan
| | - Mikito Kawamata
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine, Nagano, Japan
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21
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Greenspon CM, Battell EE, Devonshire IM, Donaldson LF, Chapman V, Hathway GJ. Lamina-specific population encoding of cutaneous signals in the spinal dorsal horn using multi-electrode arrays. J Physiol 2018; 597:377-397. [PMID: 30390415 PMCID: PMC6332738 DOI: 10.1113/jp277036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 10/31/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Traditional, widely used in vivo electrophysiological techniques for the investigation of spinal processing of somatosensory information fail to account for the diverse functions of each lamina. To overcome this oversimplification, we have used multi-electrode arrays, in vivo, to simultaneously record neuronal activity across all laminae of the spinal dorsal horn. Multi-electrode arrays are sensitive enough to detect lamina- and region-specific encoding of different subtypes of afferent fibres and to detect short-lived changes in synaptic plasticity as measured by the application of cutaneous electrical stimulation of varying intensity and frequency. Differential encoding of innocuous and noxious thermal and mechanical stimuli were also detected across the laminae with the technique, as were the effects of the application of capsaicin. This new approach to the study of the dorsal spinal cord produces significantly more information per experiment, permitting accelerated research whilst also permitting the effects of pharmacological tools to modulate network responses. ABSTRACT The dorsal horn (DH) of the spinal cord is a complex laminar structure integrating peripheral signals into the central nervous system. Spinal somatosensory processing is commonly measured electrophysiologically in vivo by recording the activity of individual wide-dynamic-range neurons in the deep DH and extrapolating their behaviour to all cells in every lamina. This fails to account for the specialized processes that occur in each lamina and the considerable heterogeneity in cellular phenotype within and between laminae. Here we overcome this oversimplification by employing linear multi-electrode arrays (MEAs) in the DH of anaesthetized rats to simultaneously measure activity across all laminae. The MEAs, comprising 16 channels, were inserted into the lumbar dorsal horn and peripheral neurons activated electrically via transcutaneous electrodes and ethologically with von Frey hairs (vFHs) or an aluminium heating block. Ascending electrical stimuli showed fibre thresholds with distinct dorsoventral innervation profiles. Wind up was observed across the DH during the C-fibre and post-discharge latencies following 0.5 Hz stimulation. Intrathecal application of morphine (5 ng/50 μl) significantly reduced Aδ- and C-fibre-evoked activity in deep and superficial DH. Light vFHs (≤10 g) predominantly activated intermediate and deep laminae whereas noxious vFHs (26 g) also activated the superficial laminae. Noxious heat (55°C) induced significantly greater activity in the superficial and deep laminae than the innocuous control (30°C). The application of these arrays produced the first description of the processing of innocuous and noxious stimuli throughout the intact DH.
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Affiliation(s)
- Charles M Greenspon
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Emma E Battell
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Ian M Devonshire
- Bio-Support Unit, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Lucy F Donaldson
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK.,Arthritis Research UK Pain Centre, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Victoria Chapman
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK.,Arthritis Research UK Pain Centre, The University of Nottingham, Nottingham, NG7 2UH, UK
| | - Gareth J Hathway
- School of Life Sciences, The University of Nottingham, Nottingham, NG7 2UH, UK
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22
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Sato M, Sato T, Yajima T, Shimazaki K, Ichikawa H. The transient receptor potential cation channel subfamily V members 1 and 2, P2X purinoceptor 3 and calcitonin gene-related peptide in sensory neurons of the rat trigeminal ganglion, innervating the periosteum, masseter muscle and facial skin. Arch Oral Biol 2018; 96:66-73. [DOI: 10.1016/j.archoralbio.2018.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 08/17/2018] [Accepted: 08/22/2018] [Indexed: 01/30/2023]
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23
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Zannou AL, Khadka N, Truong DQ, Zhang T, Esteller R, Hershey B, Bikson M. Temperature increases by kilohertz frequency spinal cord stimulation. Brain Stimul 2018; 12:62-72. [PMID: 30482674 DOI: 10.1016/j.brs.2018.10.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 10/09/2018] [Accepted: 10/10/2018] [Indexed: 12/14/2022] Open
Abstract
INTRODUCTION Kilohertz frequency spinal cord stimulation (kHz-SCS) deposits significantly more power in tissue compared to SCS at conventional frequencies, reflecting increased duty cycle (pulse compression). We hypothesize kHz-SCS increases local tissue temperature by joule heat, which may influence the clinical outcomes. METHODS To establish the role of tissue heating in KHZ-SCS, a decisive first step is to characterize the range of temperature changes expected during conventional and KHZ-SCS protocols. Fiber optic probes quantified temperature increases around an experimental SCS lead in a bath phantom. These data were used to verify a SCS lead heat-transfer model based on joule heat. Temperature increases were then predicted in a seven-compartment (soft tissue, vertebral bone, fat, intervertebral disc, meninges, spinal cord with nerve roots) geometric human spinal cord model under varied parameterization. RESULTS The experimentally constrained bio-heat model shows SCS waveform power (waveform RMS) determines tissue heating at the spinal cord and surrounding tissues. For example, we predict temperature increased at dorsal spinal cord of 0.18-1.72 °C during 3.5 mA peak 10 KHz stimulation with a 40-10-40 μs biphasic pulse pattern, 0.09-0.22 °C during 3.5 mA 1 KHz 100-100-100 μs stimulation, and less than 0.05 °C during 3.5 mA 50 Hz 200-100-200 μs stimulation. Notably, peak heating of the spinal cord and other tissues increases superlinearly with stimulation power and so are especially sensitive to incremental changes in SCS pulse amplitude or frequency (with associated pulse compression). Further supporting distinct SCS intervention strategies based on heating; the spatial profile of temperature changes is more uniform compared to electric fields, which suggests less sensitivity to lead position. CONCLUSIONS Tissue heating may impact short and long-term outcomes of KHZ-SCS, and even as an adjunct mechanism, suggests distinct strategies for lead position and programming optimization.
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Affiliation(s)
- Adantchede L Zannou
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | - Niranjan Khadka
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | - Dennis Q Truong
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA
| | - Tianhe Zhang
- Boston Scientific Inc., Neuromodulation Research and Advanced Concepts, Valencia, CA, USA
| | - Rosana Esteller
- Boston Scientific Inc., Neuromodulation Research and Advanced Concepts, Valencia, CA, USA
| | - Brad Hershey
- Boston Scientific Inc., Neuromodulation Research and Advanced Concepts, Valencia, CA, USA
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, New York, NY, 10031, USA.
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24
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Lu P, Hudgins RC, Liu X, Ford ZK, Hofmann MC, Queme LF, Jankowski MP. Upregulation of P2Y1 in neonatal nociceptors regulates heat and mechanical sensitization during cutaneous inflammation. Mol Pain 2018; 13:1744806917730255. [PMID: 28845731 PMCID: PMC5590703 DOI: 10.1177/1744806917730255] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The upregulation of various channels and receptors classically linked to sensory transduction from the periphery tightly correspond with changes in the responsiveness of specific subpopulations of primary afferents to mechanical and heat stimulation of the skin at different ages. Previous reports in adults have suggested that the purinergic adenosine diphosphate receptor, P2Y1 can specifically regulate sensory neuron responsiveness to heat stimuli in addition to neurochemical alterations in primary afferents during cutaneous inflammation. To determine if the upregulation of P2Y1 found in the dorsal root ganglia of neonatal mice with cutaneous inflammation initiated at postnatal day 7 (P7) was responsible for the specific alteration in heat sensitivity found in faster conducting (“A”-fiber) nociceptors, we assessed the response properties of cutaneous afferents using an ex vivo hairy hindpaw skin-saphenous nerve-dorsal root ganglion-spinal cord preparation in conjunction with nerve-targeted knockdown of P2Y1. We found that P2Y1 knockdown during neonatal cutaneous inflammation was sufficient to reduce the sensitization of “A”-fiber nociceptors to heat stimuli. Surprisingly, we also found that nerve-specific downregulation of P2Y1 could reduce the observed sensitization of these afferent subtypes to mechanical deformation of the skin. Immunocytochemical analysis of dorsal root ganglia showed that P2Y1 may mediate its effects through modulation of the injury-induced increase of transient receptor potential vanilloid type 1 receptor. This suggests that the upregulation of P2Y1 in cutaneous nociceptors during early life peripheral inflammation can regulate the sensitization of myelinated nociceptors to both mechanical and heat stimuli possibly through modulation of transient receptor potential vanilloid type 1 expression.
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Affiliation(s)
- Peilin Lu
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Renita C Hudgins
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Xiaohua Liu
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Zachary K Ford
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Megan C Hofmann
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
| | - Luis F Queme
- Department of Anesthesia, Division of Pain Management, Cincinnati Children's Hospital Medical Center
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25
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Djouhri L, Smith T, Ahmeda A, Alotaibi M, Weng X. Hyperpolarization-activated cyclic nucleotide-gated channels contribute to spontaneous activity in L4 C-fiber nociceptors, but not Aβ-non-nociceptors, after axotomy of L5-spinal nerve in the rat in vivo. Pain 2018; 159:1392-1402. [PMID: 29578948 DOI: 10.1097/j.pain.0000000000001224] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Peripheral neuropathic pain associated with partial nerve injury is believed to be driven partly by aberrant spontaneous activity (SA) in both injured and uninjured dorsal root ganglion (DRG) neurons. The underlying ionic mechanisms are not fully understood, but hyperpolarization-activated cyclic nucleotide-gated (HCN) channels which underlie the excitatory Ih current have been implicated in SA generation in axotomized A-fiber neurons after L5-spinal nerve ligation/axotomy (SNL/SNA). Here, using a modified model of SNA (mSNA) which involves, in addition to L5-SNA, loose ligation of the L4-spinal nerve with neuroinflammation-inducing chromic gut, we examined whether HCN channels also contribute to SA in the adjacent L4-neurons. Intracellular recordings from L4-DRG neurons in control rats, and L4-DRG neurons in mSNA rats were made using in vivo voltage- and current-clamp techniques. Compared with control, L4 C-nociceptors and Aβ-low-threshold mechanoreceptors (LTMs) exhibited SA 7 days after mSNA. This was accompanied, in C-nociceptors, by a significant increase in Ih amplitude, the percentage of Ih-expressing neurons, and Ih activation rate. Hyperpolarization-activated cyclic nucleotide-gated channel blockade with ZD7288 (10 mg/kg, intravenously) suppressed SA in C-nociceptors, but not Aβ-LTMs, and caused in C-nociceptors, membrane hyperpolarization and a decrease in Ih activation rate. Furthermore, intraplantar injection of ZD7288 (100 μM) was found to be as effective as gabapentin (positive control) in attenuating cold hypersensitivity in mSNA rats. These findings suggest that HCN channels contribute to nerve injury-induced SA in L4 C-nociceptors, but not Aβ-LTMs, and that ZD7288 exerts its analgesic effects by altering Ih activation properties and/or causing membrane hyperpolarization in L4 C-nociceptors.
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Affiliation(s)
- Laiche Djouhri
- Department of Physiology, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
- Department of Clinical and Molecular Pharmacology, Institute of Translational Medicine, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Trevor Smith
- Wolfson CARD, Neurorestoration Group, King's College London, London, United Kingdom
| | - Ahmad Ahmeda
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mohammad Alotaibi
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Xiechuan Weng
- State Key Laboratory of Proteomics, Department of Neurobiology, Beijing Institute of Basic Medical Sciences, Beijing, China
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26
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Jurcakova D, Ru F, Kollarik M, Sun H, Krajewski J, Undem BJ. Voltage-Gated Sodium Channels Regulating Action Potential Generation in Itch-, Nociceptive-, and Low-Threshold Mechanosensitive Cutaneous C-Fibers. Mol Pharmacol 2018; 94:1047-1056. [DOI: 10.1124/mol.118.112839] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/20/2018] [Indexed: 01/25/2023] Open
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27
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Urata K, Shinoda M, Ikutame D, Iinuma T, Iwata K. Involvement of transient receptor potential vanilloid 2 in intra-oral incisional pain. Oral Dis 2018; 24:1093-1100. [PMID: 29505690 DOI: 10.1111/odi.12853] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 02/27/2018] [Accepted: 02/27/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To examine whether transient receptor potential vanilloid 2 (TRPV2) contributes to the changes in intra-oral thermal and mechanical sensitivity following the incision of buccal mucosa. MATERIALS AND METHODS Buccal mucosal pain threshold was measured after the incision. Changes in the number of TRPV2-immunoreactive (IR) trigeminal ganglion (TG) neurons which innervate the whisker pad skin and buccal mucosa, changes in the number of isolectin B4-negative/isolectin B4-positive TRPV2-IR TG neurons which innervate the whisker pad skin and the buccal mucosa, and the effect of peripheral TRPV2 antagonism on the pain threshold of incisional whisker pad skin and buccal mucosa were examined after these injuries. RESULTS Buccal mucosal pain hypersensitivities were induced on day 3 following the incision. The total number of TRPV2-IR TG neurons and the number of isolectin B4-negative TRPV2-IR TG neurons which innervate the whisker pad skin and buccal mucosa were increased. Buccal mucosal TRPV2 antagonism completely suppressed the heat and mechanical hypersensitivities, but not cold hypersensitivity. TRPV2 antagonist administration to the incisional whisker pad skin only partially suppressed pain hypersensitivities. CONCLUSION The increased expression of TRPV2 in peptidergic TG neurons innervating the incisional buccal mucosa is predominantly involved in buccal mucosal heat hyperalgesia and mechanical allodynia following buccal mucosal incision.
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Affiliation(s)
- K Urata
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - M Shinoda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - D Ikutame
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - T Iinuma
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - K Iwata
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
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28
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Jankowski MP, Rau KK, Koerber HR. Cutaneous TRPM8-expressing sensory afferents are a small population of neurons with unique firing properties. Physiol Rep 2017; 5:5/7/e13234. [PMID: 28381446 PMCID: PMC5392520 DOI: 10.14814/phy2.13234] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 03/03/2017] [Accepted: 03/08/2017] [Indexed: 11/24/2022] Open
Abstract
It has been well documented that the transient receptor potential melastatin 8 (TRPM8) receptor is involved in environmental cold detection. The role that this receptor plays in nociception however, has been somewhat controversial since conflicting reports have shown different neurochemical identities and responsiveness of TRPM8 neurons. In order to functionally characterize cutaneous TRMP8 fibers, we used two ex vivo somatosensory recording preparations to functionally characterize TRPM8 neurons that innervate the hairy skin in mice genetically engineered to express GFP from the TRPM8 locus. We found several types of cold-sensitive neurons that innervate the hairy skin of the mouse but the TRPM8-expressing neurons were found to be of two specific populations that responded with rapid firing to cool temperatures. The first group was mechanically insensitive but the other did respond to high threshold mechanical deformation of the skin. None of these fibers were found to contain calcitonin gene-related peptide, transient receptor potential vanilloid type 1 or bind isolectin B4. These results taken together with other reports suggest that TRPM8 containing sensory neurons are environmental cooling detectors that may be nociceptive or non-nociceptive depending on the sensitivity of individual fibers to different combinations of stimulus modalities.
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Affiliation(s)
- Michael P Jankowski
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Kristofer K Rau
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - H Richard Koerber
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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29
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Duan B, Cheng L, Ma Q. Spinal Circuits Transmitting Mechanical Pain and Itch. Neurosci Bull 2017; 34:186-193. [PMID: 28484964 PMCID: PMC5799122 DOI: 10.1007/s12264-017-0136-z] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/01/2017] [Indexed: 12/11/2022] Open
Abstract
In 1905, Henry Head first suggested that transmission of pain-related protopathic information can be negatively modulated by inputs from afferents sensing innocuous touch and temperature. In 1965, Melzak and Wall proposed a more concrete gate control theory of pain that highlights the interaction between unmyelinated C fibers and myelinated A fibers in pain transmission. Here we review the current understanding of the spinal microcircuits transmitting and gating mechanical pain or itch. We also discuss how disruption of the gate control could cause pain or itch evoked by innocuous mechanical stimuli, a hallmark symptom for many chronic pain or itch patients.
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Affiliation(s)
- Bo Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 830 North University Ave, Ann Arbor, MI, 48109, USA.
| | - Longzhen Cheng
- Institute of Brain Science, the State Key Laboratory of Medical Neurobiology and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
| | - Qiufu Ma
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, 1 Jimmy Fund Way, Boston, MA, 02115, USA.
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30
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Liu X, Green KJ, Ford ZK, Queme LF, Lu P, Ross JL, Lee FB, Shank AT, Hudgins RC, Jankowski MP. Growth hormone regulates the sensitization of developing peripheral nociceptors during cutaneous inflammation. Pain 2017; 158:333-346. [PMID: 27898492 PMCID: PMC5239735 DOI: 10.1097/j.pain.0000000000000770] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cutaneous inflammation alters the function of primary afferents and gene expression in the affected dorsal root ganglia (DRG). However, specific mechanisms of injury-induced peripheral afferent sensitization and behavioral hypersensitivity during development are not fully understood. Recent studies in children suggest a potential role for growth hormone (GH) in pain modulation. Growth hormone modulates homeostasis and tissue repair after injury, but how GH affects nociception in neonates is not known. To determine whether GH played a role in modulating sensory neuron function and hyperresponsiveness during skin inflammation in young mice, we examined behavioral hypersensitivity and the response properties of cutaneous afferents using an ex vivo hairy skin-saphenous nerve-DRG-spinal cord preparation. Results show that inflammation of the hairy hind paw skin initiated at either postnatal day 7 (P7) or P14 reduced GH levels specifically in the affected skin. Furthermore, pretreatment of inflamed mice with exogenous GH reversed mechanical and thermal hypersensitivity in addition to altering nociceptor function. These effects may be mediated through an upregulation of insulin-like growth factor 1 receptor (IGFr1) as GH modulated the transcriptional output of IGFr1 in DRG neurons in vitro and in vivo. Afferent-selective knockdown of IGFr1 during inflammation also prevented the observed injury-induced alterations in cutaneous afferents and behavioral hypersensitivity similar to that after GH pretreatment. These results suggest that GH can block inflammation-induced nociceptor sensitization during postnatal development leading to reduced pain-like behaviors, possibly by suppressing the upregulation of IGFr1 within DRG.
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Affiliation(s)
- Xiaohua Liu
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Kathryn J. Green
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Zachary K. Ford
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Luis F. Queme
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Peilin Lu
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Jessica L. Ross
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Frank B. Lee
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Aaron T. Shank
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Renita C. Hudgins
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
| | - Michael P. Jankowski
- Department of Anesthesia, Division of Pain Management, Cincinnati Children’s Hospital Medical Center, Cincinnati OH 45229
- Department of Pediatrics, University of Cincinnati, Cincinnati OH 45229
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31
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François A, Scherrer G. Delta Opioid Receptor Expression and Function in Primary Afferent Somatosensory Neurons. Handb Exp Pharmacol 2017; 247:87-114. [PMID: 28993838 DOI: 10.1007/164_2017_58] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The functional diversity of primary afferent neurons of the dorsal root ganglia (DRG) generates a variety of qualitatively and quantitatively distinct somatosensory experiences, from shooting pain to pleasant touch. In recent years, the identification of dozens of genetic markers specifically expressed by subpopulations of DRG neurons has dramatically improved our understanding of this diversity and provided the tools to manipulate their activity and uncover their molecular identity and function. Opioid receptors have long been known to be expressed by discrete populations of DRG neurons, in which they regulate cell excitability and neurotransmitter release. We review recent insights into the identity of the DRG neurons that express the delta opioid receptor (DOR) and the ion channel mechanisms that DOR engages in these cells to regulate sensory input. We highlight recent findings derived from DORGFP reporter mice and from in situ hybridization and RNA sequencing studies in wild-type mice that revealed DOR presence in cutaneous mechanosensory afferents eliciting touch and implicated in tactile allodynia. Mechanistically, we describe how DOR modulates opening of voltage-gated calcium channels (VGCCs) to control glutamatergic neurotransmission between somatosensory neurons and postsynaptic neurons in the spinal cord dorsal horn. We additionally discuss other potential signaling mechanisms, including those involving potassium channels, which DOR may engage to fine tune somatosensation. We conclude by discussing how this knowledge may explain the analgesic properties of DOR agonists against mechanical pain and uncovers an unanticipated specialized function for DOR in cutaneous mechanosensation.
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Affiliation(s)
- Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.,Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.,Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA. .,Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA. .,Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University School of Medicine, Palo Alto, CA, USA.
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32
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Jankowski MP, Baumbauer KM, Wang T, Albers KM, Davis BM, Koerber HR. Cutaneous neurturin overexpression alters mechanical, thermal, and cold responsiveness in physiologically identified primary afferents. J Neurophysiol 2016; 117:1258-1265. [PMID: 28031403 PMCID: PMC5349329 DOI: 10.1152/jn.00731.2016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 12/16/2016] [Accepted: 12/23/2016] [Indexed: 11/22/2022] Open
Abstract
Neurotrophic factors play an important role in the regulation of functional properties of sensory neurons under normal and pathological conditions. The GDNF family member neurturin is one such factor that has been linked to modulating responsiveness to peripheral stimuli. Neurturin binds to the GFRα2 receptor, a receptor found primarily in isolectin B4-expressing polymodal cutaneous nociceptors. Previous work has shown that knockout of GFRα2 alters heat, but not mechanical, responses in dissociated sensory neurons and reduces pain-related behaviors during the second phase of the formalin test. Research has also shown that overexpression of neurturin in basal keratinocytes increases behavioral responsiveness to mechanical stimulation and innocuous cooling of the skin without affecting noxious heat responses. Here we directly examined the impact of neurturin overexpression on cutaneous afferent function. We compared physiological responses of individual sensory neurons to mechanical and thermal stimulation of the skin, using an ex vivo skin-nerve-dorsal root ganglion-spinal cord preparation produced from neurturin-overexpressing (NRTN/OE) mice and wild-type littermate controls. We found that neurturin overexpression increases responsiveness to innocuous mechanical stimuli in A-fiber nociceptors, alters thermal responses in the polymodal subpopulation of C-fiber sensory neurons, and changes the relative numbers of mechanically sensitive but thermally insensitive C-fiber afferents. These results demonstrate the potential roles of different functional groups of sensory neurons in the behavioral changes observed in mice overexpressing cutaneous neurturin and highlight the importance of neurturin in regulating cutaneous afferent response properties.NEW & NOTEWORTHY GDNF family neurotrophic factors regulate the development and function of primary sensory neurons. Of these, neurturin has been shown to modulate mechanical and cooling sensitivity behaviorally. Here we show that overexpression of neurturin in basal keratinocytes regulates mechanical responsiveness in A-fiber primary sensory neurons while increasing the overall numbers of cold-sensing units. Results demonstrate a crucial role for cutaneous neurturin in modulating responsiveness to peripheral stimuli at the level of the primary afferent.
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Affiliation(s)
- Michael P Jankowski
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kyle M Baumbauer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ting Wang
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kathryn M Albers
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - H Richard Koerber
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania
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33
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Hachisuka J, Baumbauer KM, Omori Y, Snyder LM, Koerber HR, Ross SE. Semi-intact ex vivo approach to investigate spinal somatosensory circuits. eLife 2016; 5:e22866. [PMID: 27991851 PMCID: PMC5214752 DOI: 10.7554/elife.22866] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 12/16/2016] [Indexed: 11/19/2022] Open
Abstract
The somatosensory input that gives rise to the perceptions of pain, itch, cold and heat are initially integrated in the superficial dorsal horn of the spinal cord. Here, we describe a new approach to investigate these neural circuits in mouse. This semi-intact somatosensory preparation enables recording from spinal output neurons, while precisely controlling somatosensory input, and simultaneously manipulating specific populations of spinal interneurons. Our findings suggest that spinal interneurons show distinct temporal and spatial tuning properties. We also show that modality selectivity - mechanical, heat and cold - can be assessed in both retrogradely labeled spinoparabrachial projection neurons and genetically labeled spinal interneurons. Finally, we demonstrate that interneuron connectivity can be determined via optogenetic activation of specific interneuron subtypes. This new approach may facilitate key conceptual advances in our understanding of the spinal somatosensory circuits in health and disease.
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Affiliation(s)
- Junichi Hachisuka
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
| | - Kyle M Baumbauer
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
| | - Yu Omori
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
| | - Lindsey M Snyder
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
| | - H Richard Koerber
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States
- Pittsburgh Center for Pain Research, University of Pittsburgh, Pittsburgh, United States
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34
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Smith-Edwards KM, DeBerry JJ, Saloman JL, Davis BM, Woodbury CJ. Profound alteration in cutaneous primary afferent activity produced by inflammatory mediators. eLife 2016; 5. [PMID: 27805567 PMCID: PMC5117853 DOI: 10.7554/elife.20527] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 11/01/2016] [Indexed: 12/13/2022] Open
Abstract
Inflammatory pain is thought to arise from increased transmission from nociceptors and recruitment of 'silent' afferents. To evaluate inflammation-induced changes, mice expressing GCaMP3 in cutaneous sensory neurons were generated and neuronal responses to mechanical stimulation in vivo before and after subcutaneous infusion of an 'inflammatory soup' (IS) were imaged in an unanesthetized preparation. Infusion of IS rapidly altered mechanical responsiveness in the majority of neurons. Surprisingly, more cells lost, rather than gained, sensitivity and 'silent' afferents that were mechanically insensitive and gained mechanosensitivity after IS exposure were rare. However, the number of formerly 'silent' afferents that became mechanosensitive was increased five fold when the skin was heated briefly prior to infusion of IS. These findings suggest that pain arising from inflamed skin reflects a dramatic shift in the balance of sensory input, where gains and losses in neuronal populations results in novel output that is ultimately interpreted by the CNS as pain.
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Affiliation(s)
- Kristen M Smith-Edwards
- Department of Zoology and Physiology, University of Wyoming, Laramie, United States.,University of Wyoming Graduate Program in Neuroscience, Laramie, United States
| | - Jennifer J DeBerry
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - Jami L Saloman
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - Brian M Davis
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for Neuroscience at the University of Pittsburgh, Pittsburgh, United States.,Pittsburgh Center for Pain Research, Pittsburgh, United States
| | - C Jeffery Woodbury
- Department of Zoology and Physiology, University of Wyoming, Laramie, United States
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Khariv V, Ni L, Ratnayake A, Sampath S, Lutz BM, Tao XX, Heary RF, Elkabes S. Impaired sensitivity to pain stimuli in plasma membrane calcium ATPase 2 (PMCA2) heterozygous mice: a possible modality- and sex-specific role for PMCA2 in nociception. FASEB J 2016; 31:224-237. [PMID: 27702770 DOI: 10.1096/fj.201600541r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 09/22/2016] [Indexed: 11/11/2022]
Abstract
Plasma membrane calcium ATPase 2 (PMCA2) is a calcium pump that plays important roles in neuronal function. Although it is expressed in pain-associated regions of the CNS, including in the dorsal horn (DH), its contribution to pain remains undefined. The present study assessed the role of PMCA2 in pain responsiveness and the link between PMCA2 and glutamate receptors, GABA receptors (GABARs), and glutamate transporters that have been implicated in pain processing in the DH of adult female and male PMCA2+/+ and PMCA2+/- mice. Behavioral assays evaluated mechanical and thermal pain responsiveness. Mechanical sensitivity was significantly increased by 52% and heat sensitivity was reduced by 29% in female, but not male, PMCA2+/- mice compared with PMCA2+/+ controls. There were female-specific changes in metabotropic glutamate receptor 1, NMDA receptor 2A, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluR1, GABABR1, and GABABR2 levels, whereas metabotropic glutamate receptor 5, NMDA receptor 2B, GluR2, and GABAARα2 levels were not altered. Glutamate aspartate transporter levels were higher and glial glutamate transporter 1 levels were lower in the DH of female, but not male, PMCA2+/- mice. These findings indicate a novel role for PMCA2 in modality- and sex-dependent pain responsiveness. Female-specific molecular changes potentially account for the altered pain responses.-Khariv, V., Ni, L., Ratnayake, A., Sampath, S., Lutz, B. M., Tao, X.-X., Heary, R. F., Elkabes, S. Impaired sensitivity to pain stimuli in plasma membrane calcium ATPase 2 (PMCA2) heterozygous mice: a possible modality- and sex-specific role for PMCA2 in nociception.
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Affiliation(s)
- Veronika Khariv
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA.,Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Li Ni
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Ayomi Ratnayake
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Sujitha Sampath
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Brianna M Lutz
- Graduate School of Biomedical Sciences, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA.,Department of Anesthesiology, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA; and
| | - Xuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA; and
| | - Robert F Heary
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA
| | - Stella Elkabes
- Department of Neurological Surgery, The Reynolds Family Spine Laboratory, New Jersey Medical School-Rutgers, The State University of New Jersey, Newark, New Jersey, USA;
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Hoeck EA, Marker JB, Gazerani P, H. Andersen H, Arendt-Nielsen L. Preclinical and human surrogate models of itch. Exp Dermatol 2016; 25:750-7. [DOI: 10.1111/exd.13078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Emil A. Hoeck
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Jens B. Marker
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Parisa Gazerani
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Hjalte H. Andersen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Lars Arendt-Nielsen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
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Merkel Cell-Driven BDNF Signaling Specifies SAI Neuron Molecular and Electrophysiological Phenotypes. J Neurosci 2016; 36:4362-76. [PMID: 27076431 DOI: 10.1523/jneurosci.3781-15.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 03/07/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED The extent to which the skin instructs peripheral somatosensory neuron maturation is unknown. We studied this question in Merkel cell-neurite complexes, where slowly adapting type I (SAI) neurons innervate skin-derived Merkel cells. Transgenic mice lacking Merkel cells had normal dorsal root ganglion (DRG) neuron numbers, but fewer DRG neurons expressed the SAI markers TrkB, TrkC, and Ret. Merkel cell ablation also decreased downstream TrkB signaling in DRGs, and altered the expression of genes associated with SAI development and function. Skin- and Merkel cell-specific deletion of Bdnf during embryogenesis, but not postnatal Bdnf deletion or Ntf3 deletion, reproduced these results. Furthermore, prototypical SAI electrophysiological signatures were absent from skin regions where Bdnf was deleted in embryonic Merkel cells. We conclude that BDNF produced by Merkel cells during a precise embryonic period guides SAI neuron development, providing the first direct evidence that the skin instructs sensory neuron molecular and functional maturation. SIGNIFICANCE STATEMENT Peripheral sensory neurons show incredible phenotypic and functional diversity that is initiated early by cell-autonomous and local environmental factors found within the DRG. However, the contribution of target tissues to subsequent sensory neuron development remains unknown. We show that Merkel cells are required for the molecular and functional maturation of the SAI neurons that innervate them. We also show that this process is controlled by BDNF signaling. These findings provide new insights into the regulation of somatosensory neuron development and reveal a novel way in which Merkel cells participate in mechanosensation.
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The TRPM2 ion channel is required for sensitivity to warmth. Nature 2016; 536:460-3. [PMID: 27533035 PMCID: PMC5720344 DOI: 10.1038/nature19074] [Citation(s) in RCA: 190] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 07/01/2016] [Indexed: 12/26/2022]
Abstract
How do we detect warmth? Thermally-activated ion channels expressed in somatosensory neurons detect the entire thermal range from extreme heat (TRPV2), painful heat (TRPV1, TRPM3, ANO1), non-painful warmth (TRPV3 and TRPV4) and non-painful coolness (TRPM8) through to painful cold (TRPA1)1–7. Genetic deletion of each of these ion channels, however, has only modest effects on thermal behaviour in mice6–12, with the exception of TRPM8, whose deletion has marked effects on the perception of moderate coolness in the range 10°C - 25°C13. The molecular mechanism responsible for detecting non-painful warmth, in particular, is unresolved. Here we used calcium imaging to identify a population of novel thermally-sensitive somatosensory neurons which do not express any of the known thermally-activated TRP channels. We then used a combination of calcium imaging, electrophysiology and RNA sequencing to show that the ion channel generating heat sensitivity in these neurons is TRPM2. Autonomic neurons, usually thought of as exclusively motor, also express TRPM2 and respond directly to heat. Mice in which TRPM2 had been genetically deleted showed a striking deficit in their sensation of non-noxious warm temperatures, consistent with the idea that TRPM2 initiates a “warm” signal which drives cool-seeking behaviour.
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Deletion of the murine ATP/UTP receptor P2Y2 alters mechanical and thermal response properties in polymodal cutaneous afferents. Neuroscience 2016; 332:223-30. [PMID: 27393251 DOI: 10.1016/j.neuroscience.2016.06.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/27/2016] [Accepted: 06/29/2016] [Indexed: 12/18/2022]
Abstract
P2Y2 is a member of the P2Y family of G protein-coupled nucleotide receptors that is widely co-expressed with TRPV1 in peripheral sensory neurons of the dorsal root ganglia. To characterize P2Y2 function in cutaneous afferents, intracellular recordings from mouse sensory neurons were made using an ex vivo preparation in which hindlimb skin, saphenous nerve, dorsal root ganglia and spinal cord are dissected intact. The peripheral response properties of individual cutaneous C-fibers were analyzed using digitally controlled mechanical and thermal stimuli in male P2Y2(+/+) and P2Y2(-/-) mice. Selected sensory neurons were labeled with Neurobiotin and further characterized by immunohistochemistry. In wildtype preparations, C-fibers responding to both mechanical and thermal stimuli (CMH or CMHC) preferentially bound the lectin marker IB4 and were always immunonegative for TRPV1. Conversely, cells that fired robustly to noxious heat, but were insensitive to mechanical stimuli, were TRPV1-positive and IB4-negative. P2Y2 gene deletion resulted in reduced firing by TRPV1-negative CMH fibers to a range of heat stimuli. However, we also identified an atypical population of IB4-negative, TRPV1-positive CMH fibers. Compared to wildtype CMH fibers, these TRPV1-positive neurons exhibited lower firing rates in response to mechanical stimulation, but had increased firing to noxious heat (43-51°C). Collectively, these results demonstrate that P2Y2 contributes to response properties of cutaneous afferents, as P2Y2 deletion reduces responsiveness of conventional unmyelinated polymodal afferents to heat and appears to result in the acquisition of mechanical responsiveness in a subset of TRPV1-expressing afferents.
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Alexandrou AJ, Brown AR, Chapman ML, Estacion M, Turner J, Mis MA, Wilbrey A, Payne EC, Gutteridge A, Cox PJ, Doyle R, Printzenhoff D, Lin Z, Marron BE, West C, Swain NA, Storer RI, Stupple PA, Castle NA, Hounshell JA, Rivara M, Randall A, Dib-Hajj SD, Krafte D, Waxman SG, Patel MK, Butt RP, Stevens EB. Subtype-Selective Small Molecule Inhibitors Reveal a Fundamental Role for Nav1.7 in Nociceptor Electrogenesis, Axonal Conduction and Presynaptic Release. PLoS One 2016; 11:e0152405. [PMID: 27050761 PMCID: PMC4822888 DOI: 10.1371/journal.pone.0152405] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 03/14/2016] [Indexed: 01/08/2023] Open
Abstract
Human genetic studies show that the voltage gated sodium channel 1.7 (Nav1.7) is a key molecular determinant of pain sensation. However, defining the Nav1.7 contribution to nociceptive signalling has been hampered by a lack of selective inhibitors. Here we report two potent and selective arylsulfonamide Nav1.7 inhibitors; PF-05198007 and PF-05089771, which we have used to directly interrogate Nav1.7’s role in nociceptor physiology. We report that Nav1.7 is the predominant functional TTX-sensitive Nav in mouse and human nociceptors and contributes to the initiation and the upstroke phase of the nociceptor action potential. Moreover, we confirm a role for Nav1.7 in influencing synaptic transmission in the dorsal horn of the spinal cord as well as peripheral neuropeptide release in the skin. These findings demonstrate multiple contributions of Nav1.7 to nociceptor signalling and shed new light on the relative functional contribution of this channel to peripheral and central noxious signal transmission.
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Affiliation(s)
- Aristos J. Alexandrou
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Adam R. Brown
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Mark L. Chapman
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Mark Estacion
- Center for Neuroscience & Regeneration Research, Yale Medical School and Veterans Affairs Hospital, West Haven, CT, 06516, United States of America
| | - Jamie Turner
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Malgorzata A. Mis
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Anna Wilbrey
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Elizabeth C. Payne
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Alex Gutteridge
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Peter J. Cox
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Rachel Doyle
- Pfizer Global R&D, Ramsgate Road, Sandwich, Kent, CT13 9NJ, United Kingdom
| | - David Printzenhoff
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Zhixin Lin
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Brian E. Marron
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Christopher West
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Nigel A. Swain
- Worldwide Medicinal Chemistry, Pfizer Neusentis, The Portway Building, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - R. Ian Storer
- Worldwide Medicinal Chemistry, Pfizer Neusentis, The Portway Building, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Paul A. Stupple
- Worldwide Medicinal Chemistry, Pfizer Neusentis, The Portway Building, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
| | - Neil A. Castle
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - James A. Hounshell
- Dept. Anesthesiology, University of Virginia Health System, Charlottesville, Virginia, 22911, United States of America
| | - Mirko Rivara
- Dept. Anesthesiology, University of Virginia Health System, Charlottesville, Virginia, 22911, United States of America
| | - Andrew Randall
- Medical School, Hatherly Building, University of Exeter, Prince of Wales Road, Exeter, EX4 4PS, United Kingdom
| | - Sulayman D. Dib-Hajj
- Center for Neuroscience & Regeneration Research, Yale Medical School and Veterans Affairs Hospital, West Haven, CT, 06516, United States of America
| | - Douglas Krafte
- Pfizer Neusentis, 4222 Emperor Boulevard, Durham, North Carolina, 27703, United States of America
| | - Stephen G. Waxman
- Center for Neuroscience & Regeneration Research, Yale Medical School and Veterans Affairs Hospital, West Haven, CT, 06516, United States of America
| | - Manoj K. Patel
- Dept. Anesthesiology, University of Virginia Health System, Charlottesville, Virginia, 22911, United States of America
| | - Richard P. Butt
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
- * E-mail: (EBS); (RPB)
| | - Edward B. Stevens
- Pfizer Neusentis, The Portway Buiding, Granta Park, Great Abington, Cambridge, CB21 6GS, United Kingdom
- * E-mail: (EBS); (RPB)
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Zhang X, Strassman AM, Novack V, Brin MF, Burstein R. Extracranial injections of botulinum neurotoxin type A inhibit intracranial meningeal nociceptors' responses to stimulation of TRPV1 and TRPA1 channels: Are we getting closer to solving this puzzle? Cephalalgia 2016; 36:875-86. [PMID: 26984967 PMCID: PMC4959034 DOI: 10.1177/0333102416636843] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/09/2016] [Indexed: 12/28/2022]
Abstract
BACKGROUND Administration of onabotulinumtoxinA (BoNT-A) to peripheral tissues outside the calvaria reduces the number of days chronic migraine patients experience headache. Because the headache phase of a migraine attack, especially those preceded by aura, is thought to involve activation of meningeal nociceptors by endogenous stimuli such as changes in intracranial pressure (i.e. mechanical) or chemical irritants that appear in the meninges as a result of a yet-to-be-discovered sequence of molecular/cellular events triggered by the aura, we sought to determine whether extracranial injections of BoNT-A alter the chemosensitivity of meningeal nociceptors to stimulation of their intracranial receptive fields. MATERIAL AND METHODS Using electrophysiological techniques, we identified 161 C- and 135 Aδ-meningeal nociceptors in rats and determined their mechanical response threshold and responsiveness to chemical stimulation of their dural receptive fields with TRPV1 and TRPA1 agonists seven days after BoNT-A administration to different extracranial sites. Two paradigms were compared: distribution of 5 U BoNT-A to the lambdoid and sagittal sutures alone, and 1.25 U to the sutures and 3.75 U to the temporalis and trapezius muscles. RESULTS Seven days after it was administered to tissues outside the calvaria, BoNT-A inhibited responses of C-type meningeal nociceptors to stimulation of their intracranial dural receptive fields with the TRPV1 agonist capsaicin and the TRPA1 agonist mustard oil. BoNT-A inhibition of responses to capsaicin was more effective when the entire dose was injected along the suture lines than when it was injected into muscles and sutures. As in our previous study, BoNT-A had no effect on non-noxious mechanosensitivity of C-fibers or on responsiveness of Aδ-fibers to mechanical and chemical stimulation. DISCUSSION This study demonstrates that extracranial administration of BoNT-A suppresses meningeal nociceptors' responses to stimulation of their intracranial dural receptive fields with capsaicin and mustard oil. The findings suggest that surface expression of TRPV1 and TRPA1 channels in dural nerve endings of meningeal nociceptors is reduced seven days after extracranial administration of BoNT-A. In the context of chronic migraine, reduced sensitivity to molecules that activate meningeal nociceptors through the TRPV1 and TRPA1 channels can be important for BoNT-A's ability to act as a prophylactic.
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Affiliation(s)
- XiChun Zhang
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, USA Harvard Medical School, USA
| | - Andrew M Strassman
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, USA Harvard Medical School, USA
| | - Victor Novack
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, USA Clinical Research Center, Soroka University Medical Center, Israel Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | | | - Rami Burstein
- Department of Anesthesia and Critical Care, Beth Israel Deaconess Medical Center, USA Harvard Medical School, USA
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Probing the Effects and Mechanisms of Electroacupuncture at Ipsilateral or Contralateral ST36-ST37 Acupoints on CFA-induced Inflammatory Pain. Sci Rep 2016; 6:22123. [PMID: 26906464 PMCID: PMC4764889 DOI: 10.1038/srep22123] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/04/2016] [Indexed: 11/23/2022] Open
Abstract
Transient receptor potential vanilloid 1 (TRPV1) and associated signaling pathways have been reported to be increased in inflammatory pain signaling. There are accumulating evidences surrounding the therapeutic effect of electroacupuncture (EA). EA can reliably attenuate the increase of TRPV1 in mouse inflammatory pain models with unclear signaling mechanisms. Moreover, the difference in the clinical therapeutic effects between using the contralateral and ipsilateral acupoints has been rarely studied. We found that inflammatory pain, which was induced by injecting the complete Freund’s adjuvant (CFA), (2.14 ± 0.1, p < 0.05, n = 8) can be alleviated after EA treatment at either ipsilateral (3.91 ± 0.21, p < 0.05, n = 8) or contralateral acupoints (3.79 ± 0.25, p < 0.05, n = 8). EA may also reduce nociceptive Nav sodium currents in dorsal root ganglion (DRG) neurons. The expression of TRPV1 and associated signaling pathways notably increased after the CFA injection; this expression can be further attenuated significantly in EA treatment. TRPV1 and associated signaling pathways can be prevented in TRPV1 knockout mice, suggesting that TRPV1 knockout mice are resistant to inflammatory pain. Through this study, we have increased the understanding of the mechanism that both ipsilateral and contralateral EA might alter TRPV1 and associated signaling pathways to reduce inflammatory pain.
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Abstract
The detection of temperature is one of the most fundamental sensory functions across all species, and is critical for animal survival. Animals have thus evolved a diversity of thermosensory mechanisms allowing them to sense and respond to temperature changes (thermoreception). A key process underlying thermoreception is the translation of thermal energy into electrical signals, a process mediated by thermal sensors (thermoreceptors) that are sensitive to a specific range of temperatures. In disease conditions, the temperature sensitivity of thermoreceptors is altered, leading to abnormal temperature sensation such as heat hyperalgesia. Therefore, the identification of thermal sensors and understanding their functions and regulation hold great potential for developing novel therapeutics against many medical conditions such as pain.
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Affiliation(s)
- Xuming Zhang
- a Rowett Institute of Nutrition and Health & Institute of Medical Sciences ; University of Aberdeen , Foresterhill , Aberdeen , UK
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Baumbauer KM, DeBerry JJ, Adelman PC, Miller RH, Hachisuka J, Lee KH, Ross SE, Koerber HR, Davis BM, Albers KM. Keratinocytes can modulate and directly initiate nociceptive responses. eLife 2015; 4. [PMID: 26329459 PMCID: PMC4576133 DOI: 10.7554/elife.09674] [Citation(s) in RCA: 119] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/28/2015] [Indexed: 01/24/2023] Open
Abstract
How thermal, mechanical and chemical stimuli applied to the skin are transduced into signals transmitted by peripheral neurons to the CNS is an area of intense study. Several studies indicate that transduction mechanisms are intrinsic to cutaneous neurons and that epidermal keratinocytes only modulate this transduction. Using mice expressing channelrhodopsin (ChR2) in keratinocytes we show that blue light activation of the epidermis alone can produce action potentials (APs) in multiple types of cutaneous sensory neurons including SA1, A-HTMR, CM, CH, CMC, CMH and CMHC fiber types. In loss of function studies, yellow light stimulation of keratinocytes that express halorhodopsin reduced AP generation in response to naturalistic stimuli. These findings support the idea that intrinsic sensory transduction mechanisms in epidermal keratinocytes can directly elicit AP firing in nociceptive as well as tactile sensory afferents and suggest a significantly expanded role for the epidermis in sensory processing. DOI:http://dx.doi.org/10.7554/eLife.09674.001 When a person touches a hot saucepan, nerve cells in the skin send a message to the brain that causes the person to pull away quickly. Similar messages alert the brain when the skin comes in contact with an object that is cold or causes pain. These nerve cells also help to transmit information about other sensations like holding a ball. Scientists believe that skin cells may release messages that influence how the nerves in the skin respond to sensations. But it is difficult to distinguish the respective roles of skin cells and nerve cells in experiments because these cells often appear to react at the same time. Researchers have discovered that a technique called optogenetics, which originally developed to study the brain, can help. Optogenetics uses genetic engineering to create skin cells that respond to light instead of touch. Baumbauer, DeBerry, Adelman et al. genetically engineered mice to express a light-sensitive protein in their skin cells. When these skin cells were exposed to light, the mice pulled away just like they would if they were responding to painful contact. This behavior coincided with electrical signals in the nerve cells even though the nerve cells themselves were not light sensitive. In further experiments, mice were genetically engineered to express another protein in their skin cells that prevents the neurons from being able to generate electrical signals. When these skin cells were exposed to light, the surrounding nerve cells produced fewer electrical signals. Together, the experiments show that skin cells are able to directly trigger electrical signals in nerve cells. Baumbauer, DeBerry, Adelman et al.'s findings may help researchers to understand why some patients with particular inflammatory conditions are in pain due to overactive nerve cells. DOI:http://dx.doi.org/10.7554/eLife.09674.002
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Affiliation(s)
- Kyle M Baumbauer
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Jennifer J DeBerry
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Peter C Adelman
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Richard H Miller
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Junichi Hachisuka
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Kuan Hsien Lee
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Sarah E Ross
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - H Richard Koerber
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Brian M Davis
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
| | - Kathryn M Albers
- Department of Neurobiology, Pittsburgh Center for Pain Research, Center for Neuroscience, School of Medicine, University of Pittsburgh, Pittsburgh, United States
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Smith T, Al Otaibi M, Sathish J, Djouhri L. Increased expression of HCN2 channel protein in L4 dorsal root ganglion neurons following axotomy of L5- and inflammation of L4-spinal nerves in rats. Neuroscience 2015; 295:90-102. [DOI: 10.1016/j.neuroscience.2015.03.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 02/28/2015] [Accepted: 03/19/2015] [Indexed: 12/31/2022]
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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
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Thermosensitive transient receptor potential (TRP) channel agonists and their role in mechanical, thermal and nociceptive sensations as assessed using animal models. CHEMOSENS PERCEPT 2015; 8:96-108. [PMID: 26388966 DOI: 10.1007/s12078-015-9176-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION The present paper summarizes research using animal models to investigate the roles of thermosensitive transient receptor potential (TRP) channels in somatosensory functions including touch, temperature and pain. We present new data assessing the effects of eugenol and carvacrol, agonists of the warmth-sensitive TRPV3, on thermal, mechanical and pain sensitivity in rats. METHODS Thermal sensitivity was assessed using a thermal preference test, which measured the amount of time the animal occupied one of two adjacent thermoelectric plates set at different temperatures. Pain sensitivity was assessed as an increase in latency of hindpaw withdrawal away from a noxious thermal stimulus directed to the plantar hindpaw (Hargreaves test). Mechanical sensitivity was assessed by measuring the force exerted by an electronic von Frey filament pressed against the plantar surface that elicited withdrawal. RESULTS Topical application of eugenol and carvacrol did not significantly affect thermal preference, although there was a trend toward avoidance of the hotter surface in a 30 vs. 45°C preference test for rats treated with 1 or 10% eugenol and carvacrol. Both eugenol and carvacrol induced a concentration-dependent increase in thermal withdrawal latency (analgesia), with no significant effect on mechanosensitivity. CONCLUSIONS The analgesic effect of eugenol and carvacrol is consistent with previous studies. The tendency for these chemicals to increase the avoidance of warmer temperatures suggests a possible role for TRPV3 in warmth detection, also consistent with previous studies. Additional roles of other thermosensitive TRP channels (TRPM8 TRPV1, TRPV2, TRPV4, TRPM3, TRPM8, TRPA1, TRPC5) in touch, temperature and pain are reviewed.
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Herrmann S, Schnorr S, Ludwig A. HCN channels--modulators of cardiac and neuronal excitability. Int J Mol Sci 2015; 16:1429-47. [PMID: 25580535 PMCID: PMC4307311 DOI: 10.3390/ijms16011429] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 12/31/2014] [Indexed: 01/06/2023] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels comprise a family of cation channels activated by hyperpolarized membrane potentials and stimulated by intracellular cyclic nucleotides. The four members of this family, HCN1-4, show distinct biophysical properties which are most evident in the kinetics of activation and deactivation, the sensitivity towards cyclic nucleotides and the modulation by tyrosine phosphorylation. The four isoforms are differentially expressed in various excitable tissues. This review will mainly focus on recent insights into the functional role of the channels apart from their classic role as pacemakers. The importance of HCN channels in the cardiac ventricle and ventricular hypertrophy will be discussed. In addition, their functional significance in the peripheral nervous system and nociception will be examined. The data, which are mainly derived from studies using transgenic mice, suggest that HCN channels contribute significantly to cellular excitability in these tissues. Remarkably, the impact of the channels is clearly more pronounced in pathophysiological states including ventricular hypertrophy as well as neural inflammation and neuropathy suggesting that HCN channels may constitute promising drug targets in the treatment of these conditions. This perspective as well as the current therapeutic use of HCN blockers will also be addressed.
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Affiliation(s)
- Stefan Herrmann
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Sabine Schnorr
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Andreas Ludwig
- Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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Calcitonin gene-related peptide is involved in inflammatory pain but not in postoperative pain. Anesthesiology 2014; 121:1068-79. [PMID: 24992521 DOI: 10.1097/aln.0000000000000364] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND The aim of this study was to clarify the roles of calcitonin gene-related peptide (CGRP) in postoperative pain and inflammatory pain. METHODS αCGRP knockout mice that the authors have developed and wild-type mice were used. Pain behaviors were assessed after incision and complete Freund's adjuvant (CFA) injection. Changes in CGRP and c-Fos expression in the dorsal horn were also examined. RESULTS Guarding pain scores in αCGRP knockout mice were lower than those in wild-type mice at 24 h (3.8 ± 1.6 vs. 6.8 ± 1.5, P = 0.044) and 48 h (1.8 ± 1.7 vs. 6.0 ± 1.5, P = 0.001) after CFA injection (n = 8 to 9). Withdrawal latencies to heat stimulation in αCGRP knockout mice were higher than those in wild-type mice at 24 to 72 h after CFA injection (4.9 ± 1.0 vs. 3.4 ± 0.8 at 24 h, P = 0.04; 5.1 ± 0.3 vs. 3.2 ± 0.9 at 48 h, P = 0.047; and 5.4 ± 1.6 vs. 3.5 ± 0.5 s at 72 h, P = 0.045) (n = 11 to 13), but withdrawal thresholds to mechanical stimulation were comparable. CGRP expression was increased at 24 h after CFA injection in wild-type mice, and the c-Fos-positive profile was increased at 4 h after CFA injection (ipsilateral vs. contralateral: 12.3 ± 4.6 vs. 1.3 ± 1.9, P < 0.0001) and maintained at 24 h (10.0 ± 4.1 vs. 0.8 ± 1.3, P < 0.0001) (n = 4 to 6). CONCLUSION These results suggest that contribution of the αCGRP system depends on the modality of pain and the stage of inflammation.
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Petitjean H, Hugel S, Barthas F, Bohren Y, Barrot M, Yalcin I, Schlichter R. Activation of transient receptor potential vanilloid 2-expressing primary afferents stimulates synaptic transmission in the deep dorsal horn of the rat spinal cord and elicits mechanical hyperalgesia. Eur J Neurosci 2014; 40:3189-201. [PMID: 25104469 DOI: 10.1111/ejn.12688] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 05/30/2014] [Accepted: 07/10/2014] [Indexed: 11/29/2022]
Abstract
Probenecid, an agonist of transient receptor vanilloid (TRPV) type 2, was used to evaluate the effects of TRPV2 activation on excitatory and inhibitory synaptic transmission in the dorsal horn (DH) of the rat spinal cord and on nociceptive reflexes induced by thermal heat and mechanical stimuli. The effects of probenecid were compared with those of capsaicin, a TRPV1 agonist. Calcium imaging experiments on rat dorsal root ganglion (DRG) and DH cultures indicated that functional TRPV2 and TRPV1 were expressed by essentially non-overlapping subpopulations of DRG neurons, but were absent from DH neurons and DH and DRG glial cells. Pretreatment of DRG cultures with small interfering RNAs against TRPV2 suppressed the responses to probenecid. Patch-clamp recordings from spinal cord slices showed that probenecid and capsaicin increased the frequencies of spontaneous excitatory postsynaptic currents (sEPSCs) and spontaneous inhibitory postsynaptic currents in a subset of laminae III-V neurons. In contrast to capsaicin, probenecid failed to stimulate synaptic transmission in lamina II. Intrathecal or intraplantar injections of probenecid induced mechanical hyperalgesia/allodynia without affecting nociceptive heat responses. Capsaicin induced both mechanical hyperalgesia/allodynia and heat hyperalgesia. Activation of TRPV1 or TRPV2 in distinct sets of primary afferents increased the sEPSC frequencies in a largely common population of DH neurons in laminae III-V, and might underlie the development of mechanical hypersensitivity following probenecid or capsaicin treatment. However, only TRPV1-expressing afferents facilitated excitatory and/or inhibitory transmission in a subpopulation of lamina II neurons, and this phenomenon might be correlated with the induction of thermal heat hyperalgesia.
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Affiliation(s)
- Hugues Petitjean
- Institut des Neurosciences Cellulaires et Integratives, UPR 3212 Centre National de la Recherche Scientifique, Strasbourg, France; Universite de Strasbourg, 5 rue Blaise Pascal, F-67084, Strasbourg, France
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