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Liu W, Chen QY, Li XH, Zhou Z, Zhuo M. Cortical Tagged Synaptic Long-Term Depression in the Anterior Cingulate Cortex of Adult Mice. J Neurosci 2024; 44:e0028242024. [PMID: 39054067 PMCID: PMC11358531 DOI: 10.1523/jneurosci.0028-24.2024] [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: 01/05/2024] [Revised: 07/02/2024] [Accepted: 07/05/2024] [Indexed: 07/27/2024] Open
Abstract
The anterior cingulate cortex (ACC) is a key cortical region for pain perception and emotion. Different forms of synaptic plasticity, including long-term potentiation (LTP) and long-term depression (LTD), have been reported in the ACC. Synaptic tagging of LTP plays an important role in hippocampus-related associative memory. In this study, we demonstrate that synaptic tagging of LTD is detected in the ACC of adult male and female mice. This form of tagged LTD requires the activation of metabotropic glutamate receptor subtype 1 (mGluR1). The induction of tagged LTD is time-related with the strongest tagged LTD appearing when the interval between two independent stimuli is 30 min. Inhibitors of mGluR1 blocked the induction of tagged LTD; however, blocking N-methyl-d-aspartate receptors did not affect the induction of tagged LTD. Nimodipine, an inhibitor of L-type voltage-gated calcium channels, also blocked tagged LTD. In an animal model of amputation, we found that tagged LTD was either reduced or completely blocked. Together with our previous report of tagged LTP in the ACC, this study strongly suggests that excitatory synapses in the adult ACC are highly plastic. The biphasic tagging of synaptic transmission provides a new form of heterosynaptic plasticity in the ACC which has functional and pathophysiological significance in phantom pain.
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Affiliation(s)
- Weiqi Liu
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
- Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China
| | - Qi-Yu Chen
- Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China
- CAS Key Laboratory of Brain Connectome and Manipulation, Interdisciplinary Center for Brain Information, The Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xu-Hui Li
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
- Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China
| | - Zhaoxiang Zhou
- Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China
- Department of Exercise & Health Science, Xi'an Physical Education University, Xi'an 710068, China
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
- Zhuomin Institute of Brain Research, Qingdao International Academician Park, Qingdao 266000, China
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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Wei HR, Tang L, Yang XL, Chen CM, Li LX, Mao Y, Wang D, Kang F, Qun S, Zhang Z, Cao P, Jin Y. A microglial activation cascade across cortical regions underlies secondary mechanical hypersensitivity to amputation. Cell Rep 2024; 43:113804. [PMID: 38368612 DOI: 10.1016/j.celrep.2024.113804] [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: 02/28/2023] [Revised: 08/03/2023] [Accepted: 01/31/2024] [Indexed: 02/20/2024] Open
Abstract
Neural mechanisms underlying amputation-related secondary pain are unclear. Using in vivo two-photon imaging, three-dimensional reconstruction, and fiber photometry recording, we show that a microglial activation cascade from the primary somatosensory cortex of forelimb (S1FL) to the primary somatosensory cortex of hindlimb (S1HL) mediates the disinhibition and subsequent hyperexcitation of glutamatergic neurons in the S1HL (S1HLGlu), which then drives secondary mechanical hypersensitivity development in ipsilateral hindpaws of mice with forepaw amputation. Forepaw amputation induces rapid S1FL microglial activation that further activates S1HL microglia via the CCL2-CCR2 signaling pathway. Increased engulfment of GABAergic presynapses by activated microglia stimulates S1HLGlu neuronal activity, ultimately leading to secondary mechanical hypersensitivity of hindpaws. It is widely believed direct neuronal projection drives interactions between distinct brain regions to prime specific behaviors. Our study reveals microglial interactions spanning different subregions of the somatosensory cortex to drive a maladaptive neuronal response underlying secondary mechanical hypersensitivity at non-injured sites.
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Affiliation(s)
- Hong-Rui Wei
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Lan Tang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Xin-Lu Yang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Department of Anesthesiology, The First Affiliated Hospital of Wannan Medical College, Wuhu, Anhui 241000, China
| | - Chang-Mao Chen
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Le-Xian Li
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Yu Mao
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Di Wang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Fang Kang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Sen Qun
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zhi Zhang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Center for Advanced Interdisciplinary Science and Biomedicine, Institute of Health and Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
| | - Peng Cao
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
| | - Yan Jin
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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Sparling T, Iyer L, Pasquina P, Petrus E. Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery. J Neurosci 2024; 44:e1051232024. [PMID: 38171645 PMCID: PMC10851691 DOI: 10.1523/jneurosci.1051-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/28/2023] [Accepted: 09/29/2023] [Indexed: 01/05/2024] Open
Abstract
Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.
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Affiliation(s)
- Tawnee Sparling
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Laxmi Iyer
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland 20817
| | - Paul Pasquina
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Emily Petrus
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland 20814
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Manahan-Vaughan D. Special Considerations When Using Mice for In Vivo Electrophysiology and Long-Term Studies of Hippocampal Synaptic Plasticity During Behavior. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2018. [DOI: 10.1016/b978-0-12-812028-6.00003-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Di Giminiani P, Edwards SA, Malcolm EM, Leach MC, Herskin MS, Sandercock DA. Characterization of short- and long-term mechanical sensitisation following surgical tail amputation in pigs. Sci Rep 2017; 7:4827. [PMID: 28684801 PMCID: PMC5500571 DOI: 10.1038/s41598-017-05404-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/26/2017] [Indexed: 12/25/2022] Open
Abstract
Commercial pigs are frequently exposed to tail mutilations in the form of preventive husbandry procedures (tail docking) or as a result of abnormal behaviour (tail biting). Although tissue and nerve injuries are well-described causes of pain hypersensitivity in humans and in rodent animal models, there is no information on the changes in local pain sensitivity induced by tail injuries in pigs. To determine the temporal profile of sensitisation, pigs were exposed to surgical tail resections and mechanical nociceptive thresholds (MNT) were measured in the acute (one week post-operatively) and in the long-term (either eight or sixteen weeks post-surgery) phase of recovery. The influence of the degree of amputation on MNTs was also evaluated by comparing three different tail-resection treatments (intact, ‘short tail’, ‘long tail’). A significant reduction in MNTs one week following surgery suggests the occurrence of acute sensitisation. Long-term hypersensitivity was also observed in tail-resected pigs at either two or four months following surgery. Tail amputation in pigs appears to evoke acute and sustained changes in peripheral mechanical sensitivity, which resemble features of neuropathic pain reported in humans and other species and provides new information on implications for the welfare of animals subjected to this type of injury.
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Affiliation(s)
- Pierpaolo Di Giminiani
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom.
| | - Sandra A Edwards
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Emma M Malcolm
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Matthew C Leach
- School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - Mette S Herskin
- Aarhus University, Department of Animal Science, Au-Foulum, Tjele, Denmark
| | - Dale A Sandercock
- Animal and Veterinary Science Research Group, Scotland's Rural College (SRUC), West Mains Road, Edinburgh, EH16 4SA, United Kingdom
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References. Lab Anim 2016. [DOI: 10.1258/002367703766452985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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GluA1 phosphorylation contributes to postsynaptic amplification of neuropathic pain in the insular cortex. J Neurosci 2015; 34:13505-15. [PMID: 25274827 DOI: 10.1523/jneurosci.1431-14.2014] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Long-term potentiation of glutamatergic transmission has been observed after physiological learning or pathological injuries in different brain regions, including the spinal cord, hippocampus, amygdala, and cortices. The insular cortex is a key cortical region that plays important roles in aversive learning and neuropathic pain. However, little is known about whether excitatory transmission in the insular cortex undergoes plastic changes after peripheral nerve injury. Here, we found that peripheral nerve ligation triggered the enhancement of AMPA receptor (AMPAR)-mediated excitatory synaptic transmission in the insular cortex. The synaptic GluA1 subunit of AMPAR, but not the GluA2/3 subunit, was increased after nerve ligation. Genetic knock-in mice lacking phosphorylation of the Ser845 site, but not that of the Ser831 site, blocked the enhancement of the synaptic GluA1 subunit, indicating that GluA1 phosphorylation at the Ser845 site by protein kinase A (PKA) was critical for this upregulation after nerve injury. Furthermore, A-kinase anchoring protein 79/150 (AKAP79/150) and PKA were translocated to the synapses after nerve injury. Genetic deletion of adenylyl cyclase subtype 1 (AC1) prevented the translocation of AKAP79/150 and PKA, as well as the upregulation of synaptic GluA1-containing AMPARs. Pharmacological inhibition of calcium-permeable AMPAR function in the insular cortex reduced behavioral sensitization caused by nerve injury. Our results suggest that the expression of AMPARs is enhanced in the insular cortex after nerve injury by a pathway involving AC1, AKAP79/150, and PKA, and such enhancement may at least in part contribute to behavioral sensitization together with other cortical regions, such as the anterior cingulate and the prefrontal cortices.
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Watanabe A, Watari R, Ogawa K, Shimizu R, Tanaka Y, Takai N, Nezasa KI, Yamaguchi Y. Using improved serial blood sampling method of mice to study pharmacokinetics and drug-drug interaction. J Pharm Sci 2014; 104:955-961. [PMID: 25452230 DOI: 10.1002/jps.24236] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 09/22/2014] [Accepted: 10/08/2014] [Indexed: 11/06/2022]
Abstract
In pharmacokinetic evaluation of mice, using serial sampling methods rather than a terminal blood sampling method could reduce the number of animals needed and lead to more reliable data by excluding individual differences. In addition, using serial sampling methods can be valuable for evaluation of the drug-drug interaction (DDI) potential of drug candidates. In this study, we established an improved method for serially sampling the blood from one mouse by only one incision of the lateral tail vein, and investigated whether our method could be adapted to pharmacokinetic and DDI studies. After intravenous and oral administration of ibuprofen and fexofenadine (BCS class II and III), the plasma concentration and pharmacokinetic parameters were evaluated by our method and a terminal blood sampling method, with the result that both methods gave comparable results (ibuprofen: 63.8 ± 4.0% and 64.4%, fexofenadine: 6.5 ± 0.7% and 7.9%, respectively, in bioavailability). In addition, our method could be adapted to DDI study for cytochrome P450 and organic anion transporting polypeptide inhibition. These results demonstrate that our method can be useful for pharmacokinetic evaluation from the perspective of reliable data acquisition as well as easy handling and low stress to mice and improve the quality of pharmacokinetic and DDI studies.
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Affiliation(s)
- Ayahisa Watanabe
- Drug Metabolism and Pharmacokinetics, Research Laboratory for Development, Shionogi & Co., Ltd. Toyonaka, Osaka, Japan
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Silverman J, Hendricks G. Sensory neuron development in mouse coccygeal vertebrae and its relationship to tail biopsies for genotyping. PLoS One 2014; 9:e88158. [PMID: 24505409 PMCID: PMC3913764 DOI: 10.1371/journal.pone.0088158] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 01/03/2014] [Indexed: 11/19/2022] Open
Abstract
A common method of genotyping mice is via tissue obtained from tail biopsies. However, there is no available information on the temporal development of sensory neurons in the tail and how their presence or absence might affect the age for performing tail biopsies. The goals of this study were to determine if afferent sensory neurons, and in particular nociceptive neurons, are present in the coccygeal vertebrae at or near the time of birth and if not, when they first can be visualized on or in those vertebrae. Using toluidine blue neuronal staining, transmission electron microscopy, and calcitonin-related gene peptide immunostaining, we found proximal to distal maturation of coccygeal nerve growth in the C57BL/6J mouse. Single nerve bundles were first seen on postpartum day (PPD) 0. On PPD 3 presumptive nociceptive sensory nerve fibers were seen entering the vertebral perichondrium. Neural development continued through the last time point (PPD 7) but at no time were neural fibers seen entering the body of the vertebrae. The effect of age on the development of pain perception in the neonatal mouse is discussed.
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Affiliation(s)
- Jerald Silverman
- Department of Animal Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
- * E-mail:
| | - Gregory Hendricks
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
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Liu MG, Zhuo M. Loss of long-term depression in the insular cortex after tail amputation in adult mice. Mol Pain 2014; 10:1. [PMID: 24398034 PMCID: PMC3912895 DOI: 10.1186/1744-8069-10-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/30/2013] [Indexed: 01/01/2023] Open
Abstract
The insular cortex (IC) is an important forebrain structure involved in pain perception and taste memory formation. Using a 64-channel multi-electrode array system, we recently identified and characterized two major forms of synaptic plasticity in the adult mouse IC: long-term potentiation (LTP) and long-term depression (LTD). In this study, we investigate injury-related metaplastic changes in insular synaptic plasticity after distal tail amputation. We found that tail amputation in adult mice produced a selective loss of low frequency stimulation-induced LTD in the IC, without affecting (RS)-3,5-dihydroxyphenylglycine (DHPG)-evoked LTD. The impaired insular LTD could be pharmacologically rescued by priming the IC slices with a lower dose of DHPG application, a form of metaplasticity which involves activation of protein kinase C but not protein kinase A or calcium/calmodulin-dependent protein kinase II. These findings provide important insights into the synaptic mechanisms of cortical changes after peripheral amputation and suggest that restoration of insular LTD may represent a novel therapeutic strategy against the synaptic dysfunctions underlying the pathophysiology of phantom pain.
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Affiliation(s)
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
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Zhuo M. Cortical depression and potentiation: basic mechanisms for phantom pain. Exp Neurobiol 2012; 21:129-35. [PMID: 23319872 PMCID: PMC3538176 DOI: 10.5607/en.2012.21.4.129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/30/2012] [Indexed: 01/07/2023] Open
Abstract
People experience the feeling of the missing body part long after it has been removed after amputation are known as phantom limb sensations. These sensations can be painful, sometimes becoming chronic and lasting for several years (or called phantom pain). Medical treatment for these individuals is limited. Recent neurobiological investigations of brain plasticity after amputation have revealed new insights into the changes in the brain that may cause phantom limb sensations and phantom pain. In this article, I review recent progresses of the cortical plasticity in the anterior cingulate cortex (ACC), a critical cortical area for pain sensation, and explore how they are related to abnormal sensory sensations such as phantom pain. An understanding of these alterations may guide future research into medical treatment for these disorders.
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Affiliation(s)
- Min Zhuo
- Department of Physiology, Faculty of Medicine, Centre for the Study of Pain, University of Toronto, Medical Sciences Building, King's College Circle, Toronto, Ontario, Canada. ; Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an, China
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Sandercock DA, Gibson IF, Rutherford KMD, Donald RD, Lawrence AB, Brash HM, Scott EM, Nolan AM. The impact of prenatal stress on basal nociception and evoked responses to tail-docking and inflammatory challenge in juvenile pigs. Physiol Behav 2011; 104:728-37. [PMID: 21803065 DOI: 10.1016/j.physbeh.2011.07.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 07/12/2011] [Accepted: 07/13/2011] [Indexed: 10/18/2022]
Abstract
The consequences of tail-docking (at 2-4 days) and prenatal stress (maternal social stress during the 2nd third of pregnancy) on baseline nociceptive thresholds and responses to acute inflammatory challenge were investigated in juvenile pigs in two studies. Nociceptive thresholds were assessed on the tail root and on the hind foot using noxious mechanical and cold stimulation before and after acute inflammatory challenge by intradermal injection of 30 μg capsaicin (study 1) or 3% carrageenan (study 2) into the tail root. Four groups of 8 (study 1, n=14-16 pigs/treatment) or 5 (study 2, n=6 pigs/treatment/sex) week-old pigs were exposed to the main factors: maternal stress and treatment (docked vs. intact tails). In study 1, tail docking did not significantly alter thresholds to noxious mechanical stimulation, whilst prenatally stressed pigs had significantly higher baseline thresholds to noxious mechanical stimulation on the tail root and on the hind foot than unstressed pigs, whether tail-docked or intact. Capsaicin injection induced localised mechanical allodynia around the tail root in all treatment groups, but had no effect on noxious plantar mechanical responses; however prenatally stressed offspring exhibited significantly attenuated response thresholds to capsaicin compared to controls. In study 2 tail docking did not alter thresholds to either mechanical or noxious cold stimulation. Baseline response durations to noxious cold stimulation of the tail root were significantly shorter in both sexes of prenatally stressed pigs, whilst male but not female prenatally stressed pigs exhibited significantly higher baseline thresholds to mechanical stimulation than controls, although results in female pigs tended towards significance. Carrageenan injection into the tail root induced localised mechanical and cold allodynia in all treatment groups, effects that were attenuated in prenatally stressed pigs. Collectively, these findings indicate that prenatal stress can induce long-term alterations in nociceptive responses, manifest as a reduced sensitivity to noxious mechanical and cold stimulation and evoked inflammatory allodynia. Neonatal tail-docking does not lead to long-term alterations in nociception in pigs.
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Affiliation(s)
- Dale A Sandercock
- College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G61 1QH, UK
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Boyette-Davis J, Fuchs PN. Chronic administration of phencyclidine produces decreased sensitivity to mechanical stimulation in the absence of altered affective behavior: Implications for pain processing in schizophrenia. Neurosci Lett 2011; 498:153-7. [DOI: 10.1016/j.neulet.2011.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 04/29/2011] [Accepted: 05/02/2011] [Indexed: 11/16/2022]
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Kasanen IHE, Voipio HM, Leskinen H, Luodonpää M, Nevalainen TO. Comparison of ear tattoo, ear notching and microtattoo in rats undergoing cardiovascular telemetry. Lab Anim 2011; 45:154-9. [PMID: 21504993 DOI: 10.1258/la.2011.010113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Individual and permanent identification of experimental animals is a common and often essential research practice. There is little information available on the short-term effects of these procedures on the animals. In this study, seven rats were implanted with telemetric devices. The effects of three different identification methods (ear tattoo, ear notching and microtattoo) were compared. Cardiovascular data were collected for 24 h after the procedures. Time periods of 0-1, 1-4, 4-16 h (dark) and 16-24 h after the procedure were analysed separately. The most pronounced differences in measured parameters were observed during the first hour after the procedures were performed. Mean arterial pressure (MAP) was significantly higher (P < 0.012) following the ear tattoo than the microtattoo procedure by a difference of approximately 5 mmHg. Heart rate (HR) was significantly elevated (P < 0.001) after ear tattoo compared with both ear notching (Δ = 31 beats per minute [bpm]) and microtattoo (Δ = 44 bpm). During the 1-4 h period and the following dark period, the MAP was highest in the ear notching group, but no differences were observed in the HRs. During the following dark period (4-16 h) and the next day (16-24 h) differences in MAP and HR were minor. In conclusion, microtattoo appears to cause the mildest changes in HR and blood pressure. Based on these results, ear tattoo and ear notching should be replaced by microtattoo whenever possible.
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Affiliation(s)
- I H E Kasanen
- Laboratory Animal Center, University of Eastern Finland, Kuopio, Finland.
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Walker KA, Horning M, Mellish JAE, Weary DM. Behavioural responses of juvenile Steller sea lions to abdominal surgery: Developing an assessment of post-operative pain. Appl Anim Behav Sci 2009. [DOI: 10.1016/j.applanim.2009.06.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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The effects of tail biopsy for genotyping on behavioral responses to nociceptive stimuli. PLoS One 2009; 4:e6457. [PMID: 19649248 PMCID: PMC2714470 DOI: 10.1371/journal.pone.0006457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Accepted: 07/01/2009] [Indexed: 11/18/2022] Open
Abstract
Removal of a small segment of tail at weaning is a common method used to obtain tissue for the isolation of genomic DNA to identify genetically modified mice. When genetically manipulated mice are used for pain research, this practice could result in confounding changes to the animals' responses to noxious stimuli. In this study, we sought to systematically investigate whether tail biopsy representative of that used in standard genotyping methods affects behavioral responses to a battery of tests of nociception. Wild-type littermate C57BL/6J and 129S6 female and male mice received either tail biopsies or control procedural handling at Day 21 after birth and were then tested at 6-9 weeks for mechanical and thermal sensitivity. C57BL/6J mice were also tested in the formalin model of inflammatory pain. In all tests performed (von Frey, Hargreaves, modified Randall Selitto, and formalin), C57BL/6J tail-biopsied animals' behavioral responses were not significantly different from control animals. In 129S6 animals, tail biopsy did not have a significant effect on behavioral responses in either sex to the von Frey and the modified Randall-Selitto tests of mechanical sensitivity. Interestingly, however, both sexes exhibited small but significant differences between tail biopsied and control responses to a radiant heat stimulus. These results indicate that tail biopsy for genotyping purposes has no effect on nocifensive behavioral responses of C57BL/6J mice, and in 129S6 mice, causes only a minor alteration in response to a radiant heat stimulus while other nocifensive behavioral responses are unchanged. The small effect seen is modality- and strain-specific.
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Schaefer DC, Asner IN, Seifert B, Bürki K, Cinelli P. Analysis of physiological and behavioural parameters in mice after toe clipping as newborns. Lab Anim 2009; 44:7-13. [PMID: 19535388 DOI: 10.1258/la.2009.009020] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study, we have investigated the short- and long-term impact of toe clipping, a commonly used method for marking and simultaneously taking biopsies of pups, which is controversially discussed because of its potentially negative impact on animals. Furthermore, we have analysed animal welfare aspects such as health, behaviour, development, stress and detrimental effects in young animals and in adults after toe clipping at postnatal days 3 (P3) and 7 (P7). Our findings indicate that for both P3 and P7 pups amputations at the second phalange of one toe of each paw do not have any negative effects on growth and physical development and that the clipped pups do not suffer from rejection by their mother. Our data indicate that even though at both ages no abnormalities have been detected in histology, clipping at P7 is the preferable age for an adequate marking mostly because of the small size of the toes at P3. This was also confirmed by grip tests at the age of 12 weeks where P3 animals had lower grip strength than control animals, whereas P7 pups did not show any impairment. Hotplate tests indicated that toe clipping performed at P3 and P7 did not cause hyperalgesia at the amputation stump. Serum corticosterone analysis directly performed on P7 pups after clipping indicated that major stress was provoked mainly through the handling and not because of the clipping itself. Taken together, these data lead to the conclusion that toe clipping is from a morphological, physiological and welfare point of view an acceptable method for marking and genotyping newborn mice.
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Affiliation(s)
- Dagmar C Schaefer
- Institute of Laboratory Animal Science, University of Zurich, CH-8057 Zurich, Switzerland
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19
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Wei F, Zhuo M. Activation of Erk in the anterior cingulate cortex during the induction and expression of chronic pain. Mol Pain 2008; 4:28. [PMID: 18651976 PMCID: PMC2503974 DOI: 10.1186/1744-8069-4-28] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Accepted: 07/23/2008] [Indexed: 11/21/2022] Open
Abstract
The extracellular signal-regulated kinase (Erk) activity contributes to synaptic plasticity, a key mechanism for learning, memory and chronic pain. Although the anterior cingulate cortex (ACC) has been reported as an important cortical region for neuronal mechanisms underlying the induction and expression of chronic pain, it has yet to be investigated whether or not Erk activity in the ACC may be affected by peripheral injury or in chronic pain state. In the present study, we use adult rat animal models of inflammatory and neuropathic pain and demonstrate that Erk signaling pathway in the ACC is potently activated after peripheral tissue or nerve injury. Furthermore, we demonstrate that mechanical allodynia significantly activated Erk activity at synaptic sites at two weeks after the injury. We propose a synaptic model for explaining the roles of Erk activity during different phases of chronic pain. Our findings suggest that cortical activation of Erk may contribute to both induction and expression of chronic pain.
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Affiliation(s)
- Feng Wei
- Department of Biomedical Sciences, University of Maryland Dental School, Baltimore, Maryland 20201, USA.
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20
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Viñuela-Fernández I, Jones E, Welsh EM, Fleetwood-Walker SM. Pain mechanisms and their implication for the management of pain in farm and companion animals. Vet J 2007; 174:227-39. [PMID: 17553712 DOI: 10.1016/j.tvjl.2007.02.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Revised: 02/01/2007] [Accepted: 02/01/2007] [Indexed: 12/17/2022]
Abstract
Over the last two decades there has been a dramatic increase in the literature relating to the mechanisms and management of pain in domestic animals. Understanding the mechanisms of pain is crucial for its effective management. This review highlights the current understanding of the neurophysiology of nociception and the plastic changes involved in chronic pain states. Additionally, we describe a range of novel molecules and pathways that offer opportunities for the development of mechanism-based analgesic therapies. Pain management in animals is limited by pain assessment which remains highly subjective, with clinicians relying on indirect measures of pain, using rating scales and (less frequently) quantifiable physiological and behavioural parameters. The need for a systematic approach which would assess different pain components is well justified. Species-specific issues on pain assessment and management in mammalian companion and farm animals are addressed in the later part of this review.
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Affiliation(s)
- Ignacio Viñuela-Fernández
- Division of Veterinary Biomedical Sciences, Royal School of Veterinary Studies, Summerhall, Edinburgh EH9 1QH, UK
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21
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Wu J, Su G, Ma L, Zhang X, Lei Y, Li J, Lin Q, Fang L. Protein kinases mediate increment of the phosphorylation of cyclic AMP-responsive element binding protein in spinal cord of rats following capsaicin injection. Mol Pain 2005; 1:26. [PMID: 16159392 PMCID: PMC1224868 DOI: 10.1186/1744-8069-1-26] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Accepted: 09/13/2005] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Strong noxious stimuli cause plastic changes in spinal nociceptive neurons. Intracellular signal transduction pathways from cellular membrane to nucleus, which may further regulate gene expression by critical transcription factors, convey peripheral stimulation. Cyclic AMP-responsive element binding protein (CREB) is a well-characterized stimulus-induced transcription factor whose activation requires phosphorylation of the Serine-133 residue. Phospho-CREB can further induce gene transcription and strengthen synaptic transmission by the activation of the protein kinase cascades. However, little is known about the mechanisms by which CREB phosphorylation is regulated by protein kinases during nociception. This study was designed to use Western blot analysis to investigate the role of mitogen-activated protein (MAP)/extracellular signal-regulated kinase (ERK) kinase (MEK 1/2), PKA and PKC in regulating the phosphorylation of CREB in the spinal cord of rats following intraplantar capsaicin injection. RESULTS We found that capsaicin injection significantly increased the phosphorylation level of CREB in the ipsilateral side of the spinal cord. Pharmacological manipulation of MEK 1/2, PKA and PKC with their inhibitors (U0126, H89 and NPC 15473, respectively) significantly blocked this increment of CREB phosphorylation. However, the expression of CREB itself showed no change in any group. CONCLUSION These findings suggest that the activation of intracellular MAP kinase, PKA and PKC cascades may contribute to the regulation of phospho-CREB in central nociceptive neurons following peripheral painful stimuli.
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Affiliation(s)
- Jing Wu
- Department of Neurology, University of Texas Health Science Center, Houston, TX77030-1501, USA
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-1043, USA
| | - Guangxiao Su
- Division of Neurosurgery, Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555-0517; USA
| | - Long Ma
- Division of Neurosurgery, Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555-0517; USA
| | - Xuan Zhang
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-1043, USA
| | - Yongzhong Lei
- Division of Neurosurgery, Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555-0517; USA
| | - Junfa Li
- Institute for Biomedical Science of Pain, Department of Neurobiology, Capital University of Medical Sciences, Beijing 100054, China
| | - Qing Lin
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-1043, USA
| | - Li Fang
- Division of Neurosurgery, Department of Surgery, The University of Texas Medical Branch, Galveston, TX 77555-0517; USA
- Department of Neuroscience and Cell Biology, The University of Texas Medical Branch, Galveston, TX 77555-1043, USA
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22
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Hargraves WA, Hentall ID. Analgesic effects of dietary caloric restriction in adult mice. Pain 2005; 114:455-461. [PMID: 15777870 DOI: 10.1016/j.pain.2005.01.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 12/06/2004] [Accepted: 01/18/2005] [Indexed: 11/29/2022]
Abstract
Nociception was studied in male mice, mostly of the C57BL/6 strain, during continuous or prolonged restriction of caloric intake (60% of ad-libitum) from midlife to senescence (up to 105 weeks). Restricted mice showed fewer licking or biting responses 20-60 min after hind paw injection of 5% formalin at 46 and 70 weeks, but not at 93 weeks. Also, they showed longer response latencies around 46 weeks of age in the 52 degrees C hot-plate test, which partial tail amputation failed to affect, although it did produce at least 2 weeks of chronic neuropathic hypersensitivity in ad libitum controls. Injection of collagen subcutaneously at 36-42 weeks led to chronic hyperalgesia in the DBA/1 but not the C57BL/6 strain, measured weekly by the barely nociceptive 50 degrees C hot-plate test to minimize damage. This collagen-induced arthritic hyperalgesia was then gradually and reversibly blocked during 9-15 weeks of caloric restriction starting at 53-58 weeks. In longitudinal trials on normal mice, performed every 2-4 weeks between 42 and 105 weeks with the 50 degrees C hot-plate, caloric restriction led to altered latencies (higher relative to controls) only in the last 10-20 weeks, perhaps because it delayed the onset of age-related peripheral neuropathies. In conclusion, long-term caloric restriction leads to significant hypoalgesia in pre-senescent mice subjected to above-threshold pain of widely different durations, the effect disappearing at later ages unless spontaneous neuropathies become influential. A reduction in cumulative food intake thus appears to generate antinociceptive signals in adult male mice, perhaps serving specifically to promote riskier behavior during prolonged food shortages.
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23
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Kim SJ, Qu Z, Milbrandt J, Zhuo M. A transcription factor for cold sensation! Mol Pain 2005; 1:11. [PMID: 15813958 PMCID: PMC1079937 DOI: 10.1186/1744-8069-1-11] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Accepted: 03/22/2005] [Indexed: 11/17/2022] Open
Abstract
The ability to feel hot and cold is critical for animals and human beings to survive in the natural environment. Unlike other sensations, the physiology of cold sensation is mostly unknown. In the present study, we use genetically modified mice that do not express nerve growth factor-inducible B (NGFIB) to investigate the possible role of NGFIB in cold sensation. We found that genetic deletion of NGFIB selectively affected behavioral responses to cold stimuli while behavioral responses to noxious heat or mechanical stimuli were normal. Furthermore, behavioral responses remained reduced or blocked in NGFIB knockout mice even after repetitive application of cold stimuli. Our results provide strong evidence that the first transcription factor NGFIB determines the ability of animals to respond to cold stimulation.
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Affiliation(s)
- Susan J Kim
- Department of Physiology, University of Toronto, Medical Sciences Bldg, Rm 3342, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Zhican Qu
- Washington University, Departments of Pathology and Psychiatry, St. Louis, MO 63110, USA
| | - Jeffrey Milbrandt
- Washington University, Departments of Pathology and Psychiatry, St. Louis, MO 63110, USA
| | - Min Zhuo
- Department of Physiology, University of Toronto, Medical Sciences Bldg, Rm 3342, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
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24
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Miao FJP, Green PG, Benowitz N, Levine JD. Central terminals of nociceptors are targets for nicotine suppression of inflammation. Neuroscience 2004; 123:777-84. [PMID: 14706790 DOI: 10.1016/j.neuroscience.2003.10.027] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Spinal intrathecal administration of nicotine inhibits bradykinin-induced plasma extravasation, a component of the inflammatory response, in the knee joint of the rat in a dose-related fashion. Nociceptors contain nicotinic receptors and activation of a nociceptor at its peripheral terminal, by capsaicin, also produces inhibition of inflammation. Therefore the aim of this study was to test the hypothesis that the spinal target for this effect of nicotine is the central terminal of the primary afferent nociceptor. Intrathecal administration of the neurokinin-1 receptor antagonist, (3aR,7aR)-7,7-diphenyl-2-(1-imino-2(2-methoxyphenyl)-ethyl) perhydroisoindol-4-1 hydrochloride or the N-methyl-D-aspartate receptor antagonist, DL-2-amino-5-phosphonovaleric acid, both antagonists of the action of primary afferent neurotransmitters, markedly attenuated the inhibition of bradykinin-induced plasma extravasation produced by both intrathecal nicotine and intraplantar capsaicin.Conversely, intrathecal administration of an alpha-adrenoceptor antagonist, phentolamine or an opioid receptor antagonist, naloxone, to block descending antinociceptive controls, which provide inhibitory input to primary afferent nociceptors, enhanced the action of both nicotine and capsaicin. These findings support the hypothesis that the central terminal of the primary afferent nociceptor is a CNS target at which nicotine acts to inhibit inflammation.
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Affiliation(s)
- F J P Miao
- NIH Pain Center UCSF, University of California at San Francisco, Schools of Medicine and Dentistry, 521 Parnassus Avenue, 94143-0440, San Francisco, CA, USA
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25
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Abstract
Despite the improved survival of tiny preterm neonates, their neurodevelopmental outcomes remain a cause for grave concern. The authors propose two primary mechanisms leading to enhanced neuronal cell death in the immature brain: (1) NMDA-mediated excitotoxicity resulting from repetitive or prolonged pain, and (2) enhanced naturally occurring neuronal apoptosis during early development due to multiple metabolic stresses or lack of social stimulation. The pattern and magnitude of abnormalities will depend on genetic variability as well as the timing, intensity, and duration of adverse environmental experiences. Thus, cumulative brain damage during infancy will finally lead to reductions in brain volume, abnormal behavioral and neuroendocrine regulation, and poor cognitive outcomes during childhood and adolescence. The public health and economic importance of preventing or ameliorating the subtle brain damage caused by these mechanisms cannot be overestimated. This certainly justifies concerted efforts by neuroscientists and clinicians to investigate the mechanisms underlying early neuronal injury, to minimize the impact of adverse experiences and environmental factors in neonates, and to develop novel therapeutic strategies for improving the cognitive and behavioral outcomes of ex-preterm neonates.
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Affiliation(s)
- Adnan T Bhutta
- University of Arkansas for Medical Sciences, Arkansas Children's Hospital, 800 Marshall Street, Little Rock, AR 72202, USA
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26
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Robinson DA, Wei F, Wang GD, Li P, Kim SJ, Vogt SK, Muglia LJ, Zhuo M. Oxytocin mediates stress-induced analgesia in adult mice. J Physiol 2002; 540:593-606. [PMID: 11956346 PMCID: PMC2290243 DOI: 10.1113/jphysiol.2001.013492] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2001] [Accepted: 01/23/2002] [Indexed: 11/08/2022] Open
Abstract
As a neurohormone and as a neurotransmitter, oxytocin has been implicated in the stress response. Descending oxytocin-containing fibres project to the dorsal horn of the spinal cord, an area important for processing nociceptive inputs. Here we tested the hypothesis that oxytocin plays a role in stress-induced analgesia and modulates spinal sensory transmission. Mice lacking oxytocin exhibited significantly reduced stress-induced antinociception following both cold-swim (10 degrees C, 3 min) and restraint stress (30 min). In contrast, the mice exhibited normal behavioural responses to thermal and mechanical noxious stimuli and morphine-induced antinociception. In wild-type mice, intrathecal injection of the oxytocin antagonist dOVT (200 microM in 5 microl) significantly attenuated antinociception induced by cold-swim. Immunocytochemical staining revealed that, in the mouse, oxytocin-containing neurones in the paraventricular nucleus of the hypothalamus are activated by stress. Furthermore, oxytocin-containing fibres were present in the dorsal horn of the spinal cord. To test whether descending oxytocin-containing fibres could alter nociceptive transmission, we performed intracellular recordings of dorsal horn neurones in spinal slices from adult mice. Bath application of oxytocin (1 and 10 microM) inhibited excitatory postsynaptic potentials (EPSPs) evoked by dorsal root stimulation. This effect was reversed by the oxytocin antagonist dOVT (1 microM). Whole-cell recordings of dorsal horn neurones in postnatal rat slices revealed that the effect of oxytocin could be blocked by the addition of GTP-gamma-S to the recording pipette, suggesting activation of postsynaptic oxytocin receptors. We conclude that oxytocin is important for both cold-swim and restraint stress-induced antinociception, acting by inhibiting glutamatergic spinal sensory transmission.
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Affiliation(s)
- D A Robinson
- Department of Anesthesiology, Washington University Pain Center, Washington University, St Louis, MO 63110, USA
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27
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Abstract
Pain management has become an increasingly well researched area in medicine over recent years, and there have been advances in a number of areas. While opioids remain an integral part of pain-management strategies, there is now an emphasis on the use of adjuvant drugs, such as paracetamol and anti-inflammatory agents, which through physiological or pharmacological synergism, both enhance pain control and reduce opioid use. The management of neuropathic pain continues to be a challenge. Anti-epileptics and antidepressants, together with clonidine and ketamine, provide the foundations for treatment. Another area of interest has been the widespread use of patient-controlled analgesia and the administration of some drugs, especially opioids, by means other than traditional oral and parenteral routes. The number of new drugs that have reached the stage of clinical trials has been small, yet they offer exciting possibilities. The epibatidine analogue ABT-594 and zinconitide both offer novel approaches to the management of neuropathic pain states, while selective cyclo-oxygenase-2 inhibitors and nitroaspirins may see advances in the management of nociceptive pain states.
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Affiliation(s)
- R D MacPherson
- Department of Anaesthesia and Pain Management, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia.
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28
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Wei F, Xu ZC, Qu Z, Milbrandt J, Zhuo M. Role of EGR1 in hippocampal synaptic enhancement induced by tetanic stimulation and amputation. J Cell Biol 2000; 149:1325-34. [PMID: 10871275 PMCID: PMC2175137 DOI: 10.1083/jcb.149.7.1325] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Hippocampal neurons fire spikes when an animal is at a particular location or performs certain behaviors in a particular place, providing a cellular basis for hippocampal involvement in spatial learning and memory. In a natural environment, spatial memory is often associated with potentially dangerous sensory experiences such as noxious or painful stimuli. The central sites for such pain-associated memory or plasticity have not been identified. Here we present evidence that excitatory glutamatergic synapses within the CA1 region of the hippocampus may play a role in storing pain-related information. Peripheral noxious stimulation induced excitatory postsynaptic potentials (EPSPs) in CA1 pyramidal cells in anesthetized animals. Tissue/nerve injury caused a rapid increase in the level of the immediate-early gene product Egr1 (also called NGFI-A, Krox24, or zif/268) in hippocampal CA1 neurons. In parallel, synaptic potentiation induced by a single tetanic stimulation (100 Hz for 1 s) was enhanced after the injury. This enhancement of synaptic potentiation was absent in mice lacking Egr1. Our data suggest that Egr1 may act as an important regulator of pain-related synaptic plasticity within the hippocampus.
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Affiliation(s)
- Feng Wei
- Departments of Anesthesiology, Anatomy and Neurobiology
| | - Zao C. Xu
- Department of Anatomy, Indiana University, Indianapolis, Indiana 46202
| | - Zhican Qu
- Department of Pathology, Washington University, St. Louis, Missouri 63110
| | - Jeffrey Milbrandt
- Department of Pathology, Washington University, St. Louis, Missouri 63110
| | - Min Zhuo
- Departments of Anesthesiology, Anatomy and Neurobiology
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29
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Blandl T, Warder SE, Prorok M, Castellino FJ. Structure-function relationships of the NMDA receptor antagonist peptide, conantokin-R. FEBS Lett 2000; 470:139-46. [PMID: 10734223 DOI: 10.1016/s0014-5793(00)01309-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Conantokin-R (con-R) is a gamma-carboxyglutamate-containing 27-residue neuroactive peptide present in the venom of Conus radiatus, and acts as a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor. This peptide features a single disulfide bond, a type of structural element found in most classes of conotoxins, but not in other conantokins. The NMDA receptor antagonist activity of chemically synthesized con-R was determined through an assay involving inhibition of the spermine-enhanced binding of the NMDA receptor channel blocker, [(3)H]MK-801, to rat brain membranes, and yielded an IC(50) of 93 nM. This value represents a 2-5 times better potency than con-G or con-T, the other two characterized conantokins. Circular dichroism (CD) analysis of the metal-free form of con-R is indicative of a low alpha-helical content. There is an increase in alpha-helicity upon the addition of divalent cations, such as Ca(2+), Mg(2+), or Zn(2+). Isothermal titration calorimetry experiments showed one detectable Mg(2+) binding site with a K(d) of 6.5 microM, and two binding sites for Zn(2+), with K(d) values of 150 nM and 170 microM. Residue-specific information of the conformational state of con-R was obtained by two-dimensional (1)H-NMR. Analyses of the alpha-proton chemical shifts, NOE patterns, and hydrogen exchange rates of the peptide indicated an alpha-helical conformation for residues 1-19. Synthetic con-R-derived peptide variants, containing deletions of 7 and 10 amino acid residues from the carboxy-terminus of the wild-type peptide, displayed unaltered cation binding and NMDA receptor antagonist properties. The alpha-helical secondary structures of the two truncation peptides were more stable than full-length con-R, as evidenced by CD measurements and reduced backbone hydrogen exchange rates. These results provide experimental evidence that the structural elements common to the three conantokins thus far identified are the primary determinants for receptor function and cation binding/secondary structure stability.
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Affiliation(s)
- T Blandl
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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30
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Abstract
We investigated behavioral responses to noxious cold and heat stimuli in mice. Similar to the hot-plate test, mice showed licking or jumping responses on a cold-plate (0 degrees C). The sensitivity to noxious heat (55 degrees C) was not correlated to the sensitivity to noxious cold, indicating that nociceptive processing of cold and heat are different. Behavioral responses to noxious cold are inhibited by systemic morphine or intrathecal administration of morphine. Lesion of the medial frontal cortex, including the anterior cingulate cortex, or selective activation of two types of opioid receptors in the anterior cingulate cortex produces dose-dependent antinociceptive effects on behavioral responses to noxious cold stimuli. These results suggest that activation of opioid receptors in the anterior cingulate cortex can produce powerful antinociception.
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Affiliation(s)
- D E Lee
- Department of Anesthesiology, Washington University Medical Center, Washington University in St. Louis, St. Louis, MO 63110, USA
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31
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Li P, Wilding TJ, Kim SJ, Calejesan AA, Huettner JE, Zhuo M. Kainate-receptor-mediated sensory synaptic transmission in mammalian spinal cord. Nature 1999; 397:161-4. [PMID: 9923678 DOI: 10.1038/16469] [Citation(s) in RCA: 213] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Glutamate, the major excitatory neurotransmitter in the central nervous system, activates three different receptors that directly gate ion channels, namely receptors for AMPA (alpha-amino-3-hydroxy-5-methyl isoxozole propionic acid), NMDA (N-methyl-D-aspartate), and kainate, a structural analogue of glutamate. The contribution of AMPA and NMDA receptors to synaptic transmission and plasticity is well established. Recent work on the physiological function of kainate receptors has focused on the hippocampus, where repetitive activation of the mossy-fibre pathway generates a slow, kainate-receptor-mediated excitatory postsynaptic current (EPSC). Here we show that high-intensity single-shock stimulation (of duration 200 microseconds) of primary afferent sensory fibres produces a fast, kainate-receptor-mediated EPSC in the superficial dorsal horn of the spinal cord. Activation of low-threshold afferent fibres generates typical AMPA-receptor-mediated EPSCs only, indicating that kainate receptors may be restricted to synapses formed by high-threshold nociceptive (pain-sensing) and thermoreceptive primary afferent fibres. Consistent with this possibility, kainate-receptor-mediated EPSCs are blocked by the analgesic mu-opiate-receptor agonist Damgo and spinal blockade of both kainate and AMPA receptors produces antinociception. Thus, spinal kainate receptors contribute to transmission of somatosensory inputs from the periphery to the brain.
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Affiliation(s)
- P Li
- Department of Anesthesiology, Washington University in St Louis, Missouri 63110, USA
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