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Witkin JM, Radin DP, Rana S, Fuller DD, Fusco AF, Demers JC, Pradeep Thakre P, Smith JL, Lippa A, Cerne R. AMPA receptors play an important role in the biological consequences of spinal cord injury: Implications for AMPA receptor modulators for therapeutic benefit. Biochem Pharmacol 2024:116302. [PMID: 38763261 DOI: 10.1016/j.bcp.2024.116302] [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: 03/04/2024] [Revised: 05/07/2024] [Accepted: 05/16/2024] [Indexed: 05/21/2024]
Abstract
Spinal cord injury (SCI) afflicts millions of individuals globally. There are few therapies available to patients. Ascending and descending excitatory glutamatergic neural circuits in the central nervous system are disrupted by SCI, making α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) a potential therapeutic drug target. Emerging research in preclinical models highlights the involvement of AMPARs in vital processes following SCI including breathing, pain, inflammation, bladder control, and motor function. However, there are no clinical trial data reported in this patient population to date. No work on the role of AMPA receptors in sexual dysfunction after SCI has been disclosed. Compounds with selective antagonist and potentiating effects on AMPA receptors have benefit in animal models of SCI, with antagonists generally showing protective effects early after injury and potentiators (ampakines) producing improved breathing and bladder function. The role of AMPARs in pathophysiology and recovery after SCI depends upon the time post injury, and the timing of AMPAR augmentation or antagonism. The roles of inflammation, synaptic plasticity, sensitization, neurotrophic factors, and neuroprotection are considered in this context. The data summarized and discussed in this paper document proof of principle and strongly encourage additional studies on AMPARs as novel gateways to therapeutic benefit for patients suffering from SCI. The availability of both AMPAR antagonists such as perampanel and AMPAR allosteric modulators (i.e., ampakines) such as CX1739, that have been safely administered to humans, provides an expedited means of clinical inquiry for possible therapeutic advances.
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Affiliation(s)
- Jeffrey M Witkin
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; Departments of Neuroscience and Trauma Research, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA.
| | | | - Sabhya Rana
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - David D Fuller
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Anna F Fusco
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Julie C Demers
- Indiana University/Purdue University, Indianapolis, IN, USA
| | - Prajwal Pradeep Thakre
- Department of Physical Therapy, University of Florida, Gainesville, FL, USA; McKnight Brain Institute, University of Florida, Gainesville, FL, USA; Breathing Research and Therapeutics Center, University of Florida, Gainesville, FL, USA
| | - Jodi L Smith
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA
| | - Arnold Lippa
- RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA
| | - Rok Cerne
- Laboratory of Antiepileptic Drug Discovery, Ascension St. Vincent Hospital, Indianapolis, IN, USA; RespireRx Pharmaceuticals Inc, Glen Rock, NJ, USA; Faculty of Medicine, University of Ljubljana, Zaloška Cesta 4, Ljubljana, Slovenia
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Wu Z, Shen Z, Xu Y, Chen S, Xiao S, Ye J, Zhang H, Ma X, Zhu Y, Zhu X, Jiang Y, Fang J, Liu B, He X, Gao S, Shao X, Liu J, Fang J. A neural circuit associated with anxiety-like behaviors induced by chronic inflammatory pain and the anxiolytic effects of electroacupuncture. CNS Neurosci Ther 2024; 30:e14520. [PMID: 38018559 PMCID: PMC11017463 DOI: 10.1111/cns.14520] [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: 07/21/2023] [Revised: 10/14/2023] [Accepted: 10/22/2023] [Indexed: 11/30/2023] Open
Abstract
AIMS Negative emotions induced by chronic pain are a serious clinical problem. Electroacupuncture (EA) is a clinically proven safe and effective method to manage pain-related negative emotions. However, the circuit mechanisms underlying the effect of EA treatment on negative emotions remain unclear. METHODS Plantar injection of complete Freund's adjuvant (CFA) was performed to establish a rat model of chronic inflammatory pain-induced anxiety-like behaviors. Adeno-associated virus (AAV) tracing was used to identify excitatory synaptic transmission from the rostral anterior cingulate cortex (rACC) to the dorsal raphe nucleus (DRN). Employing chemogenetic approaches, we examined the role of the rACC-DRN circuit in chronic pain-induced anxiety-like behaviors and investigated whether EA could reverse chronic pain-induced dysfunctions of the rACC-DRN circuit and anxiety-like behaviors. RESULTS We found that chemogenetic activation of the rACC-DRN circuit alleviated CFA-induced anxiety-like behaviors, while chemogenetic inhibition of the rACC-DRN circuit resulted in short-term CFA-induced anxiety-like behaviors. Further research revealed that the development of CFA-induced anxiety-like behaviors was attributed to the dysfunction of rACC CaMKII neurons projecting to DRN serotonergic neurons (rACCCaMKII-DRN5-HT neurons) but not rACC CaMKII neurons projecting to DRN GABAergic neurons (rACCCaMKII-DRNGABA neurons). This is supported by the findings that chemogenetic activation of the rACCCaMKII-DRN5-HT circuit alleviates anxiety-like behaviors in rats with chronic pain, whereas neither chemogenetic inhibition nor chemogenetic activation of the rACCCaMKII-DRNGABA circuit altered CFA chronic pain-evoked anxiety-like behaviors in rats. More importantly, we found that EA could reverse chronic pain-induced changes in the activity of rACC CaMKII neurons and DRN 5-HTergic neurons and that chemogenetic inhibition of the rACCCaMKII-DRN5-HT circuit blocked the therapeutic effects of EA on chronic pain-induced anxiety-like behaviors. CONCLUSIONS Our data suggest that the reversal of rACCCaMKII-DRN5-HT circuit dysfunction may be a mechanism underlying the therapeutic effect of EA on chronic pain-induced anxiety-like behaviors.
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Affiliation(s)
- Zemin Wu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Department of Acupuncture and Moxibustionthe First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Zui Shen
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yingling Xu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Liangzhu LaboratoryZhejiang University Medical CenterHangzhouChina
| | - Shaozong Chen
- Institution of Acupuncture and Moxibustion, Shandong University of Traditional Chinese MedicineJinanChina
| | - Siqi Xiao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Jiayu Ye
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Haiyan Zhang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xinyi Ma
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yichen Zhu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xixiao Zhu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Yongliang Jiang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Junfan Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Boyi Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Xiaofen He
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Shuzhong Gao
- Institution of Acupuncture and Moxibustion, Shandong University of Traditional Chinese MedicineJinanChina
| | - Xiaomei Shao
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
| | - Jinggen Liu
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- National Key Laboratory of Drug ResearchShanghai Institute of Materia Medica, Chinese Academy of SciencesShanghaiChina
- Key Laboratory of Neuropharmacology and Translational Medicine of Zhejiang Province, School of Pharmaceutical SciencesZhejiang Chinese Medical UniversityHangzhouChina
| | - Jianqiao Fang
- Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Department of Neurobiology and Acupuncture ResearchThe Third Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
- Department of Acupuncture and Moxibustionthe First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhouChina
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Current Understanding of the Neural Circuitry in the Comorbidity of Chronic Pain and Anxiety. Neural Plast 2022; 2022:4217593. [PMID: 35211169 PMCID: PMC8863453 DOI: 10.1155/2022/4217593] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 01/13/2022] [Accepted: 01/27/2022] [Indexed: 12/11/2022] Open
Abstract
Chronic pain patients often develop mental disorders, and anxiety disorders are common. We hypothesize that the comorbid anxiety results from an imbalance between the reward and antireward system due to persistent pain, which leads to the dysfunction of the pain and anxiety regulatory system. In this review, we will focus on changes in neuroplasticity, especially in neural circuits, during chronic pain and anxiety as observed in animal studies. Several neural circuits within specific regions of the brain, including the nucleus accumbens, lateral habenular, parabrachial nucleus, medial septum, anterior cingulate cortex, amygdala, hippocampus, medial prefrontal cortex, and bed nucleus of the stria terminalis, will be discussed based on novel findings after chemogenetic or optogenetic manipulation. We believe that these animal studies provide novel insights into human conditions and can guide clinical practice.
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Neural Plasticity in the Brain during Neuropathic Pain. Biomedicines 2021; 9:biomedicines9060624. [PMID: 34072638 PMCID: PMC8228570 DOI: 10.3390/biomedicines9060624] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 01/02/2023] Open
Abstract
Neuropathic pain is an intractable chronic pain, caused by damage to the somatosensory nervous system. To date, treatment for neuropathic pain has limited effects. For the development of efficient therapeutic methods, it is essential to fully understand the pathological mechanisms of neuropathic pain. Besides abnormal sensitization in the periphery and spinal cord, accumulating evidence suggests that neural plasticity in the brain is also critical for the development and maintenance of this pain. Recent technological advances in the measurement and manipulation of neuronal activity allow us to understand maladaptive plastic changes in the brain during neuropathic pain more precisely and modulate brain activity to reverse pain states at the preclinical and clinical levels. In this review paper, we discuss the current understanding of pathological neural plasticity in the four pain-related brain areas: the primary somatosensory cortex, the anterior cingulate cortex, the periaqueductal gray, and the basal ganglia. We also discuss potential treatments for neuropathic pain based on the modulation of neural plasticity in these brain areas.
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Li XH, Chen QY, Zhuo M. Neuronal Adenylyl Cyclase Targeting Central Plasticity for the Treatment of Chronic Pain. Neurotherapeutics 2020; 17:861-873. [PMID: 32935298 PMCID: PMC7609634 DOI: 10.1007/s13311-020-00927-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2020] [Indexed: 12/16/2022] Open
Abstract
Chronic pain is a major health problem and the effective treatment for chronic pain is still lacking. The recent crisis created by the overuse of opioids for pain treatment has clearly shown the need for non-addictive novel pain medicine. Conventional pain medicines usually inhibit peripheral nociceptive transmission and reduce central transmission, especially pain-related excitatory transmission. For example, both opioids and gabapentin produce analgesic effects by inhibiting the release of excitatory transmitters and reducing neuronal excitability. Here, we will review recent studies of central synaptic plasticity contributing to central sensitization in chronic pain. Neuronal selective adenylyl cyclase subtype 1 (AC1) is proposed to be a key intracellular protein that causes both presynaptic and postsynaptic forms of long-term potentiation (LTP). Inhibiting the activity of AC1 by selective inhibitor NB001 blocks behavioral sensitization and injury-related anxiety in animal models of chronic pain. We propose that inhibiting injury-related LTPs will provide new mechanisms for designing novel medicines for the treatment of chronic pain and its related emotional disorders.
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Affiliation(s)
- Xu-Hui Li
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, Shandong China
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi China
- Department of Physiology, Faculty of Medicine, University of Toronto, Medical Science Building, 1 King’s College Circle, Toronto, Ontario M5S 1A8 Canada
| | - Qi-Yu Chen
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, Shandong China
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi China
| | - Min Zhuo
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, Shandong China
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi’an Jiaotong University, Xi’an, 710049 Shaanxi China
- Department of Physiology, Faculty of Medicine, University of Toronto, Medical Science Building, 1 King’s College Circle, Toronto, Ontario M5S 1A8 Canada
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Ko HG, Ye S, Han DH, Park P, Lim CS, Lee K, Zhuo M, Kaang BK. Transcription-independent expression of PKMζ in the anterior cingulate cortex contributes to chronically maintained neuropathic pain. Mol Pain 2018; 14:1744806918783943. [PMID: 29923456 PMCID: PMC6024534 DOI: 10.1177/1744806918783943] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Protein kinase M ζ is well known for its role in maintaining memory and pain. Previously, we revealed that the activation of protein kinase M ζ in the anterior cingulate cortex plays a role in sustaining neuropathic pain. However, the mechanism by which protein kinase M ζ is expressed in the anterior cingulate cortex by peripheral nerve injury, and whether blocking of protein kinase M ζ using its inhibitor, zeta inhibitory peptide, produces analgesic effects in neuropathic pain maintained chronically after injury, have not previously been resolved. In this study, we show that protein kinase M ζ expression in the anterior cingulate cortex is enhanced by peripheral nerve injury in a transcription-independent manner. We also reveal that the inhibition of protein kinase M ζ through zeta inhibitory peptide treatment is enough to reduce mechanical allodynia responses in mice with one-month-old nerve injuries. However, the zeta inhibitory peptide treatment was only effective for a limited time.
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Affiliation(s)
- Hyoung-Gon Ko
- 1 School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sanghyun Ye
- 1 School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Dae-Hee Han
- 1 School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Pojeong Park
- 1 School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Chae-Seok Lim
- 2 Department of Pharmacology, Wonkwang University School of Medicine, Iksan, Republic of Korea
| | - Kyungmin Lee
- 3 Department of Anatomy, Graduate School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Min Zhuo
- 4 Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.,5 Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an, China
| | - Bong-Kiun Kaang
- 1 School of Biological Sciences, Seoul National University, Seoul, Republic of Korea.,5 Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an, China
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Russo JF, Sheth SA. Deep brain stimulation of the dorsal anterior cingulate cortex for the treatment of chronic neuropathic pain. Neurosurg Focus 2016; 38:E11. [PMID: 26030699 DOI: 10.3171/2015.3.focus1543] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chronic neuropathic pain is estimated to affect 3%-4.5% of the worldwide population. It is associated with significant loss of productive time, withdrawal from the workforce, development of mood disorders such as depression and anxiety, and disruption of family and social life. Current medical therapeutics often fail to adequately treat chronic neuropathic pain. Deep brain stimulation (DBS) targeting subcortical structures such as the periaqueductal gray, the ventral posterior lateral and medial thalamic nuclei, and the internal capsule has been investigated for the relief of refractory neuropathic pain over the past 3 decades. Recent work has identified the dorsal anterior cingulate cortex (dACC) as a new potential neuromodulation target given its central role in cognitive and affective processing. In this review, the authors briefly discuss the history of DBS for chronic neuropathic pain in the United States and present evidence supporting dACC DBS for this indication. They review existent literature on dACC DBS and summarize important findings from imaging and neurophysiological studies supporting a central role for the dACC in the processing of chronic neuropathic pain. The available neurophysiological and empirical clinical evidence suggests that dACC DBS is a viable therapeutic option for the treatment of chronic neuropathic pain and warrants further investigation.
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Affiliation(s)
- Jennifer F Russo
- 1Columbia University College of Physicians and Surgeons and.,2Department of Neurological Surgery, Columbia University Medical Center, New York, New York
| | - Sameer A Sheth
- 2Department of Neurological Surgery, Columbia University Medical Center, New York, New York
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8
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Nudelman KNH, McDonald BC, Wang Y, Smith DJ, West JD, O'Neill DP, Zanville NR, Champion VL, Schneider BP, Saykin AJ. Cerebral Perfusion and Gray Matter Changes Associated With Chemotherapy-Induced Peripheral Neuropathy. J Clin Oncol 2015; 34:677-83. [PMID: 26527786 DOI: 10.1200/jco.2015.62.1276] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE To investigate the longitudinal relationship between chemotherapy-induced peripheral neuropathy (CIPN) symptoms (sx) and brain perfusion changes in patients with breast cancer. Interaction of CIPN-sx perfusion effects with known chemotherapy-associated gray matter density decrease was also assessed to elucidate the relationship between CIPN and previously reported cancer treatment-related brain structural changes. METHODS Patients with breast cancer treated with (n = 24) or without (n = 23) chemotherapy underwent clinical examination and brain magnetic resonance imaging at the following three time points: before treatment (baseline), 1 month after treatment completion, and 1 year after the 1-month assessment. CIPN-sx were evaluated with the self-reported Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity four-item sensory-specific scale. Perfusion and gray matter density were assessed using voxel-based pulsed arterial spin labeling and morphometric analyses and tested for association with CIPN-sx in the patients who received chemotherapy. RESULTS Patients who received chemotherapy reported significantly increased CIPN-sx from baseline to 1 month, with partial recovery by 1 year (P < .001). CIPN-sx increase from baseline to 1 month was significantly greater for patients who received chemotherapy compared with those who did not (P = .001). At 1 month, neuroimaging showed that for the group that received chemotherapy, CIPN-sx were positively associated with cerebral perfusion in the right superior frontal gyrus and cingulate gyrus, regions associated with pain processing (P < .001). Longitudinal magnetic resonance imaging analysis in the group receiving chemotherapy indicated that CIPN-sx and associated perfusion changes from baseline to 1 month were also positively correlated with gray matter density change (P < .005). CONCLUSION Peripheral neuropathy symptoms after systemic chemotherapy for breast cancer are associated with changes in cerebral perfusion and gray matter. The specific mechanisms warrant further investigation given the potential diagnostic and therapeutic implications.
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Affiliation(s)
- Kelly N H Nudelman
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Brenna C McDonald
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Yang Wang
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Dori J Smith
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - John D West
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Darren P O'Neill
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Noah R Zanville
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Victoria L Champion
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Bryan P Schneider
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI
| | - Andrew J Saykin
- Kelly N.H. Nudelman, Brenna C. McDonald, Yang Wang, Dori J. Smith, John D. West, Darren P. O'Neill, Victoria L. Champion, Bryan P. Schneider, and Andrew J. Saykin, Indiana University School of Medicine; Noah R. Zanville and Victoria L. Champion, Indiana University School of Nursing, Indianapolis, IN; and Yang Wang, Medical College of Wisconsin, Milwaukee, WI.
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Jalil SJ, Sacktor TC, Shouval HZ. Atypical PKCs in memory maintenance: the roles of feedback and redundancy. ACTA ACUST UNITED AC 2015; 22:344-53. [PMID: 26077687 PMCID: PMC4478332 DOI: 10.1101/lm.038844.115] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 05/05/2015] [Indexed: 11/24/2022]
Abstract
Memories that last a lifetime are thought to be stored, at least in part, as persistent enhancement of the strength of particular synapses. The synaptic mechanism of these persistent changes, late long-term potentiation (L-LTP), depends on the state and number of specific synaptic proteins. Synaptic proteins, however, have limited dwell times due to molecular turnover and diffusion, leading to a fundamental question: how can this transient molecular machinery store memories lasting a lifetime? Because the persistent changes in efficacy are synapse-specific, the underlying molecular mechanisms must to a degree reside locally in synapses. Extensive experimental evidence points to atypical protein kinase C (aPKC) isoforms as key components involved in memory maintenance. Furthermore, it is evident that establishing long-term memory requires new protein synthesis. However, a comprehensive model has not been developed describing how these components work to preserve synaptic efficacies over time. We propose a molecular model that can account for key empirical properties of L-LTP, including its protein synthesis dependence, dependence on aPKCs, and synapse-specificity. Simulations and empirical data suggest that either of the two aPKC subtypes in hippocampal neurons, PKMζ and PKCι/λ, can maintain L-LTP, making the system more robust. Given genetic compensation at the level of synthesis of these PKC subtypes as in knockout mice, this system is able to maintain L-LTP and memory when one of the pathways is eliminated.
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Affiliation(s)
- Sajiya J Jalil
- Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, Houston, Texas 77030, USA
| | - Todd Charlton Sacktor
- Department of Physiology, Pharmacology, Anesthesiology, and Neurology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA
| | - Harel Z Shouval
- Department of Neurobiology and Anatomy, The University of Texas Medical School at Houston, Houston, Texas 77030, USA
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10
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Chen A, Bao C, Tang Y, Luo X, Guo L, Liu B, Lin C. Involvement of protein kinase ζ in the maintenance of hippocampal long-term potentiation in rats with chronic visceral hypersensitivity. J Neurophysiol 2015; 113:3047-55. [PMID: 25761958 PMCID: PMC4455563 DOI: 10.1152/jn.00929.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/05/2015] [Indexed: 12/20/2022] Open
Abstract
The hippocampal long-term potentiation (LTP) was implicated in the formation of visceral hypersensitivity in rats with irritable bowel syndrome in our previous study. Recent studies have shown that protein kinase M ζ (PKMζ) may be responsible for the maintenance of LTP in memory formation. However, it remains unclear whether PKMζ is involved in the visceral hypersensitivity. In this study, a rat model of visceral hypersensitivity was generated by neonatal maternal separation (NMS). The visceral hypersensitivity was assessed by recording responses of the external oblique abdominal muscle to colorectal distension. Our results demonstrated that hippocampal LTP and visceral hypersensitivity were enhanced significantly in rats of NMS. ζ-Pseudosubstrate inhibitory peptide (ZIP) could dose dependently inhibit the maintenance of Cornu Ammonis area 1 LTP in rats of NMS. Furthermore, Western blot data showed that the expression of hippocampal phosphorylated PKMζ (p-PKMζ) significantly increased in rats of NMS. In addition, bilateral intrahippocampal injections of ZIP attenuated the visceral hypersensitivity dose dependently in rats of NMS. The maximal inhibition was observed at 30 min, and significant inhibition lasted for 1.5–2 h after ZIP application. Besides, data from the open-field test and Morris water maze showed that ZIP did not influence the movement and spatial procedural memory in rats of NMS. In conclusion, p-PKMζ might be a critical protein in the maintenance of hippocampal LTP, which could result in visceral hypersensitivity.
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Affiliation(s)
- Aiqin Chen
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Chengjia Bao
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Ying Tang
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Xiaoqing Luo
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Lixia Guo
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Bin Liu
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
| | - Chun Lin
- Fujian Medical University, School of Basic Medical Sciences, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fuzhou City, Fujian Province, People's Republic of China
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11
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Koga K, Descalzi G, Chen T, Ko HG, Lu J, Li S, Son J, Kim T, Kwak C, Huganir RL, Zhao MG, Kaang BK, Collingridge GL, Zhuo M. Coexistence of two forms of LTP in ACC provides a synaptic mechanism for the interactions between anxiety and chronic pain. Neuron 2014; 85:377-89. [PMID: 25556835 DOI: 10.1016/j.neuron.2014.12.021] [Citation(s) in RCA: 229] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2014] [Indexed: 12/20/2022]
Abstract
Chronic pain can lead to anxiety and anxiety can enhance the sensation of pain. Unfortunately, little is known about the synaptic mechanisms that mediate these re-enforcing interactions. Here we characterized two forms of long-term potentiation (LTP) in the anterior cingulate cortex (ACC); a presynaptic form (pre-LTP) that requires kainate receptors and a postsynaptic form (post-LTP) that requires N-methyl-D-aspartate receptors. Pre-LTP also involves adenylyl cyclase and protein kinase A and is expressed via a mechanism involving hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Interestingly, chronic pain and anxiety both result in selective occlusion of pre-LTP. Significantly, microinjection of the HCN blocker ZD7288 into the ACC in vivo produces both anxiolytic and analgesic effects. Our results provide a mechanism by which two forms of LTP in the ACC may converge to mediate the interaction between anxiety and chronic pain.
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Affiliation(s)
- Kohei Koga
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Giannina Descalzi
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Tao Chen
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Hyoung-Gon Ko
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
| | - Jinshan Lu
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China
| | - Shermaine Li
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Junehee Son
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
| | - TaeHyun Kim
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
| | - Chuljung Kwak
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
| | - Richard L Huganir
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ming-Gao Zhao
- Department of Pharmacology, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China
| | - Bong-Kiun Kaang
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Korea
| | - Graham L Collingridge
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, UK
| | - Min Zhuo
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, China; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
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12
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Chen Y, Lin C, Tang Y, Chen AQ, Liu CY, Lu DL. ZD 7288, an HCN channel blocker, attenuates chronic visceral pain in irritable bowel syndrome-like rats. World J Gastroenterol 2014; 20:2091-2097. [PMID: 24587682 PMCID: PMC3934480 DOI: 10.3748/wjg.v20.i8.2091] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 12/07/2013] [Accepted: 01/08/2014] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effects of ZD 7288, a hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, on rats with chronic visceral pain.
METHODS: Rats with visceral hypersensitivity were generated using neonatal colon irritation during postnatal days 8-15 as described previously. Visceral hypersensitivity was evaluated using electromyographic (EMG) responses of abdominal external oblique muscles to 20-80 mmHg colorectal distentions (CRD). Abdominal withdrawal reflex (AWR) scores and pain thresholds were also detected in adult rats. Different doses of ZD 7288 (25, 50, and 100 nmol/L) were intrathecally administered in rats to study the role of spinal HCN channel in chronic visceral hypersensitivity.
RESULTS: EMG responses to 20-80 mmHg CRD and AWR scores under 20-60 mmHg CRD significantly increased in rats with visceral hypersensitivity compared to control rats (P < 0.05). The pain threshold in rats with visceral hypersensitivity significantly decreased compared to control rats (P < 0.05). Treatment with 50-100 nmol/L ZD 7288 significantly inhibited EMG responses (16%-62%, 80-20 mmHg CRD, P < 0.05) and AWR scores (24%-37%, 40-20 mmHg CRD, P < 0.05; 12%-61%, 80-20 mmHg CRD, P < 0.05, respectively), and significantly increased pain thresholds (32%-77%, P < 0.05).
CONCLUSION: Spinal HCN channels may play an important role in chronic visceral hypersensitivity.
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13
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Hernández AI, Oxberry WC, Crary JF, Mirra SS, Sacktor TC. Cellular and subcellular localization of PKMζ. Philos Trans R Soc Lond B Biol Sci 2013; 369:20130140. [PMID: 24298142 DOI: 10.1098/rstb.2013.0140] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
In contrast to protein kinases that participate in long-term potentiation (LTP) induction and memory consolidation, the autonomously active atypical protein kinase C isoform, protein kinase Mzeta (PKMζ), functions in the core molecular mechanism of LTP maintenance and long-term memory storage. Here, using multiple complementary techniques for light and electron microscopic immunolocalization, we present the first detailed characterization of the cellular and subcellular distribution of PKMζ in rat hippocampus and neocortex. We find that PKMζ is widely expressed in forebrain with prominent immunostaining in hippocampal and neocortical grey matter, and weak label in white matter. In hippocampal and cortical pyramidal cells, PKMζ expression is predominantly somatodendritic, and electron microscopy highlights the kinase at postsynaptic densities and in clusters within spines. In addition, nuclear label and striking punctate immunopositive structures in a paranuclear and dendritic distribution are seen by confocal microscopy, occasionally at dendritic bifurcations. PKMζ immunoreactive granules are observed by electron microscopy in cell bodies and dendrites, including endoplasmic reticulum. The widespread distribution of PKMζ in nuclei, nucleoli and endoplasmic reticulum suggests potential roles of this kinase in cell-wide mechanisms involving gene expression, biogenesis of ribosomes and new protein synthesis. The localization of PKMζ within postsynaptic densities and spines suggests sites where the kinase stores information during LTP maintenance and long-term memory.
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Affiliation(s)
- A Iván Hernández
- Department of Pathology, State University of New York, Downstate Medical Center, , Brooklyn, NY, USA
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14
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Luo XQ, Cai QY, Chen Y, Guo LX, Chen AQ, Wu ZQ, Lin C. Tyrosine phosphorylation of the NR2B subunit of the NMDA receptor in the spinal cord contributes to chronic visceral pain in rats. Brain Res 2013; 1542:167-75. [PMID: 24125810 DOI: 10.1016/j.brainres.2013.10.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 09/18/2013] [Accepted: 10/05/2013] [Indexed: 02/07/2023]
Abstract
The roles of spinal N-methyl-d-aspartic acid receptor 2B (NR2B) subunit in central sensitization of chronic visceral pain were investigated. A rat model with irritable bowel syndrome (IBS) was established by colorectal distention (CRD) on post-natal days 8-14. Responses of the external oblique muscle of the abdomen to CRD were measured to evaluate the sensitivity of visceral pain in rats. The sensitivity of visceral pain significantly increased in IBS-like rats. Expressions of spinal NR2B subunit and phosphorylated NR2B subunit significantly increased by 50-55% in IBS-like rats when compared with those in control rats. Ro 25-6981, a selective antagonist of NR2B subunit, has a dose-dependent anti-allodynic and anti-hyperalgesic effect without causing motor dysfunction in IBS-like rats. Furthermore, the activation mechanism of the spinal NR2B subunit in chronic visceral pain was also investigated. Spinal administration of genistein, a specific inhibitor of tyrosine kinases, also decreased the visceral pain hypersensitivity of IBS-like rats in a dose-dependent manner. In addition, the expression of phosphorylated NR2B subunit was decreased after spinal administration of Ro 25-6981 or genistein in IBS-like rats. In conclusion, tyrosine kinase activation-induced phosphorylation of NR2B subunit may play a crucial role in central sensitization of chronic visceral pain.
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Affiliation(s)
- Xiao-Qing Luo
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China
| | - Qin-Yan Cai
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China
| | - Yu Chen
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China
| | - Li-Xia Guo
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China
| | - Ai-Qin Chen
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China
| | - Zhen-Quan Wu
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China
| | - Chun Lin
- School of Foundational Medical sciences, Fujian Medical University, Fuzhou City, Fujian Province 350108, PR China; Department of Physiology and Pathophysiology, Laboratory of Pain Research, Key Laboratory of Brain Aging and Neurodegenerative Diseases, Neuroscience Research Center, Fujian Medical University, No. 1 Xueyuan Road, Shangjie Zhen, Minhou County, Fuzhou City, Fujian Province 350108, PR China.
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15
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Abstract
Pain is an intricate phenomenon composed of not only sensory-discriminative aspects but also of emotional, cognitive, motivational, and affective components. There has been ample evidence for the existence of an extensive cortical network associated with pain processing over the last few decades. This network includes the anterior cingulate cortex, forebrain, insular cortex, ventrolateral orbital cortex, somatosensory cortex, occipital cortex, retrosplenial cortex, motor cortex, and prefrontal cortex. Diverse neurotransmitters participate in the cortical circuits associated with pain processing, including glutamate, gamma-aminobutyric acid, dopamine, and opioids. This work examines recent rodent studies about cortical modulation of pain, mainly at a molecular level.
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Affiliation(s)
- Gabriel C Quintero
- Florida State University - Panama, Neuroscience, Republic of Panama; Smithsonian Tropical Research Institute (STRI), Balboa, Republic of Panama
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16
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Price TJ, Ghosh S. ZIPping to pain relief: the role (or not) of PKMζ in chronic pain. Mol Pain 2013; 9:6. [PMID: 23433248 PMCID: PMC3621284 DOI: 10.1186/1744-8069-9-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 02/19/2013] [Indexed: 11/21/2022] Open
Abstract
Chronic pain remains a significant clinical problem despite substantial advances in our understanding of how persistent nociceptor stimulation drives plasticity in the CNS. A major theme that has emerged in this area of work is the strong similarity between plasticity involved in learning and memory in CNS regions such as cortex and hippocampus with mechanisms underlying chronic pain development and maintenance in the spinal dorsal horn and other CNS areas such as anterior cingulate cortex (ACC). We, and others have recently implicated an atypical PKC (aPKC), called PKMζ, in the maintenance of pain plasticity based on biochemical assays and the use of a peptide pseudosubstrate inhibitor called ZIP. These studies indicate remarkable parallels between the potential role of PKMζ as a key molecule for the maintenance of long-term memory and long-term potentiation (LTP) and the maintenance of a chronic pain state. On the other hand, very recent studies have disputed the specificity of ZIP and called into question the role of PKMζ as a memory maintenance molecule. Here we critically review the evidence that PKMζ might represent a new target for the reversal of certain chronic pain states. Furthermore, we consider whether ZIP might have other aPKC or even non-aPKC targets and the significance of such off-target effects for evaluating maintenance mechanisms of chronic pain. We conclude that, current controversies aside, utilization of ZIP as a tool to interrogate maintenance mechanisms of chronic pain and further investigations into the potential role of PKMζ, and other aPKCs, in pain plasticity are likely to lead to further insights with the potential to unravel the enigma that is the disease of chronic pain.
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Affiliation(s)
- Theodore J Price
- Department of Pharmacology, The University of Arizona School of Medicine, Arizona, USA.
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17
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Ferrari LF, Levine E, Levine JD. Role of a novel nociceptor autocrine mechanism in chronic pain. Eur J Neurosci 2013; 37:1705-13. [PMID: 23379641 DOI: 10.1111/ejn.12145] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 12/11/2012] [Accepted: 01/07/2013] [Indexed: 12/13/2022]
Abstract
We have previously shown, in the rat, that neuropathic and inflammatory events produce a neuroplastic change in nociceptor function whereby a subsequent exposure to a proinflammatory mediator (e.g. prostaglandin E2 ; PGE2 ) produces markedly prolonged mechanical hyperalgesia. While the initial approximately 30 min of this prolonged PGE2 hyperalgesia remains PKA-dependent, it subsequently switches to become dependent on protein kinase C epsilon (PKCε). In this study we tested the hypothesis that the delayed onset, PKCε-mediated, component of PGE2 hyperalgesia is generated by the active release of a nucleotide from the peripheral terminal of the primed nociceptor and this nucleotide is then metabolized to produce adenosine, which acts on a Gi-coupled A1 adenosine receptor on the nociceptor to generate PKCε-dependent hyperalgesia. We report that inhibitors of ATP-binding cassette transporters, of ecto-5'-phosphodiesterase and ecto-5'nucleotidase (enzymes involved in the metabolism of cyclic nucleotides to adenosine) and of A1 adenosine receptors each eliminated the late, but not the early, phase of PGE2 -induced hyperalgesia in primed animals. A second model of chronic pain induced by transient attenuation of G-protein-coupled receptor kinase 2, in which the prolongation of PGE2 hyperalgesia is not PKCε-dependent, was not attenuated by inhibitors of any of these mechanisms. Based on these results we propose a contribution of an autocrine mechanism, in the peripheral terminal of the nociceptor, in the hyperalgesic priming model of chronic pain.
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Affiliation(s)
- Luiz F Ferrari
- Division of Neuroscience, Departments of Medicine and Oral Surgery, University of California, San Francisco, CA 94143-0440, USA
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18
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Sacktor TC. Memory maintenance by PKMζ--an evolutionary perspective. Mol Brain 2012; 5:31. [PMID: 22986281 PMCID: PMC3517905 DOI: 10.1186/1756-6606-5-31] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 08/29/2012] [Indexed: 11/20/2022] Open
Abstract
Long-term memory is believed to be maintained by persistent modifications of synaptic transmission within the neural circuits that mediate behavior. Thus, long-term potentiation (LTP) is widely studied as a potential physiological basis for the persistent enhancement of synaptic strength that might sustain memory. Whereas the molecular mechanisms that initially induce LTP have been extensively characterized, the mechanisms that persistently maintain the potentiation have not. Recently, however, a candidate molecular mechanism linking the maintenance of LTP and the storage of long-term memory has been identified. The persistent activity of the autonomously active, atypical protein kinase C (aPKC) isoform, PKMζ, is both necessary and sufficient for maintaining LTP. Furthermore, blocking PKMζ activity by pharmacological or dominant negative inhibitors disrupts previously stored long-term memories in a variety of neural circuits, including spatial and trace memories in the hippocampus, aversive memories in the basolateral amygdala, appetitive memories in the nucleus accumbens, habit memory in the dorsal lateral striatum, and elementary associations, extinction, and skilled sensorimotor memories in the neocortex. During LTP and memory formation, PKMζ is synthesized de novo as a constitutively active kinase. This molecular mechanism for memory storage is evolutionarily conserved. PKMζ formation through new protein synthesis likely originated in early vertebrates ~500 million years ago during the Cambrian period. Other mechanisms for forming persistently active PKM from aPKC are found in invertebrates, and inhibiting this atypical PKM disrupts long-term memory in the invertebrate model systems Drosophila melanogaster and Aplysia californica. Conversely, overexpressing PKMζ enhances memory in flies and rodents. PKMζ persistently enhances synaptic strength by maintaining increased numbers of AMPA receptors at postsynaptic sites, a mechanism that might have evolved from the general function of aPKC in trafficking membrane proteins to the apical compartment of polarized cells. This mechanism of memory may have had adaptive advantages because it is both stable and reversible, as demonstrated by the downregulation of experience-dependent, long-term increases in PKMζ after extinction and reconsolidation blockade that attenuate learned behavior. Thus, PKMζ, the “working end” of LTP, is a component of an evolutionarily conserved molecular mechanism for the persistent, yet flexible storage of long-term memory.
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Affiliation(s)
- Todd Charlton Sacktor
- The Robert F. Furchgott Center for Neural and Behavioral Science, Department of Physiology, State University of New York Downstate Medical Center, 450 Clarkson Ave, Brooklyn, NY 10705, USA.
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19
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Li XY, Chen T, Descalzi G, Koga K, Qiu S, Zhuo M. Characterization of neuronal intrinsic properties and synaptic transmission in layer I of anterior cingulate cortex from adult mice. Mol Pain 2012; 8:53. [PMID: 22818293 PMCID: PMC3495677 DOI: 10.1186/1744-8069-8-53] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 06/26/2012] [Indexed: 01/29/2023] Open
Abstract
The neurons in neocortex layer I (LI) provide inhibition to the cortical networks. Despite increasing use of mice for the study of brain functions, few studies were reported about mouse LI neurons. In the present study, we characterized intrinsic properties of LI neurons of the anterior cingulate cortex (ACC), a key cortical area for sensory and cognitive functions, by using whole-cell patch clamp recording approach. Seventy one neurons in LI and 12 pyramidal neurons in LII/III were recorded. Although all of the LI neurons expressed continuous adapting firing characteristics, the unsupervised clustering results revealed five groups in the ACC, including: Spontaneous firing neurons; Delay-sAHP neurons, Delay-fAHP neurons, and two groups of neurons with ADP, named ADP1 and ADP2, respectively. Using pharmacological approaches, we found that LI neurons received both excitatory (mediated by AMPA, kainate and NMDA receptors), and inhibitory inputs (which were mediated by GABAA receptors). Our studies provide the first report characterizing the electrophysiological properties of neurons in LI of the ACC from adult mice.
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Affiliation(s)
- Xiang-Yao Li
- Center for Neuron and Disease, Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710054, China
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20
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Zhuo M. Targeting neuronal adenylyl cyclase for the treatment of chronic pain. Drug Discov Today 2012; 17:573-82. [PMID: 22405897 DOI: 10.1016/j.drudis.2012.01.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Revised: 12/13/2011] [Accepted: 01/17/2012] [Indexed: 10/14/2022]
Abstract
Pain research is currently undergoing dramatic changes. In the area of basic pain research, new discoveries have been made towards the understanding of pain transmission, modulation and plasticity. However, many of these basic discoveries have not yet led to the development of new drugs for the treatment of chronic pain. One major reason for this disconnection is the lack of translational research and drug discovery based directly on the novel pain mechanism. In this review, I focus on activity-dependent potentiation in pain-related cortical areas and recent translational research on adenylyl cyclase subtype 1 (AC1) as a novel target for treating chronic pain. In particular, I discuss the AC1 inhibitor, NB001, which produces powerful analgesic effects in animal models of chronic pain by inhibiting chronic pain-related cortical potentiation.
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Affiliation(s)
- Min Zhuo
- Department of Physiology, Faculty of Medicine, University of Toronto, Ont, Canada.
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21
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Sandkühler J, Gruber-Schoffnegger D. Hyperalgesia by synaptic long-term potentiation (LTP): an update. Curr Opin Pharmacol 2011; 12:18-27. [PMID: 22078436 PMCID: PMC3315008 DOI: 10.1016/j.coph.2011.10.018] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 10/17/2011] [Indexed: 11/17/2022]
Abstract
Long-term potentiation of synaptic strength (LTP) in nociceptive pathways shares principle features with hyperalgesia including induction protocols, pharmacological profile, neuronal and glial cell types involved and means for prevention. LTP at synapses of nociceptive nerve fibres constitutes a contemporary cellular model for pain amplification following trauma, inflammation, nerve injury or withdrawal from opioids. It provides a novel target for pain therapy. This review summarizes recent progress which has been made in unravelling the properties and functions of LTP in the nociceptive system and in identifying means for its prevention and reversal.
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Affiliation(s)
- Jürgen Sandkühler
- Medical University of Vienna, Center for Brain Research, Department of Neurophysiology, Spitalgasse 4, A-1090 Vienna, Austria.
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22
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Zhuo M. Cortical plasticity as a new endpoint measurement for chronic pain. Mol Pain 2011; 7:54. [PMID: 21798042 PMCID: PMC3157449 DOI: 10.1186/1744-8069-7-54] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 07/28/2011] [Indexed: 02/03/2023] Open
Abstract
Animal models of chronic pain are widely used to investigate basic mechanisms of chronic pain and to evaluate potential novel drugs for treating chronic pain. Among the different criteria used to measure chronic pain, behavioral responses are commonly used as the end point measurements. However, not all chronic pain conditions can be easily measured by behavioral responses such as the headache, phantom pain and pain related to spinal cord injury. Here I propose that cortical indexes, that indicate neuronal plastic changes in pain-related cortical areas, can be used as endpoint measurements for chronic pain. Such cortical indexes are not only useful for those chronic pain conditions where a suitable animal model is lacking, but also serve as additional screening methods for potential drugs to treat chronic pain in humans. These cortical indexes are activity-dependent immediate early genes, electrophysiological identified plastic changes and biochemical assays of signaling proteins. It can be used to evaluate novel analgesic compounds that may act at peripheral or spinal sites. I hope that these new cortical endpoint measurements will facilitate our search for new, and more effective, pain medicines, and help to reduce false lead drug targets.
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Affiliation(s)
- Min Zhuo
- Center for Neuron and Disease, Frontier Institute for Science and Technology, Xian Jiaotong University, China.
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