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Yu S, Yue W, Guo T, Liu Y, Zhang Y, Khademi S, Zhou T, Xu Z, Song B, Wu T, Liu F, Tai Y, Yu X, Wang H. The effect of the subthreshold oscillation induced by the neurons' resonance upon the electrical stimulation-dependent instability. Front Neurosci 2023; 17:1178606. [PMID: 37229430 PMCID: PMC10203711 DOI: 10.3389/fnins.2023.1178606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 04/10/2023] [Indexed: 05/27/2023] Open
Abstract
Repetitive electrical nerve stimulation can induce a long-lasting perturbation of the axon's membrane potential, resulting in unstable stimulus-response relationships. Despite being observed in electrophysiology, the precise mechanism underlying electrical stimulation-dependent (ES-dependent) instability is still an open question. This study proposes a model to reveal a facet of this problem: how threshold fluctuation affects electrical nerve stimulations. This study proposes a new method based on a Circuit-Probability theory (C-P theory) to reveal the interlinkages between the subthreshold oscillation induced by neurons' resonance and ES-dependent instability of neural response. Supported by in-vivo studies, this new model predicts several key characteristics of ES-dependent instability and proposes a stimulation method to minimize the instability. This model provides a powerful tool to improve our understanding of the interaction between the external electric field and the complexity of the biophysical characteristics of axons.
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Affiliation(s)
- Shoujun Yu
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Wenji Yue
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Tianruo Guo
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, Australia
| | - Yonghong Liu
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Yapeng Zhang
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Sara Khademi
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
- Institute of Polymeric Materials, Sahand University of Technology, Tabriz, Iran
| | - Tian Zhou
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Zhen Xu
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Bing Song
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Tianzhun Wu
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
- Key Laboratory of Health Bioinformatics, Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Fenglin Liu
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Yanlong Tai
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
| | - Xuefei Yu
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Hao Wang
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology (SIAT), Chinese Academy of Sciences (CAS), Shenzhen, China
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Jung GL, McDaniel KL, LoPachin RM, Geohagen BC, Smith A, Huffstickler M, Herr DW. IN VIVO NEUROPHYSIOLOGICAL ASSESSMENT OF IN SILICO PREDICTIONS OF NEUROTOXICITY: CITRONELLAL, 3,4-DICHLORO-1-BUTENE, AND BENZYL BROMOACETATE. Neurotoxicology 2022; 90:48-61. [PMID: 35227730 PMCID: PMC9133174 DOI: 10.1016/j.neuro.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 02/02/2022] [Accepted: 02/21/2022] [Indexed: 11/29/2022]
Abstract
Neurotoxicants may be widespread in the environment and can produce serious health impacts in the human population. Screening programs that use in vitro methods have generated data for thousands of chemicals. However, these methods often do not evaluate repeated or prolonged exposures, which are required for many neurotoxic outcomes. Additionally, the data produced by such screening methods may not include mechanisms which play critical biological roles necessary for in vivo neurotoxicity. The Hard and Soft Acids and Bases (HSAB) in silico model focuses on chemical structure and electrophilic properties which are important to the formation of protein adducts. A group of structurally diverse chemicals have been evaluated with an in silico screening approach incorporating HSAB parameters. However, the predictions from the expanded chemical space have not been evaluated using in vivo methods. Three chemicals predicted to be cumulative toxicants were selected for in vivo neurotoxicological testing. Adult male Long-Evans rats were treated orally with citronellal (CIT), 3,4-dichloro-1-butene (DCB), or benzyl bromoacetate (BBA) for 8 weeks. Behavioral observations were recorded weekly to assess motor function. Peripheral neurophysiological measurements were derived from nerve excitability (NE) tests which involved compound muscle action potentials (CMAPs) in the tail and foot, and mixed nerve action potentials (MNAPs) in the tail. Compound nerve action potentials (CNAPs) and nerve conduction velocity (NCV) in the tail were also quantified. Peripheral inputs into the central nervous system were examined using somatosensory evoked potentials recorded from the cortex (SEPCTX) and cerebellum (SEPCEREB). CIT or BBA did not result in significant alterations to peripheral nerve or somatosensory function. DCB reduced grip-strength and altered peripheral nerve function. The MNAPs required less current to reach 50% amplitude and had a lower calculated rheobase, suggesting increased excitability. Increased CNAP amplitudes and greater NCV were also observed. Novel changes were found in the SEPCTX with an abnormal peak forming in the early portion of the waveforms of treated rats, and decreased latencies and increased amplitudes were observed in SEPCEREB recordings. These data contribute to testing an expanded chemical space from an in silico HSAB model for predicting cumulative neurotoxicity and may assist with prioritizing chemicals to protect human health.
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Affiliation(s)
- Garyn L Jung
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Katherine L McDaniel
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
| | - Richard M LoPachin
- Professor Emeritus in the Department of Anesthesiology, Albert Einstein College of Medicine, 111 E. 210th St, Bronx, NY 10467, USA.
| | - Brian C Geohagen
- Department of Anesthesiology, Montefiore Medical Center, Albert Einstein College of Medicine, 111 E. 210th St, Bronx, NY 10467, USA.
| | - Alicia Smith
- Oak Ridge Institute for Science Education, Oak Ridge, Tennessee 37830, USA.
| | | | - David W Herr
- Center for Public Health and Environmental Assessment, US Environmental Protection Agency, Research Triangle Park, NC 27711, USA.
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Hossain MJ, Kendig MD, Wild BM, Issar T, Krishnan AV, Morris MJ, Arnold R. Evidence of Altered Peripheral Nerve Function in a Rodent Model of Diet-Induced Prediabetes. Biomedicines 2020; 8:biomedicines8090313. [PMID: 32872256 PMCID: PMC7555926 DOI: 10.3390/biomedicines8090313] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/26/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Peripheral neuropathy (PN) is a debilitating complication of diabetes that affects >50% of patients. Recent evidence suggests that obesity and metabolic disease, which often precede diabetes diagnosis, may influence PN onset and severity. We examined this in a translationally relevant model of prediabetes induced by a cafeteria (CAF) diet in Sprague–Dawley rats (n = 15 CAF versus n = 15 control). Neuropathy phenotyping included nerve conduction, tactile sensitivity, intraepidermal nerve fiber density (IENFD) and nerve excitability testing, an in vivo measure of ion channel function and membrane potential. Metabolic phenotyping included body composition, blood glucose and lipids, plasma hormones and inflammatory cytokines. After 13 weeks diet, CAF-fed rats demonstrated prediabetes with significantly elevated fasting blood glucose, insulin and impaired glucose tolerance as well as obesity and dyslipidemia. Nerve conduction, tactile sensitivity and IENFD did not differ; however, superexcitability was significantly increased in CAF-fed rats. Mathematical modeling demonstrated this was consistent with a reduction in sodium–potassium pump current. Moreover, superexcitability correlated positively with insulin resistance and adiposity, and negatively with fasting high-density lipoprotein cholesterol. In conclusion, prediabetic rats over-consuming processed, palatable foods demonstrated altered nerve function that preceded overt PN. This work provides a relevant model for pathophysiological investigation of diabetic complications.
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Affiliation(s)
- Md Jakir Hossain
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Michael D. Kendig
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Brandon M. Wild
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Tushar Issar
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Arun V. Krishnan
- Prince of Wales Clinical School, UNSW Sydney, Sydney, NSW 2052, Australia; (T.I.); (A.V.K.)
| | - Margaret J. Morris
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
| | - Ria Arnold
- School of Medical Sciences, UNSW Sydney, Sydney, NSW 2052, Australia; (M.J.H.); (M.D.K.); (B.M.W.); (M.J.M.)
- Correspondence: ; Tel.: +61-293858709
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Bruna J, Alberti P, Calls-Cobos A, Caillaud M, Damaj MI, Navarro X. Methods for in vivo studies in rodents of chemotherapy induced peripheral neuropathy. Exp Neurol 2020; 325:113154. [PMID: 31837318 PMCID: PMC7105293 DOI: 10.1016/j.expneurol.2019.113154] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 12/07/2019] [Accepted: 12/10/2019] [Indexed: 12/15/2022]
Abstract
Peripheral neuropathy is one of the most common, dose limiting, and long-lasting disabling adverse events of chemotherapy treatment. Unfortunately, no treatment has proven efficacy to prevent this adverse effect in patients or improve the nerve regeneration, once it is established. Experimental models, particularly using rats and mice, are useful to investigate the mechanisms related to axonal or neuronal degeneration and target loss of function induced by neurotoxic drugs, as well as to test new strategies to prevent the development of neuropathy and to improve functional restitution. Therefore, objective and reliable methods should be applied for the assessment of function and innervation in adequately designed in vivo studies of CIPN, taking into account the impact of age, sex and species/strains features. This review gives an overview of the most useful methods to assess sensory, motor and autonomic functions, electrophysiological and morphological tests in rodent models of peripheral neuropathy, focused on CIPN. We include as well a proposal of protocols that may improve the quality and comparability of studies undertaken in different laboratories. It is recommended to apply more than one functional method for each type of function, and to perform parallel morphological studies in the same targets and models.
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Affiliation(s)
- Jordi Bruna
- Unit of Neuro-Oncology, Hospital Universitari de Bellvitge, Institut Català d'Oncologia L'Hospitalet, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain; Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University Milano Bicocca, Monza, Italy; NeuroMI (Milan Center for Neuroscience), Milan, Italy
| | - Aina Calls-Cobos
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Martial Caillaud
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - M Imad Damaj
- Department of Pharmacology and Toxicology, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA, USA
| | - Xavier Navarro
- Department of Cell Biology, Physiology and Immunology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.
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5
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Alberti P, Canta A, Chiorazzi A, Fumagalli G, Meregalli C, Monza L, Pozzi E, Ballarini E, Rodriguez-Menendez V, Oggioni N, Sancini G, Marmiroli P, Cavaletti G. Topiramate prevents oxaliplatin-related axonal hyperexcitability and oxaliplatin induced peripheral neurotoxicity. Neuropharmacology 2019; 164:107905. [PMID: 31811874 DOI: 10.1016/j.neuropharm.2019.107905] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 11/26/2019] [Accepted: 12/03/2019] [Indexed: 12/15/2022]
Abstract
Oxaliplatin (OHP) Induced Peripheral Neurotoxicity (OIPN) is one of the dose-limiting toxicities of the drug and these adverse effects limit cancer therapy with L-OHP, used for colorectal cancer treatment. Acute neurotoxicity consists of symptoms that are the hallmarks of a transient axonal hyperexcitability; chronic neurotoxicity has a clinical picture compatible with a length-dependent sensory neuropathy. Acute OIPN pathogenesis has been linked to sodium voltage-operated channels (Na + VOC) dysfunction and it has been advocated as a possible predisposing factor to chronic neurotoxicity. We tested if topiramate (TPM), a well-known Na + VOC modulator, was able to modify acute as well as chronic OIPN. The project was divided into two parts. In Experiment 1 we tested by means of Nerve Excitability Testing (NET) a cohort of female Wistar rats to assess TPM effects after a single OHP administration (5 mg/kg, iv). In Experiment 2 we assessed TPM effects after chronic OHP treatment (5 mg/kg, 2qw4ws, iv) using NET, nerve conduction studies (NCS), behavioral tests and neuropathology (caudal nerve morphometry and morphology and Intraepidermal Nerve Fiber [IENF] density). In Experiment 1 TPM was able to prevent OHP effects on Na + VOC: OHP treatment induced a highly significant reduction of the sensory nerve's threshold, during the superexcitability period (p-value = 0.008), whereas TPM co-administration prevented this effect. In Experiment 2 we verified that TPM was able to prevent not only acute phenomena, but also to completely prevent chronic OIPN. This latter observation was supported by a multimodal approach: in fact, only OHP group showed altered findings compared to CTRL group at a neurophysiological (proximal caudal nerve sensory nerve action potential [SNAP] amplitude, p-value = 0.001; distal caudal nerve SNAP amplitude, p-value<0.001, distal caudal nerve sensory conduction velocity, p-value = 0.04), behavioral (mechanical threshold, p-value 0.003) and neuropathological levels (caudal nerve fibers density, p-value 0.001; IENF density, p-value <0.001). Our data show that TPM is a promising drug to prevent both acute and chronic OIPN. These findings have a high translational potential, since they were obtained using outcome measures that match clinical practice and TPM is already approved for clinical use being free from detrimental interaction with OHP anticancer properties.
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Affiliation(s)
- Paola Alberti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy.
| | - Annalisa Canta
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Alessia Chiorazzi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Giulia Fumagalli
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; PhD program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Cristina Meregalli
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Laura Monza
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; Human Physiology Lab., School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Eleonora Pozzi
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; PhD program in Neuroscience, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Elisa Ballarini
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Virginia Rodriguez-Menendez
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Norberto Oggioni
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Giulio Sancini
- NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; Human Physiology Lab., School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Paola Marmiroli
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
| | - Guido Cavaletti
- Experimental Neurology Unit, School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy; NeuroMI (Milan Center for Neuroscience), School of Medicine and Surgery, University of Milano-Bicocca, Via Cadore 48, 20900, Monza, Italy
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Bell JM, Lorenz C, Jones KE. Nerve excitability differences in slow and fast motor axons of the rat: more than just Ih. J Neurophysiol 2019; 122:1728-1734. [PMID: 31533011 DOI: 10.1152/jn.00269.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The objective was to determine biophysical differences between fast and slow motor axons using threshold tracking and demonstrate confounds related to anesthetic. Nerve excitability of motor axons innervating the slow-twitch soleus (SOL) and fast-twitch tibialis anterior (TA) muscles was tested. The experiments were conducted with pentobarbital sodium (SP) anesthetic and compared with previous results that used ketamine-xylazine (KX). Nerve excitability indices measured with SP show definitive differences between TA and SOL motor axons that extend beyond previous reports. Nerve excitability indices sensitive to changes in Ih indicated an increase in SOL axons compared with TA axons [e.g., S3 t = 7.949 (df = 10), P < 0.001; hyperpolarizing threshold electrotonus (90-100 ms), t = 2.659 (df = 20); P = 0.01; hyperpolarizing I/V slope, t = 4.308 (df = 19); P < 0.001]. SOL axons also had a longer strength-duration time constant [t = 3.35 (df = 20); P = 0.003] and a longer and larger magnitude relative refractory period [RRP (ms) t = 3.53 (df = 12); P = 0.004; Refractoriness at 2 ms, t = 0.0055 (df = 9); P = 0.006]. Anesthetic choice affected many measures of peripheral nerve excitability with differences most apparent in tests of threshold electrotonus and recovery cycle. For example, recovery cycle with KX lacked a clear superexcitable and late subexcitable period. We conclude that KX had a confounding effect on nerve excitability results consistent with ischemic depolarization. Results using SP revealed the full extent of differences in nerve excitability measures between putative slow and fast motor axons of the rat. These results provide empirical evidence, beyond conduction velocity, that the biophysical properties of motor axons vary with the type of muscle fiber innervated. These differences suggest that fast axons may be predisposed to dysfunction during hyperpolarizing stresses, e.g., electrogenic sodium pumping following sustained impulse conduction.NEW & NOTEWORTHY Nerve excitability testing is a tool used to provide insight into the properties of ion channels in peripheral nerves. It is used clinically to assess pathophysiology of axons. Researchers customarily think of motor axons as homogeneous; however, we demonstrate there are clear differences between fast and slow axons in the rat. This is important for interpreting results with selective motor neuronopathy, like aging where fast axons are at high risk of degeneration.
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Affiliation(s)
- James M Bell
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.,Department of Computing Science, University of Alberta, Edmonton, Alberta, Canada
| | - Chad Lorenz
- Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Kelvin E Jones
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada
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Makker PGS, Matamala JM, Park SB, Lees JG, Kiernan MC, Burke D, Moalem‐Taylor G, Howells J. A unified model of the excitability of mouse sensory and motor axons. J Peripher Nerv Syst 2018; 23:159-173. [DOI: 10.1111/jns.12278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Preet G. S. Makker
- School of Medical SciencesUniversity of New South Wales Sydney Australia
| | | | - Susanna B. Park
- Brain and Mind CentreThe University of Sydney Sydney Australia
| | - Justin G. Lees
- School of Medical SciencesUniversity of New South Wales Sydney Australia
| | - Matthew C. Kiernan
- Brain and Mind CentreThe University of Sydney Sydney Australia
- Royal Prince Alfred HospitalThe University of Sydney Sydney Australia
| | - David Burke
- Royal Prince Alfred HospitalThe University of Sydney Sydney Australia
| | - Gila Moalem‐Taylor
- School of Medical SciencesUniversity of New South Wales Sydney Australia
| | - James Howells
- Brain and Mind CentreThe University of Sydney Sydney Australia
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Tuncer S, Tuncer Peker T, Burat İ, Kiziltan E, İlhan B, Dalkiliç N. Axonal excitability and conduction alterations caused by levobupivacaine in rat. ACTA PHARMACEUTICA (ZAGREB, CROATIA) 2017; 67:293-307. [PMID: 28858839 DOI: 10.1515/acph-2017-0025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/10/2017] [Indexed: 11/15/2022]
Abstract
In this study, effects of the long-acting amide-type local anesthetic levobupivacaine on axonal conduction and excitability parameters of the rat sciatic nerve were thoroughly examined both in vitro and in vivo. In order to deduce its effects on isolated nerve conduction, compound nerve action potential (CNAP) recordings were performed using the suction method over sciatic nerves of Wistar rats before and after administration of 0.05 % (1.7 mmol L-1) levobupivacaine. Levobupivacaine caused complete CNAP area and amplitude depression by blocking conduction in a time-dependent manner. To assess the influence of levobupivacaine on in vivo excitability properties, threshold-tracking (TT) protocols were performed at sciatic nerves of rats injected with perineural 0.05 % (1.7 mmol L-1) levobupivacaine or vehicle alone. Charge-duration TT results revealed that levobupivacaine increases the rheobase and decreases the strength-duration time constant, suggesting interference of the anesthetic with the opening of Na+ channels. Twenty and 40 % threshold electrotonus curves were found for both groups to follow the same paths, suggesting no significant effect of levobupivacaine on K+ channels for either the fastest or relatively slow conducting fibers. Current-threshold relationship results revealed no significant effect on axonal rectifying channels. However, according to the results of the recovery cycle protocol yielding the pattern of excitability changes following the impulse, potential deviation was found in the recovery characteristics of Na+ channels from the absolute refractory period. Consequently, conduction blockage caused by levobupivacaine may not be due to the passive (capacitive) properties of axon or the conductance of potassium channels but to the decrease in sodium channel conductance.
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Affiliation(s)
- Seçkin Tuncer
- N.E. University , Meram Faculty of Medicine, Biophysics Department , Konya , Turkey
| | - Tülay Tuncer Peker
- Ankara University , Faculty of Medicine, Anesthesiology Department , Ankara , Turkey
| | - İlksen Burat
- N.E. University , Meram Faculty of Medicine, Biophysics Department , Konya , Turkey
| | - Erhan Kiziltan
- Başkent University , Faculty of Medicine, Physiology Department , Ankara , Turkey
| | - Barkin İlhan
- N.E. University , Meram Faculty of Medicine, Biophysics Department , Konya , Turkey
| | - Nizamettin Dalkiliç
- N.E. University , Meram Faculty of Medicine, Biophysics Department , Konya , Turkey
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Arnold R, Moldovan M, Rosberg MR, Krishnan AV, Morris R, Krarup C. Nerve excitability in the rat forelimb: a technique to improve translational utility. J Neurosci Methods 2017; 275:19-24. [DOI: 10.1016/j.jneumeth.2016.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 10/01/2016] [Accepted: 10/18/2016] [Indexed: 01/09/2023]
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10
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Banzrai C, Nodera H, Higashi S, Okada R, Osaki Y, Mori A, Kaji R. Age-dependent effects on sensory axonal excitability in normal mice. Neurosci Lett 2016; 611:81-7. [DOI: 10.1016/j.neulet.2015.11.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 11/09/2015] [Accepted: 11/20/2015] [Indexed: 01/07/2023]
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Upregulation of axonal HCN current by methylglyoxal: Potential association with diabetic polyneuropathy. Clin Neurophysiol 2015; 126:2226-32. [DOI: 10.1016/j.clinph.2015.02.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 01/15/2015] [Accepted: 02/01/2015] [Indexed: 11/18/2022]
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12
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Lorenz C, Jones KE. IH activity is increased in populations of slow versus fast motor axons of the rat. Front Hum Neurosci 2014; 8:766. [PMID: 25309406 PMCID: PMC4174588 DOI: 10.3389/fnhum.2014.00766] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 09/10/2014] [Indexed: 11/25/2022] Open
Abstract
Much is known about the electrophysiological variation in motoneuron somata across different motor units. However, comparatively less is known about electrophysiological variation in motor axons and how this could impact function or electrodiagnosis in healthy or diseased states. We performed nerve excitability testing on two groups of motor axons in Sprague–Dawley rats that are known to differ significantly in their chronic daily activity patterns and in the relative proportion of motor unit types: one group innervating the soleus (“slow motor axons”) and the other group innervating the tibialis anterior (“fast motor axons”) muscles. We found that slow motor axons have significantly larger accommodation compared to fast motor axons upon application of a 100 ms hyperpolarizing conditioning stimulus that is 40% of axon threshold (Z = 3.24, p = 0.001) or 20% of axon threshold (Z = 2.67, p = 0.008). Slow motor axons had larger accommodation to hyperpolarizing currents in the current-threshold measurement (-80% Z = 3.07, p = 0.002; -90% Z = 2.98, p = 0.003). In addition, we found that slow motor axons have a significantly smaller rheobase than fast motor axons (Z = -1.99, p = 0.047) accompanied by a lower threshold in stimulus-response curves. The results provide evidence that slow motor axons have greater activity of the hyperpolarization-activated inwardly rectifying cation conductance (IH) than fast motor axons. It is possible that this difference between fast and slow axons is caused by an adaptation to their chronic differences in daily activity patterns, and that this adaptation might have a functional effect on the motor unit. Moreover, these findings indicate that slow and fast motor axons may react differently to pathological conditions.
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Affiliation(s)
- Chad Lorenz
- Faculty of Physical Education and Recreation, University of Alberta Edmonton, AB, Canada
| | - Kelvin E Jones
- Faculty of Physical Education and Recreation, University of Alberta Edmonton, AB, Canada ; Neuroscience and Mental Health Institute, University of Alberta Edmonton, AB, Canada
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Kimura-Kuroiwa K, Adachi YU, Mimuro S, Kawamata M, Sato S, Matsuda N. Pentobarbital Decreased Nitric Oxide Release in the Rat Striatum but Ketamine Increased the Release Independent of Cholinergic Regulation. Exp Anim 2012; 61:165-70. [DOI: 10.1538/expanim.61.165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Affiliation(s)
| | - Yushi U. Adachi
- Department of Emergency Medicine, Nagoya University Hospital
| | - Soichiro Mimuro
- Department of Anesthesia and Resuscitation, Hamamatsu University School of Medicine
| | - Mikito Kawamata
- Department of Anesthesiology and Resuscitology, Shinshu University School of Medicine
| | - Shigehito Sato
- Department of Anesthesia and Resuscitation, Hamamatsu University School of Medicine
| | - Naoyuki Matsuda
- Department of Emergency & Critical Care Medicine, Nagoya University Graduate School of Medicine
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14
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Boërio D, Greensmith L, Bostock H. A model of mouse motor nerve excitability and the effects of polarizing currents. J Peripher Nerv Syst 2011; 16:322-33. [DOI: 10.1111/j.1529-8027.2011.00364.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Boërio D, Kalmar B, Greensmith L, Bostock H. Excitability properties of mouse motor axons in the mutant SOD1G93A
model of amyotrophic lateral sclerosis. Muscle Nerve 2010; 41:774-84. [DOI: 10.1002/mus.21579] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Boërio D, Greensmith L, Bostock H. Excitability properties of motor axons in the maturing mouse. J Peripher Nerv Syst 2009; 14:45-53. [PMID: 19335539 DOI: 10.1111/j.1529-8027.2009.00205.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Non-invasive excitability tests have been developed to appraise axonal membrane properties in peripheral nerves and are contributing to our understanding of neuropathies and neuronopathies. These techniques have been adapted to in vivo and in vitro rat models, but little data are available on mice, although mice provide more transgenic models of neurological disorders. This study was therefore undertaken to assess the suitability of mice to model human nerve excitability measurements and to document changes during maturation. Female mice, aged 4-19 weeks, were recorded under isoflurane anesthesia. Electrical stimuli were applied via surface electrodes to the caudal motor nerve and compound muscle action potentials (CMAPs) recorded from the tail with needle electrodes. Then, the sciatic nerve was stimulated above the ankle and CMAPs recorded from plantar muscles. The method was only minimally invasive, enabling the same animal to be tested up to eight times at weekly intervals. As in human studies, the multiple excitability program recorded stimulus-response, strength-duration, and current-threshold relationships; threshold electrotonus; and recovery cycle. The response waveforms were qualitatively similar to those from human axons. This resemblance was closer for the caudal nerve, which also showed more marked changes with age. Early hyperpolarizing electrotonus fell sharply from weeks 4 to 13 (p < 0.0001), while a progressive increase in superexcitability occurred throughout the period studied (p < 0.001). We conclude that multiple measures of nerve excitability can be performed reliably in mice in vivo, preferentially on the tail, and are suitable for longitudinal studies, but age matching is critical for younger animals.
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Affiliation(s)
- Delphine Boërio
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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Abstract
OBJECTIVE There is an increasing interest in using mouse models for electrodiagnostic research. Studying transgenic mice with various pathologies adds to our knowledge of the natural history of a disease. It is imperative, however, to compare disease models with the appropriate control. DESIGN For these animals to be used in electrodiagnostic research, reference values must be set. If reference values are not available, the validity of data are highly questionable. We propose a method of obtaining mixed nerve action potentials and collect reference values from the sural nerve of mice. RESULTS The results were a mean peak latency of 1.74 msecs on the right and 1.89 msecs on the left. The mean amplitude was 17.0 microV on the left and 21.6 microV on the right. CONCLUSIONS In future studies, these reference values can be useful tools in analysis of murine subjects.
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