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Dahlin LB, Zimmerman M, Calcagni M, Hundepool CA, van Alfen N, Chung KC. Carpal tunnel syndrome. Nat Rev Dis Primers 2024; 10:37. [PMID: 38782929 DOI: 10.1038/s41572-024-00521-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/17/2024] [Indexed: 05/25/2024]
Abstract
Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder worldwide. The epidemiology and risk factors, including family burden, for developing CTS are multi-factorial. Despite much research, its intricate pathophysiological mechanism(s) are not fully understood. An underlying subclinical neuropathy may indicate an increased susceptibility to developing CTS. Although surgery is often performed for CTS, clear international guidelines to indicate when to perform non-surgical or surgical treatment, based on stage and severity of CTS, remain to be elucidated. Neurophysiological examination, using electrophysiology or ultrasonography, performed in certain circumstances, should correlate with the history and findings in clinical examination of the person with CTS. History and clinical examination are particularly relevant globally owing to lack of other equipment. Various instruments are used to assess CTS and treatment outcomes as well as the effect of the disorder on quality of life. The surgical treatment options of CTS - open or endoscopic - offer an effective solution to mitigate functional impairments and pain. However, there are risks of post-operative persistent or recurrent symptoms, requiring meticulous diagnostic re-evaluation before any additional surgery. Health-care professionals should have increased awareness about CTS and all its implications. Future considerations of CTS include use of linked national registries to understand risk factors, explore possible screening methods, and evaluate diagnosis and treatment with a broader perspective beyond surgery, including psychological well-being.
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Affiliation(s)
- Lars B Dahlin
- Department of Translational Medicine - Hand Surgery, Lund University, Malmö, Sweden.
- Department of Hand Surgery, Skåne University Hospital, Malmö, Sweden.
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
| | - Malin Zimmerman
- Department of Translational Medicine - Hand Surgery, Lund University, Malmö, Sweden
- Department of Hand Surgery, Skåne University Hospital, Malmö, Sweden
- Department of Orthopedics, Helsingborg Hospital, Helsingborg, Sweden
| | - Maurizio Calcagni
- Department of Plastic Surgery and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Caroline A Hundepool
- Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, Rotterdam, The Netherlands
| | - Nens van Alfen
- Department of Neurology and Clinical Neurophysiology, Clinical Neuromuscular Imaging Group, Donders Center for Neuroscience, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kevin C Chung
- Professor of Surgery, Section of Plastic Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, USA
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Witkowski G, Szulczyk B, Nurowska E, Jurek M, Pasierski M, Lipiec A, Charzewska A, Dawidziuk M, Milewski M, Owsiak S, Rola R, Sienkiewicz Jarosz H, Hoffman-Zacharska D. Functional Characteristics of the Nav1.1 p.Arg1596Cys Mutation Associated with Varying Severity of Epilepsy Phenotypes. Int J Mol Sci 2024; 25:1745. [PMID: 38339022 PMCID: PMC10855957 DOI: 10.3390/ijms25031745] [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: 12/29/2023] [Revised: 01/20/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
Mutations of the SCN1A gene, which encodes the voltage-dependent Na+ channel's α subunit, are associated with diverse epileptic syndromes ranging in severity, even intra-family, from febrile seizures to epileptic encephalopathy. The underlying cause of this variability is unknown, suggesting the involvement of additional factors. The aim of our study was to describe the properties of mutated channels and investigate genetic causes for clinical syndromes' variability in the family of five SCN1A gene p.Arg1596Cys mutation carriers. The analysis of additional genetic factors influencing SCN1A-associated phenotypes was conducted through exome sequencing (WES). To assess the impact of mutations, we used patch clamp analysis of mutated channels expressed in HEK cells and in vivo neural excitability studies (NESs). In cells expressing the mutant channel, sodium currents were reduced. NESs indicated increased excitability of peripheral motor neurons in mutation carriers. WES showed the absence of non-SCA1 pathogenic variants that could be causative of disease in the family. Variants of uncertain significance in three genes, as potential modifiers of the most severe phenotype, were identified. The p.Arg1596Cys substitution inhibits channel function, affecting steady-state inactivation kinetics. Its clinical manifestations involve not only epileptic symptoms but also increased excitability of peripheral motor fibers. The role of Nav1.1 in excitatory neurons cannot be ruled out as a significant factor of the clinical phenotype.
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Affiliation(s)
- Grzegorz Witkowski
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
- Military Institute of Aviation Medicine, Krasinskiego 54/56, 01-755 Warsaw, Poland;
| | - Bartlomiej Szulczyk
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Ewa Nurowska
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Marta Jurek
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Michal Pasierski
- Chair and Department of Pharmacotherapy and Pharmaceutical Care, Faculty of Pharmacy, The Medical University of Warsaw, Banacha 1b, 02-097 Warsaw, Poland; (B.S.); (E.N.); (M.P.)
| | - Agata Lipiec
- Clinic of Pediatric Neurology, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland;
| | - Agnieszka Charzewska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Mateusz Dawidziuk
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Michal Milewski
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
| | - Szymon Owsiak
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
| | - Rafal Rola
- Military Institute of Aviation Medicine, Krasinskiego 54/56, 01-755 Warsaw, Poland;
| | - Halina Sienkiewicz Jarosz
- First Department of Neurology, Institute of Psychiatry and Neurology, Sobieskiego 9, 02-957 Warsaw, Poland; (S.O.); (H.S.J.)
| | - Dorota Hoffman-Zacharska
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211 Warsaw, Poland; (M.J.); (A.C.); (M.M.); (D.H.-Z.)
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland
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Sonawane K, Dixit H, Thota N, Mistry T, Balavenkatasubramanian J. "Knowing It Before Blocking It," the ABCD of the Peripheral Nerves: Part B (Nerve Injury Types, Mechanisms, and Pathogenesis). Cureus 2023; 15:e43143. [PMID: 37692583 PMCID: PMC10484240 DOI: 10.7759/cureus.43143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2023] [Indexed: 09/12/2023] Open
Abstract
Selander emphatically said, "Handle these nerves with care," and those words still echo, conveying a loud and clear message that, however rare, peripheral nerve injury (PNI) remains a perturbing possibility that cannot be ignored. The unprecedented nerve injuries associated with peripheral nerve blocks (PNBs) can be most tormenting for the unfortunate patient and a nightmare for the anesthetist. Possible justifications for the seemingly infrequent occurrences of PNB-related PNIs include a lack of documentation/reporting, improper aftercare, or associated legal implications. Although they make up only a small portion of medicolegal claims, they are sometimes difficult to defend. The most common allegations are attributed to insufficient informed consent; preventable damage to a nerve(s); delay in diagnosis, referral, or treatment; misdiagnosis, and inappropriate treatment and follow-up care. Also, sufficient prospective studies or randomized trials have not been conducted, as exploring such nerve injuries (PNB-related) in living patients or volunteers may be impractical or unethical. Understanding the pathophysiology of various types of nerve injury is vital to dealing with them further. Processes like degeneration, regeneration, remyelination, and reinnervation can influence the findings of electrophysiological studies. Events occurring in such a process and their impact during the assessment determine the prognosis and the need for further interventions. This educational review describes various types of PNB-related nerve injuries and their associated pathophysiology.
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Affiliation(s)
- Kartik Sonawane
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
| | - Hrudini Dixit
- Anesthesiology, Sir H. N. Reliance Foundation Hospital and Research Centre, Mumbai, IND
| | - Navya Thota
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
| | - Tuhin Mistry
- Anesthesiology, Ganga Medical Centre and Hospitals, Coimbatore, IND
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Røikjer J, Croosu SS, Frøkjær JB, Hansen TM, Arendt-Nielsen L, Ejskjaer N, Mørch CD. Perception threshold tracking: validating a novel method for assessing function of large and small sensory nerve fibers in diabetic peripheral neuropathy with and without pain. Pain 2023; 164:886-894. [PMID: 36130086 DOI: 10.1097/j.pain.0000000000002780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 08/31/2022] [Indexed: 11/26/2022]
Abstract
ABSTRACT It remains unknown why some people with diabetes develop painful neuropathies while others experience no pain. This study aimed to validate a novel method for assessing the function of small sensory nerves in diabetes to further elucidate this phenomenon. The function of large and small nerves was assessed using a novel perception threshold tracking technique in 3 well-characterized groups (n = 60) with type 1 diabetes, namely, (1) painful diabetic peripheral neuropathy (T1DM + PDPN), (2) painless diabetic peripheral neuropathy (T1DM + DPN), and (3) no neuropathy (T1DM - DPN), and healthy controls (n = 20). Electrical currents with different shapes, duration, and intensities were applied by 2 different skin electrodes activating large and small fibers, respectively. The minimal current needed to activate the fibers were analyzed as the rheobase of the stimulus-response function. Nerve fiber selectivity was measured by accommodation properties of stimulated nerves. The rheobase of both fiber types were highest for T1DM + PDPN, followed by T1DM + DPN, T1DM - DPN, and healthy controls, indicating that the nerve properties are specific in individuals with diabetes and pain. There was an overall significant difference between the groups ( P < 0.01). The accommodation properties of stimulated fibers were different between the 2 electrodes ( P < 0.05) apart from in the group with T1DM + PDPN, where both electrodes stimulated nerves displaying properties similar to large fibers. Perception threshold tracking reveals differences in large and small nerve fiber function between the groups with and without diabetes, DPN, and pain. This indicates that the methods have potential applications in screening DPN and explore further the features differentiating painful from nonpainful DPN.
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Affiliation(s)
- Johan Røikjer
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Suganthiya Santhiapillai Croosu
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Radiology, Aalborg University Hospital, Aalborg, Denmark
| | - Jens Brøndum Frøkjær
- Department of Radiology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Tine Maria Hansen
- Department of Radiology, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Lars Arendt-Nielsen
- Center for Neuroplasticity and Pain (CNAP), SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
- Department of Medical Gastroenterology, Mech-Sense, Aalborg University Hospital, Aalborg, Denmark
| | - Niels Ejskjaer
- Steno Diabetes Center North Denmark, Aalborg University Hospital, Aalborg, Denmark
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
| | - Carsten Dahl Mørch
- Center for Neuroplasticity and Pain (CNAP), SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Yoon SM, Park YB, Ko Y, Bae JS. Chronic Hypoxemia Triggers a Neuropathic Process in Chronic Obstructive Pulmonary Disease: Insight From In Vivo Neurophysiological Assessments. J Clin Neurol 2023; 19:186-194. [PMID: 36854335 PMCID: PMC9982175 DOI: 10.3988/jcn.2022.0249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 09/16/2022] [Accepted: 10/07/2022] [Indexed: 02/21/2023] Open
Abstract
BACKGROUND AND PURPOSE Peripheral neuropathies (PNs) are a common but poorly understood complication of chronic obstructive pulmonary disease (COPD). To clarify the initial trigger of a PN in COPD, we investigated the excitability of peripheral nerves in patients with COPD. METHODS The automated nerve excitability test (NET) using the threshold-tracking paradigm was applied to 20 COPD patients. The recording protocol calculated the strength-duration time constant, threshold electrotonus (TE), current-threshold relationship, and recovery cycle (RC). Each NET parameter was compared with two control groups: normal controls group (NC group) and smokers without COPD group (smoker group). RESULTS In the motor NETs, the change in the threshold in the mid-depolarizing phase of TE (40-60 ms) was smaller in the COPD group (50.7%±1.2%, mean±SEM; n=20) than in the NC group (54.5%±0.7%, n=25; p<0.01), as was the prominence of superexcitability in the RC (-22.6%±1.5% and -26.4%±1.1%, respectively; p=0.04). There were no significant differences in the sensory NETs. Comparisons between the COPD and smoker groups (n=25) also showed no differences in either the motor or sensory NETs. CONCLUSIONS The pattern of excitability in COPD revealed a membrane depolarization attributable to Na+-K+-ATPase failure in the axolemma of distal motor nerves. This finding suggests that chronic hypoxemia and adaptative process can alter axonal excitability and trigger a resultant neuropathic process that is antecedent to PN in COPD.
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Affiliation(s)
- Seon Min Yoon
- Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Young Bum Park
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Yousang Ko
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
| | - Jong Seok Bae
- Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea.
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Abstract
Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.
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Affiliation(s)
- Qihua Fan
- Department of Neurology, Division of Neuromuscular Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - A Gordon Smith
- Department of Neurology, Division of Neuromuscular Medicine, Virginia Commonwealth University, Richmond, VA, USA
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Neuroplasticity of peripheral axonal properties after ischemic stroke. PLoS One 2022; 17:e0275450. [PMID: 36194586 PMCID: PMC9531785 DOI: 10.1371/journal.pone.0275450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/15/2022] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE This study investigated how peripheral axonal excitability changes in ischemic stroke patients with hemiparesis or hemiplegia, reflecting the plasticity of motor axons due to corticospinal tract alterations along the poststroke stage. METHODS Each subject received a clinical evaluation, nerve conduction study, and nerve excitability test. Nerve excitability tests were performed on motor median nerves in paretic and non-paretic limbs in the acute stage of stroke. Control nerve excitability test data were obtained from age-matched control subjects. Some patients underwent excitability examinations several times in subacute or chronic stages. RESULTS A total of thirty patients with acute ischemic stroke were enrolled. Eight patients were excluded due to severe entrapment neuropathy in the median nerve. The threshold current for 50% compound muscle action potential (CMAP) was higher in paretic limbs than in control subjects. Furthermore, in the cohort with severe patients (muscle power ≤ 3/5 in affected hands), increased threshold current for 50% CMAP and reduced subexcitability were noted in affected limbs than in unaffected limbs. In addition, in the subsequent study of those severe patients, threshold electrotonus increased in the hyperpolarization direction: TEh (100-109 ms), and the minimum I/V slope decreased. The above findings suggest the less excitable and less accommodation in lower motor axons in the paretic limb caused by ischemic stroke. CONCLUSION Upper motor neuron injury after stroke can alter nerve excitability in lower motor neurons, and the changes are more obvious in severely paretic limbs. The accommodative changes of axons progress from the subacute to the chronic stage after stroke. Further investigation is necessary to explore the downstream effects of an upper motor neuron insult in the peripheral nerve system.
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Jankowska E, Kaczmarek D, Hammar I. Long-term modulation of the axonal refractory period. Eur J Neurosci 2022; 56:4983-4999. [PMID: 35999192 PMCID: PMC9826316 DOI: 10.1111/ejn.15801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/25/2022] [Accepted: 08/15/2022] [Indexed: 01/11/2023]
Abstract
The main question addressed in this study was whether the refractoriness of nerve fibres can be modulated by their depolarisation and, if so, whether depolarisation of nerve fibres evokes a long-term decrease in the duration of the refractory period as well as the previously demonstrated increase in their excitability. This was investigated on nerve fibres within the dorsal columns, dorsal roots and peripheral nerves in deeply anaesthetised rats in vivo. The results revealed major differences depending on the sites of fibre stimulation and polarisation. Firstly, the relative refractory period was found to be shorter in epidurally stimulated dorsal column fibres than in fibres stimulated at other sites. Secondly, the minimal effective interstimulus intervals reflecting the absolute refractory period were likewise shorter for nerve fibres within the dorsal columns even though action potentials evoked by the second of a pair of stimuli were similarly delayed with respect to the preceding action potentials at all the stimulation sites. Thirdly, the minimal interstimulus intervals were reduced by epidurally applied cathodal direct current polarisation but not at other stimulation sites. Consequently, higher proportions of dorsal column fibres could be excited at higher frequencies, especially following their depolarisation, at interstimulus intervals as short as 0.5-0.7 ms. The results demonstrate that epidural depolarisation results in long-lasting effects not only on the excitability but also on the refractoriness of dorsal column fibres. They also provide further evidence for specific features of afferent fibres traversing the dorsal columns previously linked to properties of their branching regions.
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Affiliation(s)
- Elzbieta Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Dominik Kaczmarek
- Department of Physiology and BiochemistryPoznan University of Physical EducationPoznanPoland
| | - Ingela Hammar
- Department of Neuroscience and Physiology, Sahlgrenska AcademyUniversity of GothenburgGothenburgSweden
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Kudina LP, Andreeva RE. Human motoneuron firing behavior and single motor unit F-wave. J Electromyogr Kinesiol 2022; 63:102641. [DOI: 10.1016/j.jelekin.2022.102641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/31/2022] [Accepted: 02/03/2022] [Indexed: 10/19/2022] Open
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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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Fan Q, Gordon Smith A. Recent updates in the treatment of diabetic polyneuropathy. Fac Rev 2022. [PMID: 36311537 DOI: 10.1270/r/11-30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2023] Open
Abstract
Distal symmetric diabetic peripheral polyneuropathy (DPN) is the most common form of neuropathy in the world, affecting 30 to 50% of diabetic individuals and resulting in significant morbidity and socioeconomic costs. This review summarizes updates in the diagnosis and management of DPN. Recently updated clinical criteria facilitate bedside diagnosis, and a number of new technologies are being explored for diagnostic confirmation in specific settings and for use as surrogate measures in clinical trials. Evolving literature indicates that distinct but overlapping mechanisms underlie neuropathy in type 1 versus type 2 diabetes, and there is a growing focus on the role of metabolic factors in the development and progression of DPN. Exercise-based lifestyle interventions have shown therapeutic promise. A variety of potential disease-modifying and symptomatic therapies are in development. Innovations in clinical trial design include the incorporation of detailed pain phenotyping and biomarkers for central sensitization.
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Affiliation(s)
- Qihua Fan
- Department of Neurology, Division of Neuromuscular Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - A Gordon Smith
- Department of Neurology, Division of Neuromuscular Medicine, Virginia Commonwealth University, Richmond, VA, USA
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12
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Abstract
Neuroelectrophysiology is an old science, dating to the 18th century when electrical activity in nerves was discovered. Such discoveries have led to a variety of neurophysiological techniques, ranging from basic neuroscience to clinical applications. These clinical applications allow assessment of complex neurological functions such as (but not limited to) sensory perception (vision, hearing, somatosensory function), and muscle function. The ability to use similar techniques in both humans and animal models increases the ability to perform mechanistic research to investigate neurological problems. Good animal to human homology of many neurophysiological systems facilitates interpretation of data to provide cause-effect linkages to epidemiological findings. Mechanistic cellular research to screen for toxicity often includes gaps between cellular and whole animal/person neurophysiological changes, preventing understanding of the complete function of the nervous system. Building Adverse Outcome Pathways (AOPs) will allow us to begin to identify brain regions, timelines, neurotransmitters, etc. that may be Key Events (KE) in the Adverse Outcomes (AO). This requires an integrated strategy, from in vitro to in vivo (and hypothesis generation, testing, revision). Scientists need to determine intermediate levels of nervous system organization that are related to an AO and work both upstream and downstream using mechanistic approaches. Possibly more than any other organ, the brain will require networks of pathways/AOPs to allow sufficient predictive accuracy. Advancements in neurobiological techniques should be incorporated into these AOP-base neurotoxicological assessments, including interactions between many regions of the brain simultaneously. Coupled with advancements in optogenetic manipulation, complex functions of the nervous system (such as acquisition, attention, sensory perception, etc.) can be examined in real time. The integration of neurophysiological changes with changes in gene/protein expression can begin to provide the mechanistic underpinnings for biological changes. Establishment of linkages between changes in cellular physiology and those at the level of the AO will allow construction of biological pathways (AOPs) and allow development of higher throughput assays to test for changes to critical physiological circuits. To allow mechanistic/predictive toxicology of the nervous system to be protective of human populations, neuroelectrophysiology has a critical role in our future.
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Affiliation(s)
- David W Herr
- Neurological and Endocrine Toxicology Branch, Public Health and Integrated Toxicology Division, CPHEA/ORD, U.S. Environmental Protection Agency, Washington, NC, United States
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13
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Jankowska E, Hammar I. The plasticity of nerve fibers: the prolonged effects of polarization of afferent fibers. J Neurophysiol 2021; 126:1568-1591. [PMID: 34525323 DOI: 10.1152/jn.00718.2020] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The review surveys various aspects of the plasticity of nerve fibers, in particular the prolonged increase in their excitability evoked by polarization, focusing on a long-lasting increase in the excitability of myelinated afferent fibers traversing the dorsal columns of the spinal cord. We review the evidence that increased axonal excitability 1) follows epidurally applied direct current (DC) as well as relatively short (5 or 10 ms) current pulses and synaptically evoked intrinsic field potentials; 2) critically depends on the polarization of branching regions of afferent fibers at the sites where they bifurcate and give off axon collaterals entering the spinal gray matter in conjunction with actions of extrasynaptic GABAA membrane receptors; and 3) shares the feature of being activity-independent with the short-lasting effects of polarization of peripheral nerve fibers. A comparison between the polarization evoked sustained increase in the excitability of dorsal column fibers and spinal motoneurons (plateau potentials) indicates the possibility that they are mediated by partly similar membrane channels (including noninactivating type L Cav++ 1.3 but not Na+ channels) and partly different mechanisms. We finally consider under which conditions transspinally applied DC (tsDCS) might reproduce the effects of epidural polarization on dorsal column fibers and the possible advantages of increased excitability of afferent fibers for the rehabilitation of motor and sensory functions after spinal cord injuries.NEW & NOTEWORTHY This review supplements previous reviews of properties of nerve fibers by surveying recent experimental evidence for their long-term plasticity. It also extends recent descriptions of spinal effects of DC by reviewing effects of polarization of afferent nerve fibers within the dorsal columns, the mechanisms most likely underlying the long-lasting increase in their excitability and possible clinical implications.
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Affiliation(s)
- Elzbieta Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Ingela Hammar
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Hijma HJ, Groeneveld GJ. Analgesic drug development: proof-of-mechanism and proof-of-concept in early phase clinical studies. MEDICINE IN DRUG DISCOVERY 2021. [DOI: 10.1016/j.medidd.2021.100083] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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15
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Insausti-Delgado A, López-Larraz E, Omedes J, Ramos-Murguialday A. Intensity and Dose of Neuromuscular Electrical Stimulation Influence Sensorimotor Cortical Excitability. Front Neurosci 2021; 14:593360. [PMID: 33519355 PMCID: PMC7845652 DOI: 10.3389/fnins.2020.593360] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
Neuromuscular electrical stimulation (NMES) of the nervous system has been extensively used in neurorehabilitation due to its capacity to engage the muscle fibers, improving muscle tone, and the neural pathways, sending afferent volleys toward the brain. Although different neuroimaging tools suggested the capability of NMES to regulate the excitability of sensorimotor cortex and corticospinal circuits, how the intensity and dose of NMES can neuromodulate the brain oscillatory activity measured with electroencephalography (EEG) is still unknown to date. We quantified the effect of NMES parameters on brain oscillatory activity of 12 healthy participants who underwent stimulation of wrist extensors during rest. Three different NMES intensities were included, two below and one above the individual motor threshold, fixing the stimulation frequency to 35 Hz and the pulse width to 300 μs. Firstly, we efficiently removed stimulation artifacts from the EEG recordings. Secondly, we analyzed the effect of amplitude and dose on the sensorimotor oscillatory activity. On the one hand, we observed a significant NMES intensity-dependent modulation of brain activity, demonstrating the direct effect of afferent receptor recruitment. On the other hand, we described a significant NMES intensity-dependent dose-effect on sensorimotor activity modulation over time, with below-motor-threshold intensities causing cortical inhibition and above-motor-threshold intensities causing cortical facilitation. Our results highlight the relevance of intensity and dose of NMES, and show that these parameters can influence the recruitment of the sensorimotor pathways from the muscle to the brain, which should be carefully considered for the design of novel neuromodulation interventions based on NMES.
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Affiliation(s)
- Ainhoa Insausti-Delgado
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- International Max Planck Research School (IMPRS) for Cognitive and Systems Neuroscience, Tübingen, Germany
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Eduardo López-Larraz
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Bitbrain, Zaragoza, Spain
| | - Jason Omedes
- Instituto de Investigación en Ingeniería de Aragón (I3A), Zaragoza, Spain
- Departamento de Informática e Ingeniería de Sistemas (DIIS), University of Zaragoza, Zaragoza, Spain
| | - Ander Ramos-Murguialday
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
- Neurotechnology Laboratory, TECNALIA, Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián, Spain
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Makker PGS, Keating BA, Lees JG, Burke D, Howells J, Moalem-Taylor G. Electrophysiological investigation of motor axonal excitability in a mouse model of nerve constriction injury. J Peripher Nerv Syst 2021; 26:99-112. [PMID: 33432642 DOI: 10.1111/jns.12430] [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: 11/09/2020] [Revised: 12/19/2020] [Accepted: 12/30/2020] [Indexed: 11/29/2022]
Abstract
Peripheral nerve injuries caused by focal constriction are characterised by local nerve ischaemia, axonal degeneration, demyelination, and neuroinflammation. The aim of this study was to understand temporal changes in the excitability properties of injured motor axons in a mouse model of nerve constriction injury (NCI). The excitability of motor axons following unilateral sciatic NCI was studied in male C57BL/6J mice distal to the site of injury at the acute (6 hours-1 week) and chronic (up to 20 weeks) phases of injury, using threshold tracking. Multiple measures of nerve excitability, including strength-duration properties, threshold electrotonus, current-threshold relationship, and recovery cycle were examined using the automated nerve excitability protocol (TRONDNF). Acutely, injured motor axons developed a pattern of excitability characteristic of ischemic depolarisation. In most cases, the sciatic nerve became transiently inexcitable. When a liminal compound muscle action potential could again be recorded, it had an increase in threshold and latency, compared to both pre-injury baseline and sham-injured groups. These axons showed a greater threshold change in response to hyperpolarising threshold electrotonus and a significant upward shift in the recovery cycle. Mathematical modelling suggested that the changes seen in chronically injured axons involve shortened internodes, reduced myelination, and exposed juxtaparanodal fast K+ conductances. The findings of this study demonstrate long-term changes in motor excitability following NCI (involving alterations in axonal properties and ion channel activity) and are important for understanding the mechanisms of neurapraxic injuries and traumatic mononeuropathies.
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Affiliation(s)
- Preet G S Makker
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Brooke A Keating
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - Justin G Lees
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales (UNSW), Sydney, New South Wales, Australia
| | - David Burke
- Central Clinical School, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - James Howells
- Central Clinical School, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Gila Moalem-Taylor
- Translational Neuroscience Facility, School of Medical Sciences, The University of New South Wales (UNSW), Sydney, New South Wales, Australia
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Turan Z, Zinnuroğlu M. Peripheral axonal excitability in hemiplegia related to subacute stroke. Turk J Med Sci 2020; 50:1983-1992. [PMID: 32682362 PMCID: PMC7775702 DOI: 10.3906/sag-2004-306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/18/2020] [Indexed: 11/07/2022] Open
Abstract
Background/aim This study aims to investigate peripheral nerve excitability in patients with subacute stroke. Materials and methods The study was performed in 29 stroke patients within the subacute period and 29 healthy controls using QTRAC software and TRONDNF protocol. The threshold electrotonus, recovery cycle, stimulus-response, strength-duration, and current-threshold relationships were recorded. Results The membrane was more hyperpolarized, and excitability was decreased in the hemiplegic side. The impairment of inward rectifying channel function, degree of hyperpolarization, and decrease of excitability were directly related to the Brunnstrom stages, which were more pronounced in lower stages. Conclusion The lower motor neurons were affected at the level of axonal channels as a result of upper motor neuron lesions. It can be due to dying back neuropathy, homeostasis, and neurovascular regulation changes in the axonal environment, activity-dependent plastic changes, loss of drive coming from the central nervous system, or a combination of these factors.
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Affiliation(s)
- Zeynep Turan
- Department of Physical Medicine and Rehabilitation, Koç University Hospital, İstanbul, Turkey
| | - Murat Zinnuroğlu
- Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Gazi University, Ankara, Turkey
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Does Essential Tremor Alter the Axonal Excitability Properties of Lower Motor Neurons? J Clin Neurophysiol 2020; 39:492-496. [PMID: 33369992 DOI: 10.1097/wnp.0000000000000799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Automated nerve excitability testing has identified that the altered excitability of lower motor neuron (LMN) axons in central diseases is because of trans-synaptic plasticity. Essential tremor (ET) is considered a central disorder caused by an altered cerebellar circuit. This study aimed to identify alterations in the excitability of distal motor axons in subjects with ET, with the intention of clarifying whether a trans-synaptic mechanism or LMN adaptation for tremor affects the LMNs of subjects with ET. METHODS Twenty-one consecutive patients diagnosed with ET underwent a clinical and electrophysiological evaluation. For the enrolled cases and 45 age- and gender-matched healthy controls, automated nerve excitability testing with threshold tracking techniques (QTRACS software with TRONDF multiple-excitability protocol) was used to evaluate multiple nerve excitability indices in distal median nerve motor axons. RESULTS The automated protocol calculated the strength-duration time constant, parameters of threshold electrotonus and current-threshold relationship, and the recovery cycle of excitability. Comparisons of the automated nerve excitability testing parameters revealed no significant differences between the ET and control groups in any of strength-duration time constant, threshold electrotonus, current-threshold relationship, and recovery cycle, whereas the rheobase was higher in the ET group (3.4 ± 1.1 vs. 2.3 ± 1.1, mean ± standard error mean; P < 0.01). CONCLUSIONS With the exception of an increased rheobase in ET subjects, no significant differences were observed in LMN excitability between the ET subjects and their controls. The extent of plasticity or adaptation in LMNs may be limited to a major change in central processes that exert marked effects on the pool of LMNs.
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Kandula T, Park SB, Carey KA, Lin CSY, Farrar MA. Peripheral nerve maturation and excitability properties from early childhood: Comparison of motor and sensory nerves. Clin Neurophysiol 2020; 131:2452-2459. [PMID: 32829292 DOI: 10.1016/j.clinph.2020.06.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 06/11/2020] [Accepted: 06/28/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE Understanding of maturational properties of sensory and motor axons is of central importance for determining the impact of nerve changes in health and in disease in children and young adults. METHODS This study investigated maturation of sensory axons using axonal excitability parameters of the median nerve in 47 children, adolescents and young adults (25 males, 22 females; age range 1-25 years) and compared them to concurrent motor studies. RESULTS The overall pattern of sensory maturation was similar to motor maturation demonstrating prolongation of the strength duration time constant (P < 0.001), reduction of hyperpolarising threshold electrotonus (P = 0.002), prolongation of accommodation half-time (P = 0.005), reduction in hyperpolarising current-threshold slope (P = 0.03), and a shift to the right of the refractory cycle curve (P < 0.001), reflecting changes in passive membrane properties and fast potassium channel conductances. Sensory axons, however, had a greater increase in strength duration time constant and more attenuated changes in depolarising threshold electrotonus and current-threshold parameters, attributable to a more depolarised resting membrane potential evident from early childhood and maintained in adults. Peak amplitude was established early in sensory axons whereas motor amplitude increased with age (P < 0.001), reflecting non-axonal motor unit changes. CONCLUSIONS Maturational trajectories of sensory and motor axons were broadly parallel in children and young adults, but sensory-motor differences were initiated early in maturation. SIGNIFICANCE Identifying the evolution of biophysical changes within and between sensory and motor axons through childhood and adolescence is fundamental to understanding developmental physiology and interpreting disease-related changes in immature nerves.
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Affiliation(s)
- Tejaswi Kandula
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, High Street, Randwick, NSW 2031, Australia; Department of Neurology, Sydney Children's Hospital, High Street, Randwick, NSW 2031, Australia
| | - Susanna B Park
- Brain and Mind Centre, Faculty of Medicine and Health, University of Sydney, 94 Mallett Street, Camperdown, NSW 2051, Australia
| | - Kate A Carey
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, High Street, Randwick, NSW 2031, Australia
| | - Cindy S-Y Lin
- Brain and Mind Centre, Faculty of Medicine and Health, University of Sydney, 94 Mallett Street, Camperdown, NSW 2051, Australia
| | - Michelle A Farrar
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, High Street, Randwick, NSW 2031, Australia; Department of Neurology, Sydney Children's Hospital, High Street, Randwick, NSW 2031, Australia.
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20
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Lin Y, Lin CS, Chang T, Lee J, Tani J, Chen H, Sung J. Early sensory neurophysiological changes in prediabetes. J Diabetes Investig 2020; 11:458-465. [PMID: 31563156 PMCID: PMC7078118 DOI: 10.1111/jdi.13151] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 12/14/2022] Open
Abstract
AIMS/INTRODUCTION To elucidate whether axonal changes arise in the prediabetic state and to find a biomarker for early detection of neurophysiological changes. MATERIALS AND METHODS We enrolled asymptomatic diabetes patients, as well as prediabetic and normoglycemic individuals to test sensory nerve excitability, and we analyzed those findings and their correlation with clinical profiles. RESULTS In nerve excitability tests, superexcitability in the recovery cycle showed increasing changes in the normoglycemic, prediabetes and diabetes cohorts (-19.09 ± 4.56% in normoglycemia, -22.39 ± 3.16% in prediabetes and -23.71 ± 5.15% in diabetes, P = 0.002). Relatively prolonged distal sensory latency was observed in the median nerve (3.12 ± 0.29 ms in normoglycemia, 3.23 ± 0.38 ms in prediabetes and 3.45 ± 0.43 ms in diabetes, P = 0.019). Superexcitability was positively correlated with fasting plasma glucose (r = 0.291, P = 0.009) and glycated hemoglobin (r = 0.331, P = 0.003) in all participants. CONCLUSIONS Sensory superexcitability and latencies are the most sensitive parameters for detecting preclinical physiological dysfunction in prediabetes. In addition, changes in favor of superexcitability were positively correlated with glycated hemoglobin for all participants. These results suggest that early axonal changes start in the prediabetic stage, and that the monitoring strategy for polyneuropathy should start as early as prediabetes.
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Affiliation(s)
- Yi‐Chen Lin
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Cindy Shin‐Yi Lin
- Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
- The Kam Ling Barbara Lo Chair in Neurodegenerative DisordersCentral Clinical SchoolFaculty of Medicine and Health, Brain and Mind CenterThe University of SydneySydneyAustralia
| | - Tsui‐San Chang
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Department of NeurologySchool of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
| | - Jing‐Er Lee
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Jowy Tani
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
- Ph.D. Program for Neural Regenerative MedicineCollege of Medical Science and TechnologyTaipei Medical University and National Health Research InstitutesTaipeiTaiwan
| | - Hung‐Ju Chen
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
| | - Jia‐Ying Sung
- Department of NeurologyTaipei Municipal Wanfang HospitalTaipei Medical UniversityTaipeiTaiwan
- Neuroscience InstituteTaipei Medical UniversityTaipeiTaiwan
- Department of NeurologySchool of Medicine, College of MedicineTaipei Medical UniversityTaipeiTaiwan
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Kandula T, Farrar MA, Cohn RJ, Carey KA, Johnston K, Kiernan MC, Krishnan AV, Park SB. Changes in long term peripheral nerve biophysical properties in childhood cancer survivors following neurotoxic chemotherapy. Clin Neurophysiol 2020; 131:783-790. [PMID: 32066096 DOI: 10.1016/j.clinph.2019.12.411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/14/2019] [Accepted: 12/07/2019] [Indexed: 12/28/2022]
Abstract
OBJECTIVE In the context of increasing numbers of childhood cancer survivors (CCS), this study aimed to enhance understanding of the biophysical basis for long term chemotherapy induced peripheral neuropathy from different chemotherapy agents in CCS. METHODS Detailed cross-sectional neurophysiological examination, using median nerve axonal excitability studies, alongside clinical assessments, in 103 long term CCS (10.5 ± 0.6 years post-treatment). RESULTS Cisplatin treated CCS (n = 16) demonstrated multiple sensory axonal excitability changes including increased threshold (P < 0.05), alterations in depolarising and hyperpolarising threshold electrotonus (P < 0.05) and reduction in resting and minimum IV slope (P < 0.01). Vincristine treated CCS (n = 73) were comparable to controls, except for prolonged distal motor latency (P = 0.001). No differences were seen in the non-neurotoxic chemotherapy group (n = 14). Abnormalities were more evident in the cisplatin subgroup with greater clinical neuropathy manifestations. CONCLUSION Persistent long term changes in axonal biophysical properties vary with different chemotherapy agents, most evident after cisplatin exposure. Longitudinal studies of nerve function during chemotherapy treatment are required to further evaluate these differences and their mechanistic basis. SIGNIFICANCE This study provides a unique biophysical perspective for persistent cisplatin related neurotoxicity in children, previously under recognised.
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Affiliation(s)
- T Kandula
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, Australia; Department of Neurology, Sydney Children's Hospital, Australia
| | - M A Farrar
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, Australia; Department of Neurology, Sydney Children's Hospital, Australia
| | - R J Cohn
- Kids Cancer Centre, Sydney Children's Hospital, Australia
| | - K A Carey
- School of Women's and Children's Health, UNSW Medicine, UNSW Sydney, Australia
| | - K Johnston
- Kids Cancer Centre, Sydney Children's Hospital, Australia
| | - M C Kiernan
- Brain & Mind Centre, University of Sydney, Australia
| | - A V Krishnan
- Prince of Wales Clinical School, UNSW Medicine, UNSW Sydney, Australia
| | - S B Park
- Brain & Mind Centre, University of Sydney, Australia; Prince of Wales Clinical School, UNSW Medicine, UNSW Sydney, Australia.
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Caetano A, Pereira P, Pereira M, de Carvalho M. Modulation of sensory nerve fiber excitability by transcutaneous cathodal direct current stimulation. Neurophysiol Clin 2019; 49:385-390. [PMID: 31735493 DOI: 10.1016/j.neucli.2019.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To assess the lasting effects on sensory nerve membrane excitability of transcutaneous peripheral nerve stimulation with cathodal direct currents (pDCS). METHODS We performed pDCS in 10 healthy subjects with the active electrode placed over the distal right forearm and the reference electrode on the back of the right hand. We used 5×5cm rubber electrodes and the current applied was 2.5mA during 15min. Three pDCS sessions were performed on the same day: first, a baseline stimulation was performed, followed by a sham stimulation and lastly a cathodal stimulation. Median sensory nerve excitability measurements were performed at baseline and immediately after each pDCS session using the TRONDNF nerve excitability protocol of the QTRAC program (measurement on the second finger). RESULTS The protocol was completed and well tolerated in all subjects. RRP (relative refractory period) and refractoriness at 2.5ms were significantly different across the three study conditions, with a significant increase of RRP immediately following cathodal stimulation compared with baseline assessment (mean 4.2 versus 5.3, P=0.002). Other measurements were not modulated by the intervention. Sham-stimulation did not change axonal excitability. CONCLUSIONS Cathodal pDCS stimulation increased RRP of sensory fibers, but no other consistent long-lasting effect was observed. This finding might suggest a reduction of sensory fiber excitability induced by cathodal pDCS.
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Affiliation(s)
- André Caetano
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Lisbon, Portugal.
| | - Pedro Pereira
- Department of Neurology, Hospital Garcia de Orta, Almada, Portugal
| | - Mariana Pereira
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurosciences, Hospital de Santa Maria, Centro Hospitalar de Lisboa Norte, Lisbon, Portugal
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A 15-minute session of direct current stimulation does not produce lasting changes in axonal excitability. Neurophysiol Clin 2019; 49:277-282. [DOI: 10.1016/j.neucli.2019.05.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 05/26/2019] [Accepted: 05/28/2019] [Indexed: 12/14/2022] Open
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Pharmacodynamics and Pharmacokinetics of Lidocaine in a Rodent Model of Diabetic Neuropathy. Anesthesiology 2018; 128:609-619. [DOI: 10.1097/aln.0000000000002035] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Abstract
Background
Clinical and experimental data show that peripheral nerve blocks last longer in the presence of diabetic neuropathy. This may occur because diabetic nerve fibers are more sensitive to local anesthetics or because the local anesthetic concentration decreases more slowly in the diabetic nerve. The aim of this study was to investigate both hypotheses in a rodent model of neuropathy secondary to type 2 diabetes.
Methods
We performed a series of sciatic nerve block experiments in 25 Zucker Diabetic Fatty rats aged 20 weeks with a neuropathy component confirmed by neurophysiology and control rats. We determined in vivo the minimum local anesthetic dose of lidocaine for sciatic nerve block. To investigate the pharmacokinetic hypothesis, we determined concentrations of radiolabeled (14C) lidocaine up to 90 min after administration. Last, dorsal root ganglia were excised for patch clamp measurements of sodium channel activity.
Results
First, in vivo minimum local anesthetic dose of lidocaine for sciatic nerve motor block was significantly lower in diabetic (0.9%) as compared to control rats (1.4%). Second, at 60 min after nerve block, intraneural lidocaine was higher in the diabetic animals. Third, single cell measurements showed a lower inhibitory concentration of lidocaine for blocking sodium currents in neuropathic as compared to control neurons.
Conclusions
We demonstrate increased sensitivity of the diabetic neuropathic nerve toward local anesthetics, and prolonged residence time of local anesthetics in the diabetic neuropathic nerve. In this rodent model of neuropathy, both pharmacodynamic and pharmacokinetic mechanisms contribute to prolonged nerve block duration.
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Kaczmarek D, Jankowska E. DC-Evoked Modulation of Excitability of Myelinated Nerve Fibers and Their Terminal Branches; Differences in Sustained Effects of DC. Neuroscience 2018; 374:236-249. [DOI: 10.1016/j.neuroscience.2018.01.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/16/2018] [Accepted: 01/17/2018] [Indexed: 12/20/2022]
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Vitzel KF, Fortes MA, Marzuca-Nassr GN, Scervino MVM, Pinheiro CH, Silveira LR, Curi R. In Vivo Electrical Stimulation for the Assessment of Skeletal Muscle Contractile Function in Murine Models. Methods Mol Biol 2018; 1735:381-395. [PMID: 29380329 DOI: 10.1007/978-1-4939-7614-0_26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Skeletal muscle electrical stimulation is commonly used for clinical purposes, assisting recovery, preservation, or even improvement of muscle mass and function in healthy and pathological conditions. Additionally, it is a useful research tool for evaluation of skeletal muscle contractile function. It may be applied in vitro, using cell culture or isolated fibers/muscles, and in vivo, using human subjects or animal models (neuromuscular electrical stimulation - NMES). This chapter focuses on the electrical stimulation of the sciatic nerve as a research method for evaluation of the contractile properties of murine hind limb muscles. Variations of this protocol allow for the assessment of muscle force, fatigue resistance, contraction and relaxation times, and can be used as a model of contraction-induced muscle injury, reactive oxygen species production, and muscle adaptation to contractile activity.
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Affiliation(s)
- Kaio F Vitzel
- School of Health Sciences, College of Health, Massey University, Auckland, New Zealand.
| | - Marco A Fortes
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | | | - Maria V M Scervino
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Carlos H Pinheiro
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Leonardo R Silveira
- Obesity and Comorbidities Research Center, Department of Structural and Functional Biology, Institute of Biology, Unicamp, Campinas, Sao Paulo, Brazil
| | - Rui Curi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil.,Interdisciplinary Post-Graduate Program in Health Sciences, Cruzeiro do Sul University, Sao Paulo, Brazil
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Zhu HY, Liu X, Miao X, Li D, Wang S, Xu GY. Up-regulation of CXCR4 expression contributes to persistent abdominal pain in rats with chronic pancreatitis. Mol Pain 2017; 13:1744806917697979. [PMID: 28337946 PMCID: PMC5407662 DOI: 10.1177/1744806917697979] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background Pain in patients with chronic pancreatitis is critical hallmark that accompanied inflammation, fibrosis, and destruction of glandular pancreas. Many researchers have demonstrated that stromal cell-derived factor 1 (also named as CXCL12) and its cognate receptor C-X-C chemokine receptor type 4 (CXCR4) involved in mediating neuropathic and bone cancer pain. However, their roles in chronic pancreatic pain remain largely unclear. Methods Chronic pancreatitis was induced by intraductal injection of trinitrobenzene sulfonic acid to the pancreas. Von Frey filament tests were conducted to evaluate pancreas hypersensitivity of rat. Expression of CXCL12, CXCR4, NaV1.8, and pERK in rat dorsal root ganglion was detected by Western blot analyses. Dorsal root ganglion neuronal excitability was assessed by electrophysiological recordings. Results We showed that both CXCL12 and CXCR4 were dramatically up-regulated in the dorsal root ganglion in trinitrobenzene sulfonic acid-induced chronic pancreatitis pain model. Intrathecal application with AMD3100, a potent and selective CXCR4 inhibitor, reversed the hyperexcitability of dorsal root ganglion neurons innervating the pancreas of rats following trinitrobenzene sulfonic acid injection. Furthermore, trinitrobenzene sulfonic acid-induced extracellular signal-regulated kinase activation and Nav1.8 up-regulation in dorsal root ganglias were reversed by intrathecal application with AMD3100 as well as by blockade of extracellular signal-regulated kinase activation by intrathecal U0126. More importantly, the trinitrobenzene sulfonic acid-induced persistent pain was significantly suppressed by CXCR4 and extracellular signal-regulated kinase inhibitors. Conclusions The present results suggest that the activation of CXCL12–CXCR4 signaling might contribute to pancreatic pain and that extracellular signal-regulated kinase-dependent Nav1.8 up-regulation might lead to hyperexcitability of the primary nociceptor neurons in rats with chronic pancreatitis.
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Affiliation(s)
- Hong-Yan Zhu
- 1 Center for Translation Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang, P.R. China
| | - Xuelian Liu
- 2 Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, P.R. China
| | - Xiuhua Miao
- 1 Center for Translation Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang, P.R. China
| | - Di Li
- 1 Center for Translation Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang, P.R. China
| | - Shusheng Wang
- 1 Center for Translation Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang, P.R. China
| | - Guang-Yin Xu
- 1 Center for Translation Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Zhangjiagang, P.R. China.,2 Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, P.R. China
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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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Kudina LP, Andreeva RE. Excitability and firing behavior of single slow motor axons transmitting natural repetitive firing of human motoneurons. J Neurophysiol 2017; 118:1355-1360. [PMID: 28615333 DOI: 10.1152/jn.00233.2017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/14/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
Abstract
Excitability of motor axons is critically important for realizing their main function, i.e., transmitting motoneuron firing to muscle fibers. The present study was designed to explore excitability recovery and firing behavior in single slow axons transmitting human motoneuron firing during voluntary muscle contractions. The abductor digiti minimi, flexor carpi ulnaris, and tibialis anterior were investigated during threshold stimulation of corresponding motor nerves. Motor unit (MU) firing index in response to testing volleys evoking M-responses was used as a physiological measure of axonal excitability and its changes throughout a target interspike interval (ISI) were explored. It was shown that axons displayed an early irresponsive period (within the first ~2-5 ms of a target ISI) that was followed by a responsive period (for the next 5-17 ms of the ISI), in which MUs fired axonal doublets, and a later irresponsive period. At the beginning of the responsive period, M-responses showed small latency delays. However, since at that ISI moment, MUs displayed excitability recovery with high firing index, slight latency changes may be considered as a functionally insignificant phenomenon. The duration of axonal doublet ISIs did not depend on motoneuron firing frequencies (range 4.3-14.6 imp/s). The question of whether or not traditionally described axonal recovery excitability cycle is realistic in natural motor control is discussed. In conclusion, the present approach, exploring, for the first time, excitability recovery in single slow axons during motoneuron natural activation, can provide further insight into axonal firing behavior in normal states and diseases.NEW & NOTEWORTHY Excitability of single slow axons was estimated by motor unit firing index in response to motor nerve stimulation, and its changes throughout a target interspike interval were explored during transmitting human motoneuron natural firing. It was found that axons exhibited early irresponsive, responsive, and later irresponsive periods. Findings question whether the traditionally described axonal excitability recovery cycle is realistic in natural motor control.
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Affiliation(s)
- Lydia P Kudina
- Institute for Information Transmission Problems, Kharkevich Institute, Russian Academy of Sciences, Moscow, Russia
| | - Regina E Andreeva
- Institute for Information Transmission Problems, Kharkevich Institute, Russian Academy of Sciences, Moscow, Russia
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Pyun SY, Kang MR, Lee JY, Kuk KJ, Oh SI, Bae JS. Early discrimination of sensorimotor Guillain-Barré syndrome into demyelinating or axonal subtype by automated nerve excitability testing. J Peripher Nerv Syst 2017; 22:85-91. [DOI: 10.1111/jns.12208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 01/25/2023]
Affiliation(s)
- So Young Pyun
- Department of Neurology; National Police Hospital; Seoul Korea
| | - Mi-Ri Kang
- Department of Neurology; Busan Paik Hospital, Inje University College of Medicine; Busan Korea
| | - Ju Young Lee
- Department of Neurology, Kangdong Sacred Heart Hospital; Hallym University College of Medicine; Seoul Korea
| | - Kim Jong Kuk
- Department of Neurology; Dong-A University College of Medicine; Busan Korea
| | - Seong-Il Oh
- Department of Neurology; Busan Paik Hospital, Inje University College of Medicine; Busan Korea
| | - Jong Seok Bae
- Department of Neurology, Kangdong Sacred Heart Hospital; Hallym University College of Medicine; Seoul Korea
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Jankowska E, Kaczmarek D, Bolzoni F, Hammar I. Long-lasting increase in axonal excitability after epidurally applied DC. J Neurophysiol 2017; 118:1210-1220. [PMID: 28515284 DOI: 10.1152/jn.00148.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/15/2017] [Accepted: 05/15/2017] [Indexed: 12/25/2022] Open
Abstract
Effects of direct current (DC) on nerve fibers have primarily been investigated during or just after DC application. However, locally applied cathodal DC was recently demonstrated to increase the excitability of intraspinal preterminal axonal branches for >1 h. The aim of this study was therefore to investigate whether DC evokes a similarly long-lasting increase in the excitability of myelinated axons within the dorsal columns. The excitability of dorsal column fibers stimulated epidurally was monitored by recording compound action potentials in peripheral nerves in acute experiments in deeply anesthetized rats. The results show that 1) cathodal polarization (0.8-1.0 µA) results in a severalfold increase in the number of epidurally activated fibers and 2) the increase in the excitability appears within seconds, 3) lasts for >1 h, and 4) is activity independent, as it does not require fiber stimulation during the polarization. These features demonstrate an unexplored form of plasticity of myelinated fibers and indicate the conditions under which it develops. They also suggest that therapeutic effects of epidural stimulation may be significantly enhanced if it is combined with DC polarization. In particular, by using DC to increase the number of fibers activated by low-intensity epidural stimuli, the low clinical tolerance to higher stimulus intensities might be overcome. The activity independence of long-lasting DC effects would also allow the use of only brief periods of DC polarization preceding epidural stimulation to increase the effect.NEW & NOTEWORTHY The study indicates a new form of plasticity of myelinated fibers. The differences in time course of DC-evoked increases in the excitability of myelinated nerve fibers in the dorsal columns and in preterminal axonal branches suggest that distinct mechanisms are involved in them. The results show that combining epidural stimulation and transspinal DC polarization may dramatically improve their outcome and result in more effective pain control and the return of impaired motor functions.
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Affiliation(s)
- Elzbieta Jankowska
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden;
| | - Dominik Kaczmarek
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Department of Neurobiology and Department of Biochemistry, Poznań University of Physical Education, Poznań, Poland; and
| | - Francesco Bolzoni
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.,Human Physiology Section, Department of Pathophysiology and Transplantation, Università degli Studi di Milano, Milan, Italy
| | - Ingela Hammar
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Tomlinson SE, Howells J, Burke D. In vivo assessment of neurological channelopathies: Application of peripheral nerve excitability studies. Neuropharmacology 2017; 132:98-107. [PMID: 28476643 DOI: 10.1016/j.neuropharm.2017.04.045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/19/2017] [Accepted: 04/29/2017] [Indexed: 12/14/2022]
Abstract
With the rapid evolution of understanding of neurological channelopathies comes a need for sensitive tools to evaluate patients in clinical practice. Neurological channelopathies with a single-gene basis can manifest as seizures, headache, ataxia, vertigo, confusion, weakness and neuropathic pain and it is likely that other genetic factors contribute to the phenotype of many of these disorders. Ion channel dysfunction can result in abnormal cell membrane excitability but utilisation of advanced neurophysiology techniques has lagged behind developments in clinical, genetic and imaging evaluation of channelopathies. However, momentum in the application of in vivo axonal excitability testing sees these tests emerging as valuable tools, with the capacity to provide sensitive and specific insights into the mechanism of disease. While single-channel function cannot be directly measured in vivo, evaluation of subjects with single-gene channelopathies has provided insights into the effects of mutation-related alterations of membrane excitability, as well as compensatory adaptive changes. By showing how ion channel dysfunction can affect axonal excitability in vivo, studies of the excitability of peripheral nerve axons complement in vitro analysis of single channel activity. The interpretation of results is enhanced by mathematical modelling of axonal function and insights provided by in vitro work. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Susan E Tomlinson
- Sydney Medical School, University of Sydney, Sydney, Australia; Department of Neurology, St Vincent's Hospital, Sydney, Australia.
| | - James Howells
- Brain and Mind Centre, University of Sydney, Sydney, Australia
| | - David Burke
- Sydney Medical School, University of Sydney, Sydney, Australia; Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
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Sclabassi RJ, Liang YV, Mace Z. Letter to the editor regarding cardiac arrest with vagal stimulation during intraoperative nerve monitoring. Head Neck 2016; 39:612. [PMID: 27995683 DOI: 10.1002/hed.24636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 10/10/2016] [Indexed: 11/06/2022] Open
Affiliation(s)
- Robert J Sclabassi
- Department of Neurological Surgery, Allegheny Health Network, Pittsburgh, Pennsylvania
| | - Ye V Liang
- Department of Neurology, Allegheny Health Network, Pittsburgh, Pennsylvania
| | - Zachary Mace
- Computational Diagnostics, Inc, Pittsburgh, Pennsylvania
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KCC3 deficiency-induced disruption of paranodal loops and impairment of axonal excitability in the peripheral nervous system. Neuroscience 2016; 335:91-102. [DOI: 10.1016/j.neuroscience.2016.08.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 08/17/2016] [Accepted: 08/18/2016] [Indexed: 12/15/2022]
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36
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Heschl S, Hallmann B, Zilke T, Gemes G, Schoerghuber M, Auer-Grumbach M, Quehenberger F, Lirk P, Hogan Q, Rigaud M. Diabetic neuropathy increases stimulation threshold during popliteal sciatic nerve block. Br J Anaesth 2016; 116:538-45. [PMID: 26994231 PMCID: PMC4797685 DOI: 10.1093/bja/aew027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Peripheral nerve stimulation is commonly used for nerve localization in regional anaesthesia, but recommended stimulation currents of 0.3-0.5 mA do not reliably produce motor activity in the absence of intraneural needle placement. As this may be particularly true in patients with diabetic neuropathy, we examined the stimulation threshold in patients with and without diabetes. METHODS Preoperative evaluation included a neurological exam and electroneurography. During ultrasound-guided popliteal sciatic nerve block, we measured the current required to produce motor activity for the tibial and common peroneal nerve in diabetic and non-diabetic patients. Proximity to the nerve was evaluated post-hoc using ultrasound imaging. RESULTS Average stimulation currents did not differ between diabetic (n=55) and non-diabetic patients (n=52). Although the planned number of patients was not reached, the power goal for the mean stimulation current was met. Subjects with diminished pressure perception showed increased thresholds for the common peroneal nerve (median 1.30 vs. 0.57 mA in subjects with normal perception, P=0.042), as did subjects with decreased pain sensation (1.60 vs. 0.50 mA in subjects with normal sensation, P=0.038). Slowed ulnar nerve conduction velocity predicted elevated mean stimulation current (r=-0.35, P=0.002). Finally, 15 diabetic patients required more than 0.5 mA to evoke a motor response, despite intraneural needle placement (n=4), or required currents ≥2 mA despite needle-nerve contact, vs three such patients (1 intraneural, 2 with ≥2 mA) among non-diabetic patients (P=0.003). CONCLUSIONS These findings suggest that stimulation thresholds of 0.3-0.5 mA may not reliably determine close needle-nerve contact during popliteal sciatic nerve block, particularly in patients with diabetic neuropathy. CLINICAL TRIAL REGISTRATION NCT01488474.
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Affiliation(s)
- S Heschl
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - B Hallmann
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - T Zilke
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - G Gemes
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - M Schoerghuber
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
| | - M Auer-Grumbach
- Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, Graz 8036, Austria
| | - F Quehenberger
- Institute for Medical Informatics, Statistics and Documentation, Medical University of Graz, Auenbruggerplatz 2, Graz 8036, Austria
| | - P Lirk
- Department of Anaesthesiology, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, Amsterdam 1105AZ, The Netherlands
| | - Q Hogan
- Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - M Rigaud
- Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Auenbruggerplatz 29/I, Graz 8036, Austria
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Chali F, Desseille C, Houdebine L, Benoit E, Rouquet T, Bariohay B, Lopes P, Branchu J, Della Gaspera B, Pariset C, Chanoine C, Charbonnier F, Biondi O. Long-term exercise-specific neuroprotection in spinal muscular atrophy-like mice. J Physiol 2016; 594:1931-52. [PMID: 26915343 DOI: 10.1113/jp271361] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 12/22/2015] [Indexed: 01/15/2023] Open
Abstract
KEY POINTS The real impact of physical exercise parameters, i.e. intensity, type of contraction and solicited energetic metabolism, on neuroprotection in the specific context of neurodegeneration remains poorly explored. In this study behavioural, biochemical and cellular analyses were conducted to compare the effects of two different long-term exercise protocols, high intensity swimming and low intensity running, on motor units of a type 3 spinal muscular atrophy (SMA)-like mouse model. Our data revealed a preferential SMA-induced death of intermediate and fast motor neurons which was limited by the swimming protocol only, suggesting a close relationship between neuron-specific protection and their activation levels by specific exercise. The exercise-induced neuroprotection was independent of SMN protein expression and associated with specific metabolic and behavioural adaptations with notably a swimming-induced reduction of muscle fatigability. Our results provide new insight into the motor units' adaptations to different physical exercise parameters and will contribute to the design of new active physiotherapy protocols for patient care. ABSTRACT Spinal muscular atrophy (SMA) is a group of autosomal recessive neurodegenerative diseases differing in their clinical outcome, characterized by the specific loss of spinal motor neurons, caused by insufficient level of expression of the protein survival of motor neuron (SMN). No cure is at present available for SMA. While physical exercise might represent a promising approach for alleviating SMA symptoms, the lack of data dealing with the effects of different exercise types on diseased motor units still precludes the use of active physiotherapy in SMA patients. In the present study, we have evaluated the efficiency of two long-term physical exercise paradigms, based on either high intensity swimming or low intensity running, in alleviating SMA symptoms in a mild type 3 SMA-like mouse model. We found that 10 months' physical training induced significant benefits in terms of resistance to muscle damage, energetic metabolism, muscle fatigue and motor behaviour. Both exercise types significantly enhanced motor neuron survival, independently of SMN expression, leading to the maintenance of neuromuscular junctions and skeletal muscle phenotypes, particularly in the soleus, plantaris and tibialis of trained mice. Most importantly, both exercises significantly improved neuromuscular excitability properties. Further, all these training-induced benefits were quantitatively and qualitatively related to the specific characteristics of each exercise, suggesting that the related neuroprotection is strongly dependent on the specific activation of some motor neuron subpopulations. Taken together, the present data show significant long-term exercise benefits in type 3 SMA-like mice providing important clues for designing rehabilitation programmes in patients.
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Affiliation(s)
- Farah Chali
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Céline Desseille
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Léo Houdebine
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Evelyne Benoit
- Institut des Neurosciences Paris-Saclay UMR 9197, CNRS, Bât 32-33, and Service d'Ingénierie Moléculaire des Protéines (DSV/iBiTec-S/SIMOPRO), CEA de Saclay, Bât. 152, 91190, Gif-sur-Yvette, France
| | - Thaïs Rouquet
- BIOMEOSTASIS, Nutritional behavior and metabolic disorders, FST St Jérôme, Service B52, Avenue Escadrille Normandie-Niemen, 13397, Marseille, France
| | - Bruno Bariohay
- BIOMEOSTASIS, Nutritional behavior and metabolic disorders, FST St Jérôme, Service B52, Avenue Escadrille Normandie-Niemen, 13397, Marseille, France
| | - Philippe Lopes
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France.,Université d'Evry-val-d'Essonne, Bd F. Mitterrand, 91000, Evry, France
| | - Julien Branchu
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Bruno Della Gaspera
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Claude Pariset
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Christophe Chanoine
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Frédéric Charbonnier
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
| | - Olivier Biondi
- Université Paris Descartes and INSERM UMRS 1124, 45 rue des Saints-Pères, F-75270, Paris Cedex 06, France
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Tomlinson SE, Tan SV, Burke D, Labrum RW, Haworth A, Gibbons VS, Sweeney MG, Griggs RC, Kullmann DM, Bostock H, Hanna MG. In vivo impact of presynaptic calcium channel dysfunction on motor axons in episodic ataxia type 2. Brain 2016; 139:380-91. [PMID: 26912519 PMCID: PMC4795516 DOI: 10.1093/brain/awv380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 10/22/2015] [Accepted: 10/26/2015] [Indexed: 11/13/2022] Open
Abstract
Ion channel dysfunction causes a range of neurological disorders by altering transmembrane ion fluxes, neuronal or muscle excitability, and neurotransmitter release. Genetic neuronal channelopathies affecting peripheral axons provide a unique opportunity to examine the impact of dysfunction of a single channel subtype in detail in vivo. Episodic ataxia type 2 is caused by mutations in CACNA1A, which encodes the pore-forming subunit of the neuronal voltage-gated calcium channel Cav2.1. In peripheral motor axons, this channel is highly expressed at the presynaptic neuromuscular junction where it contributes to action potential-evoked neurotransmitter release, but it is not expressed mid-axon or thought to contribute to action potential generation. Eight patients from five families with genetically confirmed episodic ataxia type 2 underwent neurophysiological assessment to determine whether axonal excitability was normal and, if not, whether changes could be explained by Cav2.1 dysfunction. New mutations in the CACNA1A gene were identified in two families. Nerve conduction studies were normal, but increased jitter in single-fibre EMG studies indicated unstable neuromuscular transmission in two patients. Excitability properties of median motor axons were compared with those in 30 age-matched healthy control subjects. All patients had similar excitability abnormalities, including a high electrical threshold and increased responses to hyperpolarizing (P < 0.00007) and depolarizing currents (P < 0.001) in threshold electrotonus. In the recovery cycle, refractoriness (P < 0.0002) and superexcitability (P < 0.006) were increased. Cav2.1 dysfunction in episodic ataxia type 2 thus has unexpected effects on axon excitability, which may reflect an indirect effect of abnormal calcium current fluxes during development.
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Affiliation(s)
- Susan E Tomlinson
- 1 Sydney Medical School, University of Sydney, Australia 2 Department of Neurology, St Vincent's Hospital, Sydney, Australia
| | - S Veronica Tan
- 3 Institute of Neurology, University College London and MRC Centre for Neuromuscular Disease, Queen Square, UK
| | - David Burke
- 1 Sydney Medical School, University of Sydney, Australia 4 Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia
| | - Robyn W Labrum
- 5 Neurogenetics Unit, National Hospital for Neurology, Queen Square, UK
| | - Andrea Haworth
- 5 Neurogenetics Unit, National Hospital for Neurology, Queen Square, UK
| | | | - Mary G Sweeney
- 5 Neurogenetics Unit, National Hospital for Neurology, Queen Square, UK
| | | | - Dimitri M Kullmann
- 3 Institute of Neurology, University College London and MRC Centre for Neuromuscular Disease, Queen Square, UK 5 Neurogenetics Unit, National Hospital for Neurology, Queen Square, UK
| | - Hugh Bostock
- 3 Institute of Neurology, University College London and MRC Centre for Neuromuscular Disease, Queen Square, UK
| | - Michael G Hanna
- 3 Institute of Neurology, University College London and MRC Centre for Neuromuscular Disease, Queen Square, UK 5 Neurogenetics Unit, National Hospital for Neurology, Queen Square, UK
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Takamatsu N, Nodera H, Mori A, Maruyama-Saladini K, Osaki Y, Shimatani Y, Oda M, Izumi Y, Kaji R. Which muscle shows fasciculations by ultrasound in patients with ALS? THE JOURNAL OF MEDICAL INVESTIGATION 2016; 63:49-53. [DOI: 10.2152/jmi.63.49] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Naoko Takamatsu
- Department of Neurology, Tokushima University
- Department of Neurology, Vihara Hananosato Hospital
| | | | - Atsuko Mori
- Department of Neurology, Tokushima University
| | | | | | | | - Masaya Oda
- Department of Neurology, Vihara Hananosato Hospital
| | - Yuishin Izumi
- Department of Neurology, Tokushima University
- Department of Neurology, Vihara Hananosato Hospital
| | - Ryuji Kaji
- Department of Neurology, Tokushima University
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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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Kudina LP, Andreeva RE. Triplet firing origin in human motor units: emerging hypotheses. Exp Brain Res 2015; 234:837-44. [PMID: 26661335 DOI: 10.1007/s00221-015-4514-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 11/25/2015] [Indexed: 12/12/2022]
Abstract
A specific feature of motor unit (MU) firing behaviour is rhythmic trains of single discharges at low rate resulting from the prolonged motoneuronal afterhyperpolarization. However, some MUs exhibit occasional doublets with uniquely short interspike intervals (2.5-20.0 ms). Motoneuronal delayed depolarization is commonly accepted to be doublet underlying mechanism. Apart from doublets, much scarcer MU triple discharges were described, but their mechanisms are disputable. The aim of the present study was to analyse MU triplet firing origin in healthy humans. MU triple discharges occasionally arising during gentle voluntary muscle contractions were compared with those arising in axons during motor nerve stimulation. Firing pattern was analysed in 109 MUs of four muscles: the tibialis anterior, the flexor carpi ulnaris, the abductor pollicis brevis, and the abductor digiti minimi. Our findings present evidence that during voluntary contractions two kinds of MU triplet firing can be occasionally observed: "true" motoneuronal triplets (interspike intervals of 3.6-17.3 ms) with the delayed depolarization as the possible underlying mechanism and axonal triple discharges including the M-response and F-wave. The findings can be useful not only for understanding mechanisms of the very rare motoneuronal firing in healthy humans but also for estimation of pathological triplet firing origin.
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Affiliation(s)
- Lydia P Kudina
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, 19, Bol'shoi Karetnyi pereulok, Moscow, Russia, 127994.
| | - Regina E Andreeva
- Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, 19, Bol'shoi Karetnyi pereulok, Moscow, Russia, 127994
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Yang F, Sun W, Yang Y, Wang Y, Li CL, Fu H, Wang XL, Yang F, He T, Chen J. SDF1-CXCR4 signaling contributes to persistent pain and hypersensitivity via regulating excitability of primary nociceptive neurons: involvement of ERK-dependent Nav1.8 up-regulation. J Neuroinflammation 2015; 12:219. [PMID: 26597700 PMCID: PMC4657286 DOI: 10.1186/s12974-015-0441-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 11/18/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Pain is one critical hallmark of inflammatory responses. A large number of studies have demonstrated that stromal cell-derived factor 1 (SDF1, also named as CXCL12) and its cognate receptor C-X-C chemokine receptor type 4 (CXCR4) play an important role in immune reaction and inflammatory processes. However, whether and how SDF1-CXCR4 signaling is involved in inflammatory pain remains unclear. METHODS Under the intraplantar (i.pl.) bee venom (BV) injection-induced persistent inflammatory pain state, the changes of SDF1 and CXCR4 expression and cellular localization in the rat dorsal root ganglion (DRG) were detected by immunofluorescent staining. The role of SDF1 and CXCR4 in the hyperexcitability of primary nociceptor neurons was assessed by electrophysiological recording. Western blot analysis was used to quantify the DRG Nav1.8 and phosphorylation of ERK (pERK) expression. Behavioral tests were conducted to evaluate the roles of CXCR4 as well as extracellular signal-regulated kinase (ERK) and Nav1.8 in the BV-induced persistent pain and hypersensitivity. RESULTS We showed that both SDF1 and CXCR4 were dramatically up-regulated in the DRG in i.pl. BV-induced inflammatory pain model. Double immunofluorescent staining showed that CXCR4 was localized in all sizes (large, medium, and small) of DRG neuronal soma, while SDF1 was exclusively expressed in satellite glial cells (SGCs). Electrophysiological recording showed that bath application with AMD3100, a potent and selective CXCR4 inhibitor, could reverse the hyperexcitability of medium- and small-sized DRG neurons harvested from rats following i.pl. BV injection. Furthermore, we demonstrated that the BV-induced ERK activation and Nav1.8 up-regulation in the DRG could be blocked by pre-antagonism against CXCR4 in the periphery with AMD3100 as well as by blockade of ERK activation by intrathecal (i.t.) or intraplantar (i.pl.) U0126. At behavioral level, the BV-induced persistent spontaneous pain as well as primary mechanical and thermal hypersensitivity could also be significantly suppressed by blocking CXCR4 and Nav1.8 in the periphery as well as by inhibition of ERK activation at the DRG level. CONCLUSIONS The present results suggest that peripheral inflammatory pain state can trigger over release of SDF1 from the activated SGCs in the DRG by which SGC-neuronal cross-talk is mediated by SDF1-CXCR4 coupling that result in subsequent ERK-dependent Nav1.8 up-regulation, leading to hyperexcitability of tonic type of the primary nociceptor cells and development and maintenance of persistent spontaneous pain and hypersensitivity.
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Affiliation(s)
- Fei Yang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China
| | - Wei Sun
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Yan Yang
- Beijing Institute for Brain Disorders, Beijing, 100069, People's Republic of China
| | - Yan Wang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Chun-Li Li
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Han Fu
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Xiao-Liang Wang
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Fan Yang
- Beijing Institute for Brain Disorders, Beijing, 100069, People's Republic of China
| | - Ting He
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China.,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China
| | - Jun Chen
- Institute for Biomedical Sciences of Pain, Tangdu Hospital, The Fourth Military Medical University, #569 Xinsi Road, Baqiao, Xi'an, 710038, People's Republic of China. .,Key Laboratory of Brain Stress and Behavior, PLA, Xi'an, 710038, People's Republic of China. .,Beijing Institute for Brain Disorders, Beijing, 100069, People's Republic of China.
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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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Moldovan M, Alvarez S, Rosberg MR, Krarup C. Persistent alterations in active and passive electrical membrane properties of regenerated nerve fibers of man and mice. Eur J Neurosci 2015; 43:388-403. [DOI: 10.1111/ejn.13047] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/31/2015] [Accepted: 08/13/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Mihai Moldovan
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
- Department of Clinical Neurophysiology; NF3063 Rigshospitalet 9 Blegdamsvej 2100 Copenhagen Denmark
| | - Susana Alvarez
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
- Department of Clinical Neurophysiology; NF3063 Rigshospitalet 9 Blegdamsvej 2100 Copenhagen Denmark
| | - Mette R. Rosberg
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
- Department of Clinical Neurophysiology; NF3063 Rigshospitalet 9 Blegdamsvej 2100 Copenhagen Denmark
| | - Christian Krarup
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
- Department of Clinical Neurophysiology; NF3063 Rigshospitalet 9 Blegdamsvej 2100 Copenhagen Denmark
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Mitsuma S, Misawa S, Shibuya K, Isose S, Sekiguchi Y, Iwai Y, Beppu M, Watanabe K, Amino H, Kuwabara S. Altered axonal excitability properties and nerve edema in POEMS syndrome. Clin Neurophysiol 2015; 126:2014-8. [DOI: 10.1016/j.clinph.2015.01.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 01/02/2015] [Accepted: 01/15/2015] [Indexed: 10/24/2022]
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Osaki Y, Nodera H, Banzrai C, Endo S, Takayasu H, Mori A, Shimatani Y, Kaji R. Effects of anesthetic agents on in vivo axonal HCN current in normal mice. Clin Neurophysiol 2015; 126:2033-9. [DOI: 10.1016/j.clinph.2014.12.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 12/01/2014] [Accepted: 12/29/2014] [Indexed: 12/17/2022]
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Czesnik D, Howells J, Negro F, Wagenknecht M, Hanner S, Farina D, Burke D, Paulus W. Increased HCN channel driven inward rectification in benign cramp fasciculation syndrome. Brain 2015; 138:3168-79. [DOI: 10.1093/brain/awv254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/08/2015] [Indexed: 12/13/2022] Open
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Shimatani Y, Nodera H, Shibuta Y, Miyazaki Y, Misawa S, Kuwabara S, Kaji R. Abnormal gating of axonal slow potassium current in cramp-fasciculation syndrome. Clin Neurophysiol 2015; 126:1246-1254. [DOI: 10.1016/j.clinph.2014.09.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 07/30/2014] [Accepted: 09/03/2014] [Indexed: 12/13/2022]
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49
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Sung JY, Tani J, Hung KS, Lui TN, Lin CSY. Sensory axonal dysfunction in cervical radiculopathy. J Neurol Neurosurg Psychiatry 2015; 86:640-5. [PMID: 25143629 DOI: 10.1136/jnnp-2014-308088] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 08/01/2014] [Indexed: 11/03/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate changes in sensory axonal excitability in the distal nerve in patients with cervical radiculopathy. METHODS The patients were classified by the findings of cervical MRI into two subgroups: 22 patients with C6/7 root compression and 25 patients with cervical cord and root compression above/at C6/7. Patients were investigated using conventional nerve conduction studies (NCS) and nerve excitability testing. Sensory nerve excitability testing was undertaken with stimulation at the wrist and recording from digit II (dermatome C6/7). The results were compared with healthy controls. Both preoperative and postoperative tests were performed if the patient underwent surgery. RESULTS Sensory axonal excitability was significantly different in both cohorts compared with healthy controls, including prolonged strength-duration time constant, reduced S2 accommodation, increased threshold electrotonus hyperpolarisation (TEh (90-100 ms)), and increased superexcitability. The changes in these excitability indices are compatible with axonal membrane hyperpolarisation. In five patients who underwent surgery, the postoperative sensory excitability was tested after 1 week, and showed significant changes in TE (TEh (90-100 ms) and TEh slope, p<0.05) between presurgery and postsurgery. CONCLUSIONS The present study demonstrated distal nerve axonal hyperpolarisation in patients with cervical radiculopathy. These findings suggest that the hyperpolarised pattern might be due to Na(+)-K(+) ATPase overactivation induced by proximal ischaemia, or could reflect the remyelinating process. Distal sensory axons were hyperpolarised even though there were no changes in NCS, suggesting that nerve excitability testing may be more sensitive to clinical symptoms than NCS in patients with cervical radiculopathy.
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Affiliation(s)
- Jia-Ying Sung
- Department of Neurology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan Department of Neurology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Jowy Tani
- Department of Neurology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Kuo-Sheng Hung
- Division of Neurosurgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan Department of Neurosurgery, Clinical Research Center, Graduate Institute of Injury Prevention and Control, Taipei Medical University, Wan Fang Hospital, Taipei, Taiwan
| | - Tai-Ngar Lui
- Division of Neurosurgery, Department of Surgery, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Cindy Shin-Yi Lin
- Department of Neurology, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan Translational Neuroscience, Department of Physiology, School of Medicine Science, Faculty of Medicine, University of New South Wales, Sydney, Australia
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Bolzoni F, Jankowska E. Presynaptic and postsynaptic effects of local cathodal DC polarization within the spinal cord in anaesthetized animal preparations. J Physiol 2014; 593:947-66. [PMID: 25416625 DOI: 10.1113/jphysiol.2014.285940] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/11/2014] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS Trans-spinal DC stimulation affects both postsynaptic neurons and the presynaptic axons providing input to these neurons. In the present study, we show that intraspinally applied cathodal current replicates the effects of trans-spinal direct current stimulation in deeply anaesthetized animals and affects spinal neurons both during the actual current application and during a post-polarization period. Presynaptic effects of local cathodal polarization were expressed in an increase in the excitability of skin afferents (in the dorsal horn) and group Ia afferents (in motor nuclei), both during and at least 30 min after DC application. However, although the postsynaptic facilitation (i.e. more effective) activation of motoneurons by stimuli applied in a motor nucleus was very potent during local DC application, it was only negligible once DC was discontinued. The results suggest that the prolonged effects of cathodal polarization are primarily associated with changes in synaptic transmission. ABSTRACT The present study aimed to compare presynaptic and postsynaptic actions of direct current polarization in the spinal cord, focusing on DC effects on primary afferents and motoneurons. To reduce the directly affected spinal cord region, a weak polarizing direct current (0.1-0.3 μA) was applied locally in deeply anaesthetized cats and rats; within the hindlimb motor nuclei in the caudal lumbar segments, or in the dorsal horn within the terminal projection area of low threshold skin afferents. Changes in the excitability of primary afferents activated by intraspinal stimuli (20-50 μA) were estimated using increases or decreases in compound action potentials recorded from the dorsal roots or peripheral nerves as their measure. Changes in the postsynaptic actions of the afferents were assessed from intracellularly recorded monosynaptic EPSPs in hindlimb motoneurons and monosynaptic extracellular field potentials (evoked by group Ia afferents in motor nuclei, or by low threshold cutaneous afferents in the dorsal horn). The excitability of motoneurons activated by intraspinal stimuli was assessed using intracellular records or motoneuronal discharges recorded from a ventral root or a muscle nerve. Cathodal polarization was found to affect motoneurons and afferents providing input to them to a different extent. The excitability of both was markedly increased during DC application, although post-polarization facilitation was found to involve presynaptic afferents and some of their postsynaptic actions, but only negligibly motoneurons themselves. Taken together, these results indicate that long-lasting post-polarization facilitation of spinal activity induced by locally applied cathodal current primarily reflects the facilitation of synaptic transmission.
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Affiliation(s)
- F Bolzoni
- Department of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Human Physiology Section of the DEPT, Università degli Studi di Milano, Milano, Italy
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