1
|
Thome C, Roth FC, Obermayer J, Yanez A, Draguhn A, Egorov AV. Synaptic entrainment of ectopic action potential generation in hippocampal pyramidal neurons. J Physiol 2018; 596:5237-5249. [PMID: 30144079 DOI: 10.1113/jp276720] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 08/15/2018] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Ectopic action potentials (EAPs) arise at distal locations in axonal fibres and are often associated with neuronal pathologies such as epilepsy or nerve injury, but they also occur during physiological network conditions. This study investigates whether initiation of such EAPs is modulated by subthreshold synaptic activity. Somatic subthreshold potentials invade the axonal compartment to considerable distances (>350 μm), whereas spread of axonal subthreshold potentials to the soma is inefficient. Ectopic spike generation is entrained by conventional synaptic signalling mechanisms. Excitatory synaptic potentials promote EAPs, whereas inhibitory synaptic potentials block EAPs. The modulation of ectopic excitability depends on propagation of somatic voltage deflections to the axonal EAP initiation site. Synaptic modulation of EAP initiation challenges the view of the distal axon being independent of synaptic activity and may contribute to mechanisms underlying fast network oscillations and pathological network activity. ABSTRACT While most action potentials are generated at the axon initial segment, they can also be triggered at more distal sites along the axon. Such ectopic action potentials (EAPs) occur during several neuronal pathologies such as epilepsy, nerve injuries and inflammation but have also been observed during physiological network activity. EAPs propagate antidromically towards the somato-dendritic compartment where they modulate synaptic plasticity. Here we investigate the converse signal direction: do somato-dendritic synaptic potentials affect the generation of ectopic spikes? We measured anti- and orthodromic spikes in the soma and axon of mouse hippocampal CA1 pyramidal cells. We found that synaptic potentials propagate reliably through the axon, causing significant voltage transients at distances >350 μm. At these sites, excitatory input efficiently facilitated EAP initiation in distal axons and, conversely, inhibitory input suppressed EAP initiation. Our data reveal a new mechanism by which ectopically generated spikes can be entrained by conventional synaptic signalling during normal and pathological network activity.
Collapse
Affiliation(s)
- Christian Thome
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University, 69120, Heidelberg, Germany
| | - Fabian C Roth
- Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway
| | - Joshua Obermayer
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University, 69120, Heidelberg, Germany
| | - Antonio Yanez
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University, 69120, Heidelberg, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University, 69120, Heidelberg, Germany
| | - Alexei V Egorov
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Heidelberg University, 69120, Heidelberg, Germany
| |
Collapse
|
2
|
Braido F, Scichilone N, Lavorini F, Usmani OS, Dubuske L, Boulet LP, Mosges R, Nunes C, Sanchez-Borges M, Ansotegui IJ, Ebisawa M, Levi-Schaffer F, Rosenwasser LJ, Bousquet J, Zuberbier T, Canonica GW, Cruz A, Yanez A, Yorgancioglu A, Deleanu D, Rodrigo G, Berstein J, Ohta K, Vichyanond P, Pawankar R, Gonzalez-Diaz SN, Nakajima S, Slavyanskaya T, Fink-Wagner A, Loyola CB, Ryan D, Passalacqua G, Celedon J, Ivancevich JC, Dobashi K, Zernotti M, Akdis M, Benjaponpitak S, Bonini S, Burks W, Caraballo L, El-Sayed ZA, Fineman S, Greenberger P, Hossny E, Ortega-Martell JA, Saito H, Tang M, Zhang L. Manifesto on small airway involvement and management in asthma and chronic obstructive pulmonary disease: an Interasma (Global Asthma Association - GAA) and World Allergy Organization (WAO) document endorsed by Allergic Rhinitis and its Impact on Asthma (ARIA) and Global Allergy and Asthma European Network (GA 2LEN). World Allergy Organ J 2016; 9:37. [PMID: 27800118 PMCID: PMC5084415 DOI: 10.1186/s40413-016-0123-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/24/2016] [Indexed: 12/21/2022] Open
Abstract
Evidence that enables us to identify, assess, and access the small airways in asthma and chronic obstructive pulmonary disease (COPD) has led INTERASMA (Global Asthma Association) and WAO to take a position on the role of the small airways in these diseases. Starting from an extensive literature review, both organizations developed, discussed, and approved the manifesto, which was subsequently approved and endorsed by the chairs of ARIA and GA2LEN. The manifesto describes the evidence gathered to date and defines and proposes issues on small airway involvement and management in asthma and COPD with the aim of challenging assumptions, fostering commitment, and bringing about change. The small airways (defined as those with an internal diameter <2 mm) are involved in the pathogenesis of asthma and COPD and are the major determinant of airflow obstruction in these diseases. Various tests are available for the assessment of the small airways, and their results must be integrated to confirm a diagnosis of small airway dysfunction. In asthma and COPD, the small airways play a key role in attempts to achieve disease control and better outcomes. Small-particle inhaled formulations (defined as those that, owing to their size [usually <2 μm], ensure more extensive deposition in the lung periphery than large molecules) have proved beneficial in patients with asthma and COPD, especially those in whom small airway involvement is predominant. Functional and biological tools capable of accurately assessing the lung periphery and more intensive use of currently available tools are necessary. In patients with suspected COPD or asthma, small airway involvement must be assessed using currently available tools. In patients with subotpimal disease control and/or functional or biological signs of disease activity, the role of small airway involvement should be assessed and treatment tailored. Therefore, the choice between large- and small-particle inhaled formulations must reflect the physician’s considerations of disease features, phenotype, and response to previous therapy. This article is being co-published in Asthma Research and Practice and the World Allergy Organization Journal.
Collapse
Affiliation(s)
- F Braido
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - N Scichilone
- Dipartimento Biomedico di Medicina Interna e Specialistica, University of Palermo, Palermo, Italy
| | - F Lavorini
- Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy
| | - O S Usmani
- Airway Disease Section, National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, London, UK
| | - L Dubuske
- Immunology Research Institute of New England, Harvard, USA
| | - L P Boulet
- Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, Québec, Canada
| | - R Mosges
- Institute of Medical Statistics, Informatics and Epidemiology, University Hospital of Cologne, Cologne, Germany
| | - C Nunes
- Centro de ImmunoAlergologia de Algarve, Porto, Portugal
| | - M Sanchez-Borges
- Centro Medico Docente La Trinidad, Caracas, Venezuela ; Clinica El Avila, Caracas, Venezuela
| | - I J Ansotegui
- Department of Allergy and Immunology, Hospital Quirón Bizkaia, Carretera Leioa-Inbe, Erandio, Bilbao Spain
| | - M Ebisawa
- Department of Allergy, Clinical Research Center for Allergy & Rheumatology, Sagamihara National Hospital, Sagamihara, Kanagawa Japan
| | - F Levi-Schaffer
- Department of Pharmacology and Experimental Therapeutics, Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - L J Rosenwasser
- University of Missouri - Kansas City, School of Medicine, Kansas City, Missouri USA
| | - J Bousquet
- Service des Maladies Respiratoires, Hopital Arnaud de Villeneuve, Montpellier, France
| | - T Zuberbier
- Department of Dermatology and Allergy, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - G Walter Canonica
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - A Cruz
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - A Yanez
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - A Yorgancioglu
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - D Deleanu
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - G Rodrigo
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - J Berstein
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - K Ohta
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - P Vichyanond
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - R Pawankar
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - S N Gonzalez-Diaz
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - S Nakajima
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - T Slavyanskaya
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - A Fink-Wagner
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - C Baez Loyola
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - D Ryan
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - G Passalacqua
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - J Celedon
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - J C Ivancevich
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - K Dobashi
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - M Zernotti
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - M Akdis
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - S Benjaponpitak
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - S Bonini
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - W Burks
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - L Caraballo
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - Z Awad El-Sayed
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - S Fineman
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - P Greenberger
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - E Hossny
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - J A Ortega-Martell
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - H Saito
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - M Tang
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | - L Zhang
- Allergy and Respiratory Diseases Department DIMI, University of Genoa, IRCCS AOU San Martino-IST, Genoa, Italy
| | | | | | | |
Collapse
|