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Ephaptic communication in the vertebrate retina

In the vertebrate retina, cones project to the horizontal cells (HCs) and bipolar cells (BCs). The communication between cones and HCs uses both chemical and ephaptic mechanisms. Cones release glutamate in a Ca(2+)-dependent manner, while HCs feed back to cones via an ephaptic mechanism. Hyperpolari...

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Autores principales: Vroman, Rozan, Klaassen, Lauw J., Kamermans, Maarten
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780359/
https://www.ncbi.nlm.nih.gov/pubmed/24068997
http://dx.doi.org/10.3389/fnhum.2013.00612
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author Vroman, Rozan
Klaassen, Lauw J.
Kamermans, Maarten
author_facet Vroman, Rozan
Klaassen, Lauw J.
Kamermans, Maarten
author_sort Vroman, Rozan
collection PubMed
description In the vertebrate retina, cones project to the horizontal cells (HCs) and bipolar cells (BCs). The communication between cones and HCs uses both chemical and ephaptic mechanisms. Cones release glutamate in a Ca(2+)-dependent manner, while HCs feed back to cones via an ephaptic mechanism. Hyperpolarization of HCs leads to an increased current through connexin hemichannels located on the tips of HC dendrites invaginating the cone synaptic terminals. Due to the high resistance of the extracellular synaptic space, this current makes the synaptic cleft slightly negative. The result is that the Ca(2+)-channels in the cone presynaptic membrane experience a slightly depolarized membrane potential and therefore more glutamate is released. This ephaptic mechanism forms a very fast and noise free negative feedback pathway. These characteristics are crucial, since the retina has to perform well in demanding conditions such as low light levels. In this mini-review we will discuss the critical components of such an ephaptic mechanism. Furthermore, we will address the question whether such communication appears in other systems as well and indicate some fundamental features to look for when attempting to identify an ephaptic mechanism.
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spelling pubmed-37803592013-09-25 Ephaptic communication in the vertebrate retina Vroman, Rozan Klaassen, Lauw J. Kamermans, Maarten Front Hum Neurosci Neuroscience In the vertebrate retina, cones project to the horizontal cells (HCs) and bipolar cells (BCs). The communication between cones and HCs uses both chemical and ephaptic mechanisms. Cones release glutamate in a Ca(2+)-dependent manner, while HCs feed back to cones via an ephaptic mechanism. Hyperpolarization of HCs leads to an increased current through connexin hemichannels located on the tips of HC dendrites invaginating the cone synaptic terminals. Due to the high resistance of the extracellular synaptic space, this current makes the synaptic cleft slightly negative. The result is that the Ca(2+)-channels in the cone presynaptic membrane experience a slightly depolarized membrane potential and therefore more glutamate is released. This ephaptic mechanism forms a very fast and noise free negative feedback pathway. These characteristics are crucial, since the retina has to perform well in demanding conditions such as low light levels. In this mini-review we will discuss the critical components of such an ephaptic mechanism. Furthermore, we will address the question whether such communication appears in other systems as well and indicate some fundamental features to look for when attempting to identify an ephaptic mechanism. Frontiers Media S.A. 2013-09-23 /pmc/articles/PMC3780359/ /pubmed/24068997 http://dx.doi.org/10.3389/fnhum.2013.00612 Text en Copyright © 2013 Vroman, Klaassen and Kamermans. http://creativecommons.org/licenses/by/3.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Neuroscience
Vroman, Rozan
Klaassen, Lauw J.
Kamermans, Maarten
Ephaptic communication in the vertebrate retina
title Ephaptic communication in the vertebrate retina
title_full Ephaptic communication in the vertebrate retina
title_fullStr Ephaptic communication in the vertebrate retina
title_full_unstemmed Ephaptic communication in the vertebrate retina
title_short Ephaptic communication in the vertebrate retina
title_sort ephaptic communication in the vertebrate retina
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3780359/
https://www.ncbi.nlm.nih.gov/pubmed/24068997
http://dx.doi.org/10.3389/fnhum.2013.00612
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