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Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123
The cellular mechanisms underlying feedback signaling from horizontal cells to photoreceptors, which are important for the formation of receptive field surrounds of early visual neurons, remain unsettled. Mammalian horizontal cells express a complement of synaptic proteins that are necessary and suf...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Society for Neuroscience
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785380/ https://www.ncbi.nlm.nih.gov/pubmed/27022629 http://dx.doi.org/10.1523/ENEURO.0148-15.2016 |
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author | Hirano, Arlene A. Liu, Xue Boulter, Jim Grove, James Pérez de Sevilla Müller, Luis Barnes, Steven Brecha, Nicholas C. |
author_facet | Hirano, Arlene A. Liu, Xue Boulter, Jim Grove, James Pérez de Sevilla Müller, Luis Barnes, Steven Brecha, Nicholas C. |
author_sort | Hirano, Arlene A. |
collection | PubMed |
description | The cellular mechanisms underlying feedback signaling from horizontal cells to photoreceptors, which are important for the formation of receptive field surrounds of early visual neurons, remain unsettled. Mammalian horizontal cells express a complement of synaptic proteins that are necessary and sufficient for calcium-dependent exocytosis of inhibitory neurotransmitters at their contacts with photoreceptor terminals, suggesting that they are capable of releasing GABA via vesicular release. To test whether horizontal cell vesicular release is involved in feedback signaling, we perturbed inhibitory neurotransmission in these cells by targeted deletion of the vesicular GABA transporter (VGAT), the protein responsible for the uptake of inhibitory transmitter by synaptic vesicles. To manipulate horizontal cells selectively, an iCre mouse line with Cre recombinase expression controlled by connexin57 (Cx57) regulatory elements was generated. In Cx57-iCre mouse retina, only horizontal cells expressed Cre protein, and its expression occurred in all retinal regions. After crossing with a VGAT(flox/flox) mouse line, VGAT was selectively eliminated from horizontal cells, which was confirmed immunohistochemically. Voltage-gated ion channel currents in horizontal cells of Cx57-VGAT(−/−) mice were the same as Cx57-VGAT(+/+) controls, as were the cell responses to the ionotropic glutamate receptor agonist kainate, but the response to the GABA(A) receptor agonist muscimol in Cx57-VGAT(−/−) mice was larger. In contrast, the feedback inhibition of photoreceptor calcium channels, which in control animals is induced by horizontal cell depolarization, was completely absent in Cx57-VGAT(−/−) mice. The results suggest that vesicular release of GABA from horizontal cells is required for feedback inhibition of photoreceptors. |
format | Online Article Text |
id | pubmed-4785380 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | Society for Neuroscience |
record_format | MEDLINE/PubMed |
spelling | pubmed-47853802016-03-28 Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 Hirano, Arlene A. Liu, Xue Boulter, Jim Grove, James Pérez de Sevilla Müller, Luis Barnes, Steven Brecha, Nicholas C. eNeuro New Research The cellular mechanisms underlying feedback signaling from horizontal cells to photoreceptors, which are important for the formation of receptive field surrounds of early visual neurons, remain unsettled. Mammalian horizontal cells express a complement of synaptic proteins that are necessary and sufficient for calcium-dependent exocytosis of inhibitory neurotransmitters at their contacts with photoreceptor terminals, suggesting that they are capable of releasing GABA via vesicular release. To test whether horizontal cell vesicular release is involved in feedback signaling, we perturbed inhibitory neurotransmission in these cells by targeted deletion of the vesicular GABA transporter (VGAT), the protein responsible for the uptake of inhibitory transmitter by synaptic vesicles. To manipulate horizontal cells selectively, an iCre mouse line with Cre recombinase expression controlled by connexin57 (Cx57) regulatory elements was generated. In Cx57-iCre mouse retina, only horizontal cells expressed Cre protein, and its expression occurred in all retinal regions. After crossing with a VGAT(flox/flox) mouse line, VGAT was selectively eliminated from horizontal cells, which was confirmed immunohistochemically. Voltage-gated ion channel currents in horizontal cells of Cx57-VGAT(−/−) mice were the same as Cx57-VGAT(+/+) controls, as were the cell responses to the ionotropic glutamate receptor agonist kainate, but the response to the GABA(A) receptor agonist muscimol in Cx57-VGAT(−/−) mice was larger. In contrast, the feedback inhibition of photoreceptor calcium channels, which in control animals is induced by horizontal cell depolarization, was completely absent in Cx57-VGAT(−/−) mice. The results suggest that vesicular release of GABA from horizontal cells is required for feedback inhibition of photoreceptors. Society for Neuroscience 2016-03-10 /pmc/articles/PMC4785380/ /pubmed/27022629 http://dx.doi.org/10.1523/ENEURO.0148-15.2016 Text en Copyright © 2016 Hirano et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution and reproduction in any medium provided that the original work is properly attributed. |
spellingShingle | New Research Hirano, Arlene A. Liu, Xue Boulter, Jim Grove, James Pérez de Sevilla Müller, Luis Barnes, Steven Brecha, Nicholas C. Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title | Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title_full | Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title_fullStr | Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title_full_unstemmed | Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title_short | Targeted Deletion of Vesicular GABA Transporter from Retinal Horizontal Cells Eliminates Feedback Modulation of Photoreceptor Calcium Channels123 |
title_sort | targeted deletion of vesicular gaba transporter from retinal horizontal cells eliminates feedback modulation of photoreceptor calcium channels123 |
topic | New Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4785380/ https://www.ncbi.nlm.nih.gov/pubmed/27022629 http://dx.doi.org/10.1523/ENEURO.0148-15.2016 |
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