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A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse
The spinal dorsal horn contains numerous inhibitory interneurons that control transmission of somatosensory information. Although these cells have important roles in modulating pain, we still have limited information about how they are incorporated into neuronal circuits, and this is partly due to d...
Autores principales: | , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Wolters Kluwer
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751741/ https://www.ncbi.nlm.nih.gov/pubmed/26882346 http://dx.doi.org/10.1097/j.pain.0000000000000407 |
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author | Iwagaki, Noboru Ganley, Robert P. Dickie, Allen C. Polgár, Erika Hughes, David I. Del Rio, Patricia Revina, Yulia Watanabe, Masahiko Todd, Andrew J. Riddell, John S. |
author_facet | Iwagaki, Noboru Ganley, Robert P. Dickie, Allen C. Polgár, Erika Hughes, David I. Del Rio, Patricia Revina, Yulia Watanabe, Masahiko Todd, Andrew J. Riddell, John S. |
author_sort | Iwagaki, Noboru |
collection | PubMed |
description | The spinal dorsal horn contains numerous inhibitory interneurons that control transmission of somatosensory information. Although these cells have important roles in modulating pain, we still have limited information about how they are incorporated into neuronal circuits, and this is partly due to difficulty in assigning them to functional populations. Around 15% of inhibitory interneurons in laminae I-III express neuropeptide Y (NPY), but little is known about this population. We therefore used a combined electrophysiological/morphological approach to investigate these cells in mice that express green fluorescent protein (GFP) under control of the NPY promoter. We show that GFP is largely restricted to NPY-immunoreactive cells, although it is only expressed by a third of those in lamina I-II. Reconstructions of recorded neurons revealed that they were morphologically heterogeneous, but never islet cells. Many NPY-GFP cells (including cells in lamina III) appeared to be innervated by C fibres that lack transient receptor potential vanilloid-1, and consistent with this, we found that some lamina III NPY-immunoreactive cells were activated by mechanical noxious stimuli. Projection neurons in lamina III are densely innervated by NPY-containing axons. Our results suggest that this input originates from a small subset of NPY-expressing interneurons, with the projection cells representing only a minority of their output. Taken together with results of previous studies, our findings indicate that somatodendritic morphology is of limited value in classifying functional populations among inhibitory interneurons in the dorsal horn. Because many NPY-expressing cells respond to noxious stimuli, these are likely to have a role in attenuating pain and limiting its spread. |
format | Online Article Text |
id | pubmed-4751741 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Wolters Kluwer |
record_format | MEDLINE/PubMed |
spelling | pubmed-47517412016-02-29 A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse Iwagaki, Noboru Ganley, Robert P. Dickie, Allen C. Polgár, Erika Hughes, David I. Del Rio, Patricia Revina, Yulia Watanabe, Masahiko Todd, Andrew J. Riddell, John S. Pain Research Paper The spinal dorsal horn contains numerous inhibitory interneurons that control transmission of somatosensory information. Although these cells have important roles in modulating pain, we still have limited information about how they are incorporated into neuronal circuits, and this is partly due to difficulty in assigning them to functional populations. Around 15% of inhibitory interneurons in laminae I-III express neuropeptide Y (NPY), but little is known about this population. We therefore used a combined electrophysiological/morphological approach to investigate these cells in mice that express green fluorescent protein (GFP) under control of the NPY promoter. We show that GFP is largely restricted to NPY-immunoreactive cells, although it is only expressed by a third of those in lamina I-II. Reconstructions of recorded neurons revealed that they were morphologically heterogeneous, but never islet cells. Many NPY-GFP cells (including cells in lamina III) appeared to be innervated by C fibres that lack transient receptor potential vanilloid-1, and consistent with this, we found that some lamina III NPY-immunoreactive cells were activated by mechanical noxious stimuli. Projection neurons in lamina III are densely innervated by NPY-containing axons. Our results suggest that this input originates from a small subset of NPY-expressing interneurons, with the projection cells representing only a minority of their output. Taken together with results of previous studies, our findings indicate that somatodendritic morphology is of limited value in classifying functional populations among inhibitory interneurons in the dorsal horn. Because many NPY-expressing cells respond to noxious stimuli, these are likely to have a role in attenuating pain and limiting its spread. Wolters Kluwer 2015-11-04 2016-03 /pmc/articles/PMC4751741/ /pubmed/26882346 http://dx.doi.org/10.1097/j.pain.0000000000000407 Text en © 2015 International Association for the Study of Pain This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY) (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Research Paper Iwagaki, Noboru Ganley, Robert P. Dickie, Allen C. Polgár, Erika Hughes, David I. Del Rio, Patricia Revina, Yulia Watanabe, Masahiko Todd, Andrew J. Riddell, John S. A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title | A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title_full | A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title_fullStr | A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title_full_unstemmed | A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title_short | A combined electrophysiological and morphological study of neuropeptide Y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
title_sort | combined electrophysiological and morphological study of neuropeptide y–expressing inhibitory interneurons in the spinal dorsal horn of the mouse |
topic | Research Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4751741/ https://www.ncbi.nlm.nih.gov/pubmed/26882346 http://dx.doi.org/10.1097/j.pain.0000000000000407 |
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