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Action Potential Initiation in Neocortical Inhibitory Interneurons

Action potential (AP) generation in inhibitory interneurons is critical for cortical excitation-inhibition balance and information processing. However, it remains unclear what determines AP initiation in different interneurons. We focused on two predominant interneuron types in neocortex: parvalbumi...

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Autores principales: Li, Tun, Tian, Cuiping, Scalmani, Paolo, Frassoni, Carolina, Mantegazza, Massimo, Wang, Yonghong, Yang, Mingpo, Wu, Si, Shu, Yousheng
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159120/
https://www.ncbi.nlm.nih.gov/pubmed/25203314
http://dx.doi.org/10.1371/journal.pbio.1001944
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author Li, Tun
Tian, Cuiping
Scalmani, Paolo
Frassoni, Carolina
Mantegazza, Massimo
Wang, Yonghong
Yang, Mingpo
Wu, Si
Shu, Yousheng
author_facet Li, Tun
Tian, Cuiping
Scalmani, Paolo
Frassoni, Carolina
Mantegazza, Massimo
Wang, Yonghong
Yang, Mingpo
Wu, Si
Shu, Yousheng
author_sort Li, Tun
collection PubMed
description Action potential (AP) generation in inhibitory interneurons is critical for cortical excitation-inhibition balance and information processing. However, it remains unclear what determines AP initiation in different interneurons. We focused on two predominant interneuron types in neocortex: parvalbumin (PV)- and somatostatin (SST)-expressing neurons. Patch-clamp recording from mouse prefrontal cortical slices showed that axonal but not somatic Na(+) channels exhibit different voltage-dependent properties. The minimal activation voltage of axonal channels in SST was substantially higher (∼7 mV) than in PV cells, consistent with differences in AP thresholds. A more mixed distribution of high- and low-threshold channel subtypes at the axon initial segment (AIS) of SST cells may lead to these differences. Surprisingly, Na(V)1.2 was found accumulated at AIS of SST but not PV cells; reducing Na(V)1.2-mediated currents in interneurons promoted recurrent network activity. Together, our results reveal the molecular identity of axonal Na(+) channels in interneurons and their contribution to AP generation and regulation of network activity.
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spelling pubmed-41591202014-09-12 Action Potential Initiation in Neocortical Inhibitory Interneurons Li, Tun Tian, Cuiping Scalmani, Paolo Frassoni, Carolina Mantegazza, Massimo Wang, Yonghong Yang, Mingpo Wu, Si Shu, Yousheng PLoS Biol Research Article Action potential (AP) generation in inhibitory interneurons is critical for cortical excitation-inhibition balance and information processing. However, it remains unclear what determines AP initiation in different interneurons. We focused on two predominant interneuron types in neocortex: parvalbumin (PV)- and somatostatin (SST)-expressing neurons. Patch-clamp recording from mouse prefrontal cortical slices showed that axonal but not somatic Na(+) channels exhibit different voltage-dependent properties. The minimal activation voltage of axonal channels in SST was substantially higher (∼7 mV) than in PV cells, consistent with differences in AP thresholds. A more mixed distribution of high- and low-threshold channel subtypes at the axon initial segment (AIS) of SST cells may lead to these differences. Surprisingly, Na(V)1.2 was found accumulated at AIS of SST but not PV cells; reducing Na(V)1.2-mediated currents in interneurons promoted recurrent network activity. Together, our results reveal the molecular identity of axonal Na(+) channels in interneurons and their contribution to AP generation and regulation of network activity. Public Library of Science 2014-09-09 /pmc/articles/PMC4159120/ /pubmed/25203314 http://dx.doi.org/10.1371/journal.pbio.1001944 Text en © 2014 Li et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Li, Tun
Tian, Cuiping
Scalmani, Paolo
Frassoni, Carolina
Mantegazza, Massimo
Wang, Yonghong
Yang, Mingpo
Wu, Si
Shu, Yousheng
Action Potential Initiation in Neocortical Inhibitory Interneurons
title Action Potential Initiation in Neocortical Inhibitory Interneurons
title_full Action Potential Initiation in Neocortical Inhibitory Interneurons
title_fullStr Action Potential Initiation in Neocortical Inhibitory Interneurons
title_full_unstemmed Action Potential Initiation in Neocortical Inhibitory Interneurons
title_short Action Potential Initiation in Neocortical Inhibitory Interneurons
title_sort action potential initiation in neocortical inhibitory interneurons
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159120/
https://www.ncbi.nlm.nih.gov/pubmed/25203314
http://dx.doi.org/10.1371/journal.pbio.1001944
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