Action Potential Initiation in Neocortical Inhibitory Interneurons

Tun Li, Cuiping Tian, Paolo Scalmani, Carolina Frassoni, Massimo Mantegazza, Yonghong Wang, Mingpo Yang, Si Wu, Yousheng Shu

Research output: Contribution to journalArticle

Abstract

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, NaV1.2 was found accumulated at AIS of SST but not PV cells; reducing NaV1.2-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.

Original languageEnglish
JournalPLoS Biology
Volume12
Issue number9
DOIs
Publication statusPublished - 2014

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ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Neuroscience(all)
  • Medicine(all)

Cite this

Li, T., Tian, C., Scalmani, P., Frassoni, C., Mantegazza, M., Wang, Y., Yang, M., Wu, S., & Shu, Y. (2014). Action Potential Initiation in Neocortical Inhibitory Interneurons. PLoS Biology, 12(9). https://doi.org/10.1371/journal.pbio.1001944