K+ Channels at the Axon Initial Segment Dampen Near-Threshold Excitability of Neocortical Fast-Spiking GABAergic Interneurons
| Autor: | Marc Nahmani, Brian D. Clark, Edward Zagha, Ethan M. Goldberg, Alev Erisir, Bernardo Rudy |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Patch-Clamp Techniques
Action potential Neuroscience(all) Green Fluorescent Proteins Action Potentials Mice Transgenic Neocortex Biology MOLNEURO Article 03 medical and health sciences Mice 0302 clinical medicine Organ Culture Techniques Interneurons medicine Animals Computer Simulation Patch clamp gamma-Aminobutyric Acid 030304 developmental biology 0303 health sciences General Neuroscience Excitatory Postsynaptic Potentials Somatosensory Cortex Barrel cortex Axon initial segment Potassium channel Axons Electrophysiology Microscopy Electron medicine.anatomical_structure Excitatory postsynaptic potential Shaker Superfamily of Potassium Channels Neuroscience 030217 neurology & neurosurgery |
| Zdroj: | Neuron. 58(3):387-400 |
| ISSN: | 0896-6273 |
| DOI: | 10.1016/j.neuron.2008.03.003 |
| Popis: | SummaryFast-spiking cells (FS cells) are a prominent subtype of neocortical GABAergic interneurons with important functional roles. Multiple FS cell properties are coordinated for rapid response. Here, we describe an FS cell feature that serves to gate the powerful inhibition produced by FS cell activity. We show that FS cells in layer 2/3 barrel cortex possess a dampening mechanism mediated by Kv1.1-containing potassium channels localized to the axon initial segment. These channels powerfully regulate action potential threshold and allow FS cells to respond preferentially to large inputs that are fast enough to “outrun” Kv1 activation. In addition, Kv1.1 channel blockade converts the delay-type discharge pattern of FS cells to one of continuous fast spiking without influencing the high-frequency firing that defines FS cells. Thus, Kv1 channels provide a key counterbalance to the established rapid-response characteristics of FS cells, regulating excitability through a unique combination of electrophysiological properties and discrete subcellular localization. |
| Databáze: | OpenAIRE |
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