Axon initial segment Kv1 channels control axonal action potential waveform and synaptic efficacy

Action potentials are binary signals that transmit information via their rate and temporal pattern. In this context, the axon is thought of as a transmission line, devoid of a role in neuronal computation. Here, we show a highly localized role of axonal Kv1 potassium channels in shaping the action p...

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Vydáno v:	Neuron (Cambridge, Mass.) Ročník 55; číslo 4; s. 633
Hlavní autoři:	Kole, Maarten H P, Letzkus, Johannes J, Stuart, Greg J
Médium:	Journal Article
Jazyk:	angličtina
Vydáno:	United States 16.08.2007
Témata:	4-Aminopyridine - pharmacology Action Potentials - drug effects Action Potentials - physiology Action Potentials - radiation effects Animals Axons - drug effects Axons - physiology Axons - radiation effects Cerebral Cortex - cytology Dose-Response Relationship, Drug Dose-Response Relationship, Radiation Elapid Venoms - pharmacology Electric Stimulation - methods Excitatory Postsynaptic Potentials - drug effects Excitatory Postsynaptic Potentials - physiology Excitatory Postsynaptic Potentials - radiation effects Female In Vitro Techniques Lysine - analogs & derivatives Lysine - metabolism Male Models, Neurological Patch-Clamp Techniques Potassium Channel Blockers - pharmacology Pyramidal Cells - cytology Rats Rats, Wistar Shaker Superfamily of Potassium Channels - physiology Synapses - drug effects Synapses - physiology Synapses - radiation effects
ISSN:	0896-6273
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Popis
Shrnutí:	Action potentials are binary signals that transmit information via their rate and temporal pattern. In this context, the axon is thought of as a transmission line, devoid of a role in neuronal computation. Here, we show a highly localized role of axonal Kv1 potassium channels in shaping the action potential waveform in the axon initial segment (AIS) of layer 5 pyramidal neurons independent of the soma. Cell-attached recordings revealed a 10-fold increase in Kv1 channel density over the first 50 microm of the AIS. Inactivation of AIS and proximal axonal Kv1 channels, as occurs during slow subthreshold somatodendritic depolarizations, led to a distance-dependent broadening of axonal action potentials, as well as an increase in synaptic strength at proximal axonal terminals. Thus, Kv1 channels are strategically positioned to integrate slow subthreshold signals, providing control of the presynaptic action potential waveform and synaptic coupling in local cortical circuits.
Bibliografie:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0896-6273
DOI:	10.1016/j.neuron.2007.07.031