Action potential generation requires a high sodium channel density in the axon initial segment

Kole, Maarten H. P ., Ilschner, Susanne U., Kampa, Bjorn M., Williams, Stephen R., Ruben, Peter C. and Stuart, Greg J. (2008) Action potential generation requires a high sodium channel density in the axon initial segment. Nature Neuroscience, 11 2: 178-186. doi:10.1038/nn2040


Author Kole, Maarten H. P .
Ilschner, Susanne U.
Kampa, Bjorn M.
Williams, Stephen R.
Ruben, Peter C.
Stuart, Greg J.
Title Action potential generation requires a high sodium channel density in the axon initial segment
Journal name Nature Neuroscience   Check publisher's open access policy
ISSN 1097-6256
1546-1726
Publication date 2008-02
Sub-type Article (original research)
DOI 10.1038/nn2040
Volume 11
Issue 2
Start page 178
End page 186
Total pages 9
Place of publication New York, United States
Publisher Nature Publishing Group
Language eng
Formatted abstract
The axon initial segment (AIS) is a specialized region in neurons where action potentials are initiated. It is commonly assumed that this process requires a high density of voltage-gated sodium (Na+) channels. Paradoxically, the results of patch-clamp studies suggest that the Na + channel density at the AIS is similar to that at the soma and proximal dendrites. Here we provide data obtained by antibody staining, whole-cell voltage-clamp and Na+ imaging, together with modeling, which indicate that the Na+ channel density at the AIS of cortical pyramidal neurons is ∼50 times that in the proximal dendrites. Anchoring of Na+ channels to the cytoskeleton can explain this discrepancy, as disruption of the actin cytoskeleton increased the Na+ current measured in patches from the AIS. Computational models required a high Na + channel density (∼2,500 pS μm-2) at the AIS to account for observations on action potential generation and backpropagation. In conclusion, action potential generation requires a high Na+ channel density at the AIS, which is maintained by tight anchoring to the actin cytoskeleton.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Queensland Brain Institute Publications
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Created: Thu, 20 Oct 2011, 17:29:25 EST by Stephen Williams on behalf of Queensland Brain Institute