Submit Data |  Help |  Video Tutorials |  News |  Publications |  FTP Download |  REST API |  Citing RGD |  Contact   

Kv4 potassium channel subunits control action potential repolarization and frequency-dependent broadening in rat hippocampal CA1 pyramidal neurones.

Authors: Kim, J  Wei, DS  Hoffman, DA 
Citation: Kim J, etal., J Physiol. 2005 Nov 15;569(Pt 1):41-57. Epub 2005 Sep 1.
Pubmed: (View Article at PubMed) PMID:16141270
DOI: Full-text: DOI:10.1113/jphysiol.2005.095042

A-type potassium channels regulate neuronal firing frequency and the back-propagation of action potentials (APs) into dendrites of hippocampal CA1 pyramidal neurones. Recent molecular cloning studies have found several families of voltage-gated K(+) channel genes expressed in the mammalian brain. At present, information regarding the relationship between the protein products of these genes and the various neuronal functions performed by voltage-gated K(+) channels is lacking. Here we used a combination of molecular, electrophysiological and imaging techniques to show that one such gene, Kv4.2, controls AP half-width, frequency-dependent AP broadening and dendritic action potential propagation. Using a modified Sindbis virus, we expressed either the enhanced green fluorescence protein (EGFP)-tagged Kv4.2 or an EGFP-tagged dominant negative mutant of Kv4.2 (Kv4.2g(W362F)) in CA1 pyramidal neurones of organotypic slice cultures. Neurones expressing Kv4.2g(W362F) displayed broader action potentials with an increase in frequency-dependent AP broadening during a train compared with control neurones. In addition, Ca(2)(+) imaging of Kv4.2g(W362F) expressing dendrites revealed enhanced AP back-propagation compared to control neurones. Conversely, neurones expressing an increased A-type current through overexpression of Kv4.2 displayed narrower APs with less frequency dependent broadening and decreased dendritic propagation. These results point to Kv4.2 as the major contributor to the A-current in hippocampal CA1 neurones and suggest a prominent role for Kv4.2 in regulating AP shape and dendritic signalling. As Ca(2)(+) influx occurs primarily during AP repolarization, Kv4.2 activity can regulate cellular processes involving Ca(2)(+)-dependent second messenger cascades such as gene expression and synaptic plasticity.

Annotation

Gene Ontology Annotations
Molecular Pathway Annotations
Objects Annotated

Additional Information

 
RGD Object Information
RGD ID: 1581430
Created: 2006-10-04
Species: All species
Last Modified: 2006-10-04
Status: ACTIVE



NHLBI Logo

RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.