Modeling action potential initiation using voltage-gated ion-channels kinetics from L5 pyramidal neurons of the rat cortex
© Gurkiewicz and Korngreen; licensee BioMed Central Ltd. 2009
Published: 13 July 2009
Trans-membrane protein mechanisms such as ion-channels and their activity are at the essence of neuronal transmission. The most accurate method, so far, for determining ion-channel kinetic mechanisms is single-channel recording and analysis. Nevertheless, single-channel recordings carry several hold-ups and complexities, especially when dealing with voltage-gated channels. We have previously developed a method for fitting cell-attached and whole-cell voltage-clamp data to kinetic models of ion channels using genetic search algorithms (GAs). Several newly conceptualized kinetic schemes for voltage-gated sodium and potassium channels were tested using somatic and dendritic cell-attached and nucleated patch-clamp recordings from layer 5 pyramidal neurons of the rat cortex.
Out of more than a dozen models, the best simplified Markov schemes of both channel types were then combined to simulate a somatic action potential (AP). Adding the dendritic mechanisms, we proceeded to simulate back-propagating action potentials along the apical dendrite of L5 pyramidal neurons. Our results therefore constitute yet another step towards a novel paradigm for AP initiation and propagation in cortical neurons that may be more physiologically relevant than previously suggested kinetic schemes.
This article is published under license to BioMed Central Ltd.