Computational modeling of three-dimensional electrodiffusion in biological systems: application to the node of Ranvier.
A computational model is presented for the simulation of three-dimensional electrodiffusion of ions. Finite volume techniques were used to solve the Poisson-Nernst-Planck equation, and a dual Delaunay-Voronoi mesh was constructed to evaluate fluxes of ions, as well as resulting electric potentials. The algorithm has been validated and applied to a generalized node of Ranvier, where numerical results for computed action potentials agree well with cable model predictions for large clusters of voltage-gated ion channels. At smaller channel clusters, however, the three-dimensional electrodiffusion predictions diverge from the cable model predictions and show a broadening of the action potential, indicating a significant effect due to each channel's own local electric field. The node of Ranvier complex is an elaborate organization of membrane-bound aqueous compartments, and the model presented here represents what we believe is a significant first step in simulating electrophysiological events with combined realistic structural and physiological data.
Howard Hughes Medical Institute, La Jolla, California 92037, USA.
Courtney L
CL
Lopreore
Thomas M
TM
Bartol
Jay S
JS
Coggan
Daniel X
DX
Keller
Gina E
GE
Sosinsky
Mark H
MH
Ellisman
Terrence J
TJ
Sejnowski
D000200:Action Potentials; D002462:Cell Membrane / Q000378:metabolism; D003198:Computer Simulation; D004058:Diffusion; D004560:Electricity; D015640:Ion Channel Gating; D008954:Models, Biological; D015221:Potassium Channels / Q000378:metabolism; D011901:Ranvier's Nodes / Q000378:metabolism*; D015203:Reproducibility of Results; D015222:Sodium Channels / Q000378:metabolism
D015221:Potassium Channels; D015222:Sodium Channels