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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.78: Poster

Donnerstag, 14. März 2002, 15:30–18:00, D

Electrodiffusion of ligand gated ion channels with time-dependent opening rates — •Stephan Kramer, Alexander Grundmeier, Michael Berginski, and Reiner Kree — Institut f. Theoretische Physik, Universtät Göttingen, Bunsenstr. 9, 37073 Göttingen

We present analytical and numerical results for a model describing the electrophoresis of mobile, charged ion channels in a fluid membrane. The channels may switch between an open and a closed state according to a simple two-state kinetics with rates either constant or depending on an externally controlled ligand concentration. The effective electrophoretic charge and the diffusion constant of the channels may be different in the closed and in the open state. The system is modeled by densities of channel species, obeying simple equations of electro-diffusion. The lateral transmembrane voltage profile is determined from a cable-type equation. The analytic analysis of autonomous systems reveals bifurcations from the homogeneous, stationary state to appear as hard-mode, soft-mode or hard-mode oscillatory transitions within physiologically reasonable ranges of model parameters. Numerical results will be presented for a non-autonomous system with time-dependent ligand controlled rates.