Regensburg 2004 – scientific programme

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.60: Poster

Thursday, March 11, 2004, 16:00–18:00, Poster D

Poisoning of membrane patches — •Gerhard Schmid, Igor Goychuk, and Peter Hänggi — Institut für Physik, Universität Augsburg

We consider the influence of intrinsic channel noise on the spontaneous spiking activity of poisoned excitable membrane patches by use of a stochastic generalization of the Hodgkin-Huxley model. Internal noise stemming from the stochastic dynamics of individual ion channels is known to affect the collective properties of the whole cluster [1]. In particular, there exists an optimal size of the membrane patch for which solely the internal noise causes a most regular spontaneous generation of action potentials. This phenomenon is termed intrinsic coherence resonance. In addition to the variation of the size of ion channel clusters, the living organisms may adopt the densities of ion channels in order to regulate the spontaneous spiking activity. In our model, we vary the densities resp. the number of the specific ion channels for a given patch size. Experimentally, this task could be achieved, e.g., by blocking the ion channels of a given sort with a specific channel poison. Interestingly, by poisoning the potassium, or the sodium ion channels in a certain proportion one can increase, or decrease the regularity of the spike train [2]. This work is supported by DFG (SFB 486).

[1] J.A. White, J.T. Rubinstein, and A.R. Kay, Trends Neurosci. 23, 131 (2000).

[2] G. Schmid, I. Goychuk, and P. Hänggi, Physica A.