Otto-von-Guericke-Universität Magdeburg

 
 
 
 
 
 
 
 

Effect of electric fields on self-organizing processes in neuronal model systems

The manipulation of excitability of neuronal tissue by external perturbations has a key influence on neuronal behavior. Excitability is especially known from cell membranes, where open or closed ion channels in the membrane define the actual state of the system [1]. But also some chemical reactions belong to the class of excitable systems. Characteristic for all these systems is the occurrence of different spatio-temporal patterns such as propagating waves, which can be controlled by gradients. In chemical or biological systems wave propagation is a result of changes in the concentration of a chemical species coupled to transport processes [2]. In both systems two these processes are interconnected in nerve cells that constitute intracellular compartments with high molecular complexity confined by an excitable membrane.
This PhD project is intended to better understand spatio-temporal self-organizing processes in nerve cells and consequently in the brain on the basis of longstanding experience with excitable systems in the field of nonlinear chemistry and of neuronal cell cultures. As model systems three different types will be considered. The first system should be a microemulsion with nanometer-sized droplets of water dissolved in an oil and stabilized by a surfactant. Using the Belousov-Zhabotinsky reaction dissolved in the water droplets of the water-in-oil microemulsion (reversed micelles), two relevant species of the reaction can diffuse out of these micelles into the oil phase having different diffusion components, which can give rise to various spatial patterns, as reported for the first time in refs. [3, 4]. The second model system should consist of compartments in a microreactor produced by soft lithography, where compartments with complex geometries can be formed. Microreactors are particularly suitable for systems in which diffusion process can be controlled by the inhomogeneity of the medium [5]. The third model system will investigate neuroblastoma cell lines, which can develop spontaneous neuronal processes as well as induced ones [6, 7]. Electric fields will be applied to all these model systems and the manipulation of the self-organizing processes in the systems observed with a confocal microscope.
The central aim of the project is to provide a better understanding of the transmission of information between neurons as a consequence of multisite synaptic excitations on their surface. The complexity of neuronal performance including structural plasticity cannot be based only on locally restricted synaptic couplings, but it is assumed that e.g. electrically elicited intracellular wave patterns of molecular reactions contribute to the information processing.

[1] Hodgkin, A. L. and Huxley, A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J. Physiol., 117(4), 500-544, (1952).
[2] Ross, J., Müller, S. C., and Vidal, C. Chemical waves. Science, 240(4851), 460-465, (1988).
[3] Vanag, V. K. and Epstein, I. R. Inwardly Rotating Spiral Waves in a Reaction-Diffusion System. Science, 294(5543), 835-837, (2001).
[4] Vanag, V. K. Waves and patterns in reaction-diffusion systems. Belousov-Zhabotinsky reaction in water-in-oil microemulsions. Physics-Uspekhi, 47(9), 923, (2004).
[5] Ginn, B. T., Steinbock, B., Kahveci, M., and Steinbock, O. Microfluidic Systems for the Belousov-Zhabotinsky Reaction. J. Phys. Chem. A, 108(8), 1325-1332, (2004).
[6] Masters, J. Human Cell Culture Vol. 1. Kluwer Academic Publishers, Lancaster, UK, (1998). C. J. Thiele. Neuroblastoma.
[7] Abemayor, E. and Sidell, N. Human Neuroblastoma Cell Lines as Models for the In Vitro Study of Neoplastic and Neuronal Cell Differentiation. Environ. Health Perspect., 80, 3-15, (1989).

Letzte Änderung: 04.04.2013 - Contact Person: Dr. rer. nat. Patricia Pfeiffer
 
 
 
 
Instability of an autocatalytic front
Head of Department:
Prof. Dr. rer. nat. habil.
Stefan C. Müller

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