Regensburg 2007 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 12: Neuroscience
BP 12.3: Vortrag
Dienstag, 27. März 2007, 11:15–11:30, H44
Stimulation mechanisms of neurons in dissociated networks on wide planar electrodes — •A. Reiher1, H. Witte1, A. Krtschil1, A. de Lima2, A. Nörenberg2, T. Voigt2, and A. Krost1 — 1Inst. of Exp. Physics, Uni Magdeburg, PO Box 4120, 39016 Magdeburg — 2Inst. of Physiology, Uni Magdeburg, Leipziger Str. 44, 39120 Magdeburg
Dissociated nerve cells from embryonic rat cerebral cortex form electrophysiologically active networks. If these networks are cultured on planar interdigitated gold electrodes, the stimulation conditions and the response of the cells can be analyzed. A blockade of synaptic activity in networks with antagonists to neurotransmitters glutamate and GABAA receptors offers the possibility to investigate the stimulation mechanism of isolated neurons. A significant parameter for stimulation is the lateral distribution of the field strength along the interface. Measurements and simulations of the field strength exhibited a geometry induced enhanced field strength along the electrode edges. Position dependent analysis of stimulated somata in synaptically blocked networks revealed a sporadic correlation between the number of excited neurons and the local electrical field strength. We varied the density of cell extensions along the electrode edges in specially designed networks to investigate whether the stimulation is realized via somata or dendrites and axons. After blocking the synaptic transmission, the stimulation is more efficient via dendrites and axons. We explain the excitation mechanism taking into account the geometrical distribution of cell extensions crossing electrode areas of high electric field strengths.