Measuring Membrane Fluctuations After Change in Resting Membrane Potential in Neuroblastoma Cells

Prasad, Vikash (2017) Measuring Membrane Fluctuations After Change in Resting Membrane Potential in Neuroblastoma Cells. Masters thesis, Indian Institute of Science Education and Research Kolkata.

PDF (MS dissertation of Vikash Prasad (12MS107)) MS_Thesis_Vikash_Prasad_12MS107.pdf - Submitted Version Restricted to Repository staff only Download (2MB)

Abstract

Neurons have the ability to pass on the information by firing action potentials; these firing patterns do not just ensure the information propagation but also lead to better networks that lead to plasticity through neuronal signaling. Electrical impulse generation causes several effects on not just biochemical profile but also morphological features of the cell. Some of these structural changes are volumetric changes, swelling of axons, rapid heating and cooling etc. We also know that the presence of mechanosensitive voltage channels gets activated due to any mechanical strain and to some extent, even classical voltage-gated channels are sensitive to mechanical tension. All these changes have been intrinsically related to surface charge accumulation on either side of the membrane and studies have shown the effect on membrane properties due to these charge accumulations. Still, the cellular mechanics related to the same have not been studied thoroughly in the brain and thus we are trying to comprehend a small part of it i.e. how cells (HeLa, N2A) react to the phenomena of change in polarity of these charge accumulation or membrane potential change in terms of its membrane stability. We are thus trying to understand and quantify membrane fluctuations after a change in resting cell membrane potential using optical techniques like Interference Reflection Microscopy (IRM) and fluorescence imaging. We show that there is a significant difference in the spatiotemporal fluctuations of the cell body and cell processes of these neuroblastoma cells. Both spatial and temporal fluctuations (few nanometers) are higher for cell body than the cell processes. Also, the temporal fluctuations in depolarized cells are reduced whereas the spatial undulations are increased after change in resting membrane potential.

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