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BP: Fachverband Biologische Physik

BP 21: Posters - Membranes and Vesicles

BP 21.10: Poster

Dienstag, 21. März 2017, 14:00–16:00, P1A

Electro-mechanical Coupling during Action Potentials — •Julia Muchowski, Christian Fillafer, and Matthias Schneider — TU Dortmund, Germany

Action potentials are a classical phenomenon in biological cells. Their electrical component has been studied in detail whereas little is known about other components. Action potentials were investigated in excitable plant cells (Chara Braunii).

The membrane potential was monitored by intracellular recording. The cell membrane was separated from the cell wall by plasmolysis and observed by light microscopy. During a pulse not only the electrical potential of the membrane changed (depolarization) but also a mechanical displacement of the cell membrane was observed. The displacement of the membrane took place on a timescale of 1-2 min. The electrical signal preceded the mechanical displacement by 2+/-0.5 s. To further study the mechanical properties of the excitable membrane, one method was established to obtain large plasma membrane vesicles (r=50-100 micrometer) from the cell. This was achieved by plasmolysing the cell, cutting the cell wall, deplasmolysing the cell and extracting a membrane vesicle via osmotic pressure. Size and stability of the vesicles depended on the length of the cut and the speed of plasmolysis and deplasmolysis.

Our results demonstrate electro-mechanical coupling during an action potential. Further work aims at obtaining thermodynamic state diagrams of the excitable membrane.