Dresden 2006 – scientific programme

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AKB: Biologische Physik

AKB 25: Cell Mechanics I

AKB 25.8: Talk

Thursday, March 30, 2006, 16:45–17:00, ZEU 260

Osmotically Driven Shape Instability in Axons — •Pramod Pullarkat¹, Paul Dommersnes², Pablo Fernandez¹, Jean-François Joanny², and Albrecht Ott¹ — ¹Experimentalphysik I, University of Bayreuth,*D-95440, Bayreuth, Germany — ²Institut Curie, UMR 168, 26 rue d’Ulm, F-75248, Paris Cedex 05, France

We report a cylindrical–peristaltic shape transformation occurring in axons exposed to a controlled osmotic perturbation. The peristaltic shape relaxes and the axon recovers its original geometry within minutes. Using a flow chamber technique, we show that the shape instability depends critically on swelling rate and that volume and membrane area regulation are responsible for the shape relaxation. We propose that volume regulation occurs via leakage of ions driven by elastic pressure, and present an analysis for the peristaltic shape dynamics taking into account the internal structure of the axon. The results obtained provide a framework for understanding peristaltic shape dynamics in nerve fibers occurring in vivo.