An action potential is typically described as a purely electrical change that propagates along the membrane of excitable cells. However, recent experiments have demonstrated that non-linear acoustic pulses that propagate along lipid interfaces and traverse the melting transition, share many similar properties with action potentials. Despite the striking experimental similarities, a comprehensive theoretical study of acoustic pulses in lipid systems is still lacking. Here we demonstrate that an idealized description of an interface near phase transition captures many properties of acoustic pulses in lipid monolayers, as well as action potentials in living cells. The possibility that action potentials may better be described as acoustic pulses in soft interfaces near phase transition is illustrated by the following similar properties: correspondence of time and velocity scales, qualitative pulse shape, sigmoidal response to stimulation amplitude (an ‘all-or-none’ behavior), appearance in multiple observables (particularly, an adiabatic change of temperature), excitation by many types of stimulations, as well as annihilation upon collision. An implication of this work is that crucial functional information of the cell may be overlooked by focusing only on electrical measurements.
Bibliographical noteFunding Information:
The authors thank Christian Fillafer, Kevin Kang, Julian Kappler and Konrad Kaufmann for fruitful discussions and valuable comments, and to Daniel Lecoanet for support with the Dedalus open-source code. MM thanks Uri Nevo for introducing him to the subject of non-electric aspects of action potentials, and to Jay Fineberg for useful comments. We acknowledge financial support by Deutsche Forschungsgemeinschaft and TU-Dortmund University within the funding program Open Access Publishing. MM further acknowledges funds from SHENC-research unit FOR 1543.
© 2019, The Author(s).
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