Molecular Na-channel excitability from statistical physics
1 Departament de Física Aplicada, Universitat Politécnica de Catalunya - Avinguda Doctor Marañón, 44, E-08028 Barcelona, Spain
2 Universitat de Barcelona, Departament d'Estructura i Constituents de la Matèria - Martí i Franqués, 1, E-08028 Barcelona, Spain
Received: 25 July 2014
Accepted: 21 November 2014
The excitable properties of the neural cell membrane is the driving mechanism of the neural pulses. Coordinated ionic fluxes across Na and K channels are the devices responsible of this function. Here we present a simple microscopic physical scenario which accounts for this phenomenology. The main elements are ions and channel doors that obey the standard formulation of statistical physics (overdamped Langevin equations) with appropriate nonlinear interacting potentials. From these equations we obtain the ionic flux and the dynamics of the membrane potential. We show that the excitable properties of the membrane are present in a single and simple Na channel. From this framework, additional microscopic information can be obtained, such as statistics of single-channels dynamics or the energetics of action potential events.
PACS: 05.10.Gg – Stochastic analysis methods (Fokker-Planck, Langevin, etc.) / 87.16.Vy – Ion channels / 87.15.A- – Theory, modeling, and computer simulation
© EPLA, 2014