Periodic spiking by a pair of ionic channels

TL;DR

This study demonstrates that a pair of ionic channels can intrinsically generate periodic voltage spikes through their interactions, without external energy input, aligning with experimental observations.

Contribution

It introduces a minimal stochastic model showing that two ionic channels alone can produce periodic spikes, highlighting an intrinsic mechanism.

Findings

A pair of ionic channels can sustain membrane potential spikes autonomously.

Spike dynamics are driven by interactions between membrane potential, ionic flows, and channel gates.

The model reproduces experimental spike structures and missing events.

Abstract

Neuronal cells present periodic trains of localized voltage spikes involving a large amount of different ionic channels. A relevant question is whether this is a cooperative effect or it could also be an intrinsic property of individual channels. Here we use a Langevin formulation for the stochastic dynamics of a pair of Na and K ionic channels. These two channels are simple gated pore models where a minimum set of degrees of freedom follow standard statistical physics. The whole system is totally autonomous without any external energy input, except for the chemical energy of the different ionic concentrations across the membrane. As a result it is shown that a unique pair of different ionic channels can sustain membrane potential periodic spikes. The spikes are due to the interaction between the membrane potential, the ionic flows and the dynamics of the internal parts (gates) of each channel structures. The spike involves a series of dynamical steps being the more relevant one the leak of Na ions. Missing spike events are caused by the altered functioning of specific model parts. The time dependent spike structure is comparable with experimental data.