Ionic Channel Gating under Electromagnetic Exposure: A Stochastic Model

Researchers interested in the biological effects of electromagnetic (EM) fields are focusing their attention on the behavior of transmembrane ionicchannels and on their kinetic properties. Theoretical studies of the biochemical dynamic properties of the channels have suggested the development of a modelistic approach considering the membrane channel as a non-deterministic state machine. Its behavior is fully described by a set of states, a matrix of transition rates, and a vector for the probability of the machine to be in each single state at a certain instant. In this work astochasticmodel is developed, generating random processes where the probability for each state is an aleatory variable. The model can be applied to both voltage- and ligand-dependent channels, both unexposed and exposed to EM fields. The response of the model, for voltage-dependent channels such as K+, Na+ and Ca2+ in a voltage-clamp situation, is analyzed for sinusoidal EM fields in the ELF range. The results obtained appear more satisfactory than those presented in earlier papers using similar approaches, as this model shows the sensitivity of the channel response to both the frequency and amplitude of the EM stimulation.