Effect of Moderate Static Magnetic Field on Membrane Potential of Abdominal Nerve Fiber in Metapenaeus Ensis

The effects of uniform and static moderate magnetic fields (0–400 mT) on the membrane potential of nerve fibers in
Metapenaeus ensis
shrimps were investigated. The results showed that the magnetic field caused an increase in membrane potential, eventually reaching a static state, and that effects of short-term exposure were largely reversible. A nonlinear relationship between the percentage change in membrane potential (
V%
) and magnetic field induction was observed, where
V%
increased rapidly below an inflection point (around 200 mT) and slowed down thereafter. Hypotheses suggest that ion channels in the membrane have varying sensitivities to magnetic fields and presented the distribution of ion channel activation thresholds within the 0–400 mT range. The identification of the inflection point holds great practical value in the fields of magnetic field therapy, exposure limits, and magnetic shielding design.