Electromagnetic fields modulate neuronal membrane ionic currents through altered cellular calcium homeostasis.

The biological effects of electromagnetic fields (EMFs) on the central nervous system (CNS) have been widely reported in the literature. Their nature and extent are thought to depend on parameters such as field intensity and frequency. Of these, extremely low-frequency (50 Hz) fields have been reported to influence neuronal firing in CNS regions, including the hippocampus. We applied the loose patch clamp technique to study the effects of 1 mT exposures of such fields over the course of 60 min on cornus ammonis 1 (CA1) pyramidal neuron membranes in coronal hippocampal slices. Such exposure decreased both inward and transient outward currents. Pharmacological blockers of ryanodine receptor (RyR)-dependent Ca release (dantrolene) and endoplasmic reticular Ca store reuptake (SERCA; cyclopiazonic acid) both abrogated these effects. We thus implicate Ca homeostasis in an EMF-induced modulation of neuronal excitability through its regulation of voltage-gated channels.