Calcium protects differentiating neuroblastoma cells during 50 Hz electromagnetic radiation

Despite growing concern about electromagnetic radiation, the interaction be tween 50- to 60-Hz fields and biological structures remains obscure. Epidem iological studies have failed to prove a significantly correlation between exposure to radiation fields and particular pathologies. We demonstrate tha t a 50- to 60-Hz magnetic field interacts with cell differentiation through two opposing mechanisms: it antagonizes the shift in cell membrane surface charges that occur during the early phases of differentiation and it modul ates hyperpolarizing K channels by increasing intracellular Ca. The simulta neous onset of both mechanisms prevents alterations in cell differentiation . We propose that cells are normally protected against electromagnetic insu lt. Pathologies may arise, however, if intracellular Ca regulation or K cha nnel activation malfunctions.