Magnetic fields and intracellular calcium: effects on lymphocytes exposed to conditions for 'cyclotron resonance'.

There are a number of claims in the literature that specific combinations of low-level DC and AC magnetic fields can cause biologically significant effects. The combinations of fields required to elicit these responses fulfil the theoretical conditions for classical cyclotron resonance of the selected ion. Because of the biological importance of calcium ions any effects on them are of particular interest, for instance the claimed increase in calcium uptake by electromagnetically exposed lymphocytes. We have measured the intracellular calcium concentration, by means of a sensitive fluorescent probe, during a 60 min exposure of mouse lymphocytes to 'cyclotron resonance' conditions for calcium ions. 'Resonance' conditions at two frequencies (16 Hz and 50 Hz) were tested, with a range of DC field amplitudes used to shift the frequency up to 25% either side of the calculated optimum. Treatment of the lymphocytes with concanavalin A was used as a positive control and caused a significant increase in intracellular calcium concentration. No change in intracellular calcium concentration could be detected when lymphocytes were exposed to 'cyclotron resonance' conditions or to the other magnetic field combinations used.