Effects of ELF (1–120 Hz) and modulated (50 Hz) RF fields on the efflux of calcium ions from brain tissue in vitro

Abstract

We have previously shown that 16‐Hz, sinusoidal electromagnetic fields can cause enhanced efflux of calcium ions from chick brain tissue, in vitro, in two intensity regions centered on 6 and 40 V p‐p/m. Alternatively, 1‐Hz and 30‐Hz fields at 40 V p‐p/m did not cause enhanced efflux. We now demonstrate that although there is no enhanced efflux associated with a 42‐Hz field at 30, 40, 50, or 60 V p‐p/m, a 45‐Hz field causes enhanced efflux in an intensity range around 40 V p‐p/m that is essentially identical to the response observed for 16‐Hz fields. Fields at 50 Hz induce enhanced efflux in a narrower intensity region between 45 and 50 V p‐p/m, while radiofrequency carrier waves, amplitude modulated at 50 Hz, also display enhanced efflux over a narrow power density range. Electromagnetic fields at 60 Hz cause enhanced efflux only at 35 and 40 V p‐p/m, intensities slightly lower than those that are effective at 50 Hz. Finally, exposures over a series of frequencies at 42.5 V p‐p/m reveal two frequency regions that elicit enhanced efflux—one centered on 15 Hz, the other extending from 45 to 105 Hz.