Carl F. Blackman1,2, S. G. Benane2, Dennis E. House2, William T. Joines2
1Health Effects Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711
2Health Effects Research Laboratory, U. S. Environmental Protection Agency Research Triangle Park, North Carolina
Tóm tắt
AbstractWe 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 Vp‐p/m. Alternatively, 1‐Hz and 30‐Hz fields at 40 Vp‐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 Vp‐p/m, a 45‐Hz field causes enhanced efflux in an intensity range around 40 Vp‐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 Vp‐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 Vp‐p/m, intensities slightly lower than those that are effective at 50 Hz. Finally, exposures over a series of frequencies at 42.5 Vp‐p/m reveal two frequency regions that elicit enhanced efflux—one centered on 15 Hz, the other extending from 45 to 105 Hz.
