Blackman C F, Blanchard J P, Benane S G, House D E
Health Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711-2055, USA.
FASEB J. 1995 Apr;9(7):547-51. doi: 10.1096/fasebj.9.7.7737464.
An ion parametric resonance (IPR) model recently developed by Blanchard and Blackman predicts distinct magnetic field interactions with biological systems based on a selective relation among four factors: the flux density of the static magnetic field, the frequency and flux density (Bac) of the parallel ac magnetic field, and the charge-to-mass ratio of ions of biological relevance. To test this model, PC-12 cells stimulated by nerve growth factor to produce neurites were exposed for 23 h in a 5% CO2 incubator using a multiple-coil exposure system to produce 45 Hz ac and dc (366 mG parallel to ac; less than 2 mG perpendicular to ac) magnetic fields. Our earlier work showed a cycle of inhibition/no inhibition of neurite outgrowth consistent with the IPR model predictions for Bac exposures between 0 and 468 mG rms. The work described here tests neurite outgrowth over a broader range of Bac (233-1416 mG rms). The experimental results remain consistent with earlier results, and with IPR model predictions of a second cycle of inhibition, return to control values, followed by a third cycle of inhibition of neurite outgrowth. These responses support the fundamental relationships predicted by the IPR model. The results have broad significance for biology.
