THE ION PARAMETRIC RESONANCE MODEL PREDICTS MAGNETIC-FIELD PARAMETERSTHAT AFFECT NERVE-CELLS

An ion parametric resonance (IPR) model recently developed by Blanchar d and Blackman predicts distinct magnetic field interactions with biol ogical systems based on a selective relation among four factors: the f lux density of the static magnetic field, the frequency and flux densi ty (B-ac) of the parallel ac magnetic field, and the charge to-mass ra tio of ions of biological relevance, To test this model, PC-12 cells s timulated by nerve growth factor to produce neurites were exposed for 23 h in a 5% CO2 incubator using a multiple coil exposure system to pr oduce 45 Hz ac and de (366 mG parallel to ac; less than 2 mG perpendic ular to ac) magnetic fields, Our earlier work showed a cycle of inhibi tion/no inhibition of neurite outgrowth consistent with the IPR model predictions for B-ac exposures between 0 and 468 mG rms, The work desc ribed here tests neurite outgrowth over a broader range of B-ac (233-1 416 mG rms), The experimental results remain consistent with earlier r esults, 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 relationsh ips predicted by the IPR model, The results have broad significance fo r biology.