EVIDENCE FOR DIRECT EFFECT OF MAGNETIC-FIELDS ON NEURITE OUTGROWTH

Electric fields can cause changes in cell responses both in vitro and in vivo. Alternating magnetic fields have been proposed to act through the electric fields induced in the conducting medium surrounding the cells. We have used a simple exposure system to test the relative cont ribution of magnetic fields compared to induced electric fields in a s tandard PC-12 cell culture assay, in which cells respond to nerve grow th factor by producing neurites. This response to stimulation by nerve growth factor is inhibited by sinusoidal, 50-Hz magnetic fields at fi eld strengths below 10 muT (100 mG). A standard procedure to distingui sh magnetic- vs. electric-field effects demonstrates that the induced electric field is not involved. Additional work is necessary to identi fy the critical reaction site (or sites), and to establish the molecul ar mechanisms responsible for these results.