CORRELATION BETWEEN THE AMPLITUDE OF PLASMA-MEMBRANE FLUCTUATIONS AND THE RESPONSE OF CELLS TO ELECTRIC AND MAGNETIC-FIELDS

Several hypotheses designed to explain electric and magnetic (EM) field interaction with cells propose the plasma membrane as a primary target. The present experiments tested whether the status of the plasma membrane influences the response of cells to EM fields. HL-60 cells were exposed to defined EM fields in the presence of either colchicine or cytochalasin B and transcript levels for beta-actin and c-fos were determined. The steady state of these mRNAs is known to be increased when cells are exposed to the EM fields used in this study. Treatment of cells with colchicine disturbs microtubules and can lead to small decreases in local plasma membrane fluctuations. Cytochalasin treatment affects the microfilament structure and has been shown to lead to small increases in local membrane fluctuations. The treatment of cells during EM field exposures with colchicine produces opposite effects from that observed in cells treated with cytochalasin B. The stimulatory effect of EM fields on the expression of beta-actin and c-fos is abolished in the presence of colchicine. The levels for both beta-actin and c;fos, however, are enhanced in the presence of cytochalasin B. These experiments show that the status of the plasma membrane is important in the response of the cell to EM field exposure.