Exposure to 50-HZ Electromagnetic Fields: Effects of Time and Field Strength on GAP Junctional Intercellular Communications

Abstract

The relationship between a dose of 50-Hz magnetic field (MF) and its effects on suppression of gap junctional intercellular communication (GJIC) function were studied. An experiment was conducted on the effect of exposure to different intensities of 50-Hz MFs with the same exposure duration, and to different exposure durations of MF at the same intensity on GJIC in Chinese hamster lung (CHL) cells. Lucifer yellow, a fluorescent dye, was inserted into single CHL cells by iontophoretic injection (dye transfer assay). The number of dye-coupled cells (DCC) 5 min after injection was used as an indicator of GJIC function. The results showed that suppression of GJIC by 50-Hz MFs depended on the magnetic flux density. Lower MF flux densities at 0.05, 0.2, and 0.4 mT for 24 h did not inhibit GJIC function. Higher MF flux densities (0.8 and 1.6 mT) did inhibit. No' “amplitude window effect” was found with MF exposure at 0-1.6 mT. MF exposure at a fixed intensity of 0.8 mT for 5 min had no effects, but a 1-h exposure was more than enough to inhibit GJIC. The most significant effects were for 24-h exposures. In addition, we found that the suppression of GJIC was caused by direct action of 50-Hz MF rather than induced electrical field. It is suggested that 50-Hz MFs suppress GJIC with a dose-effect relationship.