Cellular communication in clone 9 cells exposed to magnetic fields

Magnetic-field exposure (45 Hz B-a.c. over a Bur density range of 7.7 to 49 .9 mu T r.m.s. with parallel B-d.c. of 36.6 mu T) has been reported by Blac kman and coworkers to inhibit gap junction intercellular communication in C lone 9 cells treated with chloral hydrate for 24 h prior to field exposure in accord with predictions of the ion parametric resonance model. The study reported here is an attempt to reproduce this effect. Baseline experiments showed that growth in culture and state of confluence at time of addition of chloral hydrate were comparable in both laboratories, PMA inhibited cell -cell communication in a dose-dependent manner, similar to the results of B lackman and coworkers, whereas cells in the present study were somewhat mor e sensitive to chloral hydrate than reported by Blackman and coworkers. A t otal of 38 exposure experiments were undertaken using a 45 Hz magnetic fiel d with a Bur density of 23.8 mu T r.m.s., in parallel with a 36.6-mu T stat ic magnetic field for 40 to 45 min, after pretreatment with 25 mM chloral h ydrate for 24 h, In 14 unblinded experiments, a small but statistically sig nificant effect of magnetic-field exposure was observed, but due to the sub jective nature of the assay, it was deemed essential to carry out blinded e xperiments, The remaining 24 experiments were blinded. In 15 blinded experi ments, cells purchased from the American Type Culture Collection and grown only in this laboratory were used, while in 9 experiments, the cells had or iginally been grown in Blackman's laboratory and were subsequently sent to this laboratory. There was no statistically significant effect of magnetic- field exposure on gap junction intercellular communication in these blinded experiments using either cell line. (C) 2000 Radiation Research Society.