EMF Health-effects Research
Nonthermal effects of radiofrequency-field exposure on calcium dynamics in stem cell-derived neuronal cells: elucidation of calcium pathways.
Rao VS, Titushkin IA, Moros EG, Pickard WF, Thatte HS, Cho MR
Radiat Res. 169(3):319-329, 2008
.Intracellular Ca+ + spikes trigger cell proliferation, differentiation and cytoskeletal reorganization. In addition to Ca+ + spiking that can be initiated by a ligand binding to its receptor, exposure to electromagnetic stimuli has also been shown to alter Ca+ + dynamics.
Using neuronal cells differentiated from a mouse embryonic stem cell line and a custom-built, frequency-tunable applicator, we examined in real time the altered Ca+ + dynamics and observed increases in the cytosolic Ca+ + in response to nonthermal radiofrequency (RF)-radiation exposure of cells from 700 to 1100 MHz. While about 60% of control cells (not exposed to RF radiation) were observed to exhibit about five spontaneous Ca+ + spikes per cell in 60 min, exposure of cells to an 800 MHz, 0.5 W/kg RF radiation, for example, significantly increased the number of Ca+ + spikes to 15.7 +/- 0.8 (P < 0.05).
The increase in the Ca+ + spiking activities was dependent on the frequency but not on the SAR between 0.5 to 5 W/kg. Using pharmacological agents, it was found that both the N-type Ca+ + channels and phospholipase C enzymes appear to be involved in mediating increased Ca+ + spiking. Interestingly, microfilament disruption also prevented the Ca+ + spikes. Regulation of Ca+ + dynamics by external physical stimulation such as RF radiation may provide a noninvasive and useful tool for modulating the Ca+ +-dependent cellular and molecular activities of cells seeded in a 3D environment for which only a few techniques are currently available to influence the cells.