The effects of radiofrequency radiation on hippocampal long term potentiation in vitro

We have previously found that continuous wave (CW) radiofrequency (RF) fields can affect electrical activity in rat hippocampus in vitro without measurable temperature rises. The present study investigated the effects of CW and GSM RF fields on a more complex response, long term potentiation (LTP), which has been proposed as an in vitro model for cellular learning and memory. Rat hippocampal slices were exposed to RF fields within a calibrated stripline waveguide (maximum E field 71 V.m/sup -1/ r.m.s.). No change in temperature (/spl plusmn/0.1/spl deg/C) could be detected using a Luxtron probe. Exposure to RF during the induction of LTP produced a larger potentiation of the population spike (PS) amplitude but not of the excitatory postsynaptic potential. In contrast, exposure to a 700 MHz CW field 30 minutes before the LTP stimulus resulted in a significantly lower potentiation of the PS compared to control values, but this was not apparent with the other three waveforms. These results are consistent with in vivo studies which suggest that RF fields can retard learning in rats and open the possibility of correlating an in vitro effect with changes in the intact animal.