Medical/biological study (experimental study)

Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release med./bio.

By: Prochnow N, Gebing T, Ladage K, Krause-Finkeldey D, El Ouardi A, Bitz A, Streckert J, Hansen V, Dermietzel R

Published in: PLoS One 2011; 6 (5): e19437

Exposure	Parameters
Exposure 1: 2 GHz Exposure duration: continuous for 2 h	power: 0.36 W (input power for SAR = 2 W/kg) power: 1.8 W (input power for SAR = 10 W/kg) SAR: 2 W/kg SAR: 10 W/kg

Exposure source	waveguide
Setup	hexagonal double-cone waveguide placed above the six shielded exposure compartments; metal ribs with a gap of 6 mm between them fixed to the opposite walls of the inner and outer cone build into each compartment to concentrate the RF exposure; conic rat constrainers positioned inside the compartment so that the rat's brain was directly below the waveguide aperture
Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
power	0.36 W	-	-	-	input power for SAR = 2 W/kg
power	1.8 W	-	-	-	input power for SAR = 10 W/kg
SAR	2 W/kg	-	-	brain	-
SAR	10 W/kg	-	-	brain	-

Ndoumbe Mbonjo Mbonjo H et al. (2004): Generic UMTS test signal for RF bioelectromagnetic studies
Hansen VW et al. (1999): RF Exposure of Biological Systems in Radial Waveguides
Burkhardt M et al. (1997): Exposure setup to test effects of wireless communications systems on the CNS

Exposed system:

Investigated system:

Investigated organ system:

Time of investigation:

Comparison of cage control animals revealed significantly increased corticosterone and ACTH levels in the exposed and sham exposed groups which corresponded with generally decreased field excitatory postsynaptic potential slopes and amplitudes in hippocampal long-term depression and long-term potentiation.
Animals exposed at a SAR value of 2 W/kg did not differ from the sham exposed group in long-term depression and long-term potentiation experiments. In contrast, a significant reduction in long-term depression and long-term potentiation was observed at the SAR value of 10 W/kg. The data demonstrate that a rate of 2 W/kg displays no adverse impact on long-term depression and long-term potentiation, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background (due to immobilization).
The authors conclude that UMTS exposure with a SAR value in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg, non-thermal) cannot be excluded. The data suggest that long-term activity-dependent synaptic plasticity is a putative target for the effect of electromagnetic fields of extraordinary high energy absorption rates in male adult Wistar rats.

Study character:

Bouji M et al. (2012): Effects of 900 MHz radiofrequency on corticosterone, emotional memory and neuroinflammation in middle-aged rats
Cuccurazzu B et al. (2010): Exposure to extremely low-frequency (50 Hz) electromagnetic fields enhances adult hippocampal neurogenesis in C57BL/6 mice
Varro P et al. (2009): Changes in synaptic efficacy and seizure susceptibility in rat brain slices following extremely low-frequency electromagnetic field exposure
Pakhomov AG et al. (2003): Effects of high power microwave pulses on synaptic transmission and long term potentiation in hippocampus