2.45 GHz microwave radiation impairs learning, memory, and hippocampal synaptic plasticity in the rat

Microwave (MW) radiation has a close relationship with neurobehavioral disorders. Due to the widespread usage of MW radiation, especially in our homes, it is essential to investigate the direct effect of MW radiation on the central nervous system. Therefore, this study was carried out to determine the effect of MW radiation on memory and hippocampal synaptic plasticity. The rats were exposed to 2.45 GHz MW radiation (continuous wave with overall average power density of 0.016 mW/cm2 and overall average whole-body specific absorption rate value of 0.017 W/kg) for 2 h/day over a period of 40 days. Spatial learning and memory were tested by radial maze and passive avoidance tests. We evaluated the synaptic plasticity and hippocampal neuronal cells number by field potential recording and Giemsa staining, respectively. Our results showed that MW radiation exposure decreased the learning and memory performance that was associated with decrement of long-term potentiation induction and excitability of CA1 neurons. However, MW radiation did not have any effects on short-term plasticity and paired-pulse ratio as a good indirect index for measurement of glutamate release probability. The evaluation of hippocampal morphology indicated that the neuronal density in the hippocampal CA1 area was significantly decreased by MW.