An Evaluation of Neurotoxicity Markers in Rat Brains, using a Pre-Convulsive Model and Exposure to 900 MHZ Modulated GSM Radio Frequency (pp. 331-348)
Authors: (María Elena López-Martín, Francisco José Ares-Pena, Morphological Sciences Department, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain, and others)
Abstract: Studies of cerebral activity in humans and in animal models after exposure to the modulated radio frequency (RF) of mobile phones have often indicated alterations of normal physiology and signs of toxicity in the nervous system.
In recent years, in our laboratory has carried out consecutive experiments to investigate how exposure to radiation similar to that of mobile phones affects the cerebral activity of rats previously exposed to a state of pre-excitability in their neuronal activity. An experimental radiation system was designed, involving a standing wave chamber built to maintain constant electromagnetic parameters and provide stress-free exposure to non-thermal levels of radiation. Rats were given an intraperitoneal injection of a sub-convulsive dose of picrotoxin to create a pre-convulsive experimental model and then the animals were exposed to 900MHz GSM radio frequency in the radiation chamber for two hours. Afterwards, they suffered convulsions and showed marked increases in neuronal activity in the neocortex, paleocortex, hippocampus and thalamus.
Clinical differences were also found in the electroencephalographic (EEG) signals and in c-Fos expression in the brains of rats exposed to modulated and unmodulated GSM radiation. The most marked effects of GSM radiation on c-Fos expression in picrotoxin-treated rats were in the limbic structures, olfactory cortex and subcortical
areas, the Dentate Gyrus and the centro-lateral nucleus of the intralaminar nuclear group of the thalamus. Animals not treated with picrotoxin and exposed to unmodulated radiation presented higher levels of neuronal activation in cortical areas.
Morphological examination revealed that most rat brain areas except the limbic cortex have shown an important increase in neuronal activation 24 hours after picrotoxin and radiation. Three days later, radiation effects were still evident in the neocortex, Dentate Gyrus and CA3, but had diminished in the limbic cortex (entorhinal and pyriform). During this period, glial activity increased, with convulsions observed in radiated rats treated with picrotoxin.
Our findings of neurotoxicity markers in a sub-convulsive model of rat brains exposed to radiation indicates how exposure to mobile phone radiofrequency fields may induce changes in brain tissue that is physiologically susceptible to electrical instability. These results suggest that the effects of mobile phones on at-risk populations should be thoroughly studied.