36 rats were randomly divided into the following groups: 1) no febrile convulsion inductions and sham exposure, 2) febrile convulsion inductions and sham exposure, 3) exposure to magnetic field without febrile convulsion inductions, 4) daily exposure to magnetic field before febrile convulsion inductions, 5) daily exposure to magnetic field after febrile convulsion inductions, 6) daily exposure to magnetic field before and after ffebrile convulsion inductions.
All rats were operatively equipped with electrodes placed directly on the dura mater (the outermost membrane of the meninges) for recording of the EEG. Exposure to the magnetic field and inductions of febrile convulsions started 22 days after the surgery and were conducted for a period of 20 days. Febrile convulsions were induced every second day (total of 10 seizures) by placing the animals of febrile convulsion groups in water with a temperature of 45°C, whereas groups without febrile convulsion were placed in water with 37°C. Depending on the group, this was done before (group 4) or after (group 5) exposure of the respective day or in the meantime (group 6) (remark EMF-Portal: no further information in the article).
|Chamber||plexiglas cage (40 Œ 17 Œ 13 cm)|
|Setup||solenoid was 500 mm in length and 210 mm in diameter, was made of 1400 turns of an insulated soft copper wire with 1.4 mm in diameter and was placed on a fiber base; it was always kept in a north-south direction and its temperature was maintained at 25 ± 2°C|
|Sham exposure||A sham exposure was conducted.|
|Additional info||all devices that could affect the magnetic field were kept away from the experimental area|
|magnetic flux density||5 mT||-||measured and calculated||-||-|
The rectal temperature was significantly higher after a febrile seizure than before in all groups with febrile convulsion inductions (2, 4, 5, 6).
The latency duration of seizures was significantly increased in all febrile convulsion groups exposed to a magnetic field (groups 4, 5, 6) compared to group 2 (febrile convulsion inductions without exposure) after 10 and 12 days of exposure.
The seizure duration was significantly higher in group 2 after 2 days of exposure until the end of the experiment compared to groups 4, 5, 6.
The power of alpha waves was significantly increased and the power of beta waves, which were characterized as physiological waves of the waking state, significantly decreased in groups 2-6 compared to group 1 (no febrile convulsion inductions and sham exposure). The power of theta waves and delta waves, which were characterized as pathological waves, was significantly increased in groups 4, 5 and 6 compared to group 1.
The authors conclude that exposure of rats to a 50 Hz magnetic field might decrease the duration of febrile convulsions but could also have a negative effect on brain waves.