Cerebral ischemia was induced by surgical occlusion of both common carotid arteries for 10 min. Adult (3-month-old) male gerbils were divided into four groups (6-8 animals/group): 1.) control, 2.) exposure, 3.) ischemia, and 4.) ischemia + exposure. The control group was further subdivided into intact controls, sham operated, and sham exposed animals.
The behavioral parameters were investigated on days 1, 2, 4, and 7 of exposure (immediate effect) and seven days after exposure (day 14, delayed effect).
Exposure duration: continuous for 7 days
|Setup||two 26 cm x 43 cm x 15 cm polycarbonate cages with 3 - 4 animals each, positioned on both sides of the electromagnet so that the center of the cage was at a distance of 20 cm from the pole|
|Sham exposure||A sham exposure was conducted.|
|magnetic flux density||0.2 mT||minimum||measured||-||at the end of the cage with the greatest distance to the pole|
|magnetic flux density||2 mT||maximum||measured||-||at the end of the cage with the smallest distance to the pole|
|magnetic flux density||0.5 mT||spatial average||measured||-||at the center of the cage|
The 10-min global cerebral ischemia per se induced a significant increase of motor activity, stereotypy and rotations, and consequently immobility decrease until day 4 in ischemic animals compared to control gerbils. Exposure to an extremely low frequency magnetic field per se showed a tendency of increasing motor activity (data not shown).
Exposure to an extremely low frequency magnetic field + ischemia (group 4) inhibited the development of ischemia-induced motor hyperactivity during the whole period of monitoring, particularly in the first two days after reperfusion, when the post-ischemic hyperactivity was most evident.
The authors concluded that the exposure to an extremely low frequency magnetic field decreased motor hyperactivity induced by the 10-min global cerebral ischemia.