この実験研究では、グルコース投与によりヒトやげっ歯類での記憶欠損が減弱すること、認知障害は脳の特定部位でのグルコース代謝および取り込みの低下に関連することを示す広範な証拠があることを前提に、グルコース投与が、低電力密度マイクロ波（MW）慢性ばく露により生じた記憶欠損を減弱するか否か、また海馬のグルコース取り込みに対するMWばく露の影響を減弱するか否かを調べた。ばく露群（6匹×7グループ（各試験用）作成）、擬似ばく露群（6匹×3グループ）、ナイーブ対照群（6匹×3グループ）。ばく露（擬似ばく露）は円筒導波管内にプラスチックケージを置いて、1mW/cm2、2.45GHzパルス電磁界（TE11モード）に3時間／日、30日間行った。カロリメータによる測定などにより全身平均SAR 0.2 W/kg、脳平均SAR 0.7 W/kgと推定した。その結果、MWは空間記憶および学習の欠陥を引き起こした；インスリンの有無に拘わらずMWは海馬のグルコース取り込みを低下させた；ばく露により生じた空間記憶の欠陥はグルコース投与により回復した、などの知見を報告している。
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To investigate whether glucose treatment attenuated memory deficity caused by chronic low-power microwave exposure and the effect of microwave exposure on hippocampal glucose uptake.
Three experiments were performed:
1.) The levels of blood glucose and insulin and hippocampal glucose uptake were examined in three groups: 1a) exposed, 1b) sham exposed and 1c) cage control.
2.) The Morris water maze was conducted with five groups: 2 a) exposed, 2 b) exposed plus glucose injection 30 minutes before the daily training session, 2 c) exposed plus saline injection 30 minutes before the daily training session, 2 d) sham exposed and 2 e) cage control.
3.) The radial arm maze task was also conducted with five groups: 3 a) exposed, 3 b) exposed plus glucose injection 30 minutes before the daily training session, 3 c) exposed plus saline injection 30 minutes before the daily training session, 3 d) sham exposed and 3 e) cage control (The radial arm maze is used to test spatial memory, a maze consisting of eight arms with food at the end of each arm and all radiating from a small circular central platform; counted is the number of reentries into an arm already visited).
Each group consisted of 6 adult male rats.
Some groups of the rats were treated with 100 mg/ml glucose at a dose of 100 mg/kg 30 min before the daily training session.
|ばく露時間||continuous for 3 h/day on 30 days|
|Pulse width||10 µs|
|Packets per second||800|
|ばく露装置の詳細||circular waveguide constructed of galvanized wire screen in which a circulary polarized TE11-mode field configuration was excited; 23.6 cm long cylindrical transparent plastic chamber with a diameter of 17.6 cm and a floor width of 14.5 cm was located in the middle of the wave guide; single rat placed inside the plastic chamber|
|Sham exposure||A sham exposure was conducted.|
The blood glucose and insulin levels were not affected by chronic microwave exposure, but the glucose uptake decreased in hippocampal slices of exposed rats compared to sham exposed rats. This effect was also observed in the presence of insulin.
Regarding the Morris water maze task, a significant prolongation in latency time occured during the training sessions and the time, spent in the target quadrant, was significantly reduced in the probe trail in exposed groups compared to sham exposed groups. The latency of the glucose-treated group was significantly reduced compared with the saline-treated group. In the probe trial, the glucose-treated rats spent a longer time in the target quadrant as compared with the saline treated group.
In the radial arm maze task, the errors in the exposed group were significantly increased compared to the sham exposed group. The errors in the glucose-treated group were significantly reduced compared with the saline-treated group.
The authors conclude that this study demonstrated that the hippocampus-dependent spatial learning and memory of rats could be impaired by chronic microwave exposure and that glucose administration attenuated these deficits.