研究のタイプ: 医学/生物学の研究 (experimental study)

[血液脳関門と電磁界:2.45GHzに全身ばく露したラットのワーキングメモリに対する臭化メチルスコポラミンの影響] med./bio.

Blood-brain barrier and electromagnetic fields: Effects of scopolamine methylbromide on working memory after whole-body exposure to 2.45 GHz microwaves in rats.

掲載誌: Behav Brain Res 2005; 161 (2): 229-237

この研究は、ラット血液脳関門BBB)の透過性に対する2.45 GHzの電磁界パルス幅2マイクロ秒、毎秒のパルス繰り返し数500、全身平均SAR値2.0 W/kg±2 dB、脳組織平均SAR値3.0 W/kg±3 dB)ばく露の影響を調べた。本実験に先立ち、ムスカリン拮抗薬スコポラミン臭化水素酸塩を投与したSDラット誘導された記憶消失が12アーム放射迷路試験で測定されることを確認した。続いて、この拮抗薬の第4アンモニウム誘導体(臭化メチルスコポラミンMBR:本来はBBBをほとんど透過しない)を系統的に投与して、45分間の電磁界ばく露後のラットの12アーム放射迷路試験の成績が変化するか否かを調べた。成績の変化は、BBB透過性の変化を示すと考えた。実験の結果、電磁界ばく露による成績の変化は見られなかった、と報告している。

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研究目的(著者による)

To study whether a systemically-injected derivate of the muscarinic antagonist scopolamine hydrobromide (scopolamine methylbromide) altered maze performance of rats after a 45 min exposure to 2.45 GHz electromagnetic field.

詳細情報

First, it was verified that the maze test enabled demonstration of memory deficits in rats treated with the muscarinic antagonist scopolamine hydrobromide (0.5 mg/kg), which poorly crosses the blood-brain barrier and which is known to induce memory impairments. The drug was injected before and after irradiation.
Scopolamin methylbromide is another muscarinic antagonist that does not cross the blood-brain barrier easily; if observed such an alteration would reflect changes in blood-brain barrier permeability.
Finally, animals were subjected to injections of Evans blue, a dye binding serum albumin, before or after electromagnetic field exposure.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2.45 GHz
Modulation type: pulsed
ばく露時間: continuous for 45 min
  • SAR: 3 mW/g average over time (partial body) (± 3 dB; brain average)
  • SAR: 2 mW/g average over time (whole body) (± 2 dB)

ばく露1

主たる特性
周波数 2.45 GHz
タイプ
  • electromagnetic field
特性
  • guided field
偏波
  • circular
ばく露時間 continuous for 45 min
Modulation
Modulation type pulsed
Pulse width 2 µs
Repetition frequency 500 Hz
ばく露装置
ばく露の発生源/構造
  • circular waveguides/93 cm long x 20 cm in diameter
ばく露装置の詳細 Rats (n=12) were placed individually in a transparent plastic chamber (20 cm long x 17.5 cm in diameter, 13.5 cm high) located in the middle of the waveguide where they were able to move freely. Two waveguides were simultaneously excited hence exposing two rats at a time.
Additional information Naive rats (n=12) were brought into the testing room in their home cages and were left in there for 45 min to serve as cage control.
パラメータ
測定量 種別 Method Mass 備考
SAR 3 mW/g average over time 推定値 partial body ± 3 dB; brain average
SAR 2 mW/g average over time 測定値および計算値 whole body ± 2 dB

Reference articles

  • Cassel JC et al. (2004): [2.45GHz電磁界への全身ばく露はラットの放射状迷路試験の成績を変えない]

ばく露を受けた生物:

方法 影響評価項目/測定パラメータ/方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

Whether scopolamine methylbromide was injected before or after exposure, the exposed animals did not perform differently from the naive (no experience of the exposure device) or sham-exposed rats. Thus, electromagnetic fields most probably failed to disrupt the blood-brain barrier. This conclusion was further supported by the absence of Evans blue extravasation into the brain parenchyma of the exposed animals.

研究の種別:

研究助成

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