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

[ラットの皮質へのRF電磁界局所ばく露は温度とともに局所脳血流を上昇させる] med./bio.

Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature

著者: Masuda H, Hirata A, Kawai H, Wake K, Watanabe S, Arima T, Poulletier de Gannes F, Lagroye I, Veyret B
掲載誌: J Appl Physiol 2011; 110 (1): 142-148
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この研究は、麻酔したラットの頭頂葉皮質に無線周波（RF）局所ばく露を与え、ばく露量と身体および脳内の生理学的変化の関係を調べた。8の字のループアンテナで2GHzのRFばく露をSAR値10.5、40.3、130、263W/kg（組織4.04mgでの平均）でターゲット部に与えた。RFばく露中、光ファイバー血流計と温度計を用い、局所脳血流量（CBF）と3ヶ所（ターゲット部位、直腸、ふくらはぎ皮下組織）の温度を測定した。その結果、18分間ばく露では、擬似ばく露群に比べばく露群で、ふくらはぎの皮下温を除くすべてのパラメータが有意に上昇した；RFばく露終了時においては、局所CBF上昇はターゲット部位および直腸の温度上昇と相関した；RFばく露の前半部分あるいは低強度RFばく露においては、局所CBF上昇はターゲット部位の温度上昇によって引き起こされ、直腸温度上昇によらないように見えた、と報告している。

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研究目的（著者による）

To study reproducible responses to local radiofrequency exposure in the parietal cortex of anesthetized rats and to determine their dependence on exposure intensity.

詳細情報

Rats were exposed under anesthesia. A "closed cranial window" was implanted into the parietal region.
The rat cortex was locally exposed to different SAR values in the target (parietal) area (n=7 in each group).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1,950 MHz
ばく露時間: continuous for 18 min
  • SAR: 10.5 W/kg average over mass (cf. remarks) (averaged over 4.04 mg (parietal target area); brain 6.14 W/kg; whole body 0.31 W/kg)
  • SAR: 40.3 W/kg average over mass (cf. remarks) (averaged over 4.04 mg (parietal target area); brain 23.5 W/kg; whole body 1.18 W/kg)
  • SAR: 130 W/kg average over mass (cf. remarks) (averaged over 4.04 mg (parietal target area); brain 75.8 W/kg; whole body 3.8 W/kg)
  • SAR: 263 W/kg average over mass (cf. remarks) (averaged over 4.04 mg (parietal target area); brain 153 W/kg; whole body 7.69 W/kg)

ばく露1

主たる特性
周波数 1,950 MHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 18 min
ばく露装置
ばく露の発生源／構造
ばく露装置の詳細 rat placed in an anechoic chamber and fixed in an acrylic stereotaxis apparatus with the antenna positioned 4 mm over the parietal bone
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 10.5 W/kg average over mass 推定値 cf. remarks averaged over 4.04 mg (parietal target area); brain 6.14 W/kg; whole body 0.31 W/kg
SAR 40.3 W/kg average over mass 推定値 cf. remarks averaged over 4.04 mg (parietal target area); brain 23.5 W/kg; whole body 1.18 W/kg
SAR 130 W/kg average over mass 推定値 cf. remarks averaged over 4.04 mg (parietal target area); brain 75.8 W/kg; whole body 3.8 W/kg
SAR 263 W/kg average over mass 推定値 cf. remarks averaged over 4.04 mg (parietal target area); brain 153 W/kg; whole body 7.69 W/kg

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

研究対象とした臓器系:
調査の時期:
  • ばく露前
  • ばく露中
  • ばく露後

研究の主なアウトカム（著者による）

All parameters except for the calf hypodermis temperature increased significantly in exposed animals compared with sham exposed rats during an exposure of 18 minutes. Local cerebral blood flow and temperature in the parietal target area and rectum depend markedly on the intensity of radiofrequency exposure. Furthermore, local cerebral blood flow elevation was significantly correlated with both temperature rise in the parietal target region and rectum after an exposure of 18 minutes. The local cerebral blood flow elevation seemed to be elevated by the rise in target temperature, but not by that of the rectal temperature, in the early part of radiofrequency exposure or at low-intensity radiofrequency exposure.
These data suggest that local radiofrequency exposure of the rat cortex drives a regulation of cerebral blood flow accompanied by a local temperature rise. These findings may be helpful for discussing physiological changes in the cortex region which is locally exposed to radiofrequency.

研究の種別:

研究助成

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