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

[低レベルマイクロ波放射と中枢コリン作動性活動：量反応研究] med./bio.

Low-level microwave irradiation and central cholinergic activity: a dose-response study

著者: Lai H, Carino MA, Horita A, Guy AW
掲載誌: Bioelectromagnetics 1989; 10 (2): 203-208
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この研究は、ラットに、円偏波、パルス変調2,450MHzマイクロ波（パルス幅2マイクロ秒、500pps）を45分間ばく露を与え、ばく露露直後に、線条体、前頭皮質、海馬および視床下部において、神経組織におけるコリン作動性の指標であるナトリウム依存性高親和性コリン取り込みを測定した。ばく露に用いたのは、Guyら（Radio Sci 14：63-74、1979）の円柱導波管システムである。電力密度は、0.3,0.4,0.6,0.75,0.9または1.2W / kgの全身平均SARを与えるレベルに設定された。その結果、線条体でのコリン取り込み低下は0.75W / kg以上のSARで観察されたが、前頭皮質および海馬でのコリン取り込み低下は0.45W / kg以上で観察された；視床下部での有意な変化は、どのSARレベルでも観察されなかった；プロビット分析で決定したSAR50（最大応答の50％が誘発されたSARレベル）は、線条体、前頭皮質および海馬でそれぞれ、0.6、0.38および0.44W / kgであった、と報告している。

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研究目的（著者による）

To measure sodium-dependent high-affinity choline uptake in the brain of rats after acute exposure to pulsed 2450 MHz microwaves in a cylindrical waveguide system.

詳細情報

Since the dosimetry of this irradiation system is well documented, and the power density of exposure can be adjusted to give different whole-body averaged SARs in the exposed animals, the system provides a reliable means to investigate the dose (SAR)-response relationship of microwave irradiation. This preliminary report describes the effect of varying the power density of microwave exposure on choline uptake in different regions of the brain.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2,450 MHz
Modulation type: pulsed
ばく露時間: continuous for 45 min
  • 電力密度: 2 mW/cm² mean (0.5, 0.75, 1.0, 1.5, 1.75, and 2.0 mW/cm²)
  • SAR: 1.2 W/kg average over mass (whole body) (0.3, 0.45, 0.6, 0.75, 0.9, and 1.2 W/kg)

ばく露1

主たる特性
周波数 2,450 MHz
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
チャンバの詳細 The cylindrical waveguide system [Guy et al., 1979] consisted of eight individual exposure tubes consisting of a section of circular waveguide made of galvanized wire screen. The circularly polarised field in TE11 mode propagated from one end of the waveguide to the other end. The rat was housed in a plastic chamber with a floor of glass rods.
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 2 mW/cm² mean - - 0.5, 0.75, 1.0, 1.5, 1.75, and 2.0 mW/cm²
SAR 1.2 W/kg average over mass - whole body 0.3, 0.45, 0.6, 0.75, 0.9, and 1.2 W/kg
Additional parameter details

The power densities were averaged over the cross section of the waveguide at the position of exposure.

測定および計算の詳細

The dosimetry of this irradiation system was well documented [Guy et al., 1979 and Chou et al., 1985].

Reference articles

  • Chou CK et al. (1985): [7つのばく露状況下で2, 450 MHzのマイクロ波にさらされるラットの比吸収率]
  • Guy AW et al. (1979): [小動物のマイクロ波慢性ばく露に用いる円偏光2450 MHz導波管装置]

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）

The results show a dose-response relationship of central choline uptake with microwave irradiation. However, different brain areas have different sensitivities to the exposure. Decrease in choline uptake was observed in the striatum at a SAR of 0.75 W/kg and above. For the frontal cortex and hippocampus, decreases in choline uptake were observed at a SAR of 0.45 W/kg and above. No significant effect was observed in the hypothalamus at the irradiation power densities studied. The probit analysis was used to determine the SAR50 in each brain area (i.e. the SAR at which 50% of maximum response was elicited). SAR50 for the striatum, frontal cortex, and hippocampus were 0.65, 0.38, and 0.44 W/kg, respectively.

研究の種別:

研究助成

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