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

[50Hzの電磁界へのばく露はα-サソリ毒の効力を変える] med./bio.

Exposure to 50 Hz electromagnetic field changes the efficiency of the scorpion alpha toxin.

掲載誌: J Venom Anim Toxins Incl Trop Dis 2015; 21: 38

この研究は、神経のナトリウムイオンチャネルと相互作用して筋肉麻痺を引き起こすα-サソリ毒(LqhαIT:昆虫特異性あり)の効力が、超低周波磁界(ELF-MF:0.7および7mT)ばく露により変化するか否かをイン・ビボおよびイン・ビトロ実験で調べた。予めLqhαIT濃度と生体反応を試験した後、イン・ビボ実験はゴキブリで、イン・ビトロ実験はゴキブリから単離した尾角付き腹部脊髄神経束で、いずれもLqhαIT投与とELF-MFばく露を組合せて実施した。その結果、0.7 mTばく露で、尾角神経などの活動性に対するLqhαITの影響が変化した、などの所見を報告している。

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研究目的(著者による)

The effects of an in vivo exposure of cockroaches and an in vitro exposure of cockroach nerves to a 50 Hz magnetic field on the effects of the scorpion alpha toxin should be investigated.

詳細情報

The scorpion alpha toxin LqhαIT is a polypeptide highly active on insects. It binds to the sodium ion channels of nerves and inactivates them, causing hyper-excitation and paralysis. Magnetic fields might alter the effects of the toxin by modulating the nerve membrane potential and changing the binding properties or by influencing the neural transmission. The authors propose that in vitro and in vivo tests with the toxin could be a useful tool for distinguishing between primary and secondary effects of the magnetic field.
For the in vitro experiments, the abdominal nerve cord was isolated from the body of a cockroach together with the cercal nerve linked to the cerci (paired appendages of insects) and placed in culture medium. The following groups were observed (n=15 measurements each): 1) exposure to a 0.7 mT magnetic field only, 2) LqhαIT (5 Œ 10-8 M) administration only, 3) co-exposure to a 0.7 mT magnetic field and LqhαIT administration and 4) control group without exposure and with a sham administration (saline).
For the in vivo experiments cockroaches were divided into 3 groups (n=15 each): 5) exposure to a 0.7 mT magnetic field, 6) exposure to a 7 mT magnetic field and 7) sham exposure. Immediately before the beginning of the exposure, each insect was injected with 5 µl of LqhαIT (10-8 M; sublethal dose) and the animals were investigated after 1 h, 2 h and 24 hours of exposure.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 50 Hz
ばく露時間: continuous for 7 minutes
in vitro tests
ばく露2: 50 Hz
ばく露時間: continuous for up to 24 hours
in vivo tests
ばく露3: 50 Hz
ばく露時間: continuous for up to 24 hours
in vivo tests

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
ばく露時間 continuous for 7 minutes
Additional information in vitro tests
ばく露装置
ばく露の発生源/構造
チャンバの詳細 experimental chamber
ばく露装置の詳細 the coil (7 cm in diameter Œ 2 cm) was installed around the experimental chamber and produced a homogeneous field (maximum non-uniformity 16%); no changes in temperature were measured during exposure
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.7 mT - - - -

ばく露2

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for up to 24 hours
Additional information in vivo tests
Additional information vertical polarization (field lines perpendicular to the bottom plane of the animals' cage)
ばく露装置
ばく露の発生源/構造
チャンバの詳細 glass chamber (15 cm Œ 7.5 cm in diameter)
ばく露装置の詳細 coil wound around a plastic cylinder of 19 cm (inner diameter) and 21 cm in length; coil was able to ensure the maximum homogeneity (within 8%) in a central cylindrical area (radius and height of 7.5 cm) where glass chamber with free moving insects was placed; coil was located in an isolated room (temperature: 23 ± 1°C)
Sham exposure A sham exposure was conducted.
Additional information sham apparatus with the same size and temperature but lacking a coil was constructed
パラメータ
測定量 種別 Method Mass 備考
磁束密度 0.7 mT - 測定値 - -

ばく露3

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for up to 24 hours
Additional information in vivo tests
Additional information vertical polarization (field lines perpendicular to the bottom plane of the animals' cage)
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
Sham exposure A sham exposure was conducted.
パラメータ
測定量 種別 Method Mass 備考
磁束密度 7 mT - 測定値 - -

Reference articles

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:
  • cockroach nerve system
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)

In the in vitro experiments, administration of LqhαIT (group 2) led to a significantly increased bioelectrical activity in the cercal nerve compared to the control. Co-exposure to the toxin and to the magnetic field (group 3) attenuated the effect of the toxin. In the abdominal nerve, the administration of LqhαIT (group 2) led to a significantly increased bioelectrical activity similar to the cercal nerve, but co-exposure to the toxin and to the magnetic field (group 3) significantly increased the effect of the toxin in comparison to the control. In both nerves, the activity was decreased (remark EMF-Portal: significance unclear) compared to the control when the nerves were exposed to the magnetic field alone (group 1).
In the in vivo tests, exposure to the 0.7 mT (group 5) led to significantly reduced paralysis effects after 1 hours and 24 hours compared to sham exposed group (group 7). Exposure to the 7 mT (group 6) had a stronger effect and led to significantly reduced paralysis effects after 1 h, 2 h and 24 hours.
The authors conclude that exposure to a 50 Hz magnetic field could modify the effects of the scorpion alpha toxin in cockroaches. They suggest a primary effect of the magnetic field on the nerves and a secondary effect on the metabolism.

研究の種別:

研究助成

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