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

[超低周波電磁界ばく露は培養中の嗅内皮質ニューロンのカルシウム動態を変化させる] med./bio.

Exposure to extremely low frequency electromagnetic fields alters the calcium dynamics of cultured entorhinal cortex neurons.

掲載誌: Environ Res 2014; 135: 236-246

この研究は、超低周波電磁界(ELF-EMF:50Hz、1mTまたは3mT、24時間連続)ばく露下で培養中の嗅内皮質(EC)ニューロンカルシウムイオン(Ca2+)動態について、ホールセル記録法およびカルシウムイメージングを用いて調べた。結果として、電圧依存性Ca2+電流を含む入力電流はELF-EMFばく露で変化しなかった;高電圧活性化Ca2+チャネルと低電圧活性化Ca2+チャネルを区別して調べたが、両者の活性化、不活性化にELF-EMFばく露の影響は見られなかった;その一方、高濃度カリウムイオン誘発されたCa2+濃度上昇の大きさはELF-EMFばく露により減少したが、Ca2+ATP阻害剤の添加によりこの影響は見られなくなった、と報告している。

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研究目的(著者による)

To investiagte the influence of extremely low frequency magnetic fields on the calcium homeostasis in cultured entorhinal cortex neurons.

詳細情報

After a twelve-day culture period, cells were sham exposed or magnetic field exposed (1 mT or 3 mT). To test the specific currents of calcium channels with patch-clamp technique, the voltage-gated sodium and potassium ion channels were blocked by tetrodotoxin (blocks sodium ion channels), tetraethylammonium (blocks potassium ion channels) and 4-aminopyridine (blocks potassium ion channels).

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: intermittent for 24 hours (5 min on and 10 min off)
ばく露2: 50 Hz
ばく露時間: intermittent for 24 hours (5 min on and 10 min off)

ばく露1

主たる特性
周波数 50 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 intermittent for 24 hours (5 min on and 10 min off)
ばく露装置
ばく露の発生源/構造
ばく露装置の詳細 the exposure system consisted of two four-coil setups (2 coils with 56 windings, 2 coils with 50 windings), each of which was placed inside a Mu-metal box; two fans were mounted per box to guarantee enough atmospheric exchange within the exposure chambers; both setups (see additional information) were placed inside a commercial incubator to ensure constant environmental conditions (37°C, 5% CO2, 95% humidity); temperature was continuously monitored and maintained at 37-37.5°C during exposure; temperature difference between the chambers did not exceed 0.1°C
Sham exposure A sham exposure was conducted.
Additional information currents in the bifilar coils could be switched between parallel for field exposure and non-parallel for sham control, thus the field exposure and sham exposure can be achieved at the same time
パラメータ
測定量 種別 Method Mass 備考
磁束密度 1 mT - 測定値 - -

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 intermittent for 24 hours (5 min on and 10 min off)
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
パラメータ
測定量 種別 Method Mass 備考
磁束密度 3 mT - 測定値 - -

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:
調査の時期:
  • ばく露後

研究の主なアウトカム(著者による)

No influence of the magnetic field exposure on the whole cell currents and on high and low-voltage activated calcium channels was observed when compared to sham exposure. Additionally, no difference was found in the basal levels of the calcium concentration between the exposed and the sham exposed neurons. However, the analysis of the dynamic response using a potassium stimulus yielded in a dose-dependent significant derease in the calcium concentration of exposed cells compared to sham exposed cells. An addition of thapsigargin prevented this effect.
The authors conclude that extremely low frequency magnetic fields influence the calcium dynamics in neurons from the entorhinal cortex via a calcium channel independent mechanism.

研究の種別:

研究助成

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