Acute enhancement of non-rapid eye movement sleep in rats after drinking water contaminated with cadmium chloride

Katsuya Unno, Kurumi Yamoto, Kouhei Takeuchi, Aya Kataoka, Tomoya Ozaki, Takatoshi Mochizuki, Kazuki Honda, Nobuhiko Miura, Masayuki Ikeda*

*この論文の責任著者

研究成果: ジャーナルへの寄稿学術論文査読

14 被引用数 (Scopus)

抄録

Cadmium (Cd) is a heavy metal widely used or effused by industries. Serious environmental Cd pollution has been reported over the past two centuries, whereas the mechanisms underlying Cd-mediated diseases are not fully understood. Interestingly, an increase in reactive oxygen species (ROS) after Cd exposure has been shown. Our group has demonstrated that sleep is triggered via accumulation of ROS during neuronal activities, and we thus hypothesize the involvement of Cd poisoning in sleep-wake irregularities. In the present study, we analyzed the effects of Cd intake (1-100 ppm CdCl2 in drinking water) on rats by monitoring sleep encephalograms and locomotor activities. The results demonstrated that 100 ppm CdCl2 administration for 28 h was sufficient to increase non-rapid-eye-movement (non-REM) sleep and reduce locomotor activities during the night (the rat active phase). In contrast, free-running locomotor rhythms under constant dim red light and their re-entrainment to 12:12-h light/dark cycles were intact under chronic (1 month) 100 ppm CdCl2 administrations, suggesting a limited influence on circadian clock movements at this dosage. The relative amount of oxidized glutathione increased in the brain after the 28-h 100 ppm CdCl2 administrations similar to the levels in cultured astrocytes receiving H2O2 or CdCl2 in culture medium. Therefore, we propose Cd-induced sleep as a consequence of oxidative stress. As oxidized glutathione is an endogenous sleep substance, we suggest that Cd rapidly induces sleepiness and influences activity performance by occupying intrinsic sleep-inducing mechanisms. In conclusion, we propose increased non-REM sleep during the active phase as an index of acute Cd exposure.

本文言語英語
ページ(範囲)205-213
ページ数9
ジャーナルJournal of Applied Toxicology
34
2
DOI
出版ステータス出版済み - 2014/02

ASJC Scopus 主題領域

  • 毒物学

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