Evaluation of the effect of chronic exposure to 137Cesium on sleep-wake cycle in rats.
Since the Chernobyl accident, the most significant problem for the population living in the contaminated areas is chronic exposure by ingestion of radionuclides, notably (137)Cs, a radioactive isotope of cesium. It can be found in the whole body, including the central nervous system. The present study aimed to assess the effect of (137)Cs on the central nervous system and notably on open-field activity and the electroencephalographic pattern. Rats were exposed up to 90 days to drinking water contaminated with (137)Cs at a dosage of 400 Bq kg(-1), which is similar to that ingested by the population living in contaminated territories. At this level of exposure, no significant effect was observed on open-field activity. On the other hand, at 30 days exposure, (137)Cs decreased the number of episodes of wakefulness and slow wave sleep and increased the mean duration of these stages. At 90 days exposure, the power of 0.5-4 Hz band of (137)Cs-exposed rats was increased in comparison with controls. These electrophysiological changes may be due to a regional (137)Cs accumulation in the brain stem. In conclusion, the neurocognitive effects of (137)Cs need further evaluation and central disorders of population living in contaminated territories must be considered.
Lestaevel
Philippe
P
Institut de Radioprotection et de Sûreté Nucléaire, Direction de la RadioProtection de l'Homme, Service de Radiobiologie et d'Epidémiologie, Laboratoire de Radiotoxicologie Expérimentale, BP 17, 92262 Fontenay-aux-Roses, France.
Dhieux
Bernadette
B
Tourlonias
Elie
E
Houpert
Pascale
P
Paquet
François
F
Voisin
Philippe
P
Aigueperse
Jocelyne
J
Gourmelon
Patrick
P
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002588:Cesium Radioisotopes / Q000633:toxicity*; D047852:Chernobyl Nuclear Accident; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000187:drug effects*; D012895:Sleep, REM / Q000187:drug effects; D014851:Wakefulness / Q000187:drug effects*
D002588:Cesium Radioisotopes