Nonstick chemicals upset behavior.
Niclas Johansson and his coworkers at Uppsala (Sweden) University exposed 10-day-old male mice to a single oral dose of a nonstick agent, either PFOS (perfluorooctanesulfonic acid) or PFOA (perflnorooctanoic acid). That stage of mouse life roughly corresponds to a major brain-development period in children, which lasts from shortly before birth to about age 2 years. Some groups of animals in the experiment ingested 9 to 11 milligrams of a nonstick chemical per kilogram of body weight; other groups got less than 10 percent of that amount.
At 2 and 4 months of age, each mouse was put in an unfamiliar cage. Untreated animals and those from the low-dose groups initially appeared agitated and were active, but within an hour they relaxed and fell asleep. Coauthor Per Eriksson says these animals integrated the environmental information and realized that the new cage wasn't much different from their home pens.
Mice from the high-dose groups, however, never settled down, which suggests that their brains didn't process the new stimulus appropriately, says Eriksson.
In another test, the researchers injected the mice with nicotine. The stimulant increased activity in all animals except those in the high-dose -PFOS and -PFOA groups; nicotine put those mice to sleep. The difference suggests, Eriksson says, that the early, high doses altered a brain-communications system that's affected by nicotine and that shapes behavior.
PFOS and PFOA have been showing up throughout the environment and in people's bodies. Johansson notes that doses in the new mouse study, although "quite low," did exceed those few values recently measured in babies and breast milk (SN: 11/26/05, p. 341).
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|Title Annotation:||BEHAVIORAL SCIENCES|
|Date:||Mar 25, 2006|
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