Chemical exposure raises descendants'' sensitivity to stress

Researchers at The University of Texas at Austin and Washington State University have seen an increased reaction to stress in animals whose ancestors were exposed to an environmental compound generations earlier, according to a press release appearing on ScienceDaily.

The findings, published in the latest Proceedings of the National Academy of Sciences, put a new twist on the notions of nature and nurture, with broad implications for how certain behavioral tendencies might be inherited.

The researchers — David Crews at Texas , Michael Skinner at Washington State and colleagues — exposed gestating female rats to vinclozolin, a popular fruit and vegetable fungicide known to disrupt hormones and have effects across generations of animals. The researchers then put the rats'' third generation of offspring through a variety of behavioral tests and found they were more anxious, more sensitive to stress, and had greater activity in stress-related regions of the brain than descendants of unexposed rats.

"We are now in the third human generation since the start of the chemical revolution, since humans have been exposed to these kinds of toxins," says Crews. "This is the animal model of that."

"The ancestral exposure of your great grandmother alters your brain development to then respond to stress differently," says Skinner. "We did not know a stress response could be programmed by your ancestors'' environmental exposures."