Why are rats tense? Bad city air

Why are rats in Philadelphia so tense? Maybe it's the air they breathe.

A study out of Ohio State's Medical Center shows that rats get hypertension when exposed over time to airborne pollution. Over ten weeks researchers made the whiskered scavengers suck in all the crappy air any city dweller breathes – the levels weren't even as high as those found in some smog-choked cities in the U.S., India or China.

The rats developed high blood pressure.

The study, the authors contend, shows the first direct link between air pollution and its impact on high blood pressure and if the finding hold up in humans, could be important for setting environmental policy.

To conduct the test the researchers placed rats into a chamber and exposed some to polluted air and others to fresh air. After nine weeks they exposed the rats to angiotensin II, another pollutant, and documented a rise in heart rates in rats that were previously exposed to pollution in their chambers.

Co-author, Sanjay Rajagopaian, said the study, which will be published in an upcoming issue of Arteriosclerosis, Thrombosis and Vascular Biology, published by the American Heart Association, shows the need for a broader based approach to controlling pollution.