Body Clock Surprise

(Ivanhoe Newswire) -- It's a wake-up call on how we sleep -- a new discovery of our internal clock working much differently than once thought.

Scientists at the University of Utah in Salt Lake City and the University of Michigan in Ann Arbor say the finding is a complete reversal of previous research and that drug makers will have to design new medications to treat sleep disorders, jet lag and some forms of depression.

Researchers found what was previously believed about the "tau mutation" is wrong. The mutation causes hamsters to have a 20-hour day instead of a 24-hour day. The belief was a decrease in gene activity speeds up the internal clock, making the day between two and four hours shorter. But new research reveals the tau mutation instead causes an increase in gene activity to speed up the internal clock.

"The key to developing treatments for problems like depression and insomnia -- disorders influenced by circadian rhythm -- is being able to predict how the body's internal clock can be controlled," says David Virshup, M.D., co-principal investigator, University of Utah's Huntsman Cancer Institute. "If the working model is wrong, drugs will have the opposite effect."

University of Michigan mathematician Daniel Forger, Ph.D., developed a mathematical model of the circadian rhythms. He ran computer simulations of how the tau mutation affected a mammal' biological clock.

"I had this prediction for a year or two," says Forger. "Basically, people said this is ridiculous; you're a mathematician; what do you know..."

Researchers will now begin testing ways to regulate the circadian rhythm in mice so that eventually new drugs can be developed.

This article was reported by Ivanhoe.com, who offers Medical Alerts by e-mail every day of the week. To subscribe, go to: http://www.ivanhoe.com/newsalert/.

SOURCE: Proceedings of the National Academy of Sciences, published online July 3, 2006