October 30 (HealthDay News) -- A drug used to treat epilepsy and bipolar disorder may help prevent and treat Alzheimer's disease, according to Canadian researchers, who found that valproic acid (VPA) blocked the formation of Alzheimer's-related brain plaques in mice.

The team at the University of British Columbia (UBC) and Vancouver Coastal Health Research Institute also found that treatment with VPA in the early stages of Alzheimer's reversed memory decline.

The study was published in The Journal of Experimental Medicine.

"We found that if we used VPA in the early stages of Alzheimer's disease, in model mice, it reduced plaque formation and further prevented brain cell death and axon death," team leader Weihong Song, a professor of psychiatry and chair in Alzheimer's disease at UBC, said in a university news release. "The drug also improved performance in memory tests."

VPA prevents brain plaques by inhibiting the activity of an enzyme that produces the neurotoxic protein beta amyloid, which is the central component of Alzheimer's brain plaques, the researchers said.

These findings about VPA will help in the design of clinical trials to test the drug in humans.

"We are very excited about these results, because we now know when VPA should be administered to be most effective, and we now know VPA is working to prevent AD. A small human clinical trial is currently under way, and we expect results to be available in the next year," Song said.

SOURCE: University of British Columbia, news release, Oct. 27, 2008