Gene controls number of brain cells

CHAPEL HILL, N.C., Oct. 6 (UPI) -- U.S. medical scientists say they have identified the gene that determines how many neurons end up as brain cells.

University of North Carolina at Chapel Hill researchers said their finding suggests a single gene, called GSK-3, controls the signals that determine the number of brain cells and has important implications for patients with neuropsychiatric illnesses, such as schizophrenia, depression and bipolar disorder.

The researchers said the action of the newly identified gene in populating the growing brain is important because if neural stem cells proliferate too much, they could produce a tumor. If they proliferate too little, there may not be enough cells to become the billions of neurons of the brain.

One of the genes associated with schizophrenia appears to use GSK-3 as an intermediary to exert its effects on nerve cells. In addition, lithium, a popular treatment for bipolar disorder, acts, in part, by shutting down GSK-3.

"I don't believe anyone would have imagined that deleting GSK-3 would have such dramatic effects on neural stem cells," said Dr. William Snider, professor of neurology and the study's senior author. "People will have to think carefully about whether giving a drug like lithium to children could have negative effects on the underlying structure of the nervous system."

The research that included Woo-Yang Kim, Xinshuo Wang and Yaohong Wu, in addition to researchers from the University of Toronto appears in the early online issue of the journal Nature Neuroscience.