(Great Neck, NY - August 10, 2007) — A study led by John Wemmie, M.D., Ph.D., a 2004 and 2007 NARSAD Young Investigator, has shown that when a protein found in a part of the brain controlling fear is blocked, laboratory mice become less fearful. Over time, this may help researchers develop new therapies for anxiety disorders in people.

The study, recently published in the journal Biological Psychology, revealed that mice in which the gene for the ASIC1a protein had been disrupted were far less fearful than normal mice when exposed to the normally frightening experiences of open spaces, loud noises and the scent of a predator.

In the predator test, a beaker containing a fox-odor chemical placed in their enclosure caused normal mice to freeze. Mice that lacked ASIC1a, but whose sense of smell was unaffected, showed reduced “freezing” response and even climbed onto the beaker.

Ion channels control the passage of electrically charged atoms or molecules in and out of cells. Dr. Wemmie, an assistant professor of psychiatry at the University of Iowa’s Roy J. and Lucille A. Carver College of Medicine, believes his team’s findings on ASIC1a have provided a theoretical framework for investigating whether therapies that block specific ion channels in humans might be effective in anxiety disorders.

Based on their discovery that the ASIC1a gene is localized in brain regions involved in fear, Dr. Wemmie and his team speculate that targeting the ASIC1a protein might have a more focused effect on anxiety with fewer side effects than existing treatments, which affect systems throughout the brain.

“Current treatments for anxiety have problems such as risk of addiction, slow onset of action and other types of side effects that make people not want to take them,” Dr. Wemmie explained.

In the human brain, ASIC1a is found in the amygdala. The Iowa researchers plan to determine the specific sites of action and role of ASIC1a in the amygdala. Among other things, they want to learn whether mutations in the ASIC1a gene might be associated with an inherited predisposition to anxiety traits; also, whether the protein is involved in other psychiatric illnesses.

"Anxiety and other psychiatric illnesses, such as depression, are closely related. Some anxiety treatments often are effective for depression and vice-versa," Dr. Wemmie said. "This study raises the possibility that blocking this protein might be useful for depression as well as anxiety."

This story was adapted with permission of the University of Iowa.