Published on June 30, 2012 at 6:56 AM
"We found rapamycin acts like an antidepressant - it increases the time the mice are trying to get out of the situation," she said. "They don't give up; they struggle more."
The reductions of anxiety and depressive-like behavior in rapamycin-treated mice held true for all ages tested, from 4 months of age (college age in human years) to 12 months old (the equivalent of middle age) to 25 months old (advanced age).
Feel-good chemicals elevated
The researchers measured levels of three "happy, feel-good" neurotransmitters: serotonin, dopamine and norepinephrine. All were significantly augmented in the midbrains of mice treated with rapamycin. "This is super-interesting, something we are going to pursue in the lab," Dr. Galvan said.
Dr. Galvan and her team published research in 2010 showing that rapamycin rescues learning and memory in mice with Alzheimer's-like deficits. The elevation of the three neurotransmitters, which are chemical messengers in the brain, may explain how rapamycin accomplished this, Dr. Galvan said.
Rapamycin is an antifungal agent administered to transplant patients to prevent organ rejection. The drug is named for Rapa Nui, the Polynesian title for Easter Island. This island, 2,000 miles from any population centers, is the famed site of nearly 900 mysterious monolithic statues.
Source: University of Texas Health Science Center at San Antonio