- February 20, 2014
Science Daily/Ohio State University
Chronic stress that produces inflammation and anxiety in mice appears to prime their immune systems for a prolonged fight, causing the animals to have an excessive reaction to a single acute stressor weeks later, new research suggests.
After the mice recovered from the effects of chronic stress, a single stressful event 24 days later quickly returned them to a chronically stressed state in biological and behavioral terms. Mice that had not experienced the chronic stress were unaffected by the single acute stressor.
hese scientists previously determined that in mice with chronic stress, cells from the immune system were recruited to the brain and promoted symptoms of anxiety. The findings identified a subset of immune cells, called monocytes, that could be targeted by drugs for treatment of mood disorders – including, potentially, the recurrent anxiety initiated by stress that is a characteristic of PTSD.
The research reveals new ways of thinking about the cellular mechanisms behind the effects of stress, identifying two-way communication from the central nervous system to the periphery – the rest of the body – and back to the central nervous system that ultimately influences behavior.
“We haven’t proffered that there is a cellular component to PTSD, but there very well might be. And it’s very possible that it sits in the periphery as we’ve been describing in the mouse,” said John Sheridan, senior author of the study, professor of oral biology and associate director of Ohio State’s Institute for Behavioral Medicine Research.
“Our colleagues who study behavior talk about sensitization,” Sheridan said. “Clearly, the repeatedly stressed mice were sensitized. What we’re adding is that sensitization is associated with a specific cell type that resides in the spleen after the initial sensitization.