Canadian scientists, following their experiments on mice, have identified a novel mechanism through which the brain responds to stress.
University of Calgary scientist Dr. Jaideep Bains, along with is researcher colleagues at the Hotchkiss Brain Institute, have found that neurons in the hypothalamus-the brain's command centre for stress responses-interpret "off" chemical signals as "on" chemical signals when stress is perceived.
"It's as if the brakes in your car are now acting to speed up the vehicle, rather than slow it down," Nature magazine quoted Bains as saying.
The researchers point out that neurons generally receive different chemical signals that tell them to either switch on or switch off.
The off signal, also known as brake, only works if the levels of chloride ion in the cells are maintained at a low level, something that is accomplished by a protein called KCC2.
Bains says that his team have found that stress turns down the activity of KCC2, and thereby removes that ability of the brake, a chemical known as GABA, to work properly.
According to him, a loss of the brain's ability to slow down may explain some of the harmful, emotional consequences of stress.
While the findings provide a new mechanistic explanation of how the brain interprets stress signals, the researchers say "there is still much work needed in the basic science of this phenomenon before there are any new advances in the medical treatment of stress."
"This opens entirely new and quite unexpected avenues for controlling stress responses" says Dr. Yves De Koninck, president-elect of the Canadian Association for Neuroscience and professor of Psychiatry at Laval University.
Jane Stewart, PhD, a behavioural neuroscientist from Concordia University, said: "I was fascinated when I learned of this work. It has not been clear till now how the neuroendocrine stress response was activated by external stressors.
Bains' work shows a complex, yet elegant solution, involving a switch from inhibition to excitation. These findings may lead to a better understanding of the changes in sensitivity to stress that result from chronic exposure."
The study has been reported in the journal Nature Neuroscience.