The University of Leicester team worked with researchers from Japan and Poland and discovered that a protein called neuropsin plays a vital role in triggering a stress response at a cellular level. They discovered that the amygdala, the emotional centre of the brain, reacts to stressful situations by producing neuropsin, which in turn increases the activity of the amygdala. This triggers a gene that dictates a stress response at a cellular level, according to the research, which was published in Nature.
Dr Robert Pawlak led the University of Leicester team. He explained: “It was previously known that certain individuals are more susceptible to the detrimental effects of stress than others. Although the majority of us experience traumatic events, only some develop stress-associated psychiatric disorders such as depression, anxiety or post-traumatic stress disorder… we asked: what is the molecular basis of anxiety in response to noxious stimuli? How are stress-related environmental signals translated into proper behavioural responses?”
Dr Pawlak explained that he and his team used a combination of behavioural, molecular, genetic and electrophysiological approaches and discovered “a previously unknown pathway mediating anxiety in response to stress”. The four-year study involved the Nara Institute of Science and Technology in Japan, the Polish Academy of Sciences, and the Medical Research Council Toxicology Unit at the University of Leicester, in collaboration with the University’s Department of Cell Physiology and Pharmacology.
The team found that when mice were stressed, they avoided areas of a maze that were open and illuminated and which made the mice feel vulnerable and unsafe. However when the proteins produced by the amygdala were blocked, the mice behaved differently and the effects of stress disappeared.
Dr Benjamin Attwood, who was also involved in the study, commented: “It has been a thoroughly absorbing project to uncover how our experiences can change the way we behave. Hopefully this will lead to help for people who have to live with the damaging consequences of traumatic experiences.”
“We are tremendously excited about these findings,” added Dr Pawlak. “We know that all members of the neuropsin pathway are present in the human brain. They may play a similar role in humans [to the tests performed in mice] and further research will be necessary to examine the potential intervention therapies for controlling stress-induced behaviours… We conclude that the activity of neuropsin and its partners may determine vulnerability to stress.”
It is estimated that approximately 20 per cent of the population suffer from some form of clinically-defined anxiety disorder at least once in their lives and the cumulative lifetime prevalence of all stress-related disorders is estimated to be approximately 30 per cent.