The long-term effects are of greatest interest. When a person goes through a major stressful event, such as a bereavement, the effects of the stress can last for years. With some people, they can go through several major stressful events and come out relatively unaffected; whereas with other people, one significant stressful event seems to cause long-term mental health issues. These differenced appear to come down to physiological changes.
The new research has been conducted in India and the focus has been on molecular changes in the brain. These changes can be permanent or transitory. The findings from the National Centre for Biological Sciences (NCBS) and the Institute for Stem Cell Biology and Regenerative Medicine (inStem) in Bangalore indicate that alterations in the electrical activity in the brain, in the amygdala region, occurs after a stressful event. However, the changes are not always immediate, sometimes happening ten days after the stressful event has taken place.
A specific molecule is involved, called the N-Methyl-D-Aspartate Receptor (NMDA-R). This is an ion channel protein found on nerve cells. The receptor is involved in the processing of memory. Because of the difficulties in examining people, much of the work has been undertaken on rats. The rodent work has allowed the delay effect seen with brain physiology to be observed. This has shown how stress appears to re-route nerve signals and create new synapses. This effect has not been noticed before.
Speaking with Laboratory Roots, the lead researcher, Dr. Sumantra Chattarji explains: “We showed that our study system is applicable to PTSD. This delayed effect after a single episode of stress was reminiscent of what happens in PTSD patients. We know that the amygdala is hyperactive in PTSD patients. But no one knows as of now, what is going on in there.”
The knowledge about the delay could assist with post-stress or trauma treatments, with a future medicine assisting with turning off the NMDA-R protein to avoid damage.
The findings have been published in the journal Physiological Reports, with the paper headed “The delayed strengthening of synaptic connectivity in the amygdala depends on NMDA receptor activation during acute stress.”
