New research by Brain & Behavior Research Foundation Scientific Council Member and NARSAD Grantee Kerry Ressler, M.D., Ph.D. of Emory University and team shows that injecting mice with a new medication immediately following a traumatic event prevents the animals from developing behavioral symptoms indicative of post-traumatic stress disorder (PTSD). The researchers also identified the receptor in the brain likely responsible for the development of PTSD in humans.
The National Institutes of Health report that approximately 7.7 million American adults experience PTSD—a brain and behavior disorder marked by recurring frightening flashbacks and disruptive nightmares that can greatly increase stress and anger and diminish quality of life and normal functioning. This illness is especially prevalent among war veterans and can often have far-reaching ancillary traumatic effects for family members of people who have the disorder. Psychotherapy and medications can help treat the symptoms of PTSD, but these new findings, published in Science Translational Medicine on June 5, 2013, offer hope of preventing PTSD in at-risk individuals.
“PTSD is a tractable problem that can be prevented and treated if we put our mind to it,” says Dr. Ressler, the study’s lead author. “Bringing neuroscience and genetic approaches together provides a powerful way to understand this debilitating illness.”
He went on to explain, "We have a model of mice fear that is a good model of human fear. We have confidence that we're looking at the same thing." The mouse model showed that a receptor called Oprl1 is altered in mice with PTSD-like symptoms. Oprl1 is part of a family of opioid receptors responsible for controlling the brain’s response to pain processing. When Dr. Ressler and team administered a newly developed compound from the Scripps Research Institute that activates the receptor to the mice shortly before or immediately after they were “traumatized,” the medication successfully prevented the development of memory problems and symptoms of increased anxiety.
To see if the results may be translated to humans, the team analyzed the sequence of the gene that encodes the Oprl1 receptor in approximately 1,800 highly traumatized civilians, some of whom had PTSD and others who did not. One variant of Oprl1 was found to be more prevalent among those who had the disorder. Brain scans confirmed that in those with the variant of the gene, areas of the brains associated with fear had altered patterns of fear-related activity.
“There are likely many, many genes that are involved in the risk for PTSD following trauma,” says Ressler. “Oprl1 may be one of the many genes that contribute risk, though larger samples and replication studies are required to be certain of this.”
Other NARSAD Grantees at Emory who served on the research team with Dr. Ressler include Tanja Jovanovic, Ph.D. and Elisabeth B. Binder, M.D., Ph.D.
Read more about the study and related research in U.S. News & World Report
Read the study announcement from Howard Hughes Medical Institute