A mouse study has revealed the brain becomes overly stimulated after a traumatic event causes an ongoing, frenzied interaction between two brain proteins long after they should have disengaged. However, the injection of newly developed drugs into the hippocampus within a five hour window calmed this process, and prevented the development of a post-traumatic fear response.
The new research shows the potential for PTSD occurs when a stressful event causes a flood of glutamate, which then interacts with a second protein (Homer1a). This protein continues to stimulate metabotropic glutamate receptor 5 [mGluR5] after the glutamate has dissipated. The new drugs bind mGluR5 and reverse its activity.
 . Metabotropic Glutamate Receptor 5/Homer Interactions Underlie Stress Effects on Fear. Biological Psychiatry [Internet]. 2010 ;68(11):1007 - 1015. Available from: http://www.sciencedirect.com/science/article/B6T4S-51FPJ9X-9/2/951f58a15b0f6f5269091c17cc2e035e