Posted on 12/06/2010 4:43:40 PM PST by decimon
Researchers calm an overly stimulating chemical within five hours of trauma
CHICAGO --- Post-traumatic stress syndrome – when a severely stressful event triggers exaggerated and chronic fear – affects nearly 8 million people in the United States and is hard to treat. In a preclinical study, Northwestern Medicine scientists have for the first time identified the molecular cause of the debilitating condition and prevented it from occurring by injecting calming drugs into the brain within five hours of a traumatic event.
Northwestern researchers discovered the brain becomes overly stimulated after a traumatic event causes an ongoing, frenzied interaction between two brain proteins long after they should have disengaged.
“It’s like they keep dancing even after the music stops,” explained principal investigator Jelena Radulovic, associate professor of psychiatry and behavioral sciences and Dunbar Scholar at Northwestern University Feinberg School of Medicine. When newly developed research drugs MPEP and MTEP were injected into the hippocampus, the calming drugs ended “the dance.”
“We were able to stop the development of exaggerated fear with a simple, single drug treatment and found the window of time we have to intervene,” Radulovic said. “Five hours is a huge window to prevent this serious disorder.” Past studies have tried to treat the extreme fear responses, after they have already developed, she noted.
The study, conducted with mice, was published Dec. 1 in the journal Biological Psychiatry.
An exaggerated fear disorder can be triggered by combat, an earthquake, a tsunami, rape or any traumatic psychological or physical event.
“People with this syndrome feel danger in everything that surrounds them,” Radulovic said. “They are permanently alert and aroused because they expect something bad to happen. They have insomnia; their social and family bonds are severed or strained. They avoid many situations because they are afraid something bad will happen. Even the smallest cues that resemble the traumatic event will trigger a full-blown panic attack.”
In a panic attack, a person’s heart rate shoots up, they may gasp for breath, sweat profusely and have a feeling of impending death.
Many people bounce back to normal functioning after stressful or dangerous situations have passed. Others may develop an acute stress disorder that goes away after a short period of time. But some go on to develop post-traumatic stress syndrome, which can appear after a time lag.
The stage is set for post-traumatic stress disorder after a stressful event causes a natural flood of glutamate, a neurotransmitter that excites the neurons. The excess glutamate dissipates after 30 minutes, but the neurons remain frenzied. The reason is the glutamate interacts with a second protein (Homer1a), which continues to stimulate the glutamate receptor, even when glutamate is gone.
For the study, Northwestern scientists first subjected mice to a one-hour immobilization, which is distressing to them but not painful. Next, the mice explored the inside of a box and, after they perceived it as safe, received a brief electric shock. Usually after a brief shock in the box, the animals develop normal fear conditioning. If they are returned to the box, they will freeze in fear about 50 percent of the time. However, after the second stressful experience, these mice froze 80 to 90 percent of the time.
The animals’ exaggerated chronic fear response continued for at least one month and resembles post-traumatic stress disorder in humans, Radulovic said.
For the second part of the study, Natalie Tronson, a postdoctoral fellow in Radulovic’s Dunbar Laboratory for Research on Memory and Fear, and Radulovic repeated the two stressful experiences with the mice but then injected them with MPEP and MTEP five hours after the immobilization. This time the mice did not develop the exaggerated fear response and froze for only 50 percent of the time.
“The mice’s fear responses were completely normal,” Radulovic said. “Their memories of the stressful event didn’t trigger the extreme responses anymore. This means we could have a prevention approach for humans exposed to acute, severe stressful events. “
The research was supported by the National Institute of Mental Health. Marla Paul is the health sciences editor. Contact her at marla-paul@northwestern.edu
Somatic ping.
Is it up to the person that endured stress to make it to the doctor’s office in 5 hours? Intersting study but I don’t see the usefulness of it. How are we to interpret possible mental damage when it occurs?
Lost me on this one. If the PTSD has been caused by long-term trauma, i.e., war, at what point does the five hour window for prevention treatment begin?
It seems that the very nature of a traumatic situation, an experience where all heck is breaking loose and spinning out of control, often will prevent this from being useful. Maybe for isolated traumas, this could be helpful. My nephew is starting to lose it over in Afghanistan but it is a slow process and where the stress begins and ends would be hard to pinpoint for this kind of treatment. Maybe there are other pills for long term broken hearts.
I think this could be an enormously useful breakthrough. Generally, people experiencing PTSD from short-term trauma are aware of both the non-ordinary nature of the incident and the resulting psychological shock. Rape, violent car accidents, muggings, combat firefights, intensely frightening child abuses, or similiar traumas are hardly subject to long musings on whether they are significantly damaging at the time!
I guess my point is that people who incurr traumatic experiences want to go home or not talk about it. Ie- childhood sexual abuse. It may take years to express what happened. I don’t disagree with you position. I feel especially for our military personnel, who are always in a hightened state of awareness that may not be diagnosed until their return home,
“Lost me on this one. If the PTSD has been caused by long-term trauma, i.e., war, at what point does the five hour window for prevention treatment begin?”
You stated it better than I. Thanks.
Wierd, isn’t it? I mean, let’s say... even for someone involved directly in single, one-time event like 9/11, what do you do...predict within five hours of the towers falling that you’re at risk of developing PTSD so you rush to the doctor do get drugs injected into your brain, just in case? I don’t think so!
You know, I saw my husband die of prostate cancer 4 years ago and although I saw his spirit go, I was suddenly alone in the middle of a State that didn’t know me and didn’t care a whit about me.
Afterwards I kept getting these extreme heart palpitations, enough so that I took myself to the ER twice where they monitored me. I told them I needed anti-anxiety meds but all they wanted to geve me was anti depressants. All I needed was a few Ativan or somesuch for emergencies but they wanted me hooked on antidepressants instead.
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