14 DAY TRIAL // A team of researchers in the United States announces the development of a drug that has the potential to reduce fear in anxious mice by altering their brain chemistry. If a similar drug is developed for humans, it could be used to fight anxiety and post-traumatic stress disorder (PTSD), the group says.
The work was carried out by investigators at the Duke University and the US National Institutes of Health (NIH). They say that the chemical they developed showed great promise in calming the fear of overly anxious mice in a variety of tests.
During the same investigation, the researchers also showed that people display genetic differences in the mechanisms controlling the brain chemistry that is targeted by the drug. These variations influence how well each individual handles stress or fear.
Experts comment that the research is an important step forward in deciphering the brain's fear circuitry, something that researchers have been trying to do for a long time. PTSD, for instance, affects many veterans returning home from foreign theaters of operation.
The study was focused on a gene that encodes an enzyme called fatty acid amide hydrolase, or FAAH. The molecule is responsible for breaking down natural endocannabinoid chemical that plays a role in decreasing fear and anxiety, Science Blog reports.
The endocannabinoid is part of the same class of compounds that can be found in marijuana, only it occurs naturally in the human body. It has a calming effect, and so researchers have been targeting FAAH as a means of reducing anxiety for a long time.
In the new study, the team demonstrates a drug that inhibits FAAH, preventing it from breaking down the calming chemical, and increasing the concentration of endocannabinoids in the brain. This has an effect on the entire circuit coding for fear and anxiety.
“What is most compelling is our ability to translate first from mice to human neurobiology and then all the way out to human behavior,” explains investigator Ahmad Hariri, who holds an appointment as a neurobiologist at the Duke Institute for Genome Sciences & Policy.
“That kind of translation is going to define the future of psychiatry and neuroscience,” the expert adds.
“This study in mice reveals how a drug that boosts one of the brain’s naturally occurring endocannaboids enables fear extinction, a process that forms the basis of exposure therapy for PTSD,” explains Andrew Holems, from the National Institute on Alcoholism and Alcohol Abuse.
“It also shows how human gene variation in the same chemical pathways modulates the amygdala’s processing of threats and predicts how well people cope with stress,” concludes the investigator, whose lab hosted the research team.