A new study found that strengthening the brain’s natural cannabinoid signaling system reversed anxiety and social avoidance behaviors associated with post-traumatic stress disorder (PTSD) in mice, identifying a potential new approach to treating trauma-related conditions.
The study, published October 9 in the Journal of Advanced Research, was conducted by researchers from Qingdao University and other institutions in China. It examined how the endocannabinoid system, which regulates stress responses and other neurological functions, influences the development of persistent PTSD-like behaviors following repeated stressful experiences.
Researchers subjected mice to a five-day chronic social defeat stress procedure designed to produce lasting anxiety and social avoidance. They then examined activity within a neural pathway connecting the posterior basolateral amygdala to the oval bed nucleus of the stria terminalis, two brain regions involved in processing fear and stress.
The researchers found that repeated stress reduced the availability of cannabinoid type 1 (CB1) receptors within this pathway, weakening a natural mechanism that ordinarily helps regulate excessive neural activity.
When scientists administered compounds that prevented the breakdown of 2-arachidonoylglycerol (2-AG), a naturally occurring endocannabinoid, directly into the affected brain region, the mice showed a reversal of stress-induced social avoidance and anxiety-like behaviors.
Similar improvements occurred when researchers used light-based techniques to activate CB1 receptors within the same neural circuit.
In contrast, genetically suppressing the production of 2-AG intensified PTSD-like behaviors, providing additional evidence that the body’s natural cannabinoid signaling plays a protective role against prolonged stress responses.
The endocannabinoid system includes receptors that also respond to cannabinoids found in marijuana, including THC. However, the experiment focused on compounds naturally produced by the brain and targeted manipulation of cannabinoid receptors rather than administering marijuana or THC.
The findings suggest that chronic stress can disrupt the brain’s cannabinoid signaling system, allowing fear-related neural activity to remain elevated. Restoring that signaling helped normalize behavioral responses in the experimental animals.
The researchers concluded that maintaining balanced endocannabinoid activity within this particular neural pathway may help promote resilience against PTSD-like conditions, identifying a potential target for future treatments.
