Resilience to stress depends on a single protein

Not everyone reacts to stress in the same way. While some maintain emotional equilibrium, others experience anxiety and depression. A study published in the journal Nature Neuroscience found that resilience to chronic stress may depend on levels of a protein called CB1, which acts as a cannabinoid receptor in cells that protect the brain from harmful substances.

The barrier between the circulatory system and the brain prevents inflammatory molecules from entering, but under severe and prolonged stress, its integrity is compromised. As a result, harmful substances make their way in, which can cause anxiety and depressive symptoms. The scientists found that stress-resistant mice had significantly higher levels of CB1 than those who showed signs of depression. This prompted the specialists to check how exactly this protein affects stress resistance.

To confirm the hypothesis, the researchers increased the amount of CB1 in cells that support the work of cerebral blood vessels. To do this, they used a specially designed virus that increased the production of the protein exclusively in astrocytes – stellate cells that connect neurons and blood vessels. After the procedure, the mice were subjected to chronic social stress: they were briefly placed in a cage every day to a more aggressive congener, and then left in neighboring compartments separated by a transparent partition. This created a situation of constant psychological pressure.

After three weeks it turned out that the level of CB1 in astrocytes of experimental animals increased twofold. Moreover, such mice showed less frequent anxious behavior and were less stressed compared to the control group. The increase in the amount of CB1 protein contributed to the health of brain blood vessels, which directly influenced the psychological state.

Other experiments showed that there was also a natural increase in CB1 levels in mice that had access to a jogging wheel or were given antidepressants. This confirmed the link between this protein and stress tolerance.

Additionally, experts studied brain tissue samples from people who suffered from depression. It turned out that their level of CB1 in astrocytes was significantly lower than in people without mental disorders. Those who took antidepressants showed increased CB1 levels, which once again confirmed the importance of this protein in the fight against anxiety disorders.

In the future, experts plan to develop drugs that can increase CB1 activity in astrocytes without affecting other brain cells. In the meantime, the safest way to increase the level of this protein is physical activity, which has already proven its effectiveness in reducing anxiety and improving mood.