Brain Cell Protein May Explain Why Some People Resist Stress

A protein that functions as a cannabinoid receptor within the blood-brain barrier may influence why some individuals develop anxiety and depression under chronic stress while others remain resilient. A study published in Nature Neuroscience suggests that the cannabinoid receptor type 1 (CB1) could play a role in regulating stress responses by maintaining vascular integrity in the brain.

The role of CB1 in stress resilience

CB1 receptors are widely expressed in neurons but are also present in astrocytes – star-shaped glial cells that facilitate communication between brain blood vessels and neurons. Researchers observed that mice resistant to stress had a higher abundance of CB1 receptors in the blood-brain barrier compared to those displaying depressive-like behaviors or those not exposed to stress. This led to an investigation into the role of astrocytic CB1 receptors in modulating stress responses.

To test this hypothesis, the researchers developed a viral vector that selectively increased CB1 receptor expression in astrocytes. When injected into mice, this vector enhanced CB1 receptor levels in astrocytes without affecting neurons. The mice were then subjected to chronic social stress, where they were placed in proximity to a dominant male without direct physical interaction.

Increased CB1 receptor expression promotes resilience

Three weeks after injection, mice with increased CB1 receptor expression in astrocytes showed lower baseline anxiety and reduced stress-induced depressive-like behaviors. These findings suggest that CB1 receptor overexpression in astrocytes contributes to stress resilience by supporting vascular health in the brain.

Additional experiments revealed that mice given access to an exercise wheel or treated with antidepressants also exhibited increased CB1 receptor levels in astrocytes. Furthermore, analysis of human brain tissue from the Douglas-Bell Canada Brain Bank indicated that individuals with major depression had lower astrocytic CB1 receptor levels compared to those without depression or those who had received antidepressant treatment.

Implications for mental health interventions

These findings raise the possibility of developing treatments that selectively activate CB1 receptors in astrocytes to mitigate anxiety and depression. However, the challenge remains in limiting activation to astrocytes, as prolonged CB1 receptor stimulation in neurons can lead to side effects affecting alertness, anxiety and appetite. Until targeted pharmacological interventions become available, engaging in physical activity may help protect against stress-related mental health conditions by enhancing CB1 receptor expression.

Reference: Dudek KA, Paton SEJ, Binder LB, et al. Astrocytic cannabinoid receptor 1 promotes resilience by dampening stress-induced blood–brain barrier alterations. Nat Neurosci. 2025. doi: 10.1038/s41593-025-01891-9

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