Cannabinoid receptors on stress-related brain cells shape how mice respond to threats | Research

The takeaway

Removing CB1 cannabinoid receptors specifically from norepinephrine/epinephrine-producing neurons altered how mice responded to stress, but the effects depended on the type of stressor.

Neuroscientists studying the endocannabinoid system, anxiety and stress researchers, and scientists developing cannabinoid-based therapies for stress disorders.

First cell-type-specific mapping of CB1 in brainstem stress neurons

What the researchers found

Mice lacking CB1 receptors in NE/E neurons showed reduced avoidance after restraint stress, increased escape behavior to visual threats, and reduced immobility in forced swim, but normal baseline anxiety and unchanged heart rate responses to foot shock.

Why it matters

This is the first study to characterize where the CB1 receptor gene is expressed across brainstem catecholamine populations and to show that its function in these cells is context-dependent, meaning the same receptor system can produce different effects depending on the type of stress.

The numbers in context

CB1 was broadly expressed in medullary C1/A1 and C2/A2 neurons and sparsely in the locus coeruleus. Knockout mice showed reduced open field avoidance after restraint stress, increased escape across trials to looming threats, and reduced forced swim immobility.

How the study worked

Conditional knockout mouse model with CB1 receptor gene selectively deleted from dopamine beta-hydroxylase-expressing cells, assessed across multiple behavioral tests and stress paradigms with physiological monitoring.

What this study cannot tell us

Mouse behavioral models have limited translation to human stress responses. Constitutive knockout means the receptor was absent throughout development, which may trigger compensatory changes. Only male mice were used.

How to read the evidence

Sophisticated genetic mouse model with multiple behavioral and physiological measures, but limited to males and constitutive knockout may not reflect acute receptor modulation.

When this study was published

Published in 2025.

The bigger picture

The endocannabinoid system and norepinephrine system are both implicated in anxiety and PTSD, but how they interact has been unclear. This study shows their intersection is nuanced and state-dependent, which matters for developing targeted therapies.

Questions still open

Would temporary CB1 blockade in these neurons produce the same effects as lifelong deletion? Do these context-dependent effects explain why cannabinoid drugs sometimes reduce and sometimes increase anxiety?

Common questions

How do cannabinoid receptors on stress neurons affect behavior?

This study found that removing CB1 receptors from norepinephrine neurons changed how mice responded to stress, but the effects varied by context: less avoidance after one type of stress, more escape behavior in another.

Why does the same receptor system produce different effects in different situations?

The researchers found CB1 on stress neurons modulates behavior in a state-dependent manner, meaning the same neural circuit can produce opposite behavioral outcomes depending on the type and intensity of the stressor.

Read the original research

Stress reactivity is modulated by cannabinoid type-1 receptors in norepinephrine and epinephrine neurons in a context-dependent manner.

Neuroscience, 585, 14-27

View on PubMed ↗Publisher’s paper ↗

Citation

Engborg, Christopher B; Pujar, Manaswini; Kanadia, Rahul N; Sciolino, Natale R. (2025). Stress reactivity is modulated by cannabinoid type-1 receptors in norepinephrine and epinephrine neurons in a context-dependent manner.. Neuroscience, 585, 14-27. https://doi.org/10.1016/j.neuroscience.2025.08.046