Mice lacking CB2 cannabinoid receptors were protected from developing food addiction, while mice overexpressing CB2 were more vulnerable — with corresponding changes in brain gene expression.
Read this if you are interested in the neuroscience of food addiction and how the endocannabinoid system controls eating behavior.
CB2 = vulnerabilityCB2 receptor overexpression made mice vulnerable to food addiction; deletion was protective
What the researchers found
Using a validated operant model of food addiction with highly palatable chocolate pellets, researchers found that CB2 receptor knockout mice were protected from developing food addiction and associated impulsive and depressive-like behaviors. Conversely, transgenic mice overexpressing CB2 showed increased vulnerability to food addiction after long-term palatable food exposure. Brain transcriptomic analysis revealed gene expression changes associated with resilience and vulnerability that corresponded to CB2 genotype.
Why it matters
While CB1 receptors are well-known to regulate appetite, this is the first study to directly implicate CB2 receptors in food addiction — a compulsive behavior pattern distinct from normal hunger. This opens a new therapeutic target.
The numbers in context
- Three genotypes compared: wild-type, CB2 knockout, CB2 overexpressing
- Long-term operant training with chocolate pellets
- CB2 knockout: protected from food addiction
- CB2 overexpressing: vulnerable to food addiction
- Associated impulsive and depressive-like behaviors tracked
How the study worked
Validated operant mouse model of food addiction using long-term training with highly palatable food. Compared wild-type, constitutive CB2 knockout, and CB2 overexpressing transgenic mice. Behavioral phenotyping and brain transcriptomic analysis.
Who was studied
Male wild-type, CB2 knockout, and CB2 overexpressing transgenic mice
What this study cannot tell us
Constitutive genetic models cannot distinguish developmental from acute CB2 effects. Mouse food addiction models may not fully capture human eating disorders. Only male mice studied. Chocolate pellets as palatable food may not represent all food addiction patterns.
How to read the evidence
Preclinical genetic study with validated behavioral model and transcriptomic analysis. Strong mechanistic evidence in mice.
When this study was published
Published in 2023. First study directly linking CB2 receptors to food addiction.
The bigger picture
Food addiction shares neurobiological mechanisms with substance addiction. The discovery that CB2 receptors play a specific role opens the possibility of treating compulsive eating with CB2-targeted drugs that lack the psychoactive effects of CB1-targeting compounds.
Questions still open
- Would pharmacological CB2 blockade reduce food addiction in wild-type animals?
- Do CB2 receptor variants in humans predict vulnerability to binge eating disorder?
- Could selective CB2 antagonists treat food addiction without affecting normal appetite?
Read the original research
Role of CB2 cannabinoid receptor in the development of food addiction in male mice.
Neurobiology of disease, 179, 106034
Citation
García-Blanco, A; Ramírez-López, Á; Navarrete, F; García-Gutiérrez, M S; Manzanares, J; Martín-García, E; Maldonado, R. (2023). Role of CB2 cannabinoid receptor in the development of food addiction in male mice.. Neurobiology of disease, 179, 106034. https://doi.org/10.1016/j.nbd.2023.106034