Peripheral CB1 Blockade Reached Drinking Behavior Through a Stomach–Brain Pathway in Mice
A behavioral effect did not require demonstrated direct brain drug action in a mouse CB1-blockade experiment summarized by a review. The proposed link involved ghrelin-producing stomach cells and signaling to the brain.
The evidence tested a peripheral pathway
Kunos describes JD5037 reducing alcohol preference and intake in wild-type mice, with the effect absent in several relevant genetic-deficiency models, including ghrelin-related models.
The reviewed work also distinguished active acylated ghrelin from its precursor and used cellular experiments to investigate substrate availability. Disrupting vagal afferent signaling prevented the reported drinking effect.
Peripheral action can have central consequences
A hormone or neural signal generated outside the brain can alter behavior through communication with brain circuits. Observing a behavioral change therefore does not by itself establish that the drug directly occupied brain receptors.
Conversely, limited brain penetration does not mean a compound has no behavioral effects. The anatomical site of drug action and the site integrating a response are different questions.
The result remains preclinical
The findings concern an experimental antagonist, mouse drinking paradigms and selected mechanistic interventions. They do not establish a cannabis product’s effect or a human alcohol-treatment regimen.
The review supports a specific peripheral-to-central hypothesis, rather than a general claim that all cannabinoid-related behavioral effects originate in the stomach.
Related: Interpreting cannabis tolerance claims.
Research cited
Kunos G Alcoholism, clinical and experimental research · 2020 · 44(4):790 PMID 32056226 · DOI 10.1111/acer.14306. Interactions Between Alcohol and the Endocannabinoid System..
