Propofol Can Alter Endocannabinoid Signaling During an Experiment
An anesthetic used during an experiment may influence the endocannabinoid system being studied. A review identifies propofol’s effects on FAAH and anandamide as a reason to record anesthesia when interpreting in-vivo cannabinoid research.
The background drug can affect the pathway
Basavarajappa and colleagues’ 2019 review describes propofol increasing anandamide through inhibition of FAAH, the enzyme involved in anandamide breakdown. The cited experimental work implicated CB1 signaling in the anesthetic effect.
This means anesthesia can be more than a neutral condition surrounding a measurement. If the preparation changes endogenous cannabinoid signaling, it may contribute to the response attributed to another experimental exposure.
The concern needs anesthetic-specific evidence
The reviewers did not treat all anesthetics as interchangeable. They specifically noted a lack of studies addressing urethane’s influence on the endocannabinoid system in that account.
An established effect of propofol cannot be assigned automatically to urethane or to every other anesthetic. Equally, the absence of evidence in the review does not establish that another anesthetic has no effect.
What to retain in the experimental record
The anesthetic, timing and experimental preparation help define what was actually measured. Appropriate controls can help distinguish an exposure effect from changes associated with anesthesia or interactions between the two.
These mechanistic observations do not establish how much propofol an individual cannabis user needs during a medical procedure. That is a different clinical question. Here, the useful lesson is methodological: an intervention that changes FAAH or anandamide can influence an endocannabinoid experiment even when it was introduced only to enable the procedure.
Related reading: Cannabis–Sedation Associations Differed Between Upper Endoscopy and Colonoscopy.
Research cited
Basavarajappa BS and colleagues. Distinct functions of endogenous cannabinoid system in alcohol abuse disorders (2019). This analysis draws on the review’s discussion of the cited experiments.
