Investigating the Effects of Nabilone on Endocannabinoid Metabolism

Overview

The purpose of this study is to learn about the effects of a cannabis-like substance, nabilone, on the levels of endocannabinoid enzyme fatty acid amide hydrolase (FAAH) in brain of healthy individuals. Using magnetic resonance imagine (MRI) and positron emission tomography (PET), the main questions we aim to answer are: 1) Does nabilone decrease levels of FAAH in the brain? and 2) Are changes in levels of FAAH associated with clinical response to nabilone? Participants will complete: * An in-person interview (\~4 hours) * Two brain imaging scanning sessions (\~11 hours) * A one week 2 mg titrated dose of nabilone * Virtual check-ins (up to \~1.5 hours)

There is limited data regarding the effect of exogenous cannabinoids, such as tetrahydrocannabinol (THC), on the endogenous cannabinoid system (eCS). Specifically, we do not know whether brain levels of fatty acid amide hydrolase (FAAH), the catabolic enzyme for the endocannabinoid anandamide, is affected by sub-chronic THC exposure. Our primary objective is to use positron emission tomography (PET) imaging of the FAAH probe \[11C\]CURB to test the hypothesis that exposure to nabilone, a synthetic THC analogue, will reduce FAAH levels in the brain. Our secondary objective is to investigate whether reductions in FAAH levels are related to clinical response to nabilone. Participant eligibility will be assessed through a series of questionnaires and assessments on medical, family, psychiatric and alcohol and drug use history. Individuals will also be required to provide blood and urine samples which we will test for recent drug use and pregnancy in female participants. Thirty healthy participants will complete one magnetic resonance imaging scan and two PET scans with \[11C\]CURB: one at baseline prior to nabilone administration and one approximately 4 weeks apart following a one week, 2 mg titrated dose of nabilone. Venous and arterial blood draws will be done during PET scans to measure FAAH genotype and plasma radiometabolites, respectively. Mood assessments will also be administered at these visits. During the nabilone dosing period, we will meet virtually with participants to check-in and monitor their tolerance and compliance. Understanding whether recent nabilone exposure affects FAAH levels in brain may help to explain variability in clinical response to THC, the main psychoactive component in cannabis. This information can help guide therapeutic use of cannabis and cannabinoid derivatives, and aid in the development of evidence-based medicine targeting the eCS.