“An improved understanding of the endocannabinoid system has provided new avenues of drug discovery and development toward the management of pain and other behavioral maladies. Exogenous cannabinoid type-1 (CB1) receptor agonists such as Δ9-tetrahydrocannabinol are increasingly utilized for their medicinal actions; however, their utility is constrained by concern regarding abuse-related subjective effects. This has led to growing interest in the clinical benefit of indirectly enhancing the activity of the highly labile endocannabinoids N-arachidonoylethanolamine (anandamide; AEA) and/or 2-arachidonoylglycerol (2-AG) via catabolic enzyme inhibition. The present studies were conducted to determine whether such actions can lead to CB1 agonist-like subjective effects, as reflected in the presence or absence of CB1-related discriminative-stimulus effects in laboratory subjects. Squirrel monkeys (n=8) that discriminated the CB1 full agonist AM4054 (0.01 mg/kg) from vehicle were used to study, first, inhibitors of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MGL) alone or in combination [FAAH (URB597, AM4303); MGL (AM4301); FAAH/MGL (AM4302)] and, second, the ability of the endocannabinoids AEA and 2-AG to produce CB1 agonist-like effects when administered alone or after enzyme inhibition. Results indicate that CB1-related discriminative-stimulus effects were produced by combined, but not selective, inhibition of FAAH and MGL, and that these effects were non-surmountably antagonized by low doses of rimonabant. Additionally, FAAH- or MGL-inhibition revealed CB1-like subjective effects produced by AEA, but not 2-AG. Taken together, the present data suggest that therapeutic effects of combined, but not selective, enhancement of AEA or 2-AG activity via enzyme inhibition may be accompanied by CB1 receptor-mediated subjective effects.”

https://www.ncbi.nlm.nih.gov/pubmed/28947487

http://jpet.aspetjournals.org/content/early/2017/09/25/jpet.117.244392