N-Arachidonoylserotonin (AA-5-HT, 1a) is an inhibitor of fatty acid amide hydrolase (FAAH) that acts also as an antagonist of transient receptor potential vanilloid-type 1 (TRPV1) channels and is analgesic in rodents. We modified the chemical structure of 1a with the aim of developing “hybrid” FAAH/TRPV1 blockers more potent than the parent compound or obtaining analogues with single activity at either of the two targets to study the mechanism ...