Virodhamine (also known as O-arachidonoyl ethanolamine or O-AEA) was discovered in 2002 by Porter et al. Virodhamine is one of the body’s many endocannabinoids and is a combination of arachidonic acid and ethanolamine. These two components are formed by an ester linkage, which is the opposite of anandamide’s amide linkage. The name ‘virodhamine’ is based on this oppositional linkage, from the Sanskrit word “virodha”, meaning opposition. Virodhamine is a CB1 receptor partial agonist and a CB2 receptor agonist; it is a full antagonist at the CB1 receptor in vivo. Additionally, virodhamine is an agonist at the novel GPR55 receptor. Levels of virodhamine found in rat brains and human hippocampus are similar to those of anandamide. However, in peripheral tissues that express the CB2 receptor (skin, kidney, spleen, and heart tissues,) levels of virodhamine were between two to nine times higher than those of anandamide.
There is very little known regarding the biosynthesis and biosynthetic pathways of virodhamine. However, the oppositional relationship between virodhamine and anandamide may be of interest. The oppositional linkage between the two endocannabinoids, and virodhamine being a CB1 antagonist and CB2 agonist (whereas anandamide is a CB1 agonist and CB2 antagonist,) suggests that the two endocannabinoids might be able to convert to one another.
Virodhamine has not been studied as extensively as other endocannabinoids, so there is less information available regarding its potential medical benefits or negative side effects. However, one study suggested that virodhamine has potential therapeutic applications in the treatment of certain neurological disorders. Virodhamine was also shown to relax the human pulmonary artery and also may be useful in regulating and controlling the cardiovascular CYP2J2 enzyme. Additionally, virodhamine was found to lower body temperature in mice.