The Endogenous Cannabinoid System was discovered while researchers worked to understand why and how cannabis affects people. The plant cannabinoid tetrahydrocannabinol (THC) was first isolated and identified In 1964 by Dr. Ralph Mechoulam and his associates. For the following decades researchers worked to uncover why and how cannabinoids affected people. In 1988, scientists located cannabinoid receptors in animal brains. This opened the door to the discovery of the signaling network now known as the Endocannabinoid System. The name reflects the types of chemical messengers that directly affect the system: cannabinoids