Are cannabinoid receptors and the endocannabinoid system a bit of a mystery to you? If so, you’re not alone. In fact, the endogenous cannabinoid—or endocannabinoid—system is a relatively new discovery among scientists. It was through the study of marijuana that this physiological system was discovered.
Endorphins, morphine-like compounds produced in the brain, were discovered through the study of opium. Similarly, in 1992, marijuana research conducted by Israeli researcher Dr. Raphael Mechoulam—who identified THC as the main active ingredient in cannabis in the early 1960s—revealed a natural, internal, substance in the human body similar to THC. His discovery was made while collaborating with National Institute of Mental Health research fellow, William Devane, and analytical chemist, Dr. Lumír Hanuš. They called this neurotransmitter anandamide, derived from the Sanskrit word meaning “bliss.” In 1995, these researchers discovered a second neurotransmitter referred to as 2-Arachidonoyl glycerol (2-AG). Tracing the pathways through which THC was metabolized, scientists found a previously unknown molecular signaling system that regulates a broad range of biological functions. It became known as the endocannabinoid system, named for the plant responsible for its discovery.
Even though this internal signaling system is named for the cannabis plant, it started to evolve 600 million years ago, predating the appearance of cannabis. The endocannabinoid system is present not only in humans but also in other mammals, birds, fish, reptiles, amphibians, earthworms, and leeches. It does not appear to be present in insects.
Further research revealed two main receptors associated with this system, cannabinoid 1 (CB1) and cannabinoid 2 (CB2); they respond physiologically to both the endocannabinoids that are naturally produced by our bodies and plant based cannabinoids like THC and CBD. The receptors are specialized protein molecules embedded in cell membranes that function as subtle sensing devices, detecting biochemical cues that are flowing through fluids surrounding each cell. They are more abundant in the brain than any other type of neurotransmitter receptor. When cannabinoid receptors are stimulated, a variety of physiologic processes result.
The CB1 receptor is predominantly present in the nervous system, connective tissues, gonads, glands, and organs. This receptor mediates psychoactivity and plays a role in memory, mood, sleep, appetite, and pain sensation. The CB2 receptor is found primarily in the immune system and its associated structures. It regulates immune response, including reducing inflammation which is believed to be a factor in many diseases. Many tissues contain both CB1 and CB2 receptors, each linked to a different action. There is speculation that a third cannabinoid receptor may exist.
The endocannabinoid system performs different tasks, depending on the location of receptors. But the goal is always homeostasis—the maintenance of a stable internal environment regardless of fluctuations in the external environment. This system is also a bridge between body and mind which may begin to explain how states of consciousness affect health or disease. Cannabinoids promote homeostasis at every level of biological life. These breakthrough discoveries offer revolutionary insights and significant implications for health and healing, and suggest the potential for even more benefits of cannabinoids to be revealed.