For centuries how cannabis produced its many therapeutic effects was a mystery. How could a single substance derived from a plant have so many effects on different parts of the mind and body?
The chemistry of medical cannabis has been known for some time. The active ingredients are the cannabinoids. Sixty six different variations have been isolated.
Tetrahydrocannabinol (THC) is the most abundant. Delta 9 THC is the most psycho-active.
In 1988 the cannabinoid receptors were discovered in both the brain, (CB-1), and in the lymphatic system, (CB-2). The lymphatic system is involved in the production of antibodies that are critical in both fighting disease and in controlling the immune response.
The widespread distribution of CB receptors in both the brain and lymphatic tissue helped explain the many effects of cannabis.
Why the human brain would have receptors for a plant can be answered by the fact that many plants produce chemicals that are similar to those produced by our bodies. The body’s endorphins help modulate pain by stimulating receptors in the brain. As it turns out, opiates derived from poppies have structures similar to that of our endorphins, and stimulate the same (opiate) receptors.
Our bodies, as it turns out, produce our own cannabanoids. This endocannabinoid system was discovered in 1992 when anandamide was isolated. Although this substance is hard to study because it metabolizes so rapidly, it does appear to stimulate both CB1 and CB2 receptors with effects similar to cannabis. Several other endocannabinoids have been isolated and are under study.
What is clear is that the endocannabinoid system is vital to a wide range of neurological and possibly immune functions that cannabis can mimic and enhance.
Clearly more research is needed. For an excellent review of the current state of medical cannabis research, refer to “Marijuana and Medicine, Assessing the Scientific Basis”, published by the Institute of Medicine.