The cannabinoid system is evolutionally conserved and is present in invertebrates and vertebrates. One of the best-studied cannabinoids is Δ9-tetrahydrocannabinol (THC), the predominant active component of Cannabis sativa or marijuana.
The marijuana plant has been exploited by humans since their early history and was used for centuries in Asian medicine to reduce the severity of pain, inflammation and asthma. However, only recently have the mechanisms of the medicinal properties of THC begun to be understood. This understanding is largely due to the identification and cloning of two cannabinoid receptors.
The cannabinoid system is now recognized as a regulator of both the nervous and immune systems.
Although marijuana has been used for centuries for the treatment of a variety of disorders, its therapeutic mechanisms are only now being understood.
The best-studied plant cannabinoid, delta9-tetrahydrocannabinol (THC), produced by Cannabis sativa and found in marijuana, has shown evidence of being immunosuppressive in both in vivo and in vitro.
These studies are theoretically in agreement with the suggestions of others that cannabinoid receptor agonists would be beneficial for the treatment of MS in humans.”