Cannabinoids were first discovered in the 1940s, when CBD and CBN were identified. THC was not identified until 1964, but by that time cannabis had been removed from the pharmacopeiae of most countries, making further research on the plant difficult.
There are three general types of cannabinoids:
1. Phytocannabinoids occur uniquely in the cannabis plant.
2. Endogenous cannabinoids are produced in the bodies of humans and other animals.
3. Synthetic cannabinoids are similar compounds produced in a laboratory. Forms of synthetic THC are available by prescription in a number of countries, including the US. In the US, synthetic THC is marketed as Marinol®.
Phytocannabinoids, also called natural cannabinoids, herbal cannabinoids, and classical cannabinoids, are only known to occur naturally in significant quantity in the cannabis plant. They are concentrated in a viscous resin that is produced in glandular structures known as trichomes, and are most prevalent in the flowers of the female plants.
Cannabinoid receptors in the human body were not discovered until 1990. CB1 receptors are found primarily in the brain, specifically in the basal ganglia and in the limbic system, including the hippocampus. They are also found in the cerebellum and in both male and female reproductive systems.
CB1 receptors appear to be responsible for the euphoric and anti-convulsive effects of cannabis.
Cannabinoid pharmaceuticals, unlike many other pharmaceutical compounds, do not represent a risk factor for respiratory or cardiovascular failure. Cannabis has been called one of the safest drugs known by Federal Judge Young in 1977. In fact, there is no known lethal dose of cannabis. It has an estimated therapeutic index of 40,000 to one as compared to aspirin with a therapeutic index of 15.
CB2 receptors are found almost exclusively in the immune system, with the greatest density in the spleen. CB2 receptors appear to be responsible for the anti-inflammatory and possibly other therapeutic effects of cannabis.
The endocannabinoid system refers to a group of neuromodulators and receptors involved in a variety of physiological processes including appetite, pain sensation, mood, and memory. The system is named for endocannabinoids, the endogenous lipids that bind cannabinoid receptors (the same receptors that mediate the psychoactive effects of cannabis).
Science increasingly recognizes the role that endo-cannabinoids play in almost every major life function in the human body. Cannabinoids act as a bio regulatory mechanism for most life processes, which explains why medical cannabis has been recommended as a treatment for many diseases and ailments in anecdotal reports and scientific literature. Some of these ailments include: Pain, arthritic conditions, migraine headaches, anxiety, epileptic seizures, insomnia, loss of appetite, GERD (chronic heartburn), nausea, glaucoma, AIDS wasting syndrome, depression, bipolar disorder (particularly depression-manic-normal), multiple sclerosis, menstrual cramps, Parkinson’s, trigeminal neuralgia (tic douloureux), high blood pressure, irritable bowel syndrome, and bladder incontinence.
Donald Abrams, M.D. is chief of Hematology and Oncology at San Francisco General Hospital and the co-author—with Andrew Weil—of Integrative Oncology (Oxford University Press). Abrams has extensive experience working with cancer and HIV/AIDS patients and is a pioneer in the field of medical cannabis research.
The U.S. government classifies cannabis—along with heroin and LSD—as a Schedule I drug, the most tightly restricted category of drugs in the United States. According to the federal government, Schedule I drugs are unsafe and have “no currently accepted medical use in treatment in the United States.”
However, as medical cannabis proponents have pointed out since the Controlled Substances Act was passed by Congress in 1970, cannabis has been used medicinally for thousands of years, and there has never been a reported case of a marijuana overdose. Moreover, in recent years clinical researchers around the world have demonstrated the medicinal value of cannabis.
Reason.tv’s Paul Feine sat down with Dr. Abrams to learn more about the science of medical cannabis.
Approximately 10 minutes. Produced by Paul Feine and Alex Manning.
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The endocannabinoid system and multiple sclerosis
Multiple sclerosis (MS) is a neurodegenerative disease that is characterised by repeated inflammatory/demyelinating events within the central nervous system (CNS). In addition to relapsing-remitting neurological insults, leading to loss of function, patients are often left with residual, troublesome symptoms such as spasticity and pain. These greatly diminish “quality of life” and have prompted some patients to self-medicate with and perceive benefit from cannabis. Recent advances in cannabinoid biology are beginning to support these anecdotal observations, notably the demonstration that spasticity is tonically regulated by the endogenous cannabinoid system. Recent clinical trials may indeed suggest that cannabis has some potential to relieve, pain, spasms and spasticity in MS. However, because the CB(1) cannabinoid receptor mediates both the positive and adverse effects of cannabis, therapy will invariably be associated with some unwanted, psychoactive effects. In an experimental model of MS, and in MS tissue, there are local perturbations of the endocannabinoid system in lesional areas. Stimulation of endocannabinoid activity in these areas either through increase of synthesis or inhibition of endocannabinoid degradation offers the positive therapeutic potential of the cannabinoid system whilst limiting adverse events by locally targeting the lesion. In addition, CB(1) and CB(2) cannabinoid receptor stimulation may also have anti-inflammatory and neuroprotective potential as the endocannabinoid system controls the level of neurodegeneration that occurs as a result of the inflammatory insults. Therefore cannabinoids may not only offer symptom control but may also slow the neurodegenerative disease progression that ultimately leads to the accumulation of disability.