Scientists first discovered the system while trying to understand the effects of cannabis, and named it the endocannabinoid system for this reason. Endo stands for endogenous, which means originating within the body. Cannabinoid refers to the group of compounds that activate this system.
Cannabinoids are the chemical messengers for the endocannabinoid system. While many different cannabinoids exist, they all fall under two categories: endogenous or exogenous.
Endogenous means originating inside the body. Also known as endocannabinoids, these compounds are produced naturally by the human body. They interact with cannabinoid receptors to regulate basic functions including mood, memory, appetite, pain, sleep, and many more.
Exogenous means originating outside the body. The cannabinoids found in marijuana, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), are considered exogenous. When consumed, they also interact with cannabinoid receptors to produce physical and psychological effects in the body.
Receptors are message receivers. Messages come in the form of chemical messengers binding to the receptor. These messages produce a characteristic effect within the body.
The endocannabinoid system has two receptors: CB1 and CB2. Each receptor responds to different cannabinoids, but some cannabinoids can interact with both.
The distribution of CB1 and CB2 receptors within the body and brain explains why cannabinoids have certain effects.
CB1 receptors are found throughout the body, but are mostly present in the brain and spinal cord. They are concentrated in brain regions associated with the behaviors they influence. CB1 receptors are also found in nerve endings where they act to reduce sensations of pain.
CB2 receptors tend to be found in the peripheral nervous system. They are especially concentrated in immune cells. When CB2 receptors are activated, they work to reduce inflammation. Inflammation is an immune response which is believed to play a role in many diseases and conditions.
With respect to the cannabinoids found in cannabis, researchers have found that THC binds to both CB1 and CB2 receptors, activating them just like an endocannabinoid.
The endocannabinoid system is involved with regulating many basic functions of the human body, including:
|· Appetite||· Inflammation|
|· Metabolism||· Neural development|
|· Pain||· Neuroprotection|
|· Sleep||· Cardiovascular function|
|· Mood||· Digestion|
|· Movement||· Reproduction|
|· Temperature||· Neural development|
|· Memory and learning|
Besides maintaining basic functions, the endocannabinoid system also acts in response to illness.
For example, tumor cells have been shown to express more cannabinoid receptors than healthy cells. Studies also show a rise in endocannabinoid levels in patients with various disorders, such as parkinson’s disease, anxiety, chronic pain and arthritis.
As a result, some scientists believe the overall function of the endocannabinoid system is to regulate homeostasis.
Homeostasis is a key element in the biology of all living things. It is best described as the ability to maintain stable internal conditions that are necessary for survival.
Disease is largely a result of a failure in achieving homeostasis. Thus, the endocannabinoid system’s role in maintaining homeostasis makes it a unique and promising target in medicine.