The Endocannabinoid System — plays an important role in the health and well-being of many creatures outside of the vertebrates. The ability to adapt to environmental changes is essential to all living creatures, though not all have the advantage of the highly evolved endocannabinoid system in this performing function.
Scientists studying the history of the endocannabinoid system and the cannabinoid receptors have traced its origins to primordial life forms existing over 600 million years ago.
Despite the extensive research being performed over the last few decades and the many new discoveries and findings made regularly, the scientific community acknowledges it still know comparatively little about the full function and nature of this highly developed system.
Around twenty thousand scientific papers have been published on the subject and most illustrate the large gaps that stand in our understanding of the many complexities of cannabinoid receptors, the various systems involved and the individual organisms. Nevertheless, these challenges have caused scientists to look at the interactions between the major players in a whole new way.
The cannabinoid receptors that report to the endocannabinoid system network are widely considered to be the most numerous receptor network in the body. When these receptors are activated or stimulated they trigger a variety of physiological processes throughout the body.
To date, scientists have located two important cannabinoid receptors located at various parts of the body. CB1 which is primarily found in the nervous system, various organs, the gonads and glands. CB2 is found primarily in the immune system and the various associated glands and organs of this system. Many of these locations contain both CB1 and CB2 receptors each with their own individual function.
While these are the two cannabinoid receptors that have been located, documented and studied extensively, scientists believe there may be at least one more receptor with its own set of functions. More research will produce the identity of other receptors.
Cannabinoid Receptor No. 1 — or CB1 is a G protein-coupled receptor and the most prolific of its kind throughout the brain. High resolution photographs of these receptors have recently been produced by cutting edge STORM (stochastic optical reconstruction microscopy) technology.
While CB1 receptors exist in high amounts in the brain, they are also found in the many other places where they have different functions. In the liver, For example, the CB1 receptor begins the chemical process of lipogenesis, in which compounds are converted into fatty acids. This is an important to the energy consumption of the body.
Other studies have found these receptors play a vital role in pre- and postnatal development.
Cannabinoid Receptor No.2 — or CB2 is also found scattered throughout the body where they carry out various functions vital to our life. They are most commonly found in the T cells of the immune system, B cells and macrophages. They have an important role in keratinocytes that are found on the top layer of the skin and have an important role in defending the body from fungi, bacteria and other foreign contaminants.
CB2 receptors also play an important role in the way the body handles pain, this is called the process of antinociception. While they are also found in the brain, the role they play here is as yet unknown. But we do know they play an important role in the immune system and defending the body from the hazards of our environment.
Endocannabinoids — these are the chemicals produced in the body that stimulate the cannabinoid receptors. Anandamide and 2-arachidonoylglycerol are the two endocannabinoids that have been studied to some degree of understanding.
Phytocannabinoids — are plant substances that can trigger a reaction in cannabinoid receptors. The most famous of these is Delta-9 tetrahydrocannabinol or THC, but there has been a n increased interest in cannabidiol (CBD) and cannabinol (CBN) which have also been found to have a wide variety curative properties.
Cannabinoid receptors, located throughout the body, are part of the Endocannabinoid system which is involved in a variety of physiological processes including appetite, pain-sensation, mood, and memory.
Cannabinoid receptors are of a class of cell membrane receptors under the G protein-coupled receptor superfamily. As is typical of G protein-coupled receptors, the cannabinoid receptors contain seven transmembrane spanning domains. Cannabinoid receptors are activated by three major groups of ligands: endocannabinoids, produced by the mammillary body; plant cannabinoids (such as Cannabidiol, produced by the cannabis plant); and synthetic cannabinoids (such as HU-210). All of the endocannabinoids and plant cannabinoids are lipophilic, such as fat soluble compounds.
There are currently two known subtypes of cannabinoid receptors, termed CB1 and CB2. The CB1 receptor is expressed mainly in the brain (central nervous system or “CNS”), but also in the lungs, liver and kidneys. The CB2 receptor is expressed mainly in the immune system and in hematopoietic cells. Mounting evidence suggests that there are novel cannabinoid receptors that is, non-CB1 and non-CB2, which are expressed in endothelial cells and in the CNS. In 2007, the binding of several cannabinoids to the G protein-coupled receptor GPR55 in the brain was described.
The protein sequences of CB1 and CB2 receptors are about 44% similar. When only the transmembrane regions of the receptors are considered, amino acid similarity between the two receptor subtypes is approximately 68%. In addition, minor variations in each receptor have been identified. Cannabinoids bind reversibly and stereo-selectively to the cannabinoid receptors. Subtype selective cannabinoids have been developed which theoretically may have advantages for treatment of certain diseases such as obesity.