Cannabinoid receptors are located throughout the body and are involved in a variety of processes that are connected to the endocannabinoid system.
A class of cell membrane receptors known as cannabinoids is composed of seven transmembrane domains. Unlike other G protein-coupled receptors, which have no transmembrane domains, the cannabinoids have seven transmembrane domains. They are activated by three main groups of ligands: plant cannabinoids, which are produced by the glands of the body, and synthetic cannabinoids.
There are two known subtypes of cannabinoids receptors, known as CB1 and CB2. The CB1 is expressed mainly in the central nervous system (CNS) and in liver, kidneys, and the immune system. The CB2 is expressed in hematopoietic cells and in endothelial cells.
The amino acid similarity between the CB1 and CB2 receptors is about 68%. Both the transmembrane regions and the reversibly bound regions of the receptors are also similar. Although stereo-selectively focused cannabinoids have been identified, their pharmacological effects are still unknown.
Although cannabinoid receptors are unique to each animal kingdom, other organisms still have the ability to process them. Although they are only found in the phylum Chordata, enzymes involved in the biosynthesis and inactivation of endocannabinoids are also present throughout the animal kingdom.
The existence of brain cannabinoid receptors was discovered in the 1980s. The first known cannabinoid receptor type 1 was identified in 1990. A second type of receptor was also discovered in 1993.
Anandamide, which was first described in 1992, is a neurotransmitter that could be used to activate the central nervous system’s endocannabinoid system. Its discovery led to the discovery of other neurotransmitters that act as endogenous cannabinoids.
CB1 or Cannabinoid receptor type 1 is a type 1 protein-coupled receptor that’s believed to play a key role in the regulation of Gi protein-dependent neurotransmission in the brain. It is also known to induce depolarization, which occurs when a single neuron is depolarized.
CB1 and CB2 are also found in other parts the body. In the liver, they can stimulate de novo lipogenesis.
CB2 receptors are expressed on various cells of the immune system and on B cells, macrophages, and T cells. They also have a role in the relief of pain and antinociception. Although the effects of CB2 receptor-mediated drugs on various cellular targets are unknown, their potential is increasing.
There has been a long-standing suspicion that additional cannabinoid receptors are present in the body. These compounds produce cannabinoid-like effects but do not activate CB1 or CB2. It has been hypothesized that the N-arachnoidoyl glycine receptor GPR18, which is known to be activated by NAGly, plays a crucial role in the central nervous system’s activation.
Subsequent studies revealed that GPR55, which is a non-CB1 receptor, responds to both endogenous and exogenous cannabinoids. This profile has led to speculations that it should be classified as a CB3 receptor.
GPR119 is a fifth cannabinoid receptor. It can also respond to other types of cannabinoids. The PPAR family of hormone receptors can also be used to treat certain conditions.
The cannabinoids in our bodies are activated by their natural sources, which are found in the body. When introduced into the body, they produce similar responses.
After the receptor is activated, multiple intracellular signaling pathways are activated. Usually, these pathways are initiated by the adenylate cyclase, which is produced by the second messenger molecule cyclicAMP. However, they can also be triggered by other potassium channels and protein kinase A and C.
Although many of the compounds that have been identified so far have the potential to treat the non-psychoactive effects of psychoactive drugs, they have not been reported to have the clinically desirable effects.
PCE exposure during pregnancy has been shown to disrupt the function of the fetal endocannabinoid signaling system. It has been suggested that this effect may cause altered emotionality and cognitive development in offspring.
Synthetic THC is used to treat nausea and appetite enhancement in people with AIDS and chemotherapy. It is also used to treat nausea and vomiting in people with cancer.