Cannabinoids

Cannabinoids are a group of chemicals which activate the body’s cannabinoid receptors. Before other types were discovered, the term referred to a unique group of secondary metabolites found in the cannabis plant, which are responsible for the plant’s peculiar pharmacological effects. Currently, there are three general types of cannabinoids: herbal cannabinoids occur uniquely in the cannabis plant; endogenous cannabinoids are produced in the bodies of humans and other animals; and synthetic cannabinoids are similar compounds produced in a laboratory.

Cannabinoid receptors

Before the 1980s, it was often speculated that cannabinoids produced their physiological and behavioral effects via nonspecific interaction with cell membranes, instead of interacting with specific membrane-bound receptors. The discovery of the first cannabinoid receptors in the 1980s helped to resolve this debate. These receptors are common in animals, and have been found in mammals, birds, fish, and reptiles. There are currently two known types of cannabinoid receptors, termed CB1 and CB2.

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 are essentially absent in the medulla oblongata, the part of the brain stem that is responsible for respiratory and cardiovascular functions. Thus, there is not a risk of respiratory or cardiovascular failure as there is with many other drugs. CB1 receptors appear to be responsible for the euphoric and anticonvulsive effects of cannabis.

CB2 receptors are almost exclusively found 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.

Synthetic & Patented Cannabinoids

Historically, laboratory synthesis of cannabinoids were often based on the structure of herbal cannabinoids and a large number of analogs have been produced and tested, especially in a group led by Roger Adams as early as 1941 and later in a group led by Raphael Mechoulam. Newer compounds are no longer related to natural cannabinoids or are based on the structure of the endogenous cannabinoids.

Synthetic cannabinoids are particularly useful in experiments to determine the relationship between the structure and activity of cannabinoid compounds, by making systematic, incremental modifications of cannabinoid molecules.

Other notable synthetic cannabinoids include:

CP-55940 Produced in 1974, this synthetic cannabinoid receptor agonist is many times more potent than THC
HU-210 2-9 times as potent as THC
SR 141716A and SR 144528 CB1 and CB2 receptor antagonists, respectively
Nabilone Used as an anti-emetic in chemotherapy
Levonantradol Used as an anti-emetic and analgesic
Marinol Used as a presription medicine for appetite stimulation
Sativex A naturally based cannabis extract that contains both THC and CBD

Miscellaneous

delta-9-Tetrahydrocannabinol (Δ⁹-THC, THC) and delta-8-tetrahydrocannabinol (Δ⁸-THC), mimic the action of anandamide, a neurotransmitter produced naturally in the body. The THCs produce the high associated with marijuana by binding to the CB₁ cannabinoid receptors in the brain.
Tetrahydrocannabivarin (THCV), prevalent in certain South African and Southeast Asian strains of Cannabis. It is an antagonist of THC at CB₁ receptors and attenuates the psychoactive effects of THC.
Cannabidiol (CBD), non-psychoactive and not affecting psychoactivity of THC. CBD has anti-inflammatory effects. CBD is the precursor of THC and is the main cannabinoid in low-THC Cannabis strains.
Cannabinol (CBN), a degradation product of THC, produces a depressant effect
Cannabichromene (CBC), non-psychoactive and not affecting psychoactivity of THC, a precursor of CBD and THC
Cannabigerol (CBG), non-psychoactive