Tetrahydrocannabinol (THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant. Although the chemical formula for THC (C21H30O2) describes multiple isomers, the term THC usually refers to the Delta-9-THC isomer with chemical name (−)-trans-Δ9-tetrahydrocannabinol. THC is a terpenoid found in cannabis and, like many pharmacologically active phytochemicals, it is assumed to be involved in the plant's evolutionary adaptation against insect predation, ultraviolet light, and environmental stress. THC was first discovered and isolated by Israeli chemist Raphael Mechoulam in Israel in 1964. It was found that, when smoked, THC is absorbed into the bloodstream and travels to the brain, attaching itself to endocannabinoid receptors located in the cerebral cortex, cerebellum, and basal ganglia. These are the parts of the brain responsible for thinking, memory, pleasure, coordination and movement.
An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer. They may be used for severe cases of gastroenteritis, especially if the patient is dehydrated.
Medical cannabis, or medical marijuana (MMJ), is cannabis and cannabinoids that are prescribed by physicians for their patients. The use of cannabis as medicine has not been rigorously tested due to production and governmental restrictions, resulting in limited clinical research to define the safety and efficacy of using cannabis to treat diseases.
Cannabinoids are several structural classes of compounds found in the cannabis plant primarily and most animal organisms or as synthetic compounds. The most notable cannabinoid is the phytocannabinoid tetrahydrocannabinol (THC) (delta-9-THC), the primary psychoactive compound in cannabis. Cannabidiol (CBD) is also a major constituent of temperate cannabis plants and a minor constituent in tropical varieties. At least 113 distinct phytocannabinoids have been isolated from cannabis, although only four have been demonstrated to have a biogenetic origin. It was reported in 2020 that phytocannabinoids can be found in other plants such as rhododendron, licorice and liverwort, and earlier in Echinacea.
Cannabinoid receptors, located throughout the body, are part of the endocannabinoid system of vertebrates– a class of cell membrane receptors in 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; phytocannabinoids ; and synthetic cannabinoids. All endocannabinoids and phytocannabinoids are lipophilic.
Tetrahydrocannabivarin is a homologue of tetrahydrocannabinol (THC) having a propyl (3-carbon) side chain instead of pentyl (5-carbon), making it non-psychoactive in lower doses. It has been shown to exhibit neuroprotective activity, appetite suppression, glycemic control and reduced side effects compared to THC, making it a potential treatment for management of obesity and diabetes.
Nabilone, sold under the brand name Cesamet among others, is a synthetic cannabinoid with therapeutic use as an antiemetic and as an adjunct analgesic for neuropathic pain. It mimics tetrahydrocannabinol (THC), the primary psychoactive compound found naturally occurring in Cannabis.
WIN 55,212-2 is a chemical described as an aminoalkylindole derivative, which produces effects similar to those of cannabinoids such as tetrahydrocannabinol (THC) but has an entirely different chemical structure.
Nabitan (Nabutam, Benzopyranoperidine, SP-106, Abbott 40656) is a synthetic cannabinoid analog of dronabinol (Marinol) and dimethylheptylpyran. It exhibits antiemetic and analgesic effects, most likely by binding to and activating the CB1 and CB2 cannabinoid receptors, and reduced intraocular pressure in animal tests, making it potentially useful in the treatment of glaucoma.
Cannabinoid receptor 1 (CB1), is a G protein-coupled cannabinoid receptor that in humans is encoded by the CNR1 gene. The human CB1 receptor is expressed in the peripheral nervous system and central nervous system. It is activated by endocannabinoids, a group of retrograde neurotransmitters that include anandamide and 2-arachidonoylglycerol (2-AG); plant phytocannabinoids, such as docosatetraenoylethanolamide found in wild daga, the compound THC which is an active constituent of the psychoactive drug cannabis; and synthetic analogs of THC. CB1 is antagonized by the phytocannabinoid tetrahydrocannabivarin (THCV).
JWH-073, a synthetic cannabinoid, is an analgesic chemical from the naphthoylindole family that acts as a full agonist at both the CB1 and CB2 cannabinoid receptors. It is somewhat selective for the CB1 subtype, with affinity at this subtype approximately 5× the affinity at CB2. The abbreviation JWH stands for John W. Huffman, one of the inventors of the compound.
Nonabine (BRL-4664) is an experimental drug which is a synthetic THC analog. It was studied in the 1980s for the prevention of nausea and vomiting associated with cancer chemotherapy but was never marketed. It has strong antiemetic effects equivalent to those of chlorpromazine, and also produces some mild sedative effects, along with dry mouth and EEG changes typical of cannabinoid agonists, but with minimal changes in mood or perception, suggesting the abuse potential is likely to be low.
A cannabinoid receptor antagonist, also known simply as a cannabinoid antagonist or as an anticannabinoid, is a type of cannabinoidergic drug that binds to cannabinoid receptors (CBR) and prevents their activation by endocannabinoids. They include antagonists, inverse agonists, and antibodies of CBRs. The discovery of the endocannabinoid system led to the development of CB1 receptor antagonists. The first CBR inverse agonist, rimonabant, was described in 1994. Rimonabant blocks the CB1 receptor selectively and has been shown to decrease food intake and regulate body-weight gain. The prevalence of obesity worldwide is increasing dramatically and has a great impact on public health. The lack of efficient and well-tolerated drugs to cure obesity has led to an increased interest in research and development of CBR antagonists. Cannabidiol (CBD), a naturally occurring cannabinoid and a non-competitive CB1/CB2 receptor antagonist, as well as Δ9-tetrahydrocannabivarin (THCV), a naturally occurring cannabinoid, modulate the effects of THC via direct blockade of cannabinoid CB1 receptors, thus behaving like first-generation CB1 receptor inverse agonists, such as rimonabant. CBD is a very low-affinity CB1 ligand, that can nevertheless affect CB1 receptor activity in vivo in an indirect manner, while THCV is a high-affinity CB1 receptor ligand and potent antagonist in vitro and yet only occasionally produces effects in vivo resulting from CB1 receptor antagonism. THCV has also high affinity for CB2 receptors and signals as a partial agonist, differing from both CBD and rimonabant.
Synthetic cannabinoids are a class of designer drug molecules that bind to the same receptors to which cannabinoids in cannabis plants attach. These novel psychoactive substances should not be confused with synthetic phytocannabinoids or synthetic endocannabinoids from which they are in many aspects distinct.
The International Nonproprietary Name dronabinol, also known under the trade names Marinol, Syndros, Reduvo and Adversa, is a generic name for the molecule of delta-9-tetrahydrocannabinol in the pharmaceutical context. It has indications as an appetite stimulant, antiemetic, and sleep apnea reliever and is approved by the FDA as safe and effective for HIV/AIDS-induced anorexia and chemotherapy-induced nausea and vomiting only.
Canbisol (Nabidrox), is a synthetic cannabinoid derivative that is the dimethylheptyl homologue of 9-nor-9β-hydroxyhexahydrocannabinol (HHC). It is a potent agonist at both the CB1 and CB2 receptors, with a binding affinity of 0.1nM at CB1 and 0.2nM at CB2. It is mainly used in scientific research, in receptor binding studies to determine the structure and function of the cannabinoid receptors, but has been made illegal in some countries due to its possible abuse potential as a cannabinomimetic drug.
AM-2233 is a drug that acts as a highly potent full agonist for the cannabinoid receptors, with a Ki of 1.8 nM at CB1 and 2.2 nM at CB2 as the active (R) enantiomer. It was developed as a selective radioligand for the cannabinoid receptors and has been used as its 131I derivative for mapping the distribution of the CB1 receptor in the brain. AM-2233 was found to fully substitute for THC in rats, with a potency lower than that of JWH-018 but higher than WIN 55,212-2.
Δ-8-tetrahydrocannabinol is a psychoactive cannabinoid found in the cannabis plant. It is an isomer of delta-9-tetrahydrocannabinol, the compound commonly known as THC.
CP 42,096 is an analgesic drug which acts as a cannabinoid agonist. It was developed by Pfizer in the 1980s as part of the research that led to the development of levonantradol, and is more potent than THC but less potent than newer compounds such as CP 55,244.
