Cannabinoid

The cannabinoid class encompasses both the naturally occurring compounds of the cannabis plant and their synthetic analogues. As a class, they act primarily on the endocannabinoid system, particularly the CB1 receptor, to produce a characteristic combination of relaxation, altered perception, and mood modulation.

The general cannabinoid experience involves physical relaxation, mild euphoria, altered time perception, enhanced sensory appreciation, and increased appetite. Thought patterns become more associative and less linear, with a tendency toward creative or philosophical tangents. Music, food, and visual art become more absorbing and pleasurable. At higher doses or with more potent compounds, anxiety, paranoia, and perceptual disturbances can emerge.

Synthetic cannabinoids, while acting on the same receptor system, differ dramatically from plant cannabis in potency, duration, and safety. Full agonist synthetics can produce intense, sometimes frightening experiences with significant physical risk. The natural and synthetic wings of this class share a receptor target but diverge substantially in character, safety, and subjective quality.

The Endocannabinoid System

The endocannabinoid system (ECS) comprises two primary G protein-coupled receptor types, their endogenous ligands, and the enzymatic machinery for their synthesis and degradation:

CB1 Receptors: Highly expressed throughout the CNS — particularly the basal ganglia, cerebellum, hippocampus, prefrontal cortex, and pain transmission pathways. CB1 activation inhibits adenylyl cyclase and voltage-gated calcium channels, reducing presynaptic neurotransmitter release. This retrograde inhibition modulates excitatory (glutamate) and inhibitory (GABA) neurotransmission throughout the brain. CB1 receptors mediate the psychoactive, analgesic, appetite-stimulating, antiemetic, and memory-impairing effects of cannabinoids.

CB2 Receptors: Predominantly expressed in immune cells, peripheral tissues, and to a lesser extent in microglia and some CNS neurons. CB2 activation modulates immune function, inflammation, and pain. CB2 is the target for developing cannabinoid-based anti-inflammatory drugs without psychoactive effects.

Endocannabinoids: Anandamide (AEA) and 2-arachidonoylglycerol (2-AG) are synthesized on demand from membrane lipid precursors and released retrograde. They are rapidly inactivated by FAAH (fatty acid amide hydrolase) and MAGL (monoacylglycerol lipase), respectively. CBD inhibits FAAH, partially explaining its ability to elevate anandamide levels.

THC vs CBD

THC is a partial agonist at CB1 and CB2 receptors. At CB1, it produces the characteristic cannabis intoxication. CBD is a negative allosteric modulator at CB1 (reducing THC's psychoactivity at that receptor), a CB2 partial agonist, a TRPV1 channel activator, an adenosine reuptake inhibitor, and an allosteric modulator at multiple other receptor types. CBD has no significant intoxicating effect through cannabinoid receptor agonism.

Synthetic Cannabinoids

Synthetic cannabinoids are typically full agonists at CB1 (vs THC's partial agonism), producing saturating receptor activation that results in substantially more intense and toxic effects. First-generation compounds (JWH-018, AM-2201) have been replaced by more potent indazole carboxamides (AMB-FUBINACA, 5F-ADB) that are active at much lower doses and associated with severe adverse events.

Ancient and Traditional Use

Cannabis has been cultivated by human cultures for at least 5,000 years. Among the oldest evidence of use is a Chinese pharmacopoeia from around 2800 BCE attributed to Emperor Shen Nung that describes cannabis's medicinal properties. Cannabis was used in religious contexts in ancient India and in the Zoroastrian tradition. The Scythians of Central Asia used cannabis in funeral rituals described by Herodotus around 450 BCE.

19th Century Western Medicine

Cannabis preparations entered Western medicine in the 19th century, championed by Irish physician William Brooke O'Shaughnessy, who encountered cannabis medicine in India and published influential studies on its use for pain, spasms, and seizures in the 1840s. Cannabis tinctures became standard pharmacopoeial preparations in Europe and North America.

Isolation of THC

The structure of THC was definitively established and the compound first synthesized by Raphael Mechoulam and Yechiel Gaoni at the Hebrew University of Jerusalem in 1964 — a landmark achievement that enabled the scientific study of cannabinoid pharmacology. Mechoulam subsequently identified anandamide as the first endocannabinoid in 1992, establishing the existence of the endocannabinoid system.

Prohibition and the War on Drugs

Cannabis was progressively restricted in the United States from the 1930s (Marihuana Tax Act, 1937) and internationally through the UN Single Convention on Narcotic Drugs (1961), which classified it among the most strictly controlled substances. This substantially hampered research for decades.

Contemporary Developments

The 21st century has seen a dramatic reversal of cannabis's legal and medical status in many jurisdictions. Canada, Uruguay, and multiple US states have legalized recreational cannabis. The FDA approved the first plant-derived cannabis medicine (Epidiolex, CBD) in 2018, and numerous CBD products became widely commercially available following the 2018 US Farm Bill. Research into therapeutic cannabinoids is now one of the most active areas in pharmacology.