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The psychoactive effects of THC are primarily mediated by the activation of cannabinoid receptors, which result in a decrease in the concentration of the second messenger molecule cAMP through inhibition of adenylate cyclase. The actions of Delta-9-THC result from its partial agonist activity at the cannabinoid receptor CB 1 (K i = 40.7 nM ), located mainly in the central nervous system, and the CB 2 receptor (K i = 36 nM ), mainly expressed in cells of the immune system. įor a review of the mechanisms behind endocannabinoid synaptic transmission, see Endocannabinoid system.
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These are the parts of the brain responsible for thinking, memory, pleasure, coordination and movement. It was found that, when smoked, tetrahydrocannabinol is absorbed into the bloodstream and travels to the brain, attaching itself to the naturally-occurring endocannabinoid receptors located in the cerebral cortex, cerebellum, and basal ganglia. THC was first discovered and isolated by Israeli chemist Raphael Mechoulam in Israel in 1964. ĭelta-9-tetrahydrocannabinol (Δ 9-THC), better known as THC, is the marijuana plant's primary component for causing psychoactive effects. The pharmaceutical formulation dronabinol is an oily and viscous resin provided in capsules available by prescription in the United States, Canada, Germany, and New Zealand. However, dronabinol, a pharmaceutical form of THC, has been approved by the FDA as an appetite stimulant for people with AIDS and an antiemetic for people receiving chemotherapy under the trade names Marinol and Syndros. It is specifically still listed under Schedule I by US federal law under the Controlled Substances Act for having "no accepted medical use" and "lack of accepted safety". Cannabis as a plant is scheduled by the Single Convention on Narcotic Drugs (Schedule I and IV). Based on subsequent studies, the WHO has recommended the reclassification to the less-stringent Schedule III. It was listed under Schedule I in 1971, but reclassified to Schedule II in 1991 following a recommendation from the WHO. THC, along with its double bond isomers and their stereoisomers, is one of only three cannabinoids scheduled by the UN Convention on Psychotropic Substances (the other two are dimethylheptylpyran and parahexyl). Like most pharmacologically active secondary metabolites of plants, THC is a lipid found in cannabis, assumed to be involved in the plant's evolutionary adaptation, putatively against insect predation, ultraviolet light, and environmental stress. Although the chemical formula for THC (C 21H 30O 2) describes multiple isomers, the term THC usually refers to the Delta-9-THC isomer with chemical name (−)- trans-Δ 9-tetrahydrocannabinol. Tetrahydrocannabinol ( THC) is the principal psychoactive constituent of cannabis and one of at least 113 total cannabinoids identified on the plant.
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