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Tetrahydrocannabinol (THC), or more precisely its main isomer (−)-''trans''-Δ9-tetrahydrocannabinol ((6aR,10aR)-delta-9-tetrahydrocannabinol), is the principal psychoactive constituent (or cannabinoid) of cannabis. First isolated in 1964 by Israeli scientists Prof. Raphael Mechoulam and Dr. Yechiel Gaoni at the Weizmann Institute of Science〔(【引用サイトリンク】title=Interview with the winner of the first ECNP Lifetime Achievement Award: Raphael Mechoulam, Israel )〕 it is a water-clear glassy solid when cold, which becomes viscous and sticky if warmed. A pharmaceutical formulation of (−)-''trans''-Δ9-tetrahydrocannabinol, known by its INN dronabinol, is available by prescription in the U.S. and Canada under the brand name Marinol. An aromatic terpenoid, THC has a very low solubility in water, but good solubility in most organic solvents, specifically lipids and alcohols. THC, CBD, CBN, CBC, CBG and about 80 other molecules make up the phytocannabinoid family. Like most pharmacologically-active secondary metabolites of plants, THC in ''Cannabis'' is assumed to be involved in self-defense, perhaps against herbivores. THC also possesses high UV-B (280–315 nm) absorption properties, which, it has been speculated, could protect the plant from harmful UV radiation exposure. Tetrahydrocannabinol, along with its double bond isomers and their stereoisomers, is one of only three cannabinoids scheduled by the Convention on Psychotropic Substances (the other two are dimethylheptylpyran and parahexyl). Cannabis as a plant is scheduled by the Single Convention on Narcotic Drugs (Schedule I and IV). == Effects == THC has mild to moderate analgesic effects, and cannabis can be used to treat pain by altering transmitter release on dorsal root ganglion of the spinal cord and in the periaqueductal gray.〔 Other effects include relaxation, alteration of visual, auditory, and olfactory senses, fatigue, and appetite stimulation. THC has marked antiemetic properties. It may acutely reduce aggression. Due to its partial agonistic activity, THC appears to result in greater downregulation of cannabinoid receptors than endocannabinoids, further limiting its efficacy over other cannabinoids. While tolerance may limit the maximal effects of certain drugs, evidence suggests that tolerance develops irregularly for different effects with greater resistance for primary over side-effects, and may actually serve to enhance the drug's therapeutic window.〔 However, this form of tolerance appears to be irregular throughout mouse brain areas. THC, as well as other cannabinoids that contain a phenol group, possesses mild antioxidant activity sufficient to protect neurons against oxidative stress, such as that produced by glutamate-induced excitotoxicity.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「tetrahydrocannabinol」の詳細全文を読む スポンサード リンク
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