HU-210 is a synthetic cannabinoid that was first synthesized in 1988 from (1R,5S)-myrtenol by a group led by Raphael Mechoulam at the Hebrew University. HU-210 is 100 to 800 times more potent than natural THC from cannabis and has an extended duration of action. HU-210 has a binding affinity of 0.061nM at CB1 and 0.52nM at CB2 in cloned human cannabinoid receptors compared to Delta-9-THC of 40.7nM at CB1. HU-210 is the (–)-1,1-dimethylheptyl analog of 11-hydroxy- Δ8- tetrahydrocannabinol; in some references it is called 1,1-dimethylheptyl- 11-hydroxytetrahydrocannabinol. The abbreviation "HU" stands for Hebrew University. Effects and research HU-210, the (–) enantiomer of 11-OH-D8-THC-DMH, has almost all of the cannabinoid activity, while the (+) enantiomer, known as HU-211, is inactive as a cannabinoid and instead acts as an NMDA antagonist having neuroprotective effects. HU-210 promotes proliferation, but not differentiation, of cultured embryonic hippocampal neural stem and progenitor cells likely via a sequential activation of CB1 receptors, Gi/o proteins, and ERK signaling. It was also indicated by this increased neural growth to entail antianxiety and antidepressant effects. HU-210, alongside other synthetic cannabinoids like WIN 55,212-2 and JWH-133, is implicated in preventing the inflammation caused by amyloid beta proteins involved in Alzheimer's disease, in addition to preventing cognitive impairment and loss of neuronal markers. This anti-inflammatory action is induced through the activation of cannabinoid receptors, which prevents microglial activation that elicits the inflammation. In addition, cannabinoids completely abolish neurotoxicity related to microglia activation in rat models. HU-210 is a potent analgesic with many of the same effects as natural THC. HU-210 has an oral LD50 of 5,000mg/kg in rats and 14,200mg/kg in rabbits. HU-210 has an LDLO (Lowest Lethal Dose amount) of 143mg/kg in humans. Caffeine has an LD50 estimated to be 150–200 milligrams per kilogram. Delta-8-THC LD50 has not been confirmed. In a 1973 study monkeys and dogs given 9,000mg/kg of Delta-8-THC was nonlethal. Chemistry HU-210 is the enantiomer of HU-211 (Dexanabinol). The original synthesis of HU-210 is based on an acid-catalyzed condensation of (–)-Myrtenol and 1,1-Dimethylheptylresorcinol (3,5-Dihydroxy-1-(1,1-dimethylheptyl)benzol). Legal status HU-210 is not listed in the schedules set out by the United Nations' Single Convention on Narcotic Drugs from 1961 nor their Convention on Psychotropic Substances from 1971, so the signatory countries to these international drug control treaties are not required by said treaties to control HU-210. New Zealand HU-210 is banned in New Zealand as of 8 May 2014. United States HU-210