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People have used marijuana and its derivatives to relieve pain as well as get high for thousands of years. Recently, researchers have been trying to divorce pot's pain-relieving properties from its psychoactive effects. Extricating the high could aid in generating novel pharmaceuticals free of the political opposition facing medical marijuana. It might also permit high doses, strong enough to boost the drug's intrinsically modest analgesic power without detrimental side effects to the central nervous system (CNS).
CB1, the first cannabinoid receptor discovered, acts in the CNS and is psychoactive. So, some researchers have focused on CB2, discovered in 1992. CB2 has been shown to inhibit acute, inflammatory, and neuropathic pain but is not expressed in the CNS, and selective agonists for CB2 do not cause CNS effects.
Researchers at the University of Arizona in Tucson recently reported how CB2...