Δ9-Tetrahydrocannabinol (THC) is the psychoactive compound in marijuana (Cannabis sativa). It was isolated by Y. Gaoni and R. Mechoulam relatively recently (1964). THC receptor CB1 in the brain gives the marijuana "high"; receptor CB2 in the immune system is the basis for its medicinal use. From 1984 through 2006, J. W. Huffman and co-workers used THC and its analogues in immunosuppressant drug research.
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