Synthetic compounds capable of antagonizing FAAH contain functional groups reactive towards catalytically active serine and cysteine residues on the FAAH enzyme. Neither cannabinol nor cannabidiol, which also occur in the plant, is psychoactive. The relative proportions of reactants and products in the ternary interconversion above can be used to determine the age of a particular marijuana plant. It is believed that cannabis species synthesize these aromatic oils to protect their foliage from dehydration, since oil production is increased in dry climates, a fact which can be exploited to increase potency. The short-term memory loss induced by THC occurs through inhibition of mnemonic pathways in the hippocampus.
Similar inhibition occurs with antimuscarinic drugs like scopolamine.
Effects on sleep regulation are most obvious during withdrawal. The potent antiemetic properties of marijuana have led to calls for legalization for humane, medical purposes. THC alters gonadal hormone function and gametogenesis, acting as a nonsteroidal estrogen, reducing testosterone levels, and decreasing sperm count and viability. The estrogenic activity in turn causes reduction in the size of the testes in males and development of female secondary sex characteristics, e.g. breast growth. Potent strains of cannabis are widely sold as a street drug.