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Monday 23 March 2009

The mechanism of action of cannabis

The active ingredient of cannabis is ∆9-tetrahydrocannabinol (∆9-THC) and it is thought to exert its effect by binding to cannabinoid CB1 receptors on pre-synaptic nerve terminals in the brain.

∆9-THC binding to CB1 receptors activates G-proteins that activate/inhibit a number of signal transduction pathways.

The G-proteins directly inhibit N and P/Q-type voltage dependant calcium channels and sodium channels and indirectly inhibit A-type calcium channels via inhibition of adenylate cyclase.

∆9-THC binding and G-protein activation also activates inwardly rectifying potassium channels and the MAP kinase signalling pathway.

The cumulative effect of these pathways is the euphoric feelings associated with cannabis use.