So far two cannabinoid receptors have been identified in humans: CB1, which is highly expressed in the brain; and CB2, which is more prominently expressed in leukocytes and has largely been implicated in immune response. Both CB1 and CB2 are G-protein coupled receptors. Stimulation of these receptors by either endogenous or exogenous cannabinoids (e.g. THC) inhibits adenylate cyclase, activates mitogen-activated protein kinases and the inhibits and activates voltage-gated calcium and potassium channels respectively [31-35].
