10 © International Association for Cannabis as Medicine Mini-review

The human body possesses specific binding sites on the surface of many cell types for cannabi-noids, and our body produces several endocannabinoids, fatty acid derivatives that bind to these cannabinoid receptors (CB) and activate them. CB receptors and endocannabinoids together con-stitute the endocannabinoid system. Some phytocannabinoids, cannabinoids of the cannabis plant, and a multitude of synthetic cannabinoids produced in the laboratory mimic the effects of endo-cannabinoids. ∆9-THC (dronabinol), the pharmacologically most active cannabinoid of the canna-bis plant, binds to both types of cannabinoid receptors that have been identified so far, the CB1 and the CB2 receptor. These receptors have been found in the central nervous system (brain and spinal cord) and many peripheral tissues and organs. Depending on the kind of cells, on dose and state of the body, activation of CB receptors may cause a multitude of effects including euphoria, anxiety, dry mouth, muscle relaxation, hunger and pain reduction. Besides activation of CB receptors sev-eral other approaches are under investigation to influence the cannabinoid system with therapeutic intent, including blockade of CB receptors (antagonism) and modulation of endocannabinoid con-centrations by inhibition of their degradation. Currently, several preparations that stimulate can-nabinoid receptors (dronabinol, nabilone and cannabis) and one compound that blocks the CB1 re-ceptor (rimonabant) are used medicinally