Cannabinoids and the Endocannabinoid System

The human body possesses specific binding sites on the surface of many cell types for cannabinoids, and our body produces several endocannabinoids, fatty acid derivatives that bind to these cannabinoid receptors (CB) and activate them. CB receptors and endocannabinoids together constitute the endocannabinoid system. Some phytocannabinoids, cannabinoids of the cannabis plant, and a multitude of synthetic cannabinoids produced in the laboratory mimic the effects of endocannabinoids. ∆-THC (dronabinol), the pharmacologically most active cannabinoid of the cannabis 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 several other approaches are under investigation to influence the cannabinoid system with therapeutic intent, including blockade of CB receptors (antagonism) and modulation of endocannabinoid concentrations by inhibition of their degradation. Currently, several preparations that stimulate cannabinoid receptors (dronabinol, nabilone and cannabis) and one compound that blocks the CB1 receptor (rimonabant) are used medicinally.