ABSTRACT
This chapter reviews the current state of knowledge in the cannabinoid field concerning the relationship between cannabinoid (CB) receptor structure and function, with special emphasis upon computational models of the CB receptors. The cannabinoid CB1 and CB2 receptors are transmembrane proteins that belong to the G-protein coupled receptor (GPCR) family. The CB receptors bind four different structural classes of agonist ligands. Antagonists / inverse agonists of each receptor sub-type have also been identified. Recent biochemical studies have shown that the CB receptors can couple to more than one G-protein and signal to more than one effector system. These studies have led to the hypothesis that agonists induce different conformations of the CB receptors, which in turn distinguish between different G-proteins. Such agonist selective G-protein signaling is of potential therapeutic importance if ligands can be designed to regulate individual G-protein signaling pathways that are linked to specific pharmacological effects. Knowledge of CB receptor structure and the changes undergone by CB receptors upon ligand binding is, therefore, of fundamental importance.
