The influence of beta-arrestin2 on cannabinoid CB1 receptor coupling to G-proteins and subcellular localization and relative levels of beta-arrestin1 and 2 in mouse brain

AbstractContext: Beta-arrestins are known to couple to some G-protein-coupled receptors (GPCRs) to regulate receptor internalization, G-protein coupling and signal transduction, but have not been investigated for most receptors, and for very few receptors in vivo. Previous studies have shown that beta-arrestin2 deletion enhances the efficacy of specific cannabinoid agonists. Objective: The present study hypothesized that brain cannabinoid CB1 receptors are regulated by beta-arrestin2. Methods: Beta-arrestin2+/+ and −/− mice were used. Western blotting was used to determine the relative levels of each beta-arrestin subtype in mouse brain. Receptor binding was measured to determine whether deletion of beta-arrestin2 influences agonist binding to brain CB1 receptors, or the subcellular localization of CB1 in brain membranes subjected to differential centrifugation. A variety of cannabinoid agonists from different chemical classes were investigated for their ability to activate G-proteins in the presence and ...