Objectives: Cannabidiol (CBD) is a phytocannabinoid with great potential in clinical applications. The mechanism(s) of action of CBD require further investigation. Previous studies suggested that adenosine A2A receptors (A2ARs) could play a role in CBD-induced effects. Here, we evaluated the ability of CBD to modify the function of A2AR.
Methods: We used HEK-293T cells transfected with the cDNA encoding the human A2AR and Gαs protein, both modified to perform bioluminescence-based assays. We first assessed the effect of CBD on A2AR ligand binding using an A2AR NanoLuciferase sensor. Next, we evaluated whether CBD modified A2AR coupling to mini-Gαs proteins using the NanoBiT™ assay. Finally, we further assessed CBD effects on A2AR intrinsic activity by recording agonist-induced cAMP accumulation.
Results: CBD did not bind orthosterically to A2AR but reduced the coupling of A2AR to Gαs protein and the subsequent generation of cAMP.
Conclusion: CBD negatively modulates A2AR functioning.
Keywords: adenosine 2A receptor; cannabidiol; competitive binding; cyclic AMP; luminescence-based assays; negative allosteric regulation.