The actions of benzophenanthridine alkaloids, piperonyl butoxide and (S)-methoprene at the G-protein coupled cannabinoid CB1 receptor in vitro

Our data suggest that chelerythrine and sanguinarine are effacacious antagonists of G-protein-coupled CB1 receptors. They exhibit lower potencies compared to many conventional CB1 receptor blockers but act differently to AM251. Reverse modulation of CB1 receptor agonist binding resulting from benzophenanthridines engaging with the G-protein component may explain this difference. Piperonyl butoxide and (S)-methoprene are effacacious, low potency, neutral antagonists of CB1 receptors. Certain of the study compounds may represent useful starting structures for development of novel/more potent G-protein-coupled CB1 receptor blocking drugs.