Inhibition of forebrain μ-opioid receptor signaling by low concentrations of rimonabant does not require cannabinoid receptors and directly involves μ-opioid receptors

► The cannabinoid antagonist rimonabant inhibited μ-opioid receptor (MOR) activation. ► Rimonabant seemed to interact with the antagonist preferring (inactive) MOR conformation. ► Rimonabant can be docked into the inactive state of MOR.