Salvinorin A, the active compound in Salvia divinorum, slows intestinal movement by activating kappa-opioid receptors (KORs). In mice with croton oil-induced intestinal inflammation, this effect also involves cannabinoid CB1 receptors, as the CB1 antagonist rimonabant blocked the motility delay. In healthy mice, rimonabant did not affect salvinorin A's action. Binding tests showed salvinorin A has very weak affinity for CB1 and CB2 receptors and does not inhibit endocannabinoid breakdown or uptake. The findings suggest a functional interaction between CB1 receptors and KORs occurs specifically in the inflamed gut, not in the normal gut.
An extract from the hallucinogenic herb Salvia divinorum reduces nerve-induced muscle contractions in guinea-pig ileum by acting on kappa-opioid receptors. The extract lowered electrically evoked contractions without affecting responses to added acetylcholine, indicating a prejunctional site of action. This effect was blocked by the opioid antagonist naloxone and the kappa-opioid antagonist nor-binaltorphimine, but not by antagonists for delta- or mu-opioid receptors or other receptors. Salvinorin A, the main active ingredient, similarly inhibited contractions. The findings suggest that kappa-opioid receptor activation underlies the herb's traditional antidiarrhoeal use.