Salvinorin A, a diterpene from Salvia divinorum, is a high-affinity and selective full agonist at human kappa-opioid receptors. In human embryonic kidney-293 cells, salvinorin A fully inhibited forskolin-stimulated cAMP production, while derivatives like 2-propionate and 2-heptanoate were partial agonists. Further tests using chimeric G proteins confirmed its potency and efficacy. In Xenopus oocytes with minimal receptor reserve, salvinorin A acted as a full agonist, more efficacious than standard agonists U50488 and U69593, and similar to dynorphin A. The 2-position substituent is critical for receptor binding and activation. Salvinorin A is the first known naturally occurring non-nitrogenous full agonist at kappa-opioid receptors.
Salvinorin A, the active component of the hallucinogenic plant Salvia divinorum, produces pain relief (antinociception) and lowers body temperature in mice by activating the kappa-opioid receptor. These effects were observed after injection of salvinorin A or a similar compound, salvinorinyl-2-propionate, into the brain of normal mice, but not in mice genetically lacking the kappa-opioid receptor. Salvinorin A showed high affinity specifically for the kappa-1 subclass of opioid receptors. In contrast, salvinorin B, an inactive derivative, had no effect on pain or body temperature. The findings confirm that salvinorin A acts through the kappa-opioid receptor to produce its behavioral effects.
Salvinorin A, a hallucinogenic compound from the plant Salvia divinorum, selectively and potently activates kappa-opioid receptors (KORs), making it the only known lipid-like molecule to do so and the only non-nitrogenous opioid receptor agonist. Key residues in KORs responsible for its high binding affinity and agonist efficacy were identified: interactions with tyrosine residues in helix 7 (Tyr313 and Tyr320) and helix 2 (Tyr119) stabilize salvinorin A in the binding pocket, while activation requires interactions with helix 7 tyrosines Tyr312, Tyr313, and Tyr320 and with Tyr139 in helix 3.