The effects of mitragynine and morphine on schedule-controlled responding and antinociception in rats.
Takato HiranitaFrancisco LeonJasmine S FelixLuis F RestrepoMorgan E ReevesAnna E PenningtonSamuel ObengBonnie A AveryChristopher R McCurdyLance R McMahonJenny L WilkersonPublished in: Psychopharmacology (2019)
The antinociceptive effects of mitragynine and morphine occur at doses larger than those that disrupt learned behavior. Opioid receptors do not appear to mediate the disruptive effects of mitragynine on learned behavior. Mitragynine had lesser antinociceptive effects than morphine, and these did not appear to be mediated by opioid receptors. The pharmacology of mitragynine includes a substantial non-opioid mechanism.