The effects of kratom on restraint-stress-induced analgesia and its mechanisms of action.

Ethnopharmacological Relevance: Mitragyna speciosa and its extracts are called kratom (dried leaves, extract). They contain several alkaloids with an affinity for different opioid receptors. They are used in traditional medicine for the treatment of different diseases, as a substitute by opiate addicts, and to mitigate opioid withdrawal symptoms.