References
1. Matsumoto, K., Mizowaki, M., Suchitra, T., et al. Central antinociceptive effects of mitragynine in mice: Contribution of descending noradrenergic and serotonergic systems Eur. J. Pharmacol. 317(1),75-81(1996).
2. Takayama, H., Ishikawa, H., Kurihara, M., et al. Studies on the synthesis and opioid agonistic activities of mitragynine-related indole alkaloids: Discovery of opioid agonists structurally different from other opioid ligands J. Med. Chem. 45(9),1949-1956(2002).
3. Kikura-Hanajiri, R., Uchiyama, N., and Goda, Y. Survey of current trends in the abuse of psychotropic substances and plants in Japan Leg. Med. (Tokyo) 13(3),109-115(2011).