Inhibitory effect of mitragynine, an analgesic alkaloid from Thai herbal medicine, on neurogenic contraction of the vas deferens.
Matsumoto, K., Yamamoto, L.T., Watanabe, K., Yano, S., Shan, J., Pang, P.K.T., Ponglux, D., Takayama, H., Horie, S.
Life Sci., 78(2), 187-194 (2005)