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 KT; Ponglux, D; Takayama, H; Horie, S (Life Sci, 2005)