Tohda M, Thongpraditchote S, Matsumoto K, Murakami Y, Sakai S, Aimi N, Takayama H, Tongroach P, Watanabe H
Division of Pharmacology, Research Institute of Wakan-yaku (Oriental Medicines), Toyama Medical and Pharmaceutical University, Japan.
Biol Pharm Bull. 1997 Apr;20(4):338-40. doi: 10.1248/bpb.20.338.
Mitragynine, a major constituent of the young leaves of Mitragyna speciosa KORTH., has been reported to exert antinociceptive activity in mice. To determine the mechanism the influence of mitragynine on cAMP content was measured in NG108-15 cells which possess delta opioid receptors and alpha 2B-adrenoceptors. Mitragynine inhibited the forskolin-stimulated cAMP content in a concentration dependent manner as well as morphine and noradrenaline. Mitragynine- and morphine-induced inhibition of cAMP content were blocked by naloxone. Although idazoxane inhibited noradrenaline-induced inhibition of the cAMP content, idazoxane had no effect on mitragynine-induced inhibition. These results suggest that mitragynine acts directly on opioid receptors, but not on alpha 2-adrenoceptors, to show antinociceptive activity.
帽柱木碱是美丽帽柱木叶中主要成分，据报道它对小鼠有镇痛活性。为确定其作用机制，我们在拥有δ阿片受体和α2B肾上腺素能受体的NG108 - 15细胞中检测了帽柱木碱对环磷酸腺苷（cAMP）含量的影响。帽柱木碱以浓度依赖方式抑制福斯高林刺激的cAMP含量，吗啡和去甲肾上腺素也有同样作用。纳洛酮可阻断帽柱木碱和吗啡诱导的cAMP含量抑制。虽然咪唑克生抑制去甲肾上腺素诱导的cAMP含量抑制，但对帽柱木碱诱导的抑制无作用。这些结果表明，帽柱木碱通过直接作用于阿片受体而非α2肾上腺素能受体发挥镇痛活性。
