Müller-Schweinitzer E, Tapparelli C
Cephalalgia. 1986 Mar;6(1):35-41. doi: 10.1046/j.1468-2982.1986.0601035.x.
In conscious dogs methysergide (MS) caused constriction of the saphenous vein at about 3000 times lower doses than methylergometrine (MT) when infused locally, but it elicited only a short-lasting venoconstrictor response when injected systemically intravenously. MS and MT proved to be equally active venoconstrictor agents when administered orally. Analysis of canine plasma by high-performance liquid chromatography showed that after both oral and intravenous administration of MS large amounts of MT appeared in the plasma, whereas only low and transient levels of MS could be detected. It is suggested that one of the first steps in metabolism of MS is demethylation at position 1 of the indole, leading to the formation of MT, which may be a main active principle of the therapeutic effectiveness of MS in the interval treatment of migraine headache.
在清醒犬中，当局部输注时，麦角新碱（MS）引起隐静脉收缩的剂量比甲基麦角新碱（MT）低约3000倍，但静脉内全身注射时仅引起短暂的静脉收缩反应。口服时，MS和MT被证明是同等活性的静脉收缩剂。通过高效液相色谱法分析犬血浆表明，口服和静脉注射MS后，血浆中均出现大量MT，而仅能检测到低水平且短暂的MS。提示MS代谢的第一步之一是吲哚1位去甲基化，导致MT形成，这可能是MS在偏头痛间歇性治疗中发挥治疗效果的主要活性成分。
