二氢石蒜碱对α—受体的阻断作用

二氢石蒜碱(Dihydrolycorine,DL)使新福林增高猫平均动脉压的量-效曲线平行右移,不压低最大反应,使新福林增高毁脊髓大鼠舒张压的量-效反应曲线平行右移,也不压低最大反应。在大鼠肛尾肌和兔主动脉环,DL 拮抗甲氧胺收缩主动脉和肛尾肌的作用其 pA_2值分别为6.35和5.93。但是 DL 对α_2-受体选择性激动剂 B-HT_(920)升高毁脊髓大鼠舒张压的量-效曲线无影响,这些结果提示 DL 可能具有选择性地阻断α_1肾上腺素能受体的作用。

An a-Adrenoceptor Blocking Action of Dihydrolycorine

Dihydrolycorine(DL)HCI was produced semisynthetically from lycorine which is an alkaloid isolated from lycoris radiata Herb.The dose-response curves for phenylephrine iv to increase mean arterial pressure were shifted rightward by DL 40 mg/kg iv in anesthetized cats.The dose- response curves for phenylephrine iv to increase diastolic pressure were shift- ed rightward by DL iv in pithed rats:but DL didn't shift the dose-response curves of BHT_(920).In rat anococcygeal muscle,DL 3,10,30,100uM/L shifted cumulative dose-response curves of methoxamine rightward parallelly with pa2 value 6.35.In the isolated rabbit aortic ring,DL 10,30,100uM/L also shifted cumulative dose-response curves of methoxamine rightward parallelly with pA2 value 5.93.These results suggest that DL can block a-adrenoceptors.