银杏苦内酯拮抗血小板活化因子部分体外作用的实验研究

Ginkgolides Antagonizing Some Effects of Platelet-Activating Factor in Vitro

血小板活化因子（ＰＡＦ）加入血小板孵化液后能引起离体气管条的强烈收缩，５０％抑制浓度（ＩＣ５０）达到６．１４×１０－７ｍｏｌ／Ｌ，而单纯ＰＡＦ的气管收缩作用则较微弱（ＩＣ５０仅为６．３２×１０－４ｍｏｌ／Ｌ），两组差异显著（Ｐ＜０．０５）；预先在血小板孵化液中加银杏苦内酯，则ＰＡＦ和血小板混合液的缩气管作用明显减弱（Ｐ＜０．０１）。ＰＡＦ能减少肺组织β－肾上腺素受体的数量，使β－受体激动剂的舒张气管作用减弱，５０％有效浓度（ＥＣ５０）由１．４４×１０－６ｍｏｌ／Ｌ增至１．０６×１０－５ｍｏｌ／Ｌ（Ｐ＜０．０５），ＰＡＦ的这一作用同样能用银杏苦内酯拮抗（Ｐ＜０．０５）。提示银杏苦内酯是一种有希望的ＰＡＦ受体拮抗剂，能用于治疗哮喘。

The mixture of platelet-activating factor (PAF) and platelets produced significant contraction of guinea pigs'bronchus, while the contraction induced by PAF alone was mild relatively, the IC50 were 6.14×10-7mol/L and 6.32×10-4mol/L respectively. There was significant difference between these two groups (P<0. 05) . When the platelets were pre-incubated with ginkgolides for 10 minutes in Tris-Tyrode's buffered saline, effects of the PAF and platelets mixture were significantly inhibited (P<0.01). Exposure of guinea pigs' bronchus to PAF in vitro resulted in a loss of beta-adrenergic receptors and responses to isoproterenol, and this effect of PAF was prevented by prior incubation of the guinea pigs' bronchus with ginkgolides (P<0.05). The results showed ginkgolides were a potent PAF antagonist.