地龙(蚯蚓)体内磷脂的组成和血小板活化因子的生物合成

首次发现低等动物地龙(Eisenia foetida,亦称蝗蚓)体内含有血小板活化因子(PAF),含量随季节变化,平均达10.7±6.1pmol/g湿重(或1.1±0.5μmol/mol磷脂)。磷脂成分中,PAF前体物质1-O-烷基-2-酰基(长链)-sn-甘油-3-磷酸胆碱占磷脂酰胆碱的比例高达61.4%。并证实地龙体内含有与哺乳类动物相同的两种PAF合成酶蛋白。当针刺、切断等伤害性刺激时,PAF水平显著升高。此结果提示PAF是一种初始的活性介质,在地龙这类低等动物体内也参与机体的病理、生理应急反应。本研究为阐明中药地龙的降血压等药理作用机理提供新线索。

THECOMPOSITION OF PHOSPHOLIPIDE AND BIOSYNTHESIS OF PLATELET-ACTIVATING FACTOR IN EARTHWORM(EISENIA FOETIDA)

Platelet-activating factor (PAF) was for the first time confirmed to exist in a lower animal, earthworm (Eisenia foetida). It amounts to 10.7 +/- 6.1 pmol/g wet body weight, and varied seasonally. Phospholipid analysis revealed that 1-O-alkyl-2-acyl-sn-glycerophosphocholine, a stored form of PAF precursor, accounted for 61.4% of the choline glycerophospholipids. Two kinds of enzyme activities operating in PAF generation in mammalian cells were also detected from this species. The PAF level increased markedly under some injurious stimuli such as cutting and pricking. The results suggest that PAF may be a primary mediator involved in pathological and physiological reactions even in lower animal like earthworm. The findings also cast a new light on the mechanisms underlying the antihypertensive and other effects of the Chinese medicinal earthworm, pheretima.