Sánchez-Crespo M, Alonso F, Iñarrea P, Alvarez V, Egido J
Immunopharmacology. 1982 Apr;4(2):173-85. doi: 10.1016/0162-3109(82)90019-4.
Since rat platelets fully responsive to thrombin and collagen did not respond by releasing 3H-serotonin with up to 10 micrograms/ml of synthetic PAF-acether, the rat, contrariwise to the rabbit, was considered to be an appropriate model to study the actions of PAF-acether not mediated through the activation of platelets and the subsequent release of their inflammatory mediators. We developed an experimental approach using 57Co and 113Sn radiolabeled microspheres to assess the effect of PAF-acether on cardiac output, peripheral vascular resistance, and regional flows and resistance. The effect on vascular permeability and blood volume was studied by measuring the clearance of 125I-HSA and the variations of the hematocrit. A significant fall in blood pressure and peripheral vascular resistance was found with doses of PAF-acether ranging from 0.05 to 5 micrograms. Moreover, the higher doses of PAF-acether also induced a marked depletion of blood volume. A significant fall in spleen, coronary, and kidney output, but not in cardiac output, was also found. Our data show that PAF-acether, by itself, induces a drop in peripheral vascular resistance and, at higher doses, also in circulating volume, accounting for both by the hypotensive effect. The redistribution of cardiac output seems to be the expression of a nonuniform action of the compound on the vascular resistance of the different organs.
由于对凝血酶和胶原完全有反应的大鼠血小板，在高达10微克/毫升的合成血小板激活因子-乙醚（PAF-乙醚）作用下不会通过释放3H-5-羟色胺作出反应，因此与兔子相反，大鼠被认为是研究不通过激活血小板及其随后释放炎症介质介导的PAF-乙醚作用的合适模型。我们开发了一种使用57Co和113Sn放射性标记微球的实验方法，以评估PAF-乙醚对心输出量、外周血管阻力以及局部血流和阻力的影响。通过测量125I-人血清白蛋白（125I-HSA）的清除率和血细胞比容的变化来研究对血管通透性和血容量的影响。发现剂量范围为0.05至5微克的PAF-乙醚会导致血压和外周血管阻力显著下降。此外，较高剂量的PAF-乙醚还会导致血容量明显减少。还发现脾脏、冠状动脉和肾脏的输出量显著下降，但心输出量未下降。我们的数据表明，PAF-乙醚本身会导致外周血管阻力下降，在较高剂量时还会导致循环血量下降，这两者都是由其降压作用引起的。心输出量的重新分布似乎是该化合物对不同器官血管阻力的非均匀作用的表现。
