杨梅素对血小板活化因子拮抗的作用

目的研究杨梅素对血小板活化因子（PAF）的拮抗作用。方法以放射配体结合试验观察［³H］PAF与家兔血小板受体特异性结合的作用；以分光光度法测定PAF诱发血小板粘附的强度；以Fura-2荧光分光光度法测定兔多形核白细胞（PMNs）内钙离子浓度。结果杨梅素可浓度依赖地抑制［³H］PAF与血小板受体的特异性结合，其IC₅₀分别为 34.8，85.7和118.6 μmol·L^-1；该药可明显抑制PAF诱发的血小板粘附及PMNs内游离钙浓度的升高，且呈明显的量效关系，其抑制血小板粘附的IC₅₀为 13.1 μmol·L^-1。结论杨梅素具有抗PAF作用，为一新的PAF受体拮抗剂。

Antagonistic effect of myricetin on platelet activing factor

AIM: To study the antagonistic effect of myricetin on platelet activing factor (PAF). METHODS: The specific binding of 3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique. RESULTS: The specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in 3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1. CONCLUSION: The specific receptor binding of PAF can be antagonized by myricetin.