Effects of magnesium lithospermate B on aggregation and 5-HT release in rabbit washed platelets  

丹酚酸B镁盐对兔洗涤血小板聚集和5-HT释放反应的影响(英文)

作　　者：王唯[1] 王逸平[1] 孙伟康 徐亚明 宣利江 

机构地区：[1]中国科学院上海药物研究所

出　　处：《Acta Pharmacologica Sinica》2000年第9期93-97,共5页中国药理学报（英文版）

基　　金：Project supported by the special subject of Bioscience & Biotechnology Research, Chinese Academy of Sciences, No STZ-1-09.

摘　　要：AIM: To study the effects and mechanism of magnesium lithospermate B(MLB) on rabbit platelet aggregation and 5-HT release. METHODS; The platelet aggregation was determined by Horn's method. Release of serotonin (5-HT) and formation of thromboxane A2(TXA2) were measured by fluorophotometry and radioimmunoassay (RIA) respectively. Cytoplasmic free Ca2+ concentra-tion ([Ca2+ ]j) in platelets was measured by Fura 2-AM fluorescence technique. RESULTS: In washed platelets, thrombin (200 U/L) or arachidonic acid (AA) (30 μmol/L)- induced aggregation was inhibited by MLB 50 - 800 mg/L in a concentration-dependent manner. In addition, MLB had more inhibitory effects on platelet ag-gregation in the absence of extracellular calcium with IC50 of 102 mg/L than in the presence of CaCl2 1 mmol/L with IC50 of 194 mg/L. MLB concentration-dependently decreased the thrombin-activated release of 5-HT, where-as it did not affect the formation of TXA2 in platelets. Furthermore, MLB not only inhibited the rise of [Ca2+ ]; in thrombin stimulated platelets, but decreased the [ Ca2+]i in resting platelets. CONCLUSION: MLB in-hibited the aggregation and 5-HT release in rabbit platelets and it is probably by attenuating intracellular calcium con-centration .目的:研究丹酚酸B镁盐(magnesium lithospermateB)对血小板聚集和5-HT释放功能的影响及其作用机制.方法:比浊法评价兔洗涤血小板的聚集反应;荧光分光光度法和放射免疫法观察血小板的5-HT与TXA_2的释放;用Fura 2荧光探针测定血小板胞内钙浓度变化.结果:丹酚酸B镁盐50-800mg/L对凝血酶或花生四烯酸诱导的血小板聚集反应有剂量依赖性的抑制作用,当体系无外Ca^(2+)存在,丹酚酸B镁盐的抑制作用增强,IC_(50)为102 mg/L.药物对血小板的5-HT释放也有剂量依赖性的抑制作用,但对AA激发的TXA_2释放无影响.同时,丹酚酸B镁盐对凝血酶激发的胞内钙升高有明显的抑制作用,并降低静息血小板[Ca^(2+)]_ⅰ.结论:丹酚酸B镁盐对体外洗涤血小板的聚集和5-HT释放反应有明确的抑制作用,可能与影响血小板胞内Ca^(2+)浓度的机制有关.

关 键 词：magnesium lithospermate B platelet aggregation SEROTONIN THROMBIN arachidonic acids thromboxane B2 calcium 

分 类 号：R96[医药卫生—药理学]