粉防己碱特异抑制大鼠血小板聚集和ATP释放(英文)

AIM: To examine the effects of tetrandrine (Tet) on the aggregation and ATP-release of rat washed platelets induced by several platelet activators. METHODS: Gel-filtration (Sepharose 2B) was used to isolate washed platelets from adult rats and the platelet aggragation and ATP-release were measured simultaneously. RESULTS: In the presence of Ca2 1 mmol · L-1, Tet 300 μmol·L -1 inhibited the aggregation induced by ADP ( 25 μmol · L -1), collagen (2.5 g·L-1), and thrombin (103 unit·L-1) by 62 %, 60 %, and 34 %, respectively. It also inhibited arachidonic acid (1 mmol · L-1)-induced aggregation. Elevating intracellular Ca2 concentration with the Ca2 ionophore, calcimycin (30 μmol · L-1), or by blocking the intracellular calcium pump with cyclopiazonic acid (5 μmol · L-1) initiated platelet aggregation, which was also inhibited by Tet. In Ca2 -free medium, Tet still elicited an inhibitory effect on aggregation induced by ristocetin (2.5 g·L-1). Lower concentrations of Tet (30 nmol·L-1 to     

粉防己碱与牛磺酸合用对血小板聚集与血栓形成的影响

粉防己碱（Ｔｅｔ）和牛磺酸（Ｔａｕ）均能抑制ＡＤＰ、胶原和凝血酶诱导的大鼠血小板聚集及血栓形成。Ｔｅｔ抑制ＡＤＰ诱导聚集较强，Ｔａｕ则对胶原作用最明显，二药减半量合并应用时，较各药单用强     

苦豆碱对兔血小板聚集的影响

苦豆碱抑制低浓度花生四烯酸(AA)和胶原诱导的兔血小板聚集,IC_(50)分别为184μg·L~(-1)和38.3mg·L~(-1)提高AA浓度使其抑制作用明显减弱。苦豆碱还抑制兔血小板形成血栓素B_2(TXB_2),此作用可能和其对血小板聚集的抑制有关。     

高圣草素-7-O-β-D-葡萄糖苷抑制血小板活化因子诱导血小板聚集的机理探讨(英文)

高圣草素-7-O-β-D-葡萄糖苷是从中草药槲寄生中提取分离的一种黄酮类化合物。已证实该化合物在体内外对血小板活化因子（PAF）诱导的人及兔血小板聚集有明显的抑制作用。本研究应用放射配体[3H]PAF与受体结合的抑制实验证实该化合物是在受体水平上阻断了PAF对血小板的活化作用。抑制呈剂量效应关系,化合物浓度的负对数与抑制率明显相关γ=0.985,P<0.05）。在浓度大于1×10~-5 mol·L~-1时,增加浓度,不能提高抑制率,提示抑制的饱和。抑制的IC50为8×10~-7 mol·L~-1。首次发现,高圣草素-7-O-β-D-葡萄糖苷通过阻断PAF受体而抑制PAF诱导的血小板聚集。     

粉防己碱，钩藤碱和维拉帕米对兔主动脉平滑肌细胞内外钙转运的作用

粉防己碱和钩藤碱对由高钾和去甲肾上腺素引起的兔主动脉条收缩的抑制作用没有维拉帕米强。粉防己碱，钩藤碱和维拉帕米在由去甲肾上腺素和５－羟色胺引起的两相收缩中，抑制Ⅰ相收缩的ＩＣ５０小于抑制Ⅱ相收缩的ＩＣ５０．粉防己碱，钩藤碱抑制由去甲肾上腺素引起的Ⅰ相收缩的ＩＣ５０分别是抑制高钾所致收缩的１／１２．８和１／６．但维拉帕米没有表现此种关系，三种药物均不能对抗卡西霉素引起的收缩。粉防己碱和钩藤碱能增强咖啡因所致收缩，但维拉帕米抑制之，这些结果表明粉防己碱和钧藤碱为细胞内钙动员抑制剂，而且它们的作用点不同于维拉帕米。     

血小板激活因子和银杏内酯B对洗涤兔血小板中cAMP含量的影响

研究了血小板激活因子(PAF)和PAF拮抗剂银杏内酯B对洗涤兔血小板中cAMP含量的作用. 结果表明PAF(0.1-1.0 μmol·L^-1)对血小板的基础cAMP水平无影响, 但对前列腺素E₁(PGE₁) 2 μmol·L^-1及4,5-二氢-6-［4-(1H-咪唑-1)苯基］-5-甲基-3-(2H)-哒嗪酮(CI-930) 20 μmol·L^-1引起的cAMP升高有显著的抑制作用. 银杏内酯B能完全拮抗PAF抑制PGE₁和CI-930升高cAMP的作用, IC₅₀分别为4.7和12.5 μmol·L^-1. 合用磷酸肌酸/磷酸肌酸激酶和阿司匹林对PAF和银杏内酯B的作用均无影响. 提示PAF对磷酸二酯酶的激活作用及腺苷酸环化酶的抑制作用是PAF的直接作用，与其同PAF受体结合有关.     

Effects of platelet activating factor and ginkgolid B on the cAMP levels in washed rabbit platelets

研究了血小板激活因子（ＰＡＦ）和ＰＡＦ拮抗剂银杏内酯Ｂ对洗涤兔血小板中ｃＡＭＰ含量的作用．结果表明ＰＡＦ（０．１－１．０μｍｏｌ·Ｌ－１）对血小板的基础ｃＡＭＰ水平无影响，但对前列腺素Ｅ１（ＰＧＥ１）２μｍｏｌ·Ｌ－１及４，５－二氢－６－［４－（１Ｈ－咪唑－１－）苯基］－５－甲基－３－（２Ｈ）－哒嗪酮（ＣＩ－９３０）２０μｍｏｌ·Ｌ－１引起的ｃＡＭＰ升高有显著的抑制作用．银杏内酯Ｂ能完全拮抗ＰＡＦ抑制ＰＧＥ１和ＣＩ－９３０升高ｃＡＭＰ的作用，ＩＣ５０分别为４．７和１２．５μｍｏｌ·Ｌ－１．合用磷酸肌酸／磷酸肌酸激酶和阿司匹林对ＰＡＦ和银杏内酯Ｂ的作用均无影响．提示ＰＡＦ对磷酸二酯酶的激活作用及腺苷酸环化酶的抑制作用是ＰＡＦ的直接作用，与其同ＰＡＦ受体结合有关．     

Platelet-released ADP stabilizes PAF-induced rabbit platelet aggregation by stabilizing intracellular calcium

ＰｌａｔｅｌｅｔｒｅｌｅａｓｅｄＡＤＰｓｔａｂｉｌｉｚｅｓＰＡＦｉｎｄｕｃｅｄｒａｂｂｉｔｐｌａｔｅｌｅｔａｇｇｒｅｇａｔｉｏｎｂｙｓｔａｂｉｌｉｚｉｎｇｉｎｔｒａｃｅｌｕｌａｒｃａｌｃｉｕｍ１ＹＩＦｕＸｉａｎ，ＧＵＯＺｈａｏＧｕｉ２（Ｌａｂ...     

血小板激活因子刺激血小板在脑微血管内皮细胞上粘附及药物的阻断作用(英文)

目的:研究血小板激活因子(PAF)刺激脑微血管内皮细胞导致血小板在内皮细胞上粘附及WEB,DMPP和粉防己碱的抑制作用. 方法:用[~3H]腺嘌呤标记血小板探讨PAF导致血小板在脑微血管内皮细胞上粘附和药物的抑制作用. 结果:PAF 10—100 nmol L~(-1)显著增加血小板与脑微血管内皮细胞的粘附率,WEB,DMPP和粉防己碱抑制由PAF刺激而导致的血小板在脑微血管内皮细胞上的粘附. 结论:DMPP和粉防己碱能够抑制PAF对脑血管的损害作用.     

血小板活化因子和肾上腺素对人血小板凝集的钙依赖性协同作用(英文)

AIM: To investigate the mechanism (s) involved in the synergistic interaction of platelet activating factor (PAF) and epinephrine. METHODS: Blood was obtained from healthy human subjects reported to be free of medications for at least two weeks before sampling. Aggregation was monitored at 37℃ using Dual-channel Lumi-aggregometer.The resulting aggregation was recorded for 5 min by the measurement of light transmission as a function of time.RESULTS: Platelet aggregation mediated by subthreshold concentrations of PAF (5-8 nmol/L) plus epinephrine(0.5-2 μmol/L) was inhibited by α_2-receptor blocker, yohimbine, and PAF receptor antagonist WEB 2086. This synergism was inhibited by calcium channel blockers, verapamil and diltiazem. In addition, platelet aggregation by co-addition of PAF and epinephrine was also inhibited by very low concentrations of phospholipase C (PLC) inhibitor (U73122; IC_(50)=0.2 μmol/L), the MAP kinase inhibitor, PD 98059 (IC_(50)=3 μmol/L), and cyclooxygenase(COX-1) inhibitors in     

花椒油素对兔血小板聚集的影响

花椒油素（ｘａｎｔｈｏｘｙｌｉｎ，ＸＴ）是从大戟科植物乌桕［Ｓａｐｉｕｍｓｅｂｉｆｅｒｕｍ（Ｌ）Ｒｏｘｂ］根皮中提取的化合物，分子式Ｃ１０Ｈ１２Ｏ４，相对分子质量：１９６２１。乌桕是传统的中药材，乌桕根皮有利水消积，杀虫、解毒之功效，主治水肿，臌胀...     

Correlation of platelet activating factor and age-related macular degeneration

Objective: To investigate the role of Platelet Activating Factor (PAF) in the pathogenesis and development of Age-Related Macular Degeneration (ARMD).

Research design and methods: Fifty six patients with ARMD (24 patients with dry ARMD and 32 patients with wet ARMD) and 25 age-matched control participants underwent ophthalmological examination, including visual acuity measurement and evaluation of the retina. The participants were classified into three groups according to their retinal status, based on indirect fundoscopy, Optical Coherence Tomography and fluorescein angiography findings. In order to evaluate the concentrations of PAF in serum, blood samples were collected from all participants and were analyzed with ELISA technique.

Results: The concentrations of PAF differed significantly according to macular lesions and were found to be lower in patients with ARMD than control participants.

Conclusions: PAF levels are decreased along with the severity of ARMD. Understanding the role of PAF in pathogenesis of ARMD could be the impetus for the development of new therapies field of treatment of ARMD or even other retinal diseases.