3,6—[二甲氨基]—二苯骈碘杂六环枸橼酸盐对家兔血小板功能cAMP水平的影响

3,6—[二甲氨基]—二苯骈碘杂六环枸橼酸盐(IHC—6~(5))在体外明显抑制ADP、花生四烯酸和胶原诱导的血小板聚集,对这些诱导剂的抑制作用无明显的选择性,IC_(50)分别为:51.9,55.1和57.4μmol/L,同时促进ADP、花生四烯酸诱导血小板聚集的解聚,减慢胶原诱导血小板聚集的速度,延长聚集潜伏期。其效应与剂量间呈现依赖关系。IHC-65也明显抑制胶原诱导的血小板5—羟色胺的释放,但对血小板内cAMP的水平无明显影响。结果提示:IHC—65是一个非选择性的血小板功能抑制剂,作用机理可能与抑制血小板释放反应及钙拮抗作用等有关,并非通过升高血小板内cAMP水平而发挥作用。     

普罗托品对家兔血小板功能的影响

普罗托品(protopine,Pro)体外(1—1000μmol·L~(-1))和体内(10和20mg·kg~(-1))均抑制ADP,胶原,花生四烯酸(AA)和烙铁头蛇毒血小板聚集素(TMVA)诱导的兔血小板聚集及血小板5-HT释放。Pro不抑制AA诱导的免血小板TXA_2生成。也不升高血小板内cAMP水平,但升高cGMP水平。提示其抗血小板作用的机制与升高血小板内cGMP水平,抑制血小板释放活性物质有关。     

山豆根碱对血小板内TXA_2和cAMP水平的影响

山豆根硷对花生四稀酸诱发的小鼠突然死亡具有明显保护作用,抑制花生四烯酸诱导的血小板聚集和血小板内TXA_2产生,但不影响血小板内基础cAMP水平。已知抑制TXA_2产生或升高cAMP水平的药物都可抑制血小板聚集,说明山豆根硷抗血小板聚集的作用机理与抑制花生四烯酸代谢、减少TXA_2产生有关,而与cAMP无关。     

Inhibitory effect and mechanism of Danqi tablets on animal platelet aggregation

目的 研究丹七片对家兔和大鼠血小板聚集的影响,并探讨其作用机制.方法 以阿魏酸钠为阳性对照,采用比浊法测定丹七片对凝血酶和胶原诱导的血小板聚集的影响,采用酶联免疫法测定丹七片对凝血酶作用下的血小板内环磷酸腺苷(cAMP)含量的影响.结果 丹七片可明显抑制由凝血酶和胶原诱导的血小板聚集;丹七片可升高凝血霉作用下的血小板内cAMP含量.结论 丹七片抑制由凝血酶和胶原诱导的血小板聚集的作用机制与升高血小板内cAMP的含量有关.     

海兰地嗪对血小板聚集的影响及机理探讨

海兰地嗪(Her)体外对胶原,ADP,A23187和AA诱导的大鼠血小板聚集有明显抑制作用,其IC_(50)分别为14.5,41.6,44.1和48.3μg/ml。Her对AA诱导的大鼠血小板MDA生成不能抑制,但能升高兔血小板cAMP水平和抑制凝血酶诱导的人血小板胞浆内游离钙离子浓度升高。Her的抗血小板聚集作用机理可能与升高血小板内cAMP水平和抑制细胞内游离钙离子浓度升高有关。     

三乙酰莽草酸对血小板聚集的抑制作用

目的：研究三乙酰莽草酸（TSA）对血小板聚集功能的抑制作用及其作用机理。方法：用比浊法测定血小板聚集功能,分光光度法测定MDA的含量,放免法测定TXB₂,6-酮-PGF_1α,cAMP和cGMP的含量。结果：TSA 12.5,25,50,100和200 mg.kg^-1 ig明显抑制ADP和胶原诱导的大鼠血小板聚集;TSA 12.5,50和200　mg.kg^-1 ig显著增加大鼠血小板内cAMP水平,但不影响cGMP水平。TSA 200 mg.kg^-1对AA诱导的血小板中MDA的生成,ADP诱导的血小板中TXB2和腹主动脉壁6-酮-PGF_1α的生成有轻度抑制作用。结论：TSA抑制血小板聚集作用部分与血小板内cAMP水平升高有关。     

丹七片对动物血小板聚集的抑制作用及其机制研究

目的研究丹七片对家兔和大鼠血小板聚集的影响,并探讨其作用机制。方法以阿魏酸钠为阳性对照,采用比浊法测定丹七片对凝血酶和胶原诱导的血小板聚集的影响,采用酶联免疫法测定丹七片对凝血酶作用下的血小板内环磷酸腺苷(cAMP)含量的影响。结果丹七片可明显抑制由凝血酶和胶原诱导的血小板聚集;丹七片可升高凝血酶作用下的血小板内cAMP含量。结论丹七片抑制由凝血酶和胶原诱导的血小板聚集的作用机制与升高血小板内cAMP的含量有关。     

咪苯嗪酮对血小板聚集、血栓形成和血小板环磷酸腺苷含量的影响

本文观察了新型强心剂咪苯嗪酮(Cl-914)对血小板聚集、血栓形成和血小板cAMP含量的影响。用比浊法测定Cl-914体外抑制AA,ADP和胶原诱导兔血小板聚集的IC_(50),分别为2.6,8.9和15.8μM;大鼠iv Cl-914 1.25mg/kg能抑制实验性血栓形成,20 mg/kg能抑制上述三种诱导剂引起的血小板聚集。在体外,用竞争性蛋白结合法测定,CI-914可使洗涤兔血小板cAMP含量明显升高。CI-914能以剂量依赖方式协同PGE_1抑制血小板聚集和升高血小板cAMP的含量。提示CI-914升高血小板cAMP含量可能是其抑制血小板聚集和抗血栓形成的主要机理。     

眼镜蛇毒因子对大鼠血小板的激活作用(英文)

目的:研究补体激活剂眼镜蛇毒因子(CVF)对大鼠血小板的作用及其细胞机制。方法:比浊法测富血小板血浆内血小板聚集并同步记录ATP释放;生色底物法测血小板表面凝血酶原酶活性;用钙离子荧光指示剂Fura-2 AM负载血小板测细胞内游离钙;放免法测细胞内cAMP含量。结果:CVF在19.5-617nmol·L~(-1)范围内浓度依赖性地诱导血小板聚集和ATP释放,195nmol·L~(-1)诱导的ATP释放不依赖于聚集,且明显弱于凝血酶1U/ml的作用。CVF195nmol·L~(-1)时间依赖性地增加血小板表面凝血酶原酶活性。抗血小板膜糖蛋白Ⅰb/Ⅸ、Ⅲa、Ⅱb的单克隆抗体SZ-1、SZ-21、SZ-22抑制CVF诱导的血小板聚集。CVF 195nmol·L~(-1)使血小板内游离钙从静息态的(141±46)nmol·L~(-1)升高到(240±64)nmol·L~(-1),在61.7-617nmol·L~(-1)范围内轻度降低血小板内的cAMP。结论:补体激活剂CVF能诱导大鼠血小板聚集、ATP释放,增加血小板表面凝血酶原酶活性,其激活血小板的作用与血小板表面纤维蛋白原受体及血小板内游离钙升高、cAMP下降有关。     

荫风轮、风轮菜总皂甙对血小板功能影响及机理的研究

荫风轮总皂甙(TSCP)、风轮菜总皂甙(TSCC)均明显增强ADP诱导的血小板聚集、提高血小板粘附率。TSCP作用比TSCC稍强。效射免疫法测定血浆、血小板中cAMP、TXB_2含量,结果:TSCP可使TXB_2显著升高,此作用可能是该药促进血小板聚集的主要机理。     

Effects of tetrandrine on rabbit platelet aggregation, thromboxane A2 generation and calmodulin activity

The effects of tetrandrine (Tet) on platelet aggregation and thromboxane A2 (TXA2) generation were studied in rabbit platelet-rich plasma (PRP) prepared by centrifugation. The effects of Tet on calmodulin activity in platelet extracts were also investigated by measuring calmodulin-sensitive phosphodiesterase activity. ADP, collagen or arachidonic acid (AA)-induced platelet aggregation was inhibited by Tet in a dose-dependent manner. TXA2 generation in PRP treated by Tet was markedly decreased in collagen-induced group, but was not altered in AA-induced group, suggesting that the release of AA from platelet phospholipids stimulated by collagen was blocked by Tet. Further experiments showed that the effects of Tet were related to its inhibition of calmodulin-dependent phosphodiesterase activity. There was evidence that the effects originated from its anti-calmodulin properties instead of its direct action on phosphodiesterase.     

短毛五加总甙对血小板聚集和PGI_2/TXA_2平衡的影响(英文)

短毛五加总甙(AGVPS)是中药短毛五加(Acanthopanax gracilistylus var. pubescens)的有效成份。本文发现短毛五加总甙能抑制正常家兔由多种诱导因素所致的血小板聚集。同时,它还抑制花生四稀酸所致血小板聚集时TXA_2的产生,增加离体家兔胸主动脉PGI_2产生。在高脂喂养的动脉粥样硬化的家兔模型上,能提高血浆PGI_2水平。     

Effects of cefonicid on platelet aggregation

Beta-lactam antibiotics may interfere with platelet aggregation by inhibiting the binding of agonists of platelet aggregation, such as ADP and collagen, to specific receptor sites. The aim of this study was to evaluate in vitro the effects of cefonicid, a semi-synthetic cephalosporin, on platelet aggregation. Spontaneous platelet aggregation and platelet aggregation induced by ADP and collagen were assessed. Platelets from healthy subjects were incubated with cefonicid at final concentrations of 0.1 mg/ml, 1 mg/ml and 10 mg/ml (0.1 mg/ml is the concentration of cefonicid achieved in humans at therapeutic doses). When compared with saline, cefonicid at a concentration of 0.1 mg/ml had no effect on platelet aggregation, but at 1 mg/ml it inhibited ADP-induced aggregation and at 10 mg/ml it also inhibited aggregation induced by collagen. These findings suggest that therapeutic doses of cefonicid do not affect platelet aggregation.     

Novel inhibitory actions on platelet thromboxane and inositolphosphate formation by xanthones and their glycosides

Xanthones and their glycosides were tested for their antiplatelet activities in washed rabbit platelets. Tripteroside acetate and norathyriol acetate were the most potent inhibitors. Tripteroside acetate inhibited platelet aggregation and ATP release induced by ADP, arachidonic acid, platelet-activating factor (PAF), collagen, ionophore A23187 and thrombin. The IC50 values of tripteroside acetate toward arachidonic acid- (100 microM) and collagen- (10 micrograms/ml) induced platelet aggregation were 10 and 30 micrograms/ml respectively. It inhibited thromboxane B2 formation of washed platelets caused by arachidonic acid, collagen, thrombin and ionophore A23187 and also that caused by the incubation of lysed platelet homogenate with arachidonic acid. Tripteroside acetate decreased the formation of inositolphosphate caused by thrombin, collagen and PAF, whereas it had no direct effect on fibrinogen-platelet interaction. It is concluded that xanthone derivatives inhibited platelet aggregation and release reaction by diminishing thromboxane formation and phosphoinositide breakdown.     

丁基苯酞对大鼠血栓形成及血小板功能的影响

目的研究消旋、左旋和右旋丁基苯酞(dl-,l-和d-NBP)对血栓形成及血小板功能的影响。方法利用半体外血栓形成术及比浊法,观察dl-,l-和d-NBP及阿司匹林(Asp)对大鼠血栓湿重和血小板聚集率的影响,并用放免法、荧光分光光度法测定其对血小板内cAMP和TXB2的水平以及血小板5-HT释放率的影响。结果ip,dl-NBP和l-NBP可剂量依赖性地抑制大鼠血栓形成,且l-NBP作用与Asp相似,d-NBP对半体外血栓形成无显著作用;dl-,d-和l-NBP可显著抑制胶原、ADP、花生四烯酸诱导的血小板聚集。结论NBP有抗血栓作用,l-NBP作用最强,dl-NBP作用较弱,其抗栓作用与升高血小板内cAMP的含量及抑制5-HT释放有关。     

莽草酸对血小板聚集和凝血的抑制作用

目的：研究莽草酸(SA)对血小板聚集性的影响及其机制,并研究其对凝血时间的影响。 方法：采用比浊法测定血小板聚集功能,放射免疫法测定血小板TXB2和血浆6-keto-PGF_1α水平,玻管法测定凝血时间。结果：SA体外呈浓度依赖性抑制ADP、胶原诱导的兔血小板聚集,IC₅₀分别为9.25, 3.56 mmol.L^-1;在体内(ip)抑制脑血栓模型鼠由ADP诱导的血小板聚集; SA促进大鼠血浆6-keto-PGF_1α的生成并延长小鼠凝血时间。结论：SA对血小板聚集及凝血系统有显著的抑制作用。     

Inhibition of Platelet Thromboxane Formation and Phosphoinositides Breakdown by Diisoeugenol

Abstract— Diisoeugenol inhibited the platelet aggregation and ATP release of rabbit platelets caused by ADP, arachidonic acid, platelet-activating factor (PAF), collagen and thrombin. Prolongation of the incubation time of platelets with diisoeugenol did not cause further inhibition and the aggregability of platelets could not be restored after washing. In human platelet-rich plasma, diisoeugenol inhibited the biphasic aggregation and ATP release induced by adrenaline and ADP in a concentration-dependent manner. Thromboxane B₂ formation caused by arachidonic acid, collagen and thrombin was markedly inhibited by diisoeugenol in a concentration-dependent manner. Diisoeugenol also inhibited the formation of inositol monophosphate caused by collagen, PAF and thrombin. The cAMP level of washed platelets was not changed by diisoeugenol. It is concluded that the antiplatelet effect of diisoeugenol is due to the inhibition of thromboxane formation and phosphoinositides breakdown.     

Effect of 2(1-piperazinyl)-4H-pyrido[1,2-a]pyrimidin-4-one (AP155) on human platelets in vitro

The effect on human platelets of 2-(1-piperazinyl)-4H-pyrido[1,2-a]pyrimidin-4-one (AP155) was tested in vitro by measuring cyclic adenosine monophosphate (cAMP) level, cytosolic Ca⁺⁺, [¹²⁵I]fibrinogen binding as well as aggregation induced by several agonists. AP155 dose-dependently inhibited aggregation both in platelet rich plasma (PRP) and in washed platelets (WP), exerting its maximal power in the presence of collagen, ADP and platelet activating factor (PAF). It specifically inhibited the activity of cAMP high affinity phosphodiesterase (PDE), resulting in a sufficient increase in cAMP levels to activate cAMP-dependent protein kinase. AP155 was able to inhibit aggregation, the increase in cytosolic Ca⁺⁺ induced by thrombin, and fibrinogen binding to ADP or thrombin-stimulated platelets. Thus, this new pyridopyrimidine derivative exerts its antiplatelet activity by increasing cAMP intracellular concentration.