共查询到20条相似文献,搜索用时 15 毫秒
1.
目的:研究普鲁卡因胺(PA)对凝血酶诱导血小板聚集和血栓素B2(TXB2)产生的影响.方法:用比浊法和放射免疫分析法.结果:普鲁卡因胺85,34,136和544μmol·L-1有明显抑制作用.抑制率分别为45%±37%,48%±32%,88%±23%,92%±15%和53%±24%,65%±26%,90%±6%,95%±6%.PA的浓度与血小板聚集和TXB2产生的抑制效力之间,以及血小板聚集抑制率和TXB2产生的抑制率之间均存在着正相关关系,三者的线性方程和主要参数为:^Y=02075X-49157,r=09985;^Y=09546X-346724,r=09921;^Y=08202X+197062,r=09921.结论:普鲁卡因胺抑制凝血酶诱导血小板聚集和TXB2产生. 相似文献
2.
Efectsof5HTreleasedfromplateletsonthrombininducedaggregationandATPreleaseinrabbitplateletsinvitroLIBaiYan1,LIWenHan(Depar... 相似文献
3.
In vitro adrenaline and collagen-induced mobilization of platelet calcium and its inhibition by naftopidil, doxazosin and nifedipine 总被引:4,自引:0,他引:4
N. A. Alarayyed M. B. Cooper B. N. C. Prichard D. J. Betteridge & C. C. T. Smith 《British journal of clinical pharmacology》1997,43(4):415-420
Aims The aim of the study was to obtain further information regarding the modes of action of doxazosin, naftopidil and nifedipine on platelet function.Methods We conducted an in vitro study of drug influences on adrenaline and collagen-induced mobilization of platelet calcium.‘fn2\Results In the presence of fibrinogen (300 μg ml−1 ) both collagen (5 μg ml−1 ) and adrenaline (16 μm ) stimulated the aggregation of washed platelets. Collagen induced a transient rise (+4.97±0.63 μm ) in platelet Ca2+ concentration, [Ca2+]i, as measured using the photoprotein aequorin, which coincided with the onset of aggregation. Adrenaline induced a smaller rise (+3.6±0.96 μm ) which, however, occurred after the onset of aggregation. Naftopidil, an α1-adrenoreceptor antagonist produced a concentration-dependent inhibition of collagen-induced Ca2+ mobilization, maximum inhibition (22.9±4%, P<0.05) occurring with 40 μm naftopidil. The inhibition of Ca2+ mobilization was not reflected by a concentration-dependent inhibition of platelet aggregation, although 40 μm naftopidil produced statistically significant inhibition (23.3±11.7%, P<0.05). The adrenaline-induced rise in [Ca2+]i was inhibited dose dependently by naftopidil (e.g. 40 μm naftopidil, 100±0%, P<0.05), as was aggregation (40 μm naftopidil, 100±0%, P<0.05). Doxazosin, another α1-adrenoreceptor blocker, inhibited Ca2+ mobilization induced by collagen to similar extents as for naftopidil (30 μm doxazosin, 17.4±2.5%, P<0.05), but did not inhibit platelet aggregation. It also inhibited the adrenaline-induced rise in [Ca2+]i in a concentration-dependent manner (30 μm doxazosin, 37.6±13.7%, P<0.05), significant inhibitions of platelet aggregation also being produced (30 μm, 49.6±17.2%, P<0.05). As expected, the calcium channel blocker nifedipine produced concentration-dependent inhibitions of both collagen-induced Ca2+ mobilization (e.g. 28 μm nifedipine, 47.8±2.7%, P<0.05) and aggregation (28 μm, 55.1±9.2%, P<0.05).Conclusions These data indicate that the α1-adrenoreceptor blockers, naftopidil and doxazosin, inhibit Ca2+ mobilization, this mechanism being possibly the means whereby these drugs inhibit platelet aggregation. 相似文献
4.
目的:研究MK-447对家兔凝血酶诱导的血小板聚集释放反应及单细胞内钙水平的影响.方法:利用浊度法及测定PRP中ATP的含量评价聚集和释放反应,以荧光图像法分析细胞内钙浓度.结果:MK-447仅使兔多血小板血浆(PRP)透光度降低(DLT),即血小板变形,单血小板[Ca~(2 )]_i轻度增加(160 nmol·L~(-1)),并不被依他酸3 mmol·L~(-1)抑制.MK-447消除凝血酶诱导的DLT,聚集和ATP释放增强,呈剂量依赖性,且凝血酶介导的[Ca2 ]_i由369 ±45 nmol·L~(-1)增加到621±121 nmol·L~(-1).结论:MK-447的血小板变形与其[Ca~(2 )]_i释放有关.MK-447增强凝血酶的血小板聚集和ATP释放.MK-447的这一作用可能于[Ca2 ]_i的协同作用有关. 相似文献
5.
H. Chap B. Perret G. Mauco M. Plantavid F. Laffont M.F. Simon L. Douste-Blazy 《Toxicon》1982,20(1):291-298
Phospholipases A2 from various snake or bee venoms and phospholipases C secreted as exotoxins by several bacteria have been used to study the transverse distribution of phospholipids in the platelet plasma membrane and their role in platelet activation. An asymmetric distribution was described for phospholipids, characterized by a preferential localization of sphingomyelin and phosphatidylcholine in plasma membrane outer leaflet, whereas the inner half contains almost all of the anionic procoagulant phosphatidylserine and phosphatidylinositol. Such a distribution might explain the latency of procoagulant activity in resting platelets and implies an intracellular localization of arachidonic acid, the precursor of prostaglandins and thromboxanes. The external arachidonic acid is involved in phospholipase A2-induced aggregation, whereas phospholipase C from Clostridium welchii stimulates platelets through a thromboxane-independent pathway. The latter one is directly linked to the formation of phosphatidic and lysophosphatidic acids, which are able to activate cells through calcium mobilization. So, phospholipase C represents an interesting tool for studying the biochemical processes accompanying stimulation, since it is shown that it mimicks the effects of an intracellular phospholipase C, the role of which in platelet activation is discussed. 相似文献
6.
目的:研究MK-447对胶原、ADP及血栓素A_2稳定类似物(STA_2)诱导的血小板变形、聚集和释放反应的影响。方法:浊度法评价血小板变形和聚集反应,测定富含血小板血清中ATP的量确定释放反应。结果:(1)MK-447诱导血小板变形,不被吲哚美辛抑制。预置MK-447可使胶原、ADP及STA_2的血小板变形能力下降,时程延长。(2)MK-447抑制胶原的聚集反应,并使ADP和STA_2聚集增强。(3)胶原和STA_2的释放反应可被MK-447抑制和增强。MK-447对STA_2的作用与S-145无关。结论:血小板变形在其激活早期发挥重要作用。MK-447诱导血小板变形,并对不同聚集剂的作用表现为抑制和增强的双重影响。 相似文献
7.
MN-9202对兔血小板聚集、5-HT释放、TXB_2合成及Ca~(2 )转运的影响(英文) 总被引:2,自引:0,他引:2
目的:研究新二氢吡啶类钙拮抗剂MN-9202对兔血小板激活的影响,并探讨其作用机制。方法:以Fu-ra-2 AM为荧光探针,采用时间扫描方式记录血小板内Ca~(2 )的变化;分别用HPLC/ECD和放射免疫测定法检测5-HT及TXB_2。结果:MN-9202剂量依赖地抑制ADP或凝血酶诱导的血小板聚集,抑制TXA_2的释放并且能有效阻滞激活血小板胞内Ca~(2 )水平的增加。MN-9202 1μmol·L~(-1)能抑制胶原15mg·L~(-1)诱导的5-HT释放反应,但对胶原45mg·L~(-1)诱导的反应无抑制作用。结论:MN-9202阻滞血小板Ca~(2 )内流并抑制血小板花生四烯酸代谢及激活反应。 相似文献
8.
AIM: To study the effects of arachidonic acid (AA)-induced endogenous serotonin (5-HT) release on platelet aggregation and ATP release by thrombin (Thr). METHODS: Platelet aggregation and release reaction were quantified by light transmission in platelet-rich-plasma (PRP) and the amount of ATP in medium. The effects of endogenous 5-HT were evaluated by the filtration of content in cuvette A (content A) containing endogenous 5-HT into cuvette B in which Thr-induced aggregation was observed in the absence/presence of ?(+/-)-5 (Z)-7-[3-endophenylsulfonylamino [2.2.1] bicyclohept-2-exo-yl]heptanoic acid, sodium salt? (S-145) or/and methysergide (Met). RESULTS: (1) AA 100 and 200 mumol.L-1 induced aggregation and ATP release in cuvette A. When the aggregation reached a peak, the content A directly caused platelet aggregation in cuvette B, and it was inhibited by S-145 100 nmol.L-1, Met 30 mumol.L-1, and inhibited more potently by S-145 + Met. (2) In the presence of S-145 100 nmol.L-1 in cuvette B, aggregations by Thr 0.1 and 0.3 IU.L-1 were enhanced (P < 0.01) by the filtrate, while Thr 0.5 IU.L-1-caused ATP release was suppressed (P < 0.01) without the effect on aggregation. Preincubation with S-145 and Met, the effects of the filtrate on aggregation and ATP release were abolished. (3) By prolongation of the time intervals between filtration and addition of Thr, the aggregation was enhanced and ATP release was reduced. CONCLUSION: Endogenous 5-HT was released from activated platelet and plays, in turn, a role in the regulation of platelet aggregation by the superimposition of cytosolic-free calcium ([Ca2+]i) and the feedback loop to regulate release reaction and calcium. 相似文献
9.
异钩藤碱体外对家兔血小板聚集和胞浆游离钙离子浓度的影响 总被引:3,自引:0,他引:3
目的研究异钩藤碱对血小板内游离钙离子浓度([Ca2+]i)的影响,以探讨其抗血小板聚集作用的可能机制。方法比浊法测定家兔血小板聚集功能;双波长Fura-2荧光法测定血小板胞浆[Ca2+]i。结果异钩藤碱0.33~1.30mmol.L-1体外给药对ADP和凝血酶引起的血小板聚集有浓度依赖性的抑制作用。存在细胞外钙时,异钩藤碱对基础状态血小板的[Ca2+]i和ADP及凝血酶诱导的[Ca2+]i水平有浓度依赖性的降低作用,而无细胞外钙存在时,则均无明显影响,表明其可抑制血小板的外钙内流,对内钙释放无明显抑制作用。结论异钩藤碱可抑制血小板聚集,其作用机制可能与其抑制血小板胞浆[Ca2+]升高有关。 相似文献
10.
Effects of fluoride on DNA damage, S-phase cell-cycle arrest and the expression of NF-kappaB in primary cultured rat hippocampal neurons 总被引:1,自引:0,他引:1
The mechanisms underlying the neurotoxicity of fluorosis still remain obscure. To investigate DNA damage, cell-cycle distribution and expression of nuclear factor kappa B (NF-kappaB) induced by fluoride, the primary rat hippocampal neurons were incubated with various concentrations (20mg/l, 40 mg/l, and 80 mg/l) of sodium fluoride for 24 h in vitro. Our results showed that olive tail moments (OTMs) were significantly elevated in all fluoride-treated groups, while significant increases in the percentage of DNA in the tail were, respectively, observed at 40 mg/l and 80 mg/l levels of fluoride. An increase in the proportion of cells in S-phase was observed in response to the treatment of 40 mg/l and 80 mg/l fluoride. Gene expression of NF-kappaB was also enhanced by fluoride treatment in a dose-dependent manner. The results indicated that fluoride could induce S-phase cell-cycle arrest, up-regulation of NF-kappaB and DNA damage in primary rat hippocampal neurons. 相似文献
11.
Gamma-vinyl GABA (vigabatrin; VGB), an irreversible inhibitor of GABA-transaminase, was evaluated for its effect on the contractile responses to PGE(2) or its precursor arachidonic acid (AA) in guinea pig ileum (GPI) and non-pregnant rat uterus. Rationale behind this study was the rise in gamma-aminobutyric acid (GABA) contents in the peripheral organs after treatment with GABAergic agents and extensive interconnections of neuromediators and their interactions.Indomethacin, the standard NSAID, at 6.1x10(-5) and 12.2x10(-5)M concentrations highly significantly (P<0.001) inhibited contractile responses induced by AA (4.3x10(-5)M) in the isolated GPI. Incubation of the GPI segments with VGB at different concentrations (25, 100 and 200mM) failed to inhibit AA-induced contractile responses in the same preparation. In fact, VGB at 25mM significantly (P<0.05) potentiated the contractile effect of AA 4.3x10(-5)M. Incubation of the same tissue with GABA at 13x10(-3) and 26x10(-3)M inhibited responses elicited by AA at 4.3x10(-5)M that was significant (P<0.05) only with low concentration of GABA. Conversely, a higher concentration (64x10(-3)M) of GABA was needed to antagonise PGE(2) (9.4x10(-6)M)-induced contractions in the same tissue. Almost similar results (i.e. inhibition of contractile responses to AA and PGE(2)) were obtained with isolated non-pregnant rat uterus. These findings suggested that GABA had the potential to inhibit prostaglandin (PG) synthesis and/or antagonise PGE(2) responses in isolated GPI and rat uterus.The addition of 35 or 70 micro l of rat aorta incubation medium caused a dose-dependent inhibition of ADP-induced aggregation being 21.5 and 43.5%, respectively, an indication of prostacycline (PGI(2)) contents. Pre-incubation of rat aortic tissues with VGB (96.8mM) significantly (P<0.05) reversed the anti-aggregatory activity of control aortic prostacycline on ADP-induced aggregation. These findings suggested that VGB might inhibit PGI(2) activity through the inhibition of its synthesis. 相似文献
12.
P Persico F Mancuso S Metafora G Peluso G Ravagnan C Esposito R Porta 《Biochemical pharmacology》1990,40(5):1157-1161
In summary, the present study documents that platelet aggregation triggered by thrombin, ADP, collagen and PAF both in vivo and in vitro, was prevented by SV-IV in a dose-dependent manner. Only platelet aggregation by AA was not affected by the protein, thus suggesting a possible involvement of PLA2 inhibition in the molecular mechanism at the basis of SV-IV anti-thrombotic effect. 相似文献
13.
A R Eppler M E K Kraeling R R Wickett R L Bronaugh 《Food and chemical toxicology》2007,45(11):2109-2117
Arachidonic acid (AA), a precursor of pro-inflammatory mediators, and its glycerin ester, glyceryl arachidonate (GA), are reportedly used in cosmetic products. In vitro skin penetration of AA and GA and GA's ester hydrolysis was determined in flow-through diffusion cells. AA penetration with human and rat skin was 19.5% and 52.3% of the applied dose respectively, a substantial amount of which remained in the skin at 24h. Similar penetration results were obtained with GA in human skin. However, GA penetration through cultured skin (EpiDerm) was 51% of the applied dose, almost all of which appeared in the receptor fluid. At least 27.8% of GA penetrating skin was hydrolyzed to AA. In vitro methods were used to assess skin irritation in diffusion cells. Skin irritation of AA, sodium lauryl sulfate (SLS), and Tween 80 was determined by changes in transepidermal water loss (TEWL), skin viability (3-(4,5-dimethylthiaxol-2-yl)-2,5-diphenyltetrazolium bromide, MTT, formation), and cytokine release (IL-1alpha). SLS irritation was much less pronounced in an emulsion versus an aqueous vehicle. No significant irritation was observed in vitro from AA in an emulsion. This work predicts that AA would penetrate human skin in vivo and that it could be formed in skin from topically applied GA. 相似文献
14.
Abad C Teppa-Garrán A Proverbio T Piñero S Proverbio F Marín R 《Biochemical pharmacology》2005,70(11):1634-1641
The effect of the treatment with magnesium sulfate (MgSO(4)) on Ca-ATPase activity and level of lipid peroxidation of red blood cells from preeclamptic pregnant women was examined because it is known that these parameters are affected with preeclampsia. Red cell ghosts from 11 normotensive and 11 preeclamptic pregnant women, before and after treatment with MgSO(4), were assayed for Ca-ATPase activity and level of lipid peroxidation, determined as TBARS or conjugated dienes. It was found that the Ca-ATPase activity is significantly lower and the level of lipid peroxidation is significantly higher in the preeclamptic women with no treatment, as compared to normotensive pregnant women. Both parameters return to normal values after the MgSO(4) therapy. These results can be mimicked by in vitro preincubation with MgSO(4) of intact red blood cells from preeclamptic pregnant women, without any treatment. Our data indicate that MgSO(4) treatment of preeclamptic pregnant women modifies both the Ca-ATPase activity and the level of lipid peroxidation of their red blood cell membranes, reaching values similar to those of normotensive pregnant women. The diminution of the level of lipid peroxidation by MgSO(4), can account for the increase in Ca-ATPase activity. 相似文献
15.
Arruzazabala ML Mas R Molina V Carbajal D Fernández L Illnait J Castaño G Fernández J Mendoza S 《International journal of clinical pharmacology research》2004,24(2-3):55-63
D-003 is a mixture of very high molecular weight aliphatic acids purified from sugar cane wax showing cholesterol-lowering and antiplatelet effects proven in experimental and clinical studies. Experimental evidence indicates that inhibition of platelet aggregation induced by D-003 is associated with a reduction of thromboxane B2 (TxB2) and an increase of prostacyclin (Pgl2) serum levels. This double-blinded, randomized, placebo-controlled study was undertaken to investigate whether D-003 (20 mg/day) modifies serum levels of TxB2 and Pgl2 and inhibits platelet aggregation in human healthy volunteers. Thirty-one subjects were randomized to placebo or D-003 at 20 mg/day for 14 days. Serum levels of TxB2 and Pgl2 and platelet aggregation to arachidonic acid (AA) (1.75 mM) and collagen (1 microg/ml) were assessed. D-003 (20 mg/day) significantly reduced (p < 0.001) TxB2by 36.4% and increased Pgl2 serum levels by 31% compared with baseline, and these changes were different from placebo. As expected, D-003 significantly inhibited (p < 0.001) platelet aggregation to AA (81.9-65.6%) and to collagen (75.3-62.3%). No subject withdrew from the study. No drug-related disturbances were observed. We conclude that D-003 at 20 mg/day for 14 days significantly inhibited platelet aggregation to AA and collagen and reduced TxB2 and increased Pgl2 serum levels. These results are consistent with those observed in experimental models, indicating that the antiplatelet effect of D-003 is associated with the observed changes on the levels of AA metabolites. Further studies, however, should explore the mechanism involved in this action in greater depth. 相似文献
16.
Recent developments in the inhibition of angiogenesis: examples from studies on platelet factor-4 and the VEGF/VEGFR system 总被引:10,自引:0,他引:10
Bikfalvi A 《Biochemical pharmacology》2004,68(6):1017-1021
Inhibition of angiogenesis is an important strategy to block tumor growth and invasion. We discuss herein results from our ongoing investigations on platelet factor-4 (PF-4) and the VEGF/VEGFR system. Platelet factor-4 (PF-4) is an anti-angiogenic ELR-negative chemokine. PF-4 inhibits endothelial cell proliferation and migration, and angiogenesis in vitro and in vivo. We have studied the structure and anti-angiogenic activities of a C-terminal fragment of PF-4 named PF-4 CTF. This molecule retains anti-angiogenic activity, blocks the interaction of angiogenesis factors with their receptors and may also be improved by mutation or domain-swapping. It seems, therefore, to be a good candidate for further development. Furthermore, we have developed a cyclic vascular endothelial growth inhibitor (Cyclo VEGI) from the structure of VEGF-A. In aqueous solution, cyclo-VEGI adopts an alpha helix conformation. Cyclo-VEGI inhibits binding of iodinated VEGF(165) to endothelial cells and angiogenesis. Furthermore, cyclo-VEGI significantly blocks the growth of established intracranial glioma in nude and syngeneic mice and improves survival. 相似文献
17.
Taghibiglou C Van Iderstine SC Kulinski A Rudy D Adeli K 《Biochemical pharmacology》2002,63(3):349-360
We have studied the cellular and molecular mechanisms involved in the suppression of apoB secretion from HepG2 cells following incubation with avasimibe (CI-1011), a novel inhibitor of acyl-coenzyme A: cholesterol acyltransferase (ACAT). Cellular lipid analysis revealed that avasimibe significantly decreased the synthesis of cholesterol and cholesteryl ester, and, at higher doses, of triglyceride. Time-course trypsin protection assays revealed that avasimibe induced the accumulation of translocationally arrested apoB intracellularly. Pulse-chase studies showed that the treatment with avasimibe induced a >75% decrease in apoB secretion relative to control, but initially enhanced the protein stability and cellular accumulation of apoB. Subcellular fractionation of microsomes further confirmed the accumulation of secretion-incompetent apoB-lipoproteins in the endoplasmic reticulum (ER) and Golgi compartments of avasimibe-treated HepG2 cells. Although incubation of drug-treated cells with carbobenzoxyl-leucinyl-leucinyl-leucinal (MG132), a potent proteasome inhibitor, increased cellular apoB (70%), it failed to increase apoB secretion. Drug treatment induced an accumulation of secretion-incompetent apoB-containing lipoprotein particles, the majority of which demonstrated a density in a range similar to that of high-density lipoprotein. However, studies in permeabilized cells demonstrated that, at longer chase times, intracellularly accumulated apoB was eventually degraded, indicating that the inhibition of degradation may be transient. Oleate treatment of avasimibe-treated cells partially restored apoB secretion but not to the levels seen in control cells. In summary, we hypothesize that avasimibe acutely blocks the secretion of apoB and its associated lipoproteins from HepG2 cells, transiently enhancing its membrane association and cellular accumulation with eventual intracellular degradation of accumulated apoB. 相似文献
18.
4,5-二氢-6-[(苯乙酰基-哌嗪基)苯基]-5-甲基-3(2H)-哒嗪酮对血小板聚集,花生四烯酸代谢及cAMP含量的影响 总被引:1,自引:0,他引:1
4,5-二氢-6-[(苯乙酰基-哌嗪基)苯基]-5-甲基-3(2H)-达嗪酮(SMD。)0.1一2.5pmol·L能使血小板激活因子(PAn及血栓素A,类似物U46619诱导的兔血小板聚集剂量一效应曲线不移且最大反应降低。其pD2分别为6.0±s0.4及6.1±s0.3SMⅡ4还能抑制ADL花生四烯酸(AA)及U46619诱导的人血小板聚集,其IC(50)分别是12,13及1.6μmol.L.用放射性薄层层折及放射免疫测定法分别检测血小板AA代谢产物及cAMP含量表明,SMⅡ4对血小板AA代谢没有显著影响,但能剂量依赖性地升高血小板内cAMP含量,PAFμmol·L不能改变此作用 相似文献
19.
20.
The objective of the present study was to investigate the signaling mechanisms involved in the beneficial role of taurine against doxorubicin-induced cardiac oxidative stress. Male rats were administered doxorubicin. Hearts were collected 3 weeks after the last dose of doxorubicin and were analyzed. Doxorubicin administration retarded the growth of the body and the heart and caused injury in the cardiac tissue because of increased oxidative stress. Similar experiments with doxorubicin showed reduced cell viability, increased ROS generation, intracellular Ca2+ and DNA fragmentation, disrupted mitochondrial membrane potential and apoptotic cell death in primary cultured neonatal rat cardiomyocytes. Signal transduction studies showed that doxorubicin increased p53, JNK, p38 and NFκB phosphorylation; decreased the levels of phospho ERK and Akt; disturbed the Bcl-2 family protein balance; activated caspase 12, caspase 9 and caspase 3; and induced cleavage of the PARP protein. However, taurine treatment or cardiomyocyte incubation with taurine suppressed all of the adverse effects of doxorubicin. Studies with several inhibitors, including PS-1145 (an IKK inhibitor), SP600125 (a JNK inhibitor), SB203580 (a p38 inhibitor) and LY294002 (a PI3-K/Akt inhibitor), demonstrated that the mechanism of taurine-induced cardio protection involves activation of specific survival signals and PI3-K/Akt as well as the inhibition of p53, JNK, p38 and NFκB. These novel findings suggest that taurine might have clinical implications for the prevention of doxorubicin-induced cardiac oxidative stress. 相似文献