9,11-Epoxy-9-homo-14-thiaprost-5-enoic acid derivatives: potent thromboxane A2 antagonists

1989 ◽  
Vol 32 (5) ◽  
pp. 974-984 ◽  
Author(s):  
Steven E. Hall ◽  
Wen Ching Han ◽  
Don N. Harris ◽  
Anders Hedberg ◽  
Martin L. Ogletree
Keyword(s):  
Thromboxane A2 ◽  
Enoic Acid

ChemInform Abstract: 6,6-Disubstituted Hex-5-enoic Acid Derivatives as Combined Thromboxane A2 Receptor Antagonists and Synthetase Inhibitors.

ChemInform ◽  
2010 ◽  
Vol 25 (17) ◽  
pp. no-no
Author(s):  
R. SOYKA ◽  
A. HECKEL ◽  
J. NICKL ◽  
W. EISERT ◽  
T. H. MUELLER ◽  
...  
Keyword(s):  
Thromboxane A2 ◽  
Enoic Acid ◽  
Receptor Antagonists ◽  
Thromboxane A2 Receptor

9,11-Epoxy-9-homoprosta-5-enoic acid analogs as thromboxane A2 receptor antagonists

1990 ◽  
Vol 33 (6) ◽  
pp. 1741-1748 ◽  
Author(s):  
Jagabandhu Das ◽  
Steven E. Hall ◽  
Masami Nakane ◽  
Martin F. Haslanger ◽  
Joyce A. Reid ◽  
...  
Keyword(s):  
Thromboxane A2 ◽  
Enoic Acid ◽  
Receptor Antagonists ◽  
Thromboxane A2 Receptor

6,6-Disubstituted hex-5-enoic acid derivatives as combined thromboxane A2 receptor antagonists and synthetase inhibitors

1994 ◽  
Vol 37 (1) ◽  
pp. 26-39 ◽  
Author(s):  
Rainer Soyka ◽  
Armin Heckel ◽  
Josef Nickl ◽  
Wolfgang Eisert ◽  
Thomas H. Mueller ◽  
...  
Keyword(s):  
Thromboxane A2 ◽  
Enoic Acid ◽  
Receptor Antagonists ◽  
Thromboxane A2 Receptor

Effect of Ridogrel on Vascular Contractions Gaused by Vasoactive Substances Released during Platelet Activation

1990 ◽  
Vol 64 (01) ◽  
pp. 091-096 ◽  
Author(s):  
W J Janssens ◽  
F J S Cools ◽  
L A M Hoskens ◽  
J M Van Nueten
Keyword(s):  
Smooth Muscle ◽  
Blood Vessel ◽  
Platelet Activation ◽  
Prostaglandin F2α ◽  
Thromboxane A2 ◽  
Femoral Arteries ◽  
Vasoactive Substances ◽  
Caudal Artery ◽  
Isolated Rat ◽  
Rat Platelets

SummaryRidogrel (6.3 × 10−6 to 10−4 M) inhibited contractions of isolated rat caudal arteries and rabbit femoral arteries caused by U-46619. The slope of an Arunlakshana-Schild plot (pA2-value: 3.4 × 10−6 M) on the caudal artery was slightly higher than one (1.14). This effect was maximal within}D min of incubation of the blood vessel with the compound and easily reversible. Ridogrel antagonised contractions of isolated rabbit femoral arteries caused by prostaglandin Fzo2α in the same concentration range. Ridogrel also inhibited contractions induced by aggregating rat platelets on isolated rat caudal arteries (itt the presence of ketanserin 4 × 10−7 M) and on isolated rabbit pulmonary and femoral arteries (in the absence of ketanserin). Ridogrel had no effect on Ca2+-induced contractions in depolarised isolated rabbit femoral arteries, and at 10−4 M antagonised serotonin-induced contractions in this blood vessel. Its effect on serotonin-induced contractions was statistically significant but very small on isolated rat caudal arteries. These observations indicate that ridogrel is an antagonist of prostaglandin endoperoxide/thromboxane A2 and prostaglandin F2α raCeptors on vascular smooth muscle.

Cigarette Smoking Increases Thromboxane A2 Formation without Affecting Platelet Survival in Young Healthy Females

1992 ◽  
Vol 68 (05) ◽  
pp. 583-588 ◽  
Author(s):  
Annika Dotevall ◽  
Christina Rångemark ◽  
Elsa Eriksson ◽  
Jack Kutti ◽  
Hans Wadenvik ◽  
...  
Keyword(s):  
Cardiovascular Disease ◽  
Cigarette Smoking ◽  
Blood Cell ◽  
Urinary Excretion ◽  
Life Span ◽  
Cell Count ◽  
Thromboxane A2 ◽  
Blood Cell Count ◽  
Platelet Activity ◽  
Pai 1

SummarySmoking is a risk factor for the development of atherosclerotic cardiovascular disease, in men as well as in women. An increased urinary excretion of the thromboxane metabolite 2,3-dinor-thromboxane B2 (Tx-M) has been observed in smokers of both genders, suggesting that cigarette smoking may facilitate cardiovascular disease via an action on the platelets. The present study addressed the hypothesis that the increased Tx-M excretion in female smokers reflects a true facilitation of platelet reactivity in vivo, rather than an increased destruction of the platelets. In healthy female volunteers (aged 20–46 years, 18 smokers and 17 non-smokers) platelet life-span and indices of platelet activity were determined, together with plasma levels of plasminogen activator inhibitor-1 (PAI-1), fibrinogen, peripheral blood cell counts and hematocrit. The urinary excretion of Tx-M was higher in smokers than in non-smokers (361 vs. 204 pg/mg creatinine, respectively, p <0.05), while plasma and urinary β-thromboglobulin, plasma platelet factor 4, platelet mean life-span and platelet production rate did not differ between the groups. PAI-1 activity, white blood cell count and hematocrit were higher in smokers than in non-smokers (p <0.05). These data indicate that smoking facilitates platelet formation of thromboxane A2 without affecting platelet survival; i.e. it increases the activity of platelets without affecting their viability to a measurable extent. Such an increase in platelet activity, operating in parallel to a reduced fibrinolytic activity and a higher hematocrit and white blood cell count, may play an etiological role in smoking-induced cardiovascular disease in women.

Neutrophil Elastase Potentiates Cathepsin G-lnduced Platelet Activation

1992 ◽  
Vol 68 (05) ◽  
pp. 570-576 ◽  
Author(s):  
Mary A Selak
Keyword(s):  
Neutrophil Elastase ◽  
Cell Activation ◽  
Thromboxane A2 ◽  
Creatine Phosphate ◽  
Dense Granule ◽  
Cathepsin G ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Low Concentrations ◽  
High Concentrations

SummaryWe have previously demonstrated that human neutrophil cathepsin G is a strong platelet agonist that binds to a specific receptor. This work describes the effect of neutrophil elastase on cathepsin G-induced platelet responses. While platelets were not activated by high concentrations of neutrophil elastase by itself, elastase enhanced aggregation, secretion and calcium mobilization induced by low concentrations of cathepsin G. Platelet aggregation and secretion were potentiated in a concentration-dependent manner by neutrophil elastase with maximal responses observable at 200 nM. Enhancement was observed when elastase was preincubated with platelets for time intervals of 10–60 s prior to addition of a low concentration of cathepsin G and required catalytically-active elastase since phenylmethanesulphonyl fluoride-inhibited enzyme failed to potentiate cell activation. Neutrophil elastase potentiation of platelet responses induced by low concentrations of cathepsin G was markedly inhibited by creatine phosphate/creatine phosphokinase and/or indomethacin, indicating that the synergism between elastase and cathepsin G required the participation of ADP and thromboxane A2. On the other hand, platelet responses were not attenuated by the PAF antagonist BN 52021, signifying that PAF-acether did not play a role in elastase potentiation. At higher concentrations porcine pancreatic elastase exhibits similar effects to neutrophil elastase, demonstrating that the effect of elastase was not unique to the neutrophil protease. While neutrophil elastase failed to alter the ability of cathepsin G to hydrolyze a synthetic chromogenic substrate, preincubation of platelets with elastase increased the apparent affinity of cathepsin G binding to platelets. In contrast to their effect on cathepsin G-induced platelet responses, neither neutrophil nor pancreatic elasatse potentiated aggregation or dense granule release initiated by ADP, PAF-acether, arachidonic acid or U46619, a thromboxane A2 mimetic. Moreover, unlike its effect on cathepsin G, neutrophil elastase inhibited thrombin-induced responses. The current observations demonstrate that elastase can potentiate platelet responses mediated by low concentrations of cathepsin G, suggesting that both enzymes may function synergistically to activate platelets under conditions where neutrophil degranulation occurs.

Hypersensitivity to Thromboxane A2 in Cholesterol-Rich Human Platelets

1990 ◽  
Vol 64 (04) ◽  
pp. 594-599 ◽  
Author(s):  
Takuya Tomizuka ◽  
Kyohei Yamamoto ◽  
Aizan Hirai ◽  
Yasushi Tamura ◽  
Sho Yoshida
Keyword(s):  
Calcium Concentration ◽  
Binding Capacity ◽  
Thromboxane A2 ◽  
Cytosolic Calcium ◽  
Cholesterol Content ◽  
Human Platelets ◽  
Dissociation Rate ◽  
Platelet Membrane ◽  
Maximal Concentration ◽  
Equilibrium Dissociation

SummaryThe effect of changes in platelet membrane cholesterol content on thromboxane A2 (TXA2)-induced platelet activation was studied. Concentrations of 9,ll-epithio-ll,12-methano-TXA2 (STA2), a stable analogue of TXA2 which can cause half-maximal aggregation and release of [14C]serotonin in cholesterol-rich platelets were significantly lower than those in cholesterol-normal platelets. STA2-induced increase in cytosolic calcium concentration and [32P]phosphatidic acid formation in cholesterol-rich platelets were significantly greater than those in cholesterol-normal platelets. The maximal concentration of binding site (Bmax) for SQ29548 was significantly increased in cholesterol-rich platelets compared with cholesterol-normal platelets, while the equilibrium dissociation rate constant (Kd) for SQ29548 did not differ between cholesterol-rich and cholesterol-normal platelets. The present study suggested that sensitivity to TXA2 was increased by the incorporation of cholesterol into platelet membrane and that the cause of hypersensitivity to TXA2 in cholesterol-rich platelets may be partly explained by an increase in binding capacity for TXA2.

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