The Inhibition of Platelet Aggregation by an Aorta Intima Extract

1974 ◽  
Vol 32 (02/03) ◽  
pp. 417-431 ◽  
Author(s):  
A. du P Heyns ◽  
D. J van den Berg ◽  
G. M Potgieter ◽  
F. P Retief
Keyword(s):  
Platelet Aggregation ◽  
Degradation Products ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Protective Role ◽  
Vascular Trauma ◽  
Wear And Tear ◽  
Sequential Addition ◽  
Aggregation Activity

SummaryThe platelet aggregating activity of extracts of different layers of the arterial wall was compared to that of Achilles tendon. Arterial media and tendon extracts, adjusted to equivalent protein content as an index of concentration, aggregated platelets to the same extent but an arterial intima extract did not aggregate platelets. Platelet aggregation induced by collagen could be inhibited by mixing with intima extract, but only to a maximum of about 80%. Pre-mixing adenosine diphosphate (ADP) with intima extracts diminished the platelet aggregation activity of the ADP. Depending on the relationship between ADP and intima extract concentrations aggregating activity could either be completely inhibited or inhibition abolished. Incubation of ADP with intima extract and subsequent separation of degradation products by paper chromatography, demonstrated a time-dependent breakdown of ADP with AMP, adenosine, inosine and hypoxanthine as metabolic products; ADP removal was complete. Collagen, thrombin and adrenaline aggregate platelets mainly by endogenous ADP of the release reaction. Results of experiments comparing inhibition of aggregation caused by premixing aggregating agent with intima extract, before exposure to platelets, and the sequential addition of first the intima extract and then aggregating agent to platelets, suggest that the inhibitory effect of intima extract results from ADP breakdown. It is suggested that this ADP degradation by intima extract may play a protective role in vivo by limiting the size of platelet aggregates forming at the site of minimal “wear and tear” vascular trauma.

scholarly journals Inhibitory Effects of Two Ferulates from Angelica Sinensis on Platelet Aggregation and Oxytocin-induced Uterine Contraction

2009 ◽  
Vol 2 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Y. Yu ◽  
B. Q. Lin ◽  
L. Yu ◽  
Y. Q. Hua ◽  
J. A. Duan ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Uterine Contraction ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Angelica Sinensis ◽  
Hydrophobic Property ◽  
Antiplatelet Aggregation ◽  
Aggregation Activity

Ferulic acid (FA) is widely considered as a biologically active component in Angelica sinensis, and used as one of the marker compounds for the quality control of Angelica sinensis. However, in A. sinensis, FA mainly exists as its ester, coniferyl ferulate (CF). CF is unstable and readily hydrolyzed into FA during conventional extraction. Herein, their antiplatelet aggregation activities and relaxant effects on oxytocin-induced mouse uterine muscle contraction were investigated and compared. The results showed that FA inhibited arachidonic acid (AA), adenosine diphosphate (ADP) and thrombin (THR)-induced platelet aggregation with IC50 values of 974.8 ± 97.5, 737.9 ± 40.2 and 244.6 ± 25.6 μg/ml, respectively. The potency of CF is much higher than that of FA, and the IC50 values for AA, ADP and THR were 7.1 ± 0.3, 276.4 ± 53.4 and 77.5 ± 23.1 μg/ml, respectively. IC50 of FA was 23.8 ± 6.2 μg/ml for oxytocin-induced uterine contraction in vitro. CF could only be tested at low concentration and its IC50 could not be calculated thereafter because of its strong hydrophobic property. So CF has more potent antiplatelet aggregation activity, while FA has stronger inhibitory effect on oxytocin-induced uterine contraction in vitro

Effects of N-(2-Diethylaminoethyl)-N-(2-hydroxy- 2-phenylethyl)-2,5-dichloroaniline (AN 162) on Platelet Function and Blood Coagulation

1971 ◽  
Vol 26 (03) ◽  
pp. 576-587
Author(s):  
R. D Mac Kenzie ◽  
T. R Blohm
Keyword(s):  
Platelet Aggregation ◽  
Blood Clotting ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Clotting Time ◽  
Clotting Factors ◽  
Platelet Factor ◽  
Inhibition Of Platelet Aggregation

SummaryWhen AN 162 was added to human citrated platelet-rich plasma at 30-300 µg/ml, it inhibited platelet aggregation induced by adenosine diphosphate, collagen, and thrombin. When AN 162 was given orally to guinea pigs at 30 to 100 mg/kg, an in vivo inhibitory effect on platelet aggregability was found. Though it activated platelet factor 3, the concentration of AN 162 required for substantial activation was greater than that for inhibition of platelet aggregation. No effect on plasma clotting factors was found at or below 300 µg/ml. Slight prolongation of whole blood clotting time was found in the rat and monkey.

Accumulation of Macromolecular Particles in the Reticuloendothelial System (RES) Mediated by Platelet Aggregation and Disaggregation

1969 ◽  
Vol 22 (03) ◽  
pp. 496-507 ◽  
Author(s):  
W.G van Aken ◽  
J Vreeken
Keyword(s):  
Platelet Aggregation ◽  
Degradation Products ◽  
Reticuloendothelial System ◽  
Caproic Acid ◽  
Carbon Particles ◽  
Carbon Clearance ◽  
Aggregation And Disaggregation ◽  
Platelet Aggregates

SummaryCarbon particles cause platelet aggregation in vitro and in vivo. Prior studies established that substances which modify thrombocyte aggregation also influence the rate at which carbon is cleared from the blood.This study was performed in order to elucidate the mechanism by which the carbon-platelet aggregates specifically accumulate in the RES.Activation of fibrinolysis by urokinase or streptokinase reduced the carbon clearance rate, probably due to generated fibrinogen degradation products (FDP). Isolated FDP decreased the carbon clearance and caused disaggregation of platelets and particles in vitro. Inhibition of fibrinolysis by epsilon-amino-caproic acid (EACA), initially accelerated the disappearance of carbon and caused particle accumulation outside the RES, predominantly in the lungs. It is supposed that platelet aggregation and locally activated fibrinolysis act together in the clearance of particles. In the normal situation the RES with its well known low fibrinolytic activity, becomes the receptor of the particles.

Inhibitory Effect of Staphylokinase on Platelet Aggregation

1993 ◽  
Vol 70 (05) ◽  
pp. 834-837 ◽  
Author(s):  
Akira Suehiro ◽  
Yoshio Oura ◽  
Motoo Ueda ◽  
Eizo Kakishita
Keyword(s):  
Platelet Aggregation ◽  
Human Platelet ◽  
Degradation Products ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Effective Concentration ◽  
Inhibit Platelet Aggregation ◽  
Platelet Suspension ◽  
Washed Platelet ◽  
Human Platelet Aggregation

SummaryWe investigated the effect of staphylokinase (SAK), which has specific thrombolytic properties, on human platelet aggregation. Platelet aggregation induced with collagen was observed following preincubation of platelets in platelet-rich plasma (PRP) or washed platelet suspension (WP) with SAK at 37° C for 30 min. SAK inhibited platelet aggregation in PRP only at the highest examined concentration (1 x 10-4 g/ml). Although SAK did not inhibit platelet aggregation in WP which contained fibrinogen, it did when the platelets had been preincubated with SAK and plasminogen. The most effective concentration in WP was 1 x 10-6 g/ml. The effect could be inhibited by adding aprotinin or α2-antiplasmin. The highest generation of plasmin in the same preincubation fluid was detected at 1 x 10-6 g/ml SAK. We concluded that SAK can inhibit platelet aggregation in WP by generating plasmin and/or fibrinogen degradation products, but is only partially effective in PRP because of the existence of α2-antiplasmin.

The Effects of Brinolase (Fibrinolytic Enzyme from Aspergillus Oryzae) on Platelet Aggregation of Dog and Man

1972 ◽  
Vol 28 (01) ◽  
pp. 031-048 ◽  
Author(s):  
W. H. E Roschlau ◽  
R Gage
Keyword(s):  
Platelet Aggregation ◽  
Aspergillus Oryzae ◽  
Degradation Products ◽  
Blood Platelet ◽  
Human Platelets ◽  
Fibrinolytic Enzyme ◽  
Inhibitory Effects ◽  
Blood Platelet Aggregation

SummaryInhibition of blood platelet aggregation by brinolase (fibrinolytic enzyme from Aspergillus oryzae) has been demonstrated with human platelets in vitro and with dog platelets in vivo and in vitro, using both ADP and collagen as aggregating stimuli. It is suggested that the optimal inhibitory effects of brinolase occur indirectly through the generation of plasma fibrinogen degradation products, without compromising platelet viability, rather than by direct proteolysis of platelet structures.

Some Effects of Fibrinogen Degradation Products (FDP) on Blood Platelets

1966 ◽  
Vol 15 (03/04) ◽  
pp. 413-419 ◽  
Author(s):  
Z Jerushalmy ◽  
M. B Zucker
Keyword(s):  
Platelet Aggregation ◽  
Connective Tissue ◽  
Degradation Products ◽  
Blood Platelets ◽  
Adenosine Diphosphate ◽  
Serotonin Release ◽  
Fibrinogen Degradation Products ◽  
Inhibition Of Platelet Aggregation

Summary“Early” fibrinogen degradation products are more potent inhibitors of thrombin-induced clotting than “late” products and also interfere with the ability of thrombin to release serotonin from platelets. “Early” and “intermediate” FDP cause moderate inhibition of platelet aggregation induced by adenosine diphosphate or connective tissue particles. Serotonin release by connective tissue particles is probably not inhibited by FDP.

The Effect of Barbituric Acid Derivatives on Platelet Function in Vitro and in Vivo

1973 ◽  
Vol 30 (02) ◽  
pp. 315-326
Author(s):  
J. Heinz Joist ◽  
Jean-Pierre Cazenave ◽  
J. Fraser Mustard
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Barbituric Acid ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Primary Response ◽  
Sodium Pentobarbital ◽  
Barbituric Acid Derivatives

SummarySodium pentobarbital (SPB) and three other barbituric acid derivatives were found to inhibit platelet function in vitro. SPB had no effect on the primary response to ADP of platelets in platelet-rich plasma (PRP) or washed platelets but inhibited secondary aggregation induced by ADP in human PRP. The drug inhibited both phases of aggregation induced by epinephrine. SPB suppressed aggregation and the release reaction induced by collagen or low concentrations of thrombin, and platelet adherence to collagen-coated glass tubes. The inhibition by SPB of platelet aggregation was readily reversible and isotopically labeled SPB did not become firmly bound to platelets. No inhibitory effect on platelet aggregation induced by ADP, collagen, or thrombin could be detected in PRP obtained from rabbits after induction of SPB-anesthesia.

Platelet Aggregation in Whole Blood: The Role of Thromboxane A2 and Adenosine Diphosphate

1985 ◽  
Vol 54 (03) ◽  
pp. 612-616 ◽  
Author(s):  
A J Carter ◽  
S Heptinstall
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Adenosine Diphosphate ◽  
Blood Platelet ◽  
Thromboxane B2 ◽  
Lipoxygenase Inhibitor ◽  
Thromboxane Synthase Inhibitor ◽  
Synthase Inhibitor

SummaryThe platelet aggregation that occurred in whole blood in response to several aggregating agents (collagen, arachidonic acid, adenosine diphosphate, adrenaline and thrombin) was measured using an Ultra-Flo 100 Whole Blood Platelet Counter. The amounts of thromboxane B2 produced were measured by radioimmunoassay. The effects of various inhibitors of thromboxane synthesis and the effects of apyrase, an enzyme that destroys adenosine diphosphate, were determined.Platelet aggregation was always accompanied by the production of thromboxane B2, and the amounts produced depended on the nature and concentration of the aggregating agent used. The various inhibitors of thromboxane synthesis - aspirin and flurbiprofen (cyclo-oxygenase inhibitors), BW755C (a cyclo-oxygenase and lipoxygenase inhibitor) and dazoxiben (a selective thromboxane synthase inhibitor) - did not markedly inhibit aggregation. Results obtained using apyrase showed that adenosine diphosphate contributed to the aggregation process, and that its role must be acknowledged when devising means of inhibiting platelet aggregation in vivo.

Inhibition of Platelet Function by Antiarrhythmic Drugs, Verapamil and Disopyramide

1982 ◽  
Vol 47 (02) ◽  
pp. 150-153 ◽  
Author(s):  
P Han ◽  
C Boatwright ◽  
N G Ardlie
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Antiarrhythmic Drugs ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Second Phase ◽  
Ionophore A23187 ◽  
High Concentrations ◽  
Artery Disease

SummaryVarious cardiovascular drugs such as nitrates and propranolol, used in the treatment of coronary artery disease have been shown to have an antiplatelet effect. We have studied the in vitro effects of two antiarrhythmic drugs, verapamil and disopyramide, and have shown their inhibitory effect on platelet function. Verapamil, a calcium channel blocker, inhibited the second phase of platelet aggregation induced by adenosine diphosphate (ADP) and inhibited aggregation induced by collagen. Disopyramide similarly inhibited the second phase of platelet aggregation caused by ADP and aggregation induced by collagen. Either drug in synergism with propranolol inhibited ADP or collagen-induced platelet aggregation. Disopyramide at high concentrations inhibited arachidonic add whereas verapamil was without effect. Verapamil, but not disopyramide, inhibited aggregation induced by the ionophore A23187.

Opposite Effect of Lysine on Platelet Aggregation Induced by Arachidonate and by Other Aggregants

1982 ◽  
Vol 48 (01) ◽  
pp. 078-083 ◽  
Author(s):  
C Ts'ao ◽  
S J Hart ◽  
D V Krajewski ◽  
P G Sorensen
Keyword(s):  
Platelet Aggregation ◽  
Secondary Phase ◽  
Aminocaproic Acid ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Primary Phase ◽  
High Doses ◽  
The Many ◽  
Induced Aggregation

SummaryEarlier, we found that ε-aminocaproic acid (EACA) inhibited human platelet aggregation induced by adenosine diphosphate (ADP) and collagen, but not aggregation by arachidonic acid (AA). Since EACA is structurally similar to lysine, yet these two agents exhibit vast difference in their antifibrinolytic activities, we chose to study the effect of lysine on platelet aggregation. We used L-lysine-HCl in these studies because of its high solubility in aqueous solutions while causing no change in pH when added to human plasma. With lysine, we repeatedly found inhibition of ADP-, collagen- and ristocetin-induced aggregation, but potentiation of AA-induced aggregation. Both the inhibitory and potentiation effects were dose-dependent. Low doses of lysine inhibited the secondary phase of aggregation; high doses of it also inhibited the primary phase of aggregation. Potentiation of AA-induced aggregation was accompanied by increased release of serotonin and formation of malondialdehyde. These effects were not confined to human platelets; rat platelets were similarly affected. Platelets, exposed to lysine and then washed and resuspended in an artificial medium not containing lysine, remained hypersensitive to AA, but no longer showed decreased aggregation by collagen. Comparing the effects of lysine with equimolar concentrations of sucrose, EACA, and α-amino-n-butyric acid, we attribute the potent inhibitory effect of lysine to either the excess positive charge or H+ and C1− ions. The -NH2 group on the α-carbon on lysine appears to be the determining factor for the potentiation effect; the effect seems to be exerted on the cyclooxygenase level of AA metabolism. Lysine and other chemicals with platelet-affecting properties similar to lysine may be used as a tool for the study of the many aspects of a platelet aggregation reaction.

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