In vitro effect of D-myo-inositol 1,2,6-trisphosphate (PP-56) on aggregation of platelets from normal and diabetic rats: relationship to malondialdehyde release and phosphoinositide pathway

1994 ◽  
Vol 72 (6) ◽  
pp. 644-649 ◽  
Author(s):  
J. C. Ruf ◽  
M. Ciavatti ◽  
T. Gustafsson ◽  
S. Renaud
Keyword(s):  
Platelet Aggregation ◽  
Inositol Phosphates ◽  
Inhibitory Effect ◽  
Diabetic Rats ◽  
Term Administration ◽  
In Vitro Effects ◽  
Vitro Effect ◽  
Induced Aggregation

In the present study, we investigated the in vitro effects of D-myo-inositol 1,2,6-trisphosphate (PP-56) on platelets from normal and streptozotocin-induced diabetic rats. PP-56 markedly inhibited aggregation, in a dose-related manner, when added in vitro, more efficiently with thrombin- than with ADP-induced aggregation and, after 90 min incubation, more in diabetic than in normal platelets. The PP-56 platelet inhibitory effect seems to be related to its phosphate content. PP-56 blocked the release of malondialdehyde from erythrocytes, but to the same extent in normal and diabetic rats. PP-56, after 20 min incubation, restored the platelet phosphoinositide turnover, which was significantly modified in diabetic rats. This last observation could explain at least part of the specificity of PP-56 for normalizing platelet aggregation in diabetic animals after long-term administration in vivo.Key words: inositol phosphates, platelet aggregation, streptozotocin-induced diabetic rats.

Inhibition of Human Platelet Aggregation by the Proteolytic Effect of Streptokinase (SK). Role of the Factor VIII Related Antigen

1975 ◽  
Author(s):  
R. Castillo ◽  
S. Maragall ◽  
J. A. Guisasola ◽  
F. Casals ◽  
C. Ruiz ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Factor Viii ◽  
Platelet Rich Plasma ◽  
Gel Filtration ◽  
Inhibitory Effect ◽  
Factor Viii Related Antigen ◽  
Human Factor Viii ◽  
Induced Aggregation

Defective ADP-induced platelet aggregation has been observed in patients treated with streptokinase. This same effect appears “in vitro” when adding SK to platelet rich plasma (PRP). Classic hemophilia and normal platelet poor plasmas (PPP) treated with SK inhibit the aggregation of washed platelets; plasmin-treated normal human serum also shows an inhibitory effect on platelet aggregation. However, von Willebrand SK-treated plasmas do not inhibit the aggregation of washed platelets. The same results appear when plasmas are previously treated with a rabbit antibody to human factor VIII.This confirms that the antiaggregating effect is mainly linked to the digested factor VIII related antigen.The inhibition of ADP-induced platelet aggregation has been proved in gel filtration-isolated and washed platelets from SK-treated PRP.Defective ristocetin-induced platelet aggregation has also been observed- This action does not appear in washed platelets from SK-treated PRP in presence of normal PPP, but it does in presence of SK-treated PPP, which suggests that the inhibition of the ristocetin-induced aggregation is due to the lack of factor VIII and not to the factor VIII-related products.Heparin, either “in vivo” or “in vitro”, has corrected the antiaggregating effect of SK.

Meseclazone, 5-Chlorosalicylic Acid and Acetylsalicvlic Acid

1978 ◽  
Vol 40 (01) ◽  
pp. 024-036 ◽  
Author(s):  
William Diamantis ◽  
William C Kohlhepp ◽  
Barbara Haertlein ◽  
John Melton ◽  
R Duane Sofia
Keyword(s):  
Platelet Aggregation ◽  
Oral Administration ◽  
Secondary Phase ◽  
Ex Vitro ◽  
Antipyretic Activity ◽  
Inflammatory Drugs ◽  
Anti Inflammatory ◽  
In Vitro Effects ◽  
Induced Aggregation

SummaryMeseclazone and its major metabolite, 5-chlorosalicylic acid (5-CSA) have been shown to possess anti-inflammatory, analgesic and antipyretic activity. The comparative effects of these compounds on platelet aggregation were evaluated in vitro and ex vitro with acetylsalicylic acid (ASA). in vitro, meseclazone and ASA exhibited almost identical inhibitory potency of secondary phase ADP aggregation while 5-CSA was less effective. Moreover, collagen aggregation was inhibited by all three agents: ASA > meseclazone > 5- CSA. Thrombin-induced aggregation was inhibited to approximately the same extent by 5- CSA and ASA while meseclazone was inactive. The in vitro effects on the release-inducing aggregants were confirmed by ex vitro experiments in rats. These demonstrated that ASA and meseclazone inhibited collagen-induced aggregation 1 and 4 hr after oral administration although ASA was three to four times more active. ASA, but not meseclazone, was still effective 24 hr after administration. Bleeding times in rats 1 and 4 hr following oral administration of meseclazone and ASA were not altered. It is concluded that meseclazone and/or 5-CSA inhibit in vitro and ex vitro platelet aggregation initiated by the release reaction similar to ASA and other non-steroidal anti-inflammatory drugs.

The In Vitro Effect of Ticlopidine on Fibrinogen and Factor VIII Binding to Human Platelets

1981 ◽  
Vol 46 (03) ◽  
pp. 590-592 ◽  
Author(s):  
Helen Lee ◽  
R C Paton ◽  
C Ruan ◽  
J P Caen
Keyword(s):  
Factor Viii ◽  
Antiplatelet Agent ◽  
Human Platelets ◽  
Dependent Manner ◽  
Fibrinogen Binding ◽  
The Mean ◽  
In Vitro Effects ◽  
Vitro Effect ◽  
Induced Aggregation

SummaryThe mode of action of the antiplatelet agent ticlopidine is not yet fully understood. Its multiple effects on platelet function include prolongation of the bleeding time, reduction in primary and secondary Waves of ADP-induced aggregation and inhibition of collagen and thrombin-induced aggregation. We have studied the in vitro effects of ticlopidine on fibrinogen binding induced by ADP and adrenaline as well as factor VIII/vWF binding induced by ristocetin. 125I-fibrinogen binding was measured in suspensions of freshly washed normal platelets stimulated by 10 μM ADP or 10 μM adrenaline. The binding of 125I-factor VIII/vWF in the presence of 1 mg/ml ristocetin was measured in both washed and paraformaldehyde-fixed platelets. Ticlopidine at final concentrations of 200, 100, 50 and 25 μM inhibited both ADP and adrenaline-induced fibrinogen binding in a dose-dependent manner. The mean % inhibition of ADP-induced fibrinogen binding was 82, 73, 42 and 32 respectively. The mean % inhibition of adrenaline induced fibrinogen binding was 86, 82, 60 and 35 respectively. In contrast, the factor VIII/vWF binding was unaffected by ticlopidine at all concentrations except at 200 μM using fresh platelets where a slight inhibition (19%) was observed.These results suggest that ticlopidine either inhibits platelet activation and consequently fibrinogen binding, or inhibits the binding directly, presumably by having an effect on the specific configuration of the platelet membrane required for normal fibrinogen binding.

Monosubstituted Coumarins Inhibit Epinephrine-Induced Platelet Aggregation Antiplatelet Effect of Monosubstituted Coumarins

2021 ◽  
Vol 19 ◽  
Author(s):  
Fausto Alejandro Jiménez-Orozco ◽  
Sergio Galicia-Zapatero ◽  
Edgar López-López ◽  
José L. Medina-Franco ◽  
Fernando León Cedeño ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
In Silico ◽  
Drug Targets ◽  
Platelet Reactivity ◽  
Antiplatelet Agents ◽  
Human Platelets ◽  
In Silico Studies ◽  
Vitro Effect ◽  
Induced Aggregation

Aim: Evaluate the in vitro effect of coumarin and 15 monosubstituted derivatives on the inhibition of human platelet aggregation induced by various pro-aggregatory agonists, particularly by epinephrine. Background: The emergence of residual platelet reactivity during the use of conventional antiplatelet agents (acetylsalicylic acid and clopidogrel) is one of the main causes of double therapy´s therapeutic failure. Platelet adrenoceptors participate in residual platelet reactivity. Therefore, it is necessary to develop new antiplatelet agents that inhibit epinephrine-induced platelet aggregation as a new therapeutic strategy. Information on the antiplatelet activity of coumarins in inhibiting epinephrine-induced aggregation is limited. Objective: Establish the structure-activity relationship (SAR) of coumarin derivatives with hydroxy, methoxy, and acetoxy groups in different positions of the coumarin nucleus to identify the most active molecules. Using in silico studies, suggest potential drug targets to which the molecules bind to produce antiplatelet effects. Methods: The platelet aggregation was performed using a Lumi-aggregometer; the inhibitory activity of 16 compounds were evaluated by inducing the aggregation of human platelets (250 × 103/μl) with epinephrine (10 µM), collagen (2 µg / ml) or ADP (10 µM). The aggregation of controls platelets was considered 100% of the response for each pro-aggregatory agonists. Results: Eleven molecules inhibited epinephrine-induced aggregation, with 3-acetoxycoumarin and 7-methoxycoumarin being the most active. Only coumarin inhibited collagen-induced platelet aggregation, but no molecule showed activity when using ADP as an inducer. Conclusions : In silico studies suggest that most active molecules might have antagonistic interactions in the adrenoceptors α2 and β2. The antiplatelet actions of these coumarins have the potential to reduce residual platelet reactivity and thus contribute to the development of future treatments for patients who do not respond adequately to conventional agents.

The In Vitro Effect Of Ticlopidine On Fibrinogen And Factor VIII Binding To Human Platelets

1981 ◽  
Author(s):  
H Lee ◽  
R C Paton ◽  
C Ruan
Keyword(s):  
Factor Viii ◽  
Human Platelets ◽  
Dependent Manner ◽  
Prolonged Bleeding Time ◽  
Fibrinogen Binding ◽  
The Mean ◽  
In Vitro Effects ◽  
Vitro Effect ◽  
Induced Aggregation

Ticlopidine is an anti-aggregating drug whose mode of action is not yet fully understood. Its multiple effects on platelet function include prolonged bleeding time, reduction in primary and secondary waves of ADP-induced aggregation and inhibition of collagen and thrombin- induced aggregation. We have studied the in vitro effects of ticlopidine on fibrinogen binding induced by ADP and adrenaline as well as Factor VIII/vWF binding induced by ristocetin. 125I fibrinogen binding was measured in suspensions of freshly-washed normal platelets stimulated by 10 μM ADP or 10 μM adrenaline. The binding of 125I-Factor VIII/vWF in the presence of 1 mg/ml ristocetin was measured in both washed and paraformaldehyde-fixed platelets. Ticlopidine at final concentrations of 200, 100, 50 and 25 μM inhibited both ADP and adrenaline-induced fibrinogen binding in a dose-dependent manner. The mean % inhibition of ADP-induced fibrinogen binding was 82, 73, 42 and 32 respectively. The mean % inhibition of adrenaline-induced fibrinogen binding was 86, 82, 60 and 35 respectively. In contrast, the Factor VIII/vWF binding was unaffected by ticlopidine at all concentrations except at 200 μM using fresh platelets where a slight inhibition (19 %) was observed.These results suggest that ticlopidine either inhibits platelet activation and consequently fibrinogen binding, or inhibits the binding directly, presumably by having an effect on the specific configuration of the platelet membrane required for normal fibrinogen binding.

GUARANA (Paullinia cupana) INHIBITS AGGREGATION IN WHOLE BLOOD

1987 ◽  
Author(s):  
D A F Chamone ◽  
M Ivany-Silva ◽  
C Cassaro ◽  
G Bellotti ◽  
C Massumoto ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Whole Blood ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Oral Intake ◽  
Inhibitory Effect ◽  
Impedance Method ◽  
Paullinia Cupana ◽  
Induced Aggregation

Guarana, a methylxanthine obtained from the seeds of Paullinia cupana has been largely used in the Amazon region by native indians during centuries as stimulant. We evaluated the effect of guarana on ex-vivo and in vitro platelet aggregation induced by adenosine-5-diphosphate (ADP) in human and rat whole blood with an impedance (Chrono-Log, model 500) and in their platelet rich plasma (PRP) with an optical aggregometer (Chrono-Log, model 440). Ex-vivo studies were carried out after single oral intake of guarana. Seven healthy volunteers (5 male and 2 female) aged 19-26 years who had taken no drugs for 10 days before, ingested 8gm of crude powder of guarana. Blood samples were drawn before and 1 hour after guarana intake. We observed a significative inhibition of platelet aggregation in whole blood meanwhile PRP was un changed as compared to basal values. In vitro studies were performed in whole blood and PRP from human volunteers and male Wis-tar rats. The combined effect of guarana and adenosine was also studied. A control aggregation was always run with saline. The results demonstrated an inhibition statistically significative (p < 0.001) of platelet aggregation in whole blood. Differently from whole blood the PRP with the same concentration of guarana did not result in inhibition of ADP induced aggregation when eva luated with the impedance method. The blood incubation with adenosine and guarana resulted in synergistic inhibitory effect that was much more strinking in whole blood than in PRP. Guarana fails to inhibit aggregation of rat platelets.Our results demonstrate that guarana prevents platelet aggregation in whole blood which depends on red blood cells, probably involving adenosine.

Lu 23051, A New Potent Inhibitor Of Platelet Aggregation

1981 ◽  
Author(s):  
H D Lehmann ◽  
J Gries ◽  
D Lenke
Keyword(s):  
Platelet Aggregation ◽  
Ex Vivo ◽  
Platelet Rich Plasma ◽  
Coronary Vessels ◽  
Inhibitory Effect ◽  
Spontaneously Hypertensive ◽  
Dependent Inhibition ◽  
Induced Aggregation

6- [p-(2-(Chiorpropionylamino)phenyl] -4.5-dihydro-5-methyl-3(2H)-pyridazinone, LU 23051, is primarily characterized by its strong inhibition of platelet aggregation under in vitro and in vivo conditions. In vitro there is a concentration-dependent inhibition of ADP and collagen induced aggregation in platelet rich plasma of man, rat and dog. The inhibitory concentration EC 33 % is 0.0010-0.030 mg/1 (man: ADP-0.030, col 1.-0.013 mg/l) depending on species and type of aggregation. When administered orally in ex vivo experiments on rats and dogs the substance is found to have a dose-dependent antiaggregatory effect in the range from 0.1-3.16 mg/kg. The ED 33 % is 0.27-0.63 mg/kg.-In addition after oral administration the substance has a good inhibitory effect in models being based on intravascular platelet aggregation. Thus, a dose of 1 mg/kg inhibits laser-induced aggregation in mesenteric venules of rats. Mortality after i.v. injection of collagen in mice is reduced by 50 % after a dose of 0.02 mg/kg. A dose of 0.039 mg/kg prolongs the bleeding time of rats by 50 %. The aggregation-inhibiting action is of long duration (0.1 mg/kg p.o.∼24 h). The substance does not interfere with clotting.Besides its effect on platelet aggregation LU 23051 acts as vasodilatator as well. Dilatation of coronary vessels by 100 % is seen in isolated guinea-pig hearts at a concentration of 0.1 mg/l. In spontaneously hypertensive rats the substance has an anti hypertensive effect. The ED 20 % is 0.36 mg/kg p.o.The combination of antiaggregatory and vasodilatatory effects opens up interesting aspects with respect to the pharmacotherapeutic use of the new substance

Effects “in Vitro” of Some Cardiovascular Drugs and Other Agents on Human Platelet Aggregation

1973 ◽  
Vol 29 (01) ◽  
pp. 190-195 ◽  
Author(s):  
G Sacchetti ◽  
D Bellani ◽  
C Montanari ◽  
A Gibelli
Keyword(s):  
Platelet Aggregation ◽  
Mechanism Of Action ◽  
Human Platelet ◽  
Cardiovascular Drugs ◽  
Blocking Drug ◽  
Human Platelet Aggregation ◽  
Vitro Effect ◽  
Induced Aggregation

SummaryThe in vitro effect of the following substances on human platelet aggregation is studied: K 4423 (a ß-blocking drug), isoproterenol, phentolamine, papaverine, methamidoline (a myolytic agent).None of these substances causes aggregation. All inhibit aggregation induced by ADP or noradrenaline, except for phentolamine, which is active only on noradrenaline- induced aggregation.Hypothesis on the mechanism of action of the compounds tested are proposed.

Inhibitory effects of antibiotics on platelet aggregation in vitro

1997 ◽  
Vol 16 (11) ◽  
pp. 662-666 ◽  
Author(s):  
Hiroko Kariyazono ◽  
Kazuo Nakamura ◽  
Terutoshi Shinkawa ◽  
Yukinori Moriyama ◽  
Hitoshi Toyohira ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Blood Concentration ◽  
Chemical Structure ◽  
Inhibitory Action ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Carboxyl Group ◽  
Inhibitory Effects ◽  
Induced Aggregation

1 We evaluated in vitro inhibitory effects of six types of antibiotic, aztreonam (AZT), cefamandole (CMD), cefmetazole (CMZ), cefotiam (CTM), flomoxef (FMOX) and latamoxef (LMOX), on platelet aggregation, using healthy volunteers' blood. Four types-FMOX, LMOX, CTM and CMD-inhibited, in concentration of 2500 ?g/ml, the secondary aggregation induced by 3.0 ?M adenosine diphosphate (ADP), and also inhibited the aggregation induced by 0.5 ?g/ml collagen. AZT in the same concentration, did not inhibit the aggregation induced by collagen, and it inhibited only ADP induced aggregation. CMZ, in the same concentration, inhibited neither of the two aggregations. 2 The inhibitory effects of the antibiotics on collagen- induced aggregation were dependent on the concen tration of respective antibiotics. When classified by the strength of inhibitory action, LMOX and FMOX were strong, followed by CTM and CMD. The action of AZT and CMZ was weak. In particular, LMOX showed a 32% inhibitory effect at concentration of 50 ?g/ml, a level near the blood concentration obtained with clinical usual dose. 3 No relationship was observed between inhibitory effects of antibiotics on ADP- or collagen-induced aggregation and the presence or absence of carboxyl group and/or N-methyltetrazolethiol group in the chemical structure.

In Vitro Effect of Ethanol on ADP and Collagen-Induced Platelet Aggregation

1981 ◽  
Vol 46 (04) ◽  
pp. 673-675 ◽  
Author(s):  
Stig Bengmark ◽  
Olle Elmér ◽  
Göran Göransson ◽  
Evita Zoucas
Keyword(s):  
Platelet Aggregation ◽  
Ethanol Concentration ◽  
Platelet Rich Plasma ◽  
Rat Plasma ◽  
Rabbit Plasma ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Vitro Effect ◽  
Induced Aggregation

SummaryPlatelet aggregation was measured by Born’s method. Plasma from Sprague-Dawley rats and inbred albino rabbits was used. 20% ethanol in 0.9%(w/v) NaCl was added to plasma at final concentrations of 56.5 mM, 85.9 mM 171.5 mM and 343.1 mM or to whole blood at final concentrations of 8.7 mM, 17.4 mM, 52.5 mM, 171.5 mM and 343.1 mM. Experiments using 0.9% NaCl volumes equivalent to the added ethanol volume were also conducted. Dose-response aggregation tests showed that a decrease in ADP-and collagen-induced aggregation existed when ethanol was mixed with rat or rabbit blood prior to the preparation of platelet-rich plasma. There was no effect on ADP-induced platelet aggregation when ethanol was mixed with rat or rabbit plasma. Collagen-induced aggregation was impaired only in rat plasma when ethanol concentration reached 343.1 mM. These results suggested that ethanol modified platelet function possibly via red cells.

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