Sevoflurane Does Not Inhibit Human Platelet Aggregation Induced by Thrombin

Background Sevoflurane reportedly inhibits adenosine diphosphate-induced platelet aggregation by suppressing thromboxane A2 formation. The increase in intracellular calcium concentration that fosters platelet aggregation, however, is also induced by other cell signaling pathways, such as activation of the production of inositol 1,4,5-triphosphate by thrombin. The current study aimed to clarify the net influence of sevoflurane on thrombin-induced platelet aggregation. Methods Washed platelets were stimulated by thrombin after incubation with 0.5, 1.0, or 1.5 mM sevoflurane, halothane, or isoflurane. Aggregation curves were measured by an aggregometer. Intracellular calcium concentration was measured fluorometrically using fura-2. Calcium mobilization via plasma membrane calcium channels and the dense tubular system was assessed differentially. Intracellular inositol 1,4,5-triphosphate was measured by radioimmunoassay. Results Halothane significantly suppressed aggregation ratios at 5 min compared with those in controls (89 +/- 7%) to 71 +/- 10% (1.0 mM) and 60 +/- 11% (1.5 mM) and the increase in intracellular calcium concentration (controls, 821 +/- 95 nM vs. 440 +/- 124 nM [1.0 mM] or 410 +/- 74 nM [1.5 mM]). Halothane also significantly inhibited release of calcium from the dense tubular system (controls, 220 +/- 48 nM vs. 142 +/- 31 nM [1.0 mM]). Neither sevoflurane nor isoflurane produced a net change in aggregation ratios, intracellular calcium concentration, or calcium mobilization. Halothane (1 mM) significantly suppressed inositol 1,4,5-triphosphate concentrations, whereas neither 1 mM isoflurane nor 1 mM sevoflurane had any effect. Conclusions Although sevoflurane has been reported to inhibit human platelet aggregation induced by weak agonists such as adenosine diphosphate, it does not inhibit human platelet aggregation induced by strong agonists such as thrombin.

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Effects of barbiturates on human platelet aggregation differ depending on their chemical structures

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y03-075 ◽

2003 ◽

Vol 81 (8) ◽

pp. 806-814 ◽

Cited By ~ 1

Author(s):

Masami Sato ◽

Hideo Hirakata ◽

Masahiro Ikeda ◽

Kazuhiko Fukuda

Keyword(s):

Platelet Aggregation ◽

Calcium Concentration ◽

Light Transmission ◽

Human Platelet ◽

Clinical Importance ◽

Cytosolic Calcium ◽

Free Calcium ◽

Chemical Structures ◽

Human Platelet Aggregation ◽

Inositol 1,4,5 Trisphosphate

The effects of barbiturates on human platelet function are not fully understood. Since we have already revealed the effects and mechanisms of thiopental, thiamylal, and pentobarbital in platelets, the present study attempted to elucidate (i) the effects of other barbiturates on human platelet aggregation, (ii) the underlying mechanisms, and (iii) the structurefunction relationship of barbiturates in platelets. Barbiturates, including amobarbital, butalbital, secobarbital, barbital, phenobarbital, metharbital, and primidone, were examined. Human platelet aggregation induced by adenosine diphosphate (ADP), epinephrine, and (+)-9,11-epithia-11,12-methano-thromboxane A2 (STA2), a thromboxane A2 analog, was measured using an 8-channel light-transmission aggregometer. The cytosolic free calcium concentration ([Ca2+]i) was measured by fluorometer using fura-2 loaded platelets. Inositol 1,4,5-trisphosphate (IP3) formation induced by STA2 was determined by a commercially available IP3 assay kit. Amobarbital, butalbital, and secobarbital suppressed ADP-, epinephrine- and STA2-induced platelet aggregation and the STA2-induced [Ca2+]i increase, even when Ca2+ influx was blocked by Ni2+. However, they did not affect STA2-induced IP3 formation. Barbital, phenobarbital, metharbital, and primidone (up to 1 mM) had no effect on ADP- and epinephrine-induced platelet aggregation. Thus, we conclude that amobarbital, butalbital, and secobarbital inhibit platelet aggregation by suppressing [Ca2+]i increase without affecting IP3 formation. However, these antiaggregatory effects may not have clinical importance, since the barbiturate concentrations used were higher than clinically relevant ones. The other tested barbiturates had no effects on platelet aggregation. The data indicate that the effects of barbiturates on platelet aggregation differ depending on their chemical structures.Key words: platelet aggregation, barbiturates, cytosolic calcium concentration, inositol 1,4,5-trisphosphate.

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Inhibitory Effect of Hexahydrocurcumin on Human Platelet Aggregation

Natural Product Communications ◽

10.1177/1934578x1200700719 ◽

2012 ◽

Vol 7 (7) ◽

pp. 1934578X1200700 ◽

Cited By ~ 3

Author(s):

Huei-Ping Dong ◽

Rei-Cheng Yang ◽

I-Chun Chunag ◽

Li-Ju Huang ◽

Hsing-Tan Li ◽

...

Keyword(s):

Platelet Aggregation ◽

Human Platelet ◽

Platelet Rich Plasma ◽

Adenosine Diphosphate ◽

Inhibitory Effect ◽

Human Platelet Aggregation

The effects of hexahydrocurcumin on adenosine diphosphate (ADP)-induced human platelet aggregation were studied. Treatment of human platelet-rich plasma with hexahydrocurcumin resulted in an inhibitory effect on platelet aggregation, suggesting the potential of this compound as an anti-atherosclerogenic agent in humans.

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The effects of an ASA-like hydroperoxide compound on adenosine diphosphate induced platelet aggregation

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y84-053 ◽

1984 ◽

Vol 62 (3) ◽

pp. 338-340

Author(s):

J. J. F. Killackey ◽

B. A. Killackey ◽

I. Cerskus ◽

R. B. Philp

Keyword(s):

Platelet Aggregation ◽

Acetylsalicylic Acid ◽

Pharmacological Property ◽

Human Platelet ◽

Adenosine Diphosphate ◽

Second Phase ◽

Release Reaction ◽

Human Platelet Aggregation ◽

Second Phases ◽

Induced Aggregation

A hydroperoxide compound structurally related to acetylsalicylic acid, 3-hydroperoxy-3-methylphthalide, inhibits both the first and second phases of adenosine diphosphate induced, biphasic, human platelet aggregation. This occurs over the same concentration range (0.05–0.5 mM) that acetylsalicylic acid inhibits second phase aggregation and the release reaction only. The complete inhibition of adenosine diphosphate induced aggregation is a unique pharmacological property for an acetylsalicylic-acid-like compound.

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Ketamine Suppresses Platelet Aggregation Possibly by Suppressed Inositol Triphosphate Formation and Subsequent Suppression of Cytosolic Calcium Increase

Anesthesiology ◽

10.1097/00000542-200205000-00018 ◽

2002 ◽

Vol 96 (5) ◽

pp. 1147-1152 ◽

Cited By ~ 31

Author(s):

Takefumi Nakagawa ◽

Hideo Hirakata ◽

Masami Sato ◽

Kumi Nakamura ◽

Yoshio Hatano ◽

...

Keyword(s):

Platelet Aggregation ◽

Calcium Concentration ◽

Human Platelet ◽

Free Calcium ◽

Guanosine Triphosphate ◽

Cytosolic Free Calcium ◽

Human Platelet Aggregation ◽

Free Calcium Concentration ◽

Cytosolic Free Calcium Concentration ◽

Txa2 Receptor

Background Ketamine has been shown to suppress platelet aggregation, but its mechanisms of action have not been defined. The purpose of the current study is to clarify the effects of ketamine on human platelet aggregation and to elucidate the underlying mechanisms of its action. Methods Platelet aggregation was measured using an eight-channel aggregometer, and cytosolic free calcium concentration was measured in Fura-2/AM-loaded platelets using a fluorometer. Inositol 1,4,5-triphosphate (IP3) was measured with use of a commercially available IP3 assay kit. To estimate thromboxane A2 (TXA2) receptor binding affinity and expression, Scatchard analysis was performed using [3H]S145, a specific TXA2 receptor antagonist. TXA2 agonist binding assay was also performed. The membrane-bound guanosine 5'-triphosphatase activity was determined using [gamma-32P]guanosine triphosphate by liquid scintillation analyzer. Results Ketamine (500 microm) suppressed aggregation induced by adenosine diphosphate (0.5 microm), epinephrine (1 microm), (+)-9,11-epithia-11,12-methano-TXA2 (STA2) (0.5 microm), and thrombin (0.02 U/ml) to 39.1 +/- 30.9, 46.3 +/- 4.3, -2.0 +/- 16.8, and 86.6 +/- 1.4% of zero-control, respectively. Ketamine (250 microm-1 mm) also suppressed thrombin- and STA2-induced cytosolic free calcium concentration increase dose dependently. Although ketamine (2 mm) had no effect on TXA2 receptor expression and its binding affinity, it (1 mm) suppressed intracellular peak IP3 concentrations induced by thrombin and STA2 from 6.60 +/- 1.82 and 4.39 +/- 2.41 to 2.41 +/- 0.98 and 1.90 +/- 0.86 pmol/109 platelets, respectively, and it suppressed guanosine triphosphate hydrolysis induced by thrombin (0.02 units/ml) and STA2 (0.5 microm) to 50.3 +/- 3.2 and 67.5 +/- 5.5% versus zero-control, respectively. Conclusion Ketamine inhibits human platelet aggregation possibly by suppressed IP3 formation and subsequent suppression of cytosolic free calcium concentration. The site of action of ketamine is neither TXA2 nor thrombin binding sites but possibly receptor-coupled mechanisms, including G-protein.

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Macrostachyols A-D, oligostilbenes from Gnetum macrostachyum inhibited in vitro human platelet aggregation

Journal of Herbmed Pharmacology ◽

10.34172/jhp.2021.39 ◽

2021 ◽

Vol 10 (3) ◽

pp. 339-343

Author(s):

Serm Surapinit ◽

Nuttakorn Baisaeng

Keyword(s):

Platelet Aggregation ◽

Human Platelet ◽

Adenosine Diphosphate ◽

Positive Control ◽

Inhibitory Effects ◽

Aggregation Assay ◽

Human Platelet Aggregation ◽

Platelet Aggregation Assay ◽

Inhibitory Activities

Introduction: Gnetum macrostachyum is a known Thai medicinal plant as a source of bioactive oligostilbenes, which possess platelet inhibitory activities. The study aimed to evaluate the in vitro human platelet aggregation inhibitory activities of macrostachyols A-D (compounds 1-4) isolated from the roots of G. macrostachyum. Methods: The in vitro human platelet aggregation assay was assayed with a 96-well microtiter plate format. The well-known aggregating agents were used to investigate the possible mechanism of inhibition, including adenosine diphosphate (ADP), arachidonic acid (AA), thromboxane A2 analog (U-46619), collagen, thrombin, and thrombin receptor-activating peptide-6 (TRAP-6). Results: Compound 1 was more potent than ibuprofen (positive control) on the adenosine diphosphate- induced platelet aggregation assay (P < 0.05). Compound 3 was more potent than 1, 2, and 4 (P < 0.05), but all active oligostilbenes were less potent than the positive control (P < 0.05) on the arachidonic acid-induced platelet aggregation assay. The oligostilbenes 1, 2, 3, and 4 also displayed the inhibitory effects on the U-46619-induced platelet aggregation. The tetrameric stilbenes 1 was the only compound that exhibited inhibitory effects on thrombin-induced platelet aggregation without TRAP-6 mediated platelet aggregation. Conclusion: The findings revealed the inhibitory effects of oligostilbenes on human platelet aggregation through a target-specific experimental design. It suggests that oligostilbenes from this plant might be applied as antiplatelet aggregation agents in platelet hyperreactivity- related diseases.

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Fibrinogen Binding Is Independent of an Increase in Intracellular Calcium Concentration in Thrombin Degranulated Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653769 ◽

1995 ◽

Vol 73 (02) ◽

pp. 304-308 ◽

Cited By ~ 4

Author(s):

Fabio M Pulcinelli ◽

James L Daniel ◽

Silvia Riondino ◽

Pier Paolo Gazzaniga ◽

Leon Salganicoff

Keyword(s):

Platelet Aggregation ◽

Intracellular Calcium ◽

Binding Sites ◽

Calcium Concentration ◽

Calcium Release ◽

Shape Change ◽

Cytosolic Calcium ◽

Calcium Mobilization ◽

Induce Platelet Aggregation ◽

Fibrinogen Binding

SummaryIn a suspension of thrombin degranulated platelets (TDP), ADP and epinephrine can induce platelet aggregation, whereas the synthetic agonist of the thromboxane/endoperoxide receptor U46619 causes only shape change. However, U46619 can enhance platelet aggregation induced by ADP and epinephrine. In this paper, we have measured fibrinogen binding in relation to phospholipase C(PLC) activation and calcium mobilization in TDP activated by ADP, epinephrine and U46619.ADP caused fibrinogen binding in TDP but neither activated PLC nor caused a calcium mobilization. The requirement for ADP in inducing exposure of fibrinogen binding sites was not absolute since the combination of epinephrine and U46619 produced an increase in fibrinogen binding. U46619 caused significant PLC activation and cytosolic calcium release but not fibrinogen binding. These results suggest that in TDP the exposure of fibrinogen binding sites, after agonist activation, is independent of both PLC activation and calcium mobilization.

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Human Platelet Aggregation In Response To Multiple Agonists In Plasma Anticoagulated With Heparin

10.1055/s-0038-1652597 ◽

1981 ◽

Author(s):

H A Culliver ◽

N G Ardlie

Keyword(s):

Platelet Aggregation ◽

Platelet Activation ◽

Human Platelet ◽

Platelet Rich Plasma ◽

Adenosine Diphosphate ◽

Human Platelet Aggregation

The lowest concentrations at which epinephrine and vasopressin have been reported to interact positively in causing platelet aggregation in vitro are at least two orders of magnitude greater than the physiological concentrations of these hormones in blood. The aim of this study was to examine the interaction between several agonists of human platelet aggregation. The aggregating agents used were adenosine diphosphate (ADP), epinephrine, norepinephrine, 5-hydroxytryptamine and vasopressin. Platelet-rich plasma (PRP) was prepared from blood anticoagulated with minimal concentrations of heparin in an attempt to more closely reflect the in vivo situation.Aggregation caused by ADP was potentiated by epinephrine at a concentration exceeding the level obtained in circulating blood. When a third agonist (vasopressin) was used in combination with ADP and epinephrine, aggregation was enhanced at concentrations of vasopressin and epinephrine obtained in blood. When used as a fourth agonist norepinephrine and 5-hydroxytryptamine potentiated aggregation at physiological concentrations. The response to multiple agonists was greater in heparinized PRP than citrated PRP. Hirudin decreased the extent of aggregation in heparinized PRP caused by multiple agonists suggesting that thrombin may be involved.Since the concentrations of combined agonists required to induce in vitro platelet aggregation can be obtained in circulating blood these findings may explain why platelet activation occurs in certain pathological states.

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Protease-activated receptors 1 and 4 do not stimulate Gi signaling pathways in the absence of secreted ADP and cause human platelet aggregation independently of Gisignaling

Blood ◽

10.1182/blood.v99.10.3629 ◽

2002 ◽

Vol 99 (10) ◽

pp. 3629-3636 ◽

Cited By ~ 126

Author(s):

Soochong Kim ◽

Carolyn Foster ◽

Anna Lecchi ◽

Todd M. Quinton ◽

Dina M. Prosser ◽

...

Keyword(s):

Platelet Aggregation ◽

Adenylyl Cyclase ◽

Signaling Pathways ◽

Human Platelet ◽

Adenosine Diphosphate ◽

Human Platelets ◽

P2y12 Receptor ◽

General Mechanism ◽

Thrombin Receptor ◽

Human Platelet Aggregation

Thrombin is an important agonist for platelet activation and plays a major role in hemostasis and thrombosis. Thrombin activates platelets mainly through protease-activated receptor 1 (PAR1), PAR4, and glycoprotein Ib. Because adenosine diphosphate and thromboxane A2 have been shown to cause platelet aggregation by concomitant signaling through Gq and Gipathways, we investigated whether coactivation of Gq and Gi signaling pathways is the general mechanism by which PAR1 and PAR4 agonists also activate platelet fibrinogen receptor (αIIbβ3). A PAR1-activating peptide, SFLLRN, and PAR4-activating peptides GYPGKF and AYPGKF, caused inhibition of stimulated adenylyl cyclase in human platelets but not in the presence of either Ro 31-8220, a protein kinase C selective inhibitor that abolishes secretion, or AR-C66096, a P2Y12 receptor–selective antagonist; α-thrombin–induced inhibition of adenylyl cyclase was also blocked by Ro 31-8220 or AR-C66096. In platelets from a P2Y12 receptor–defective patient, α-thrombin, SFLLRN, and GYPGKF also failed to inhibit adenylyl cyclase. In platelets from mice lacking the P2Y12 receptor, neither α-thrombin nor AYPGKF caused inhibition of adenylyl cyclase. Furthermore, AR-C66096 caused a rightward shift of human platelet aggregation induced by the lower concentrations of α-thrombin and AYPGKF but had no effect at higher concentrations. Similar results were obtained with platelets from mice deficient in the P2Y12. We conclude that (1)thrombin- and thrombin receptor-activating peptide–induced inhibition of adenylyl cyclase in platelets depends exclusively on secreted adenosine diphosphate that stimulates Gi signaling pathways and (2) thrombin and thrombin receptor-activating peptides cause platelet aggregation independently of Gi signaling.

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