scholarly journals Platelet release reaction and intracellular cGMP

Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 524-531 ◽  
Author(s):  
A Weiss ◽  
NL Baenziger ◽  
JP Atkinson
Keyword(s):  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Serotonin Release ◽  
Secretory Process ◽  
Release Reaction ◽  
Intracellular Cgmp ◽  
Exogenous Addition ◽  
Human Thrombin ◽  
Platelet Release

Abstract Enchanced cAMP concentrations inhibit the aggregation and release reaction of isolated human platelets and platelet-rich plasma to all known inducing agents. An opposing role for cGMP in this phenomenon has been proposed by some but not by others, and the function of cGMP in this secretory process is unclear. To further elucidate the role of cGMP in the release reaction, the effect of increased concentrations of this cyclic nucleotide on 14C-serotonin release was evaluated utilizing isolated human platelets and highly purified human thrombin or commercially available bovine thrombin. Several recently described stimulators of guanylate cyclase, including sodium nitroprusside, sodium azide, nitrosoquanidines, and ascorbic acid, were found to markedly augment platelet cGMP levels. Enhanced platelet cGMP concentrations produced by these drugs or by the exogenous addition of cGMP and its analogues neither caused these cells to secrete nor modulated the thrombin-induced serotonin release reaction. The inhibition of serotonin release by increased cAMP concentrations was not counteracted by increased cGMP levels. Platelet cGMP concentrations were unaltered by thrombin. These data indicate that cGMP is not an obligatory signal or a modulator of the thrombin-induced platelet release reaction.

scholarly journals Platelet release reaction and intracellular cGMP

Blood ◽  
1978 ◽  
Vol 52 (3) ◽  
pp. 524-531
Author(s):  
A Weiss ◽  
NL Baenziger ◽  
JP Atkinson
Keyword(s):  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Serotonin Release ◽  
Secretory Process ◽  
Release Reaction ◽  
Intracellular Cgmp ◽  
Exogenous Addition ◽  
Human Thrombin ◽  
Platelet Release

Enchanced cAMP concentrations inhibit the aggregation and release reaction of isolated human platelets and platelet-rich plasma to all known inducing agents. An opposing role for cGMP in this phenomenon has been proposed by some but not by others, and the function of cGMP in this secretory process is unclear. To further elucidate the role of cGMP in the release reaction, the effect of increased concentrations of this cyclic nucleotide on 14C-serotonin release was evaluated utilizing isolated human platelets and highly purified human thrombin or commercially available bovine thrombin. Several recently described stimulators of guanylate cyclase, including sodium nitroprusside, sodium azide, nitrosoquanidines, and ascorbic acid, were found to markedly augment platelet cGMP levels. Enhanced platelet cGMP concentrations produced by these drugs or by the exogenous addition of cGMP and its analogues neither caused these cells to secrete nor modulated the thrombin-induced serotonin release reaction. The inhibition of serotonin release by increased cAMP concentrations was not counteracted by increased cGMP levels. Platelet cGMP concentrations were unaltered by thrombin. These data indicate that cGMP is not an obligatory signal or a modulator of the thrombin-induced platelet release reaction.

The Role Of Glycoprotein V (GPV) In Thrombin Activation Of Human Platelets

1981 ◽  
Author(s):  
K Fujimura ◽  
S Maehama ◽  
A Kuramoto
Keyword(s):  
Membrane Surface ◽  
Human Platelets ◽  
Surface Proteins ◽  
Galactose Oxidase ◽  
Membrane Glycoproteins ◽  
Release Reaction ◽  
Sds Page ◽  
Thrombin Activation ◽  
Platelet Release

The analysis of platelet membrane glycoproteins and platelet functions was conducted to disclose the role of GPI and V in the thrombin activation of platelet. Our previous study proved that native and HNB thrombin hydrolyzed GPV(M. W.8-9 × 104) selectively and released new glycoprotein fragment (M.W. 6.2-6.8 × 104 ) of GPV, resulting in the development of 14C-5HT release reaction and platelet MDA production. But DIP thrombin could not induce these phenomena.Membrane surface proteins of intact platelets were labeled with Na[3H]BH4 by neuraminidase and galactose oxidase method and analyzed by fluorography after SDS-PAGE.The high molecular weight glycoproteins, GPI, GPIII and GPV were diminished by trypsin treatment in correlation with the concentration and incubation time. In correspond to the diminution of these membrane glycoproteins, platelet release reaction was increased .Chymotrypsin treatment in various concentrations, release reaction and MDA production were not induced in spite of long incubation times. But the ristocetin aggregation was decreased in Chymotrypsin treated platelets whose membrane glycoproteins did not change significantly. The Chymotrypsin treated platelets whose GPI was modified functionally, showed normal release reaction and MDA production by thrombin stimulation. On the other hand, the thrombin treated platelets in low concentration previously whose GPV was hydrolyzed partially, demonstrated little release reaction and MDA production by thrombin or trypsin stimulation. From these results, the GPV was hydrolyzed specifically by thrombin and nonspecifically by trypsin but was not hydrolyzed by Chymotrypsin. It was concluded that the thrombin binds to the GPI and hydrolyzed GPV specifically, and hydrolysis of GPV might act as a signal to induce the platelet release reaction and prostaglandin metabolism.

Factors Influencing Thrombin Induced Platelet Release Reaction

1979 ◽  
Author(s):  
E. Hattey ◽  
B.R. Binder
Keyword(s):  
Platelet Count ◽  
Human Platelets ◽  
Serotonin Release ◽  
Major Influence ◽  
Release Reaction ◽  
Platelet Counts ◽  
Ph Values ◽  
Factors Influencing ◽  
Platelet Release ◽  
Phosphate Buffered Saline

To study the effect of pH and platelet counts on thrombin induced platelet release reaction, washed human platelets labeled with 14C-serotonin were suspended in phosphate buffered saline of varying pH values for 15 minutes with thrombin concentrations between 1,1 and 0,068 NIH U/ml of suspension. The amount of serotonin released caused by the thrombin added was dependent on the pH of the incubation medium with an optimum in the range of pH 7,4 -7,6. This effect was more marked with higher thrombin concentrations. The serotonin release controles without thrombin were not influenced by the different pH values and were always less than 10%. The amount of platelets in the reaction mixture influenced the release values not significantly at thrombin concentrations of 1,1 and 0,27 NIH U/ml While with 0,068 NIH U/ml a significant dependence of the release on the number of platelets was observed, resulting in higher release values in platelet mixtures with lower platelet counts.Therefore it can be concluded that the pH is of major influence on the release reaction especially at high thrombin concentrations while the platelet count is of importance only at low thrombin concentrations.

Effect of Lidoflazine (R 7904) on Human Platelet Function in Vitro

1972 ◽  
Vol 28 (02) ◽  
pp. 228-236 ◽  
Author(s):  
F De Clerck
Keyword(s):  
Platelet Function ◽  
Mode Of Action ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Serotonin Release ◽  
Clot Retraction ◽  
Plasma Coagulation ◽  
Release Reaction ◽  
Platelet Release

SummaryThe effect of lidoflazine and of cinnarizine on human platelet function in vitro was compared to that of dipyridamole.Pre-incubation for 30 min at 37° C of platelet rich plasma with lidoflazine or with dipyridamole 5 ×10–4 M resulted in an appreciable inhibition of collagen aggregation in particular and to a lesser extent of ADP aggregation; cinnarizine was marginally active only.Clot retraction was inhibited by lidoflazine and by dipyridamole. Experiments on biphasic ADP aggregation and C14-serotonin release during aggregation show that lidoflazine reduces the platelet release reaction.The possible mode of action of the compound is discussed.Plasma coagulation and PF – 3 availability were not affected.

The Effects of Citrate and Extracellular Calcium Ions on the Platelet Release Reaction Induced by Adenosine Diphosphate and Collagen

1979 ◽  
Vol 42 (02) ◽  
pp. 778-793 ◽  
Author(s):  
Stanley Hepinstall ◽  
Patricia M Taylor
Keyword(s):  
Calcium Ions ◽  
Sodium Citrate ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
Extracellular Calcium ◽  
Release Reaction ◽  
Calcium Dependent ◽  
Platelet Release ◽  
Dependent Mechanism

SummaryThe ADP-induced release of 3H-serotonin from human platelets in heparinized platelet rich plasma is markedly stimulated by the addition of sodium citrate. The aggregation and release that is induced by collagen is less affected by citrate. Data is presented that supports the view that the effects of citrate on both ADP-and collagen-induced release are largely via alteration of the concentration of ionized calcium in plasma.Collagen can induce release of 3H-serotonin via extracellular calcium-independent and -dependent mechanisms. The possibility that the calcium-dependent mechanism is aggregation-dependent and that the calcium is required for platelet aggregation rather than directly involved in the release reaction is discussed.

scholarly journals Effect of anti-P1A1 antibody on human platelets. I. The role of complement

Blood ◽  
1979 ◽  
Vol 53 (4) ◽  
pp. 567-577 ◽  
Author(s):  
DB Cines ◽  
AD Schreiber
Keyword(s):  
Platelet Aggregation ◽  
Complement Activation ◽  
Platelet Rich Plasma ◽  
Plasma Concentrations ◽  
Human Platelets ◽  
Serotonin Release ◽  
Buffer System ◽  
Induce Platelet Aggregation ◽  
Platelet Surface ◽  
Release Reaction

Abstract We studied the interaction of complement with human platelets. Complement was activated by IgG anti-P1A1 antibody obtained from 3 patients with the post-transfusion purpura syndrome. We used a heparin- plasma buffer system that permits complement activation and also preserves platelet function. With this system complement activation was efficient, and platelet immune alteration was extensive. Anti-P1A1 antibody was effective only in the presence of complement, in which case both platelet lysis and serotonin release (release reaction) in the absence of lysis were observed. Platelet lysis, as assessed by 51Cr loss, required 10-fold more antibody than was necessary to induce platelet aggregation and release of 14C-serotonin. This platelet release reaction required an intact classic complement sequence through C6. The extent of platelet serotonin release parallelled the depletion of C1 and C4 from platelet-rich plasma. Concentrations of antibody insufficient to induce platelet aggregation and serotonin release could still activate C1 and deposit increased C3 on the platelet surface. These studies demonstrated that complement activation by anti-P1A1 antibody can alter human platelets in a nonlytic system. Several phases of complement-mediated human platelet alteration are possible, depending on the concentration of anti-P1A1 antibody.

EFFECTS OF HUMAN ATRIAL NATRIURETIC PEPTIDES ON SECRETION REACTION IN HUMAN PLATELETS

1987 ◽  
Author(s):  
A Tanable ◽  
Y Yatomi ◽  
T Ohashi ◽  
H Oka ◽  
T Kariya ◽  
...  
Keyword(s):  
Platelet Rich Plasma ◽  
Atp Release ◽  
Smooth Muscle Contraction ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Serotonin Release ◽  
Release Reaction ◽  
Induced Aggregation ◽  
Atrial Natriuretic

Human atrial natriuretic peptide (h-ANP) has vasodilating and natriuretic properties, and inhibits smooth muscle contraction, renal renin secretion and adrenal aldosterone release. Although Schiffrin has reported that human platelets have receptors for ANP, its effects in platelets are not established in vivo. We therefore investigated the influence of h-ANP on secretion reaction in human platelets. Eight healthy subjects, males, aged 20 to 24 years, donated blood for the study. Citrated platelet-rich plasma (PRP) was incubated with or without h-ANP at 37 C for 2.5 minutes. The samples of 0.5 ml PRP then used to measure ADP induced aggregation, ATP release reaction and C-serotonin release reaction. H-ANP, at concentration of 1x10 -6M, decreased ADP induced aggregation (after h-ANP: 77.4±9.7 % of control aggregation), and inhibited ATP release reaction (after h-ANP: 31.8±13.1%). Serotonin releasereaction induced by ADP was also inhibited ( control: 15.3±2.2%, after h-ANP: 8.3±0.5 %). The inhibitory effect of h-ANP on aggregation and secretion reaction was maximal by 3 minutes. These data suggest that h-ANP inhibits secretion reaction in human platelets.

scholarly journals Effect of anti-P1A1 antibody on human platelets. I. The role of complement

Blood ◽  
1979 ◽  
Vol 53 (4) ◽  
pp. 567-577
Author(s):  
DB Cines ◽  
AD Schreiber
Keyword(s):  
Platelet Aggregation ◽  
Complement Activation ◽  
Platelet Rich Plasma ◽  
Plasma Concentrations ◽  
Human Platelets ◽  
Serotonin Release ◽  
Buffer System ◽  
Induce Platelet Aggregation ◽  
Platelet Surface ◽  
Release Reaction

We studied the interaction of complement with human platelets. Complement was activated by IgG anti-P1A1 antibody obtained from 3 patients with the post-transfusion purpura syndrome. We used a heparin- plasma buffer system that permits complement activation and also preserves platelet function. With this system complement activation was efficient, and platelet immune alteration was extensive. Anti-P1A1 antibody was effective only in the presence of complement, in which case both platelet lysis and serotonin release (release reaction) in the absence of lysis were observed. Platelet lysis, as assessed by 51Cr loss, required 10-fold more antibody than was necessary to induce platelet aggregation and release of 14C-serotonin. This platelet release reaction required an intact classic complement sequence through C6. The extent of platelet serotonin release parallelled the depletion of C1 and C4 from platelet-rich plasma. Concentrations of antibody insufficient to induce platelet aggregation and serotonin release could still activate C1 and deposit increased C3 on the platelet surface. These studies demonstrated that complement activation by anti-P1A1 antibody can alter human platelets in a nonlytic system. Several phases of complement-mediated human platelet alteration are possible, depending on the concentration of anti-P1A1 antibody.

Platelet Reactions and Immune Processes

1970 ◽  
Vol 23 (01) ◽  
pp. 110-119 ◽  
Author(s):  
F Jobin ◽  
France Tremblay ◽  
M Morissette
Keyword(s):  
Platelet Aggregation ◽  
Platelet Aggregation Inhibitors ◽  
Human Platelets ◽  
Present Knowledge ◽  
Release Reaction ◽  
Cellular Processes ◽  
Cell Release ◽  
Aggregation Inhibitors ◽  
Platelet Release

SummaryWe have studied the effect of chymotrypsin substrates and inhibitors on the aggregation of human platelets by collagen, latex, and epinephrine :1. We have found that platelet aggregation was inhibited by most chymotrypsin substrates and inhibitors which we studied.2. In general, there was a positive correlation between the effectiveness of the compounds as chymotrypsin substrates or inhibitors on one hand, and as platelet aggregation inhibitors on the other hand. However aromatic amino acid derivatives acetylated on the α-amine group were much less effective with platelets than they are with chymotrypsin.3. Chymotrypsin substrates and inhibitors also inhibit the anaphylactic release of histamine. The view is presented that the platelet release reaction and the mast cell release reaction have several common biological and biochemical features.4. The possible role of platelet esterases in platelet thrombogenetic reactions is discussed in the light of the present knowledge of the role of cell bound esterase in several inflammatory or immune cellular processes.

Effect of Aspirin on the Thrombelastogram of Human Blood

1973 ◽  
Vol 30 (03) ◽  
pp. 494-498 ◽  
Author(s):  
G de Gaetano ◽  
J Vermylen
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Platelet Function ◽  
Human Blood ◽  
Platelet Rich Plasma ◽  
Plasma Samples ◽  
Release Reaction ◽  
Platelet Release

SummaryThrombelastograms of both native blood and re-calcified platelet-rich plasma samples taken from subjects given a single oral dose of aspirin (1 gram) were not significantly different from the pretreatment recordings. Aspirin also did not modify the thrombelastogram when preincubated in vitro with platelet-rich plasma at concentrations inhibiting the platelet “release reaction” by collagen. Thrombelastography therefore cannot evaluate the effect of aspirin on platelet function.

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