Inhibition and potentiation of platelet function by lysolecithin

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 101-112 ◽  
Author(s):  
JH Joist ◽  
G Dolezel ◽  
MP Cucuianu ◽  
EE Nishizawa ◽  
JF Mustard
Keyword(s):  
Platelet Function ◽  
Platelet Rich Plasma ◽  
Membrane Damage ◽  
Adenosine Diphosphate ◽  
Lactic Dehydrogenase ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Serotonin Release ◽  
Prolonged Incubation ◽  
Induced Aggregation

Abstract The effects of lysolecithin (LPC) on aggregation, serotonin release, shape, and lysis of rabbit, pig, or human platelets in platelet-rich plasma (PRP) or Tyrode albumin solution were examined during prolonged incubation. LPC added to citrated or heparinized PRP from humans or rabbits at a final concentration above 100 muM caused instantaneous inhibition of platelet aggregation induced by adenosine diphosphate (ADP), epinephrine (human PRP only), collagen, or thrombin. The inhibitory effect of LPC was found to be partially reversible over a period of 60–90 min. LPC at final concentrations above 30 muM also caused inhibition of ADP-, collagen-, and thrombin-induced aggregation and collagen- and thrombin-induced release of serotonin in suspensions of rabbit, pig, or human platelets. With washed platelets, the inhibitory effect not only rapidly disappeared but was followed by transient potentiation of aggregation and serotonin release. This potentiating effect of LPC was most pronounced when thrombin was used as stimulus. Both inhibition and potentiation were observed at concentrations of LPC that did not cause a significant change in platelet shape or loss from platelets of lactic dehydrogenase. Inhibition and potentiation were also observed when platelets were added to suspending medium containing LPC, although considerably higher concentrations of LPC were required under these conditions. Potentiation was not observed when LPC was added to citrated or heparinized rabbit or human PRP or to washed rabbit platelets suspended in a medium containing 4% bovine serum albumin. It seemed likely that some or all of the observed effects of LPC on platelet function were due to structural modification of the platelet membrane insufficient to result in gross membrane damage or platelet lysis. In addition, the results of experiments using 14C-LPC seemed to indicate that the observed potentiating effect of LPC on platelet function may be related to its rapid uptake and metabolism by the platelets.

scholarly journals Inhibition and potentiation of platelet function by lysolecithin

Blood ◽  
1977 ◽  
Vol 49 (1) ◽  
pp. 101-112
Author(s):  
JH Joist ◽  
G Dolezel ◽  
MP Cucuianu ◽  
EE Nishizawa ◽  
JF Mustard
Keyword(s):  
Platelet Function ◽  
Platelet Rich Plasma ◽  
Membrane Damage ◽  
Adenosine Diphosphate ◽  
Lactic Dehydrogenase ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Serotonin Release ◽  
Prolonged Incubation ◽  
Induced Aggregation

The effects of lysolecithin (LPC) on aggregation, serotonin release, shape, and lysis of rabbit, pig, or human platelets in platelet-rich plasma (PRP) or Tyrode albumin solution were examined during prolonged incubation. LPC added to citrated or heparinized PRP from humans or rabbits at a final concentration above 100 muM caused instantaneous inhibition of platelet aggregation induced by adenosine diphosphate (ADP), epinephrine (human PRP only), collagen, or thrombin. The inhibitory effect of LPC was found to be partially reversible over a period of 60–90 min. LPC at final concentrations above 30 muM also caused inhibition of ADP-, collagen-, and thrombin-induced aggregation and collagen- and thrombin-induced release of serotonin in suspensions of rabbit, pig, or human platelets. With washed platelets, the inhibitory effect not only rapidly disappeared but was followed by transient potentiation of aggregation and serotonin release. This potentiating effect of LPC was most pronounced when thrombin was used as stimulus. Both inhibition and potentiation were observed at concentrations of LPC that did not cause a significant change in platelet shape or loss from platelets of lactic dehydrogenase. Inhibition and potentiation were also observed when platelets were added to suspending medium containing LPC, although considerably higher concentrations of LPC were required under these conditions. Potentiation was not observed when LPC was added to citrated or heparinized rabbit or human PRP or to washed rabbit platelets suspended in a medium containing 4% bovine serum albumin. It seemed likely that some or all of the observed effects of LPC on platelet function were due to structural modification of the platelet membrane insufficient to result in gross membrane damage or platelet lysis. In addition, the results of experiments using 14C-LPC seemed to indicate that the observed potentiating effect of LPC on platelet function may be related to its rapid uptake and metabolism by the platelets.

Effects of Lead Acetate on Platelet Aggregation, Ultrastructure and Serotonin Release

1971 ◽  
Vol 26 (03) ◽  
pp. 455-466 ◽  
Author(s):  
R. B Davis ◽  
G. C Holtz
Keyword(s):  
Platelet Aggregation ◽  
Platelet Function ◽  
Lead Acetate ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Blood Platelet ◽  
Human Platelets ◽  
Serotonin Release ◽  
Aggregation Of Platelets

SummaryThe effects of lead on blood platelet function and ultrastructure have been investigated. Lead acetate was injected intravenously in 27 rats and was added to rat and human platelet rich plasma in vitro. In vitro studies showed that concentrations of 2.5 × 10-3 M lead acetate reduced or blocked aggregation of rat and human platelets by adenosine diphosphate, collagen, and thrombin. Radioactive serotonin release from human platelets was inhibited by 10-4 M lead acetate. One hour after the injection of lead, platelet aggregation by thrombin was reduced, but platelet aggregation by adenosine diphosphate and collagen showed little change. Three days after lead, aggregation of platelets by collagen and thrombin was blocked and aggregation by adenosine diphosphate reduced. Thrombocytopenia was present 4 days after intravenous lead acetate. Electron micrographs of platelets showed that the mean number of mitochondria per platelet was increased, whereas alpha granules were reduced. Dense bodies were not significantly changed. Lead acetate affects platelet function in concentrations reported in human bone marrow in lead poisoning, and may relate to the binding of free sulfhydryl groups by lead.

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.

Inhibition of Thrombin-, Epinephrine- and Collagen-Induced Platelet Aggregation by α1-Acid Glycoprotein

1979 ◽  
Author(s):  
P. Andersen ◽  
C. Eika
Keyword(s):  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Clotting Time ◽  
Acid Glycoprotein ◽  
High Concentrations ◽  
Spontaneous Platelet Aggregation ◽  
Induced Aggregation

α1-Acid glycoprotein (α1,-acid GP) isolated from human plasma was found to inhibit thrombin-induced aggregation of washed human platelets (0.05 NIH U/ml final conc.), and inhibition was complete with physiological concentrations of α1-acid GP (1.0-1.5 g/1 final conc.). The inhibitory effect seemed to occur immediately on thrombin addition, thus similar to the effect of heparin previously observed. As opposed to heparin, however, α1-acid GP did not affect spontaneous platelet aggregation. Furthermore, α1-acid GP (in optimal cone.) reduced the combined inhibitory effect of heparin and antithrombin III on thrombin-induced platelet aggregation, thus consistent with the previous findings using heparin thrombin clotting time.Snyder and Coodley (1976) found α1-acid GP to inhibit platelet aggregation induced by epinephrine and adenosine diphosphate in platelet-rich plasma. As we also found α1-acid GP to inhibit collagen-induced platelet aggregation, α1-acid GP may possibly act as an inhibitor of the release reaction though fairly high concentrations (10 mg/ml final cone.) was needed for complete inhibition.

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.

Effect Of Solvents On Indium-111 Oxine Transport In Human Platelets And On Platelet Function In Vitro

1981 ◽  
Author(s):  
T Tsukada
Keyword(s):  
Platelet Function ◽  
Kinetic Constant ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Polysorbate 80 ◽  
Autologous Plasma ◽  
Indium 111 ◽  
Induced Aggregation ◽  
Water Space

Mechanism of Indium-111 oxine(In) transport in human platelets in buffered saline and the effect of In-labeling on platelet function were studied using In dissolved in 25% of ethanol in saline (In-ES) or 0.01% of polysorbate 80 in HEPES buffer(In-PH). Increase in temperature up to 37° C progressively enhanced the transport of In-ES, while transport of In-PH reached to plateau at 15°C. A states of equilibrium was not reached during 2 hr incubation at 22°C in In-ES. Uptake of In-PH reached to plateau after only 15 min of incubation. Distribution of In taken up by platelets in InES was 57% in cytosol and 27% in stroma, while in In-PH 69% in stroma and 22% in cytosol. 88% of In in cytosol was bound to lipids(46% in cholesterol and 27% in PS+PI). 82% of In in stroma was found in PS+PI fraction.The fact that the ratio of free In between the platelet water space and the outside medium after 30 min of incubation at up to 0.1 uM of In exceeded unity, suggests satura- , ble component of In transport prevails at this concentration in In-ES and In-PH. Kinetic constant could be calculated, Kt= 2nM, Vmax= 2.5 pmol/min/ml in In-ES, and Kt= InM, Vmax=0.7 pmol/min/ml in In-PH.Elution of In from radiolableled platelets in autologous plasma incubated at 37°C for 5 hr was less than 10% in the case of In-ES and 56% in the case of In-PH. Less than 3% of labeled-In was eluated from platelets in collagen-induced aggregation and 4-7% of In was eluated in thrombin-induced aggregation.Although 0.3% of ethanol and/or 6nM of oxine have no inhibitory effect of platelet aggregation, collagen-induced aggregation and release reaction of In-labeled platelet was impaired. 0.003% of polysorbate 80 itself abolished completely the aggregability of platelets by collagen or thrombin.It is concluded In-PH is unsuitable for platelet labeling. In-111 oxine also seems to have problems which Cr-51 has, i.e. inhomogenous distribution of In in a platelet population, elution of In from labeled platelets in circulation.

scholarly journals Cigarette Smoke Extract Inhibits Platelet Aggregation by Suppressing Cyclooxygenase Activity

TH Open ◽  
2017 ◽  
Vol 01 (02) ◽  
pp. e122-e129
Author(s):  
Hitoshi Kashiwagi ◽  
Koh-ichi Yuhki ◽  
Yoshitaka Imamichi ◽  
Fumiaki Kojima ◽  
Shima Kumei ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Cigarette Smoke ◽  
Platelet Function ◽  
Inhibitory Effect ◽  
Cigarette Smoke Extract ◽  
Human Platelets ◽  
Receptor Subtypes ◽  
Ic50 Value ◽  
Induced Aggregation ◽  
Cox 1

AbstractThe results of studies that were performed to determine whether cigarette smoking affects platelet function have been controversial, and the effects of nicotine- and tar-free cigarette smoke extract (CSE) on platelet function remain to be determined. The aim of this study was to determine the effect of CSE on platelet aggregation and to clarify the mechanism by which CSE affects platelet function. CSE inhibited murine platelet aggregation induced by 9,11-dideoxy-9α,11α-methanoepoxy-prosta-5Z,13E-dien-1-oic acid (U-46619), a thromboxane (TX) A2 receptor agonist, and that induced by collagen with respective IC50 values of 1.05 ± 0.14% and 1.34 ± 0.19%. A similar inhibitory action of CSE was also observed in human platelets. CSE inhibited arachidonic acid–induced TXA2 production in murine platelets with an IC50 value of 7.32 ± 2.00%. Accordingly, the inhibitory effect of CSE on collagen-induced aggregation was significantly blunted in platelets lacking the TXA2 receptor compared with the inhibitory effect in control platelets. In contrast, the antiplatelet effects of CSE in platelets lacking each inhibitory prostanoid receptor, prostaglandin (PG) I2 receptor and PGE2 receptor subtypes EP2 and EP4, were not significantly different from the effects in respective control platelets. Among the enzymes responsible for TXA2 production in platelets, the activity of cyclooxygenase (COX)-1 was inhibited by CSE with an IC50 value of 1.07 ± 0.15% in an uncompetitive manner. In contrast, the activity of TX synthase was enhanced by CSE. The results indicate that CSE inhibits COX-1 activity and thereby decreases TXA2 production in platelets, leading to inhibition of platelet aggregation.

scholarly journals Studies on the mechanism of the inhibition of platelet aggregation and release induced by high levels of arachidonate

Blood ◽  
1982 ◽  
Vol 60 (2) ◽  
pp. 436-445 ◽  
Author(s):  
BL Linder ◽  
DS Goodman
Keyword(s):  
Platelet Aggregation ◽  
Cyclic Amp ◽  
Platelet Function ◽  
Inhibitory Effect ◽  
Serotonin Release ◽  
Prostaglandin D2 ◽  
Active Synthesis ◽  
Low Levels ◽  
High Concentrations ◽  
Induced Aggregation

Abstract We have previously reported that arachidonic acid induced a biphasic pattern of platelet aggregation and the release of both dense and alpha- granule components. Low levels of arachidonate (0.025--0.1 mM) specifically induced aggregation and release, while high concentrations (0.15--0.35 mM) caused a progressive inhibition of these platelet responses in human gel-filtered platelets (GFP). We now report studies of the mechanism(s) responsible for this arachidonate-induced turn-off of platelet function. Electron micrographic studies demonstrated that there was no gross damage to the platelets during the turn-off. Active synthesis of malondialdehyde and thromboxane A2 was seen at the high arachidonate levels, despite the inhibition of aggregation. Furthermore, GFP inhibited by 0.25 mM arachidonate were capable of undergoing aggregation and serotonin release in response to other stimuli, such as collagen or thrombin. Thus, GFP appeared to be metabolically intact and functional during the inhibiton by high arachidonate levels. Thin-layer chromatographic studies revealed that prostaglandin metabolism was not changed at the high arachidonate levels. In addition, indomethacin (20 microM) did not abolish the arachidonate-induced inhibition of platelet function. Therefore, the inhibitory effect of high arachidonate did not depend on its conversion to other prostaglandin products. Platelet cyclic AMP levels increased twofold at the high arachidonate concentrations (1.3 +/- 0.3 pmole/10(8) platelets at peak aggregation, compared with 2.9 +/- 0.4 pmole/10(8) platelets at inhibition by 0.25 mM arachidonate, p less than 0.001). Prostaglandin-D2, a platelet inhibitor known to increase cyclic AMP, generated a similar rise (to 2.4 +/- 0.2 pmole/10(8) platelets). Thus, the magnitude of the arachidonate-induced increase in platelet cyclic AMP levels can account for the inhibition of aggregation and release.

scholarly journals Inhibitory Effect of Diamines and Polyamines on Human Platelet Aggregation and [14C]-Serotonin Release Reaction

1977 ◽  
Author(s):  
K. Subbarao ◽  
F. Forestier
Keyword(s):  
Platelet Function ◽  
Human Platelet ◽  
Platelet Rich Plasma ◽  
Inhibitory Effect ◽  
Serotonin Release ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Release Reaction ◽  
Aggregation Of Platelets

Physiological diamines and polyamines occur in high concentrations in various parts of animal tissues. These amines are known to interact with and stabilize nucleic acids, membranes and ribosomes (Tabor and Tabor, Pharmac. Rev., 16, 245). The effect of putrescine, cadaverine, spermidine and spermine on platelet function is not yet fully explored. We studied the effect of these reagents on in vitro aggregation of human platelet rich plasma (PRP) induced by the addition of ADP, thrombin, collagen and serotonin. Cadaverine, spermidine and spermine at concentrations from 2-5 μM strongly inhibited the aggregation of platelets and the [14C]-serotonin release reaction induced by ADP and thrombin in a concentration dependent manner, but did not show any effect on aggregation induced by other agents. Putrescine, on the other hand, failed to produce any effect on the aggregation of platelets and [14C]-serotonin release reaction. Studies on the binding of purified human thrombin treated with [14C]-diisopropylfluoro-phosphate (DFP) to washed human platelets indicated that cadaverine (1-5 μmoles) increased the binding of total [14C]-DFP-thrombin to platelets by 30%. The data suggest that the alteration of platelet function by diamines and polyamines was probably achieved by their binding to platelet membranes.

PLATELET AGGREGATION DYNAMICS TO ADENOSINE DIPHOSPHATE IN NON-STIRRED SUSPENSIONS: LONG-RANGEINTERACTIONS FOR HUMAN, BUT NOT RABBIT, PLATELETS

1987 ◽  
Author(s):  
K Longmire ◽  
M M Frojmovic
Keyword(s):  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
Linear Regression Analysis ◽  
Time Lag ◽  
Adenosine Diphosphate ◽  
Human Platelets ◽  
Dense Granule ◽  
Second Phase ◽  
Particle Count ◽  
Induced Aggregation

The simplest experimental approach for a theoretical description of platelet aggregation is based on kinetics of early multiplet formation (‹4 platelets per aggregate)occurring with diffusion-dependent particle collisions (no flow). The Smoluchowski theory was used to calculate collision efficiencies, αβ, from a linear plot of platelet particle count (Nt)−1 vs time (t) following addition of adenosine diphosphate (ADP) to citrated platelet-rich-plasma (PRP) for 7 human (H) and 2 rabbit (R) donors. A 0.1 ml sample of PRP was stirred with ADP for 0.5s, then immediately transferred to a 37°C bath for no-stir (diffusion) studies or further stirred with ADP for stir-induced aggregation studies. Samples were fixed with 0.5 ml 0.8% glutaraldehyde with particle count (Nt) determined with a resistive counter and % aggregation (PA) computed (reproducibility/sensitivity ‹ 5%). For stir conditions, R platelets were as sensitive and as rapidly aggregated by ADP (2-10 μM) as H platelets, with ∼ 1 s time lag for onset of PA. However, for no-stir conditions, linear regression analysis of data for ADP (5-10 μM) induced PA for H platelets for 0-30 s gave αβ = 7.5±4.6 (r = 0.9±0.05). Analysis at longer “diffusion” times showed a second phase (60-300 s) in some H donors with aB = 0.5±0.4 (4/9 donors), while R platelets showed only 1 phase with αβ = 0.65±0.15 (0-60 to 0-900 s) (r = 0.8±0.1). The ADP sensitivity ([ADP]½ corresponding to 50% of maximal changes) for the abnormally rapid PA in no stir H PRP for early times, measured over 0.4-100 μM range, was found to be ∼9 μM (5-17 μM range) and 3.5 μM (3-10 μM) for measurements respectively at 5-10 and 20-30s; these values were ∼ 3-8 × greater than lADPji measured for stirred suspensions for rate/extent of PA or rate of turbidometrically-measured macroaggregation (TA), while › [ADP] threshold for secondary aggregation in TA (10 H donors). These abnormally large aB values and their ADP sensitivity observed for human platelets are consistent with long-range interactions mediated by“chemotactic” agents released from the cells but distinct from normal dense granule release requiring macroaggregation, or by as yet uncharacterized membrane or polymetric bridges.

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