Platelet Adhesion to Collagen Is Inhibited by Adenosine Diphosphate but Unaffected by Cell Shape

1981 ◽  
Vol 46 (02) ◽  
pp. 515-520 ◽  
Author(s):  
F A Meyer ◽  
Z Weisman ◽  
M M Frojmovic
Keyword(s):  
Binding Sites ◽  
Cell Shape ◽  
Platelet Adhesion ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Time Dependent ◽  
Rabbit Platelets ◽  
Normal Adhesion ◽  
Per Se

SummaryThe effect of limited platelet activation, in the absence of aggregation, on the subsequent ability of rabbit platelets to adhere to collagen was studied in vitro. ADP at concentrations that initiate shape change (>0.01. μM) reduce platelet adhesion. Shape change per se however, was not responsible since the time-dependence of the effect of ADP on shape change and adhesion is different and ADP induces reduced adhesion even when shape change is prevented with PGE1 or fixatives. Platelets shape changed without ADP addition, e. g. by chilling or by low ethanol concentrations, display normal adhesion to collagenIt appears likely that upon binding to the platelet ADP induces a time-dependent alteration in the membrane, akin to refractoriness, that influences binding sites for collagen. The effect of ADP can be blocked by prior addition of AMP but not if the additions are reversed. The implications of the present findings for platelet adhesion studies are discussed.

Platelet Adhesion to Collagen is Inhibited by 5’ -Adenosine Diphosphate but Unaffected by Cell Shape

1979 ◽  
Author(s):  
F.A. Meyer ◽  
Z. Weisman ◽  
M. M. Frojmovic
Keyword(s):  
Cell Shape ◽  
Platelet Adhesion ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Surface Shape ◽  
Platelet Surface ◽  
Lag Period ◽  
Per Se ◽  
Platelet Shape ◽  
Do So

The effect of ADP on the adhesion of rabbit platelets to collagen from unstirred suspensions has been investigated. Reduced binding was seen at ADP concentrations sufficient for platelets in PRP suspensions to undergo shape change (>10-8M). However, shape change per se was not involved. The time dependence of the effect of ADP on platelet shape and on platelet adhesion did not correlate. Also reduced adhesion still occurred if shape change was prevented e.g. by treatment with 1 µM PGE1 or with fixatives. Washed platelet preparations in spite of being fully shape-changed also adhered less well in the presence of ADP. As expected platelets whose shape was changed without ADP being involved, e.g. by a cold exposure treatment, displayed normal binding to collagen.ADP binding to the platelet per se is not sufficient, since reduced adhesion to collagen is seen only some time after binding has taken place. Also AMP blocked the effect of ADP on platelet adhesion if added before but not after ADP. The time dependent event that occurs is likely to be local since reduced platelet adhesion was seen with fixed platelets. It is unlikely to result from the conversion of ADP to ATP. Although ATP does inhibit adhesion, it does so only at much higher concentrations and then only after a lag period similar to that seen with ADP.Our findings imply that some of the agents reported to reduce platelet adhesion to collagen may do so by causing ADP to be released from the platelet. Surface shape and chemistry

Studies on the Shape Change in Rabbit Platelets Induced by Adenosine Diphosphate or Several Metabolic Inhibitors

1974 ◽  
Vol 31 (01) ◽  
pp. 179-186
Author(s):  
Norio Kobayashi ◽  
Tadashi Maekawa
Keyword(s):  
Platelet Aggregation ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Metabolic Inhibitors ◽  
Distilled Water ◽  
Rabbit Platelets

Summary1. The shape change of platelet was induced in vitro by an addition of ADP, NEM, KCN or distilled water. The change induced by ADP occurred very rapidly.2. Among these reagents, only ADP induced the platelet aggregation.3. When ADP was added before the completion of the shape change by NEM, the shape change by ADP took place, while both ADP and NEM were added simultaneously, the pattern of the shape change was similar to that of ADP alone.4. The shape change of platelet by ADP was inhibited by the previous addition of adenosine, which did not affect the shape change induced by NEM.5. Correlation of the shape change of platelets to their aggregation was discussed.

Effects of Bupranolol, a New β-Blocker, on Platelet Functions of Rabbit and Human in Vitro

1976 ◽  
Vol 36 (02) ◽  
pp. 376-387 ◽  
Author(s):  
Teruhiko Umetsu ◽  
Kazuko Sanai ◽  
Tadakatsu Kato
Keyword(s):  
Platelet Aggregation ◽  
Platelet Adhesion ◽  
Human Platelets ◽  
Rabbit Platelet ◽  
Rabbit Platelets ◽  
Β Blocker ◽  
Platelet Aggregates ◽  
Induced Aggregation ◽  
Platelet Functions

SummaryThe effects of bupranolol, a new β-blocker, on platelet functions were investigated in vitro in rabbits and humans as compared with propranolol, a well-known β-blocker. At first, the effect of adrenaline on ADP-induced rabbit platelet aggregation was studied because adrenaline alone induces little or no aggregation of rabbit platelets. Enhancement of ADP-induced rabbit platelet aggregation by adrenaline was confirmed, as previously reported by Sinakos and Caen (1967). In addition the degree of the enhancement was proved to be markedly affected by the concentration of ADP and to increase with decreasing concentration of ADP, although the maximum aggregation (percent) was decreased.Bupranolol and propranolol inhibited the (adrenaline-ADP-)induced aggregation of rabbit platelets, bupranolol being approximately 2.4–3.2 times as effective as propranolol. Bupranolol stimulated the disaggregation of platelet aggregates induced by a combination of adrenaline and ADP, but propranolol did not. Platelet adhesion in rabbit was also inhibited by the β-blockers and bupranolol was more active than propranolol. With human platelets, aggregation induced by adrenaline was inhibited by bupranolol about 2.8–3.3 times as effectively as propranolol.From these findings. We would suggest that bupranolol might be useful for prevention or treatment of thrombosis.

Perturbation of Platelet Adhesion to Endothelial Cells by Plasminogen Activation In Vitro

1997 ◽  
Vol 78 (02) ◽  
pp. 934-938 ◽  
Author(s):  
Hsiun-ing Chen ◽  
Yueh-I Wu ◽  
Yu-Lun Hsieh ◽  
Guey-Yueh Shi ◽  
Meei-Jyh Jiang ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Endothelial Cells ◽  
Platelet Adhesion ◽  
Treatment Time ◽  
Shape Change ◽  
Umbilical Vein ◽  
Tissue Type ◽  
Apical Surface ◽  
Plasminogen Activation

SummaryTo investigate whether the endothelium-platelet interactions may be altered by plasminogen activation, cultured human umbilical vein endothelial cells (ECs) were treated with tissue-type plasminogen activator (t-PA) in the presence of plasminogen, and platelet adhesion to ECs was subsequently measured by using a tapered flow chamber. Our results demonstrated that platelets adhered more readily to t-PA treated EC monolayer than to the control monolayer at all shear stress levels tested. This phenomenon was treatment time-dependent and dose-dependent, and it could be blocked by adding plasmin inhibitors, such as e-amino caproic acid and aprotinin. Adherent platelets on t-PA treated EC monolayer underwent more severe shape change than those on the control monolayer. While the extracellular matrix directly treated with t-PA attracted less platelets than the control matrix did, platelet adhesion to the matrix that was produced by t-PA-treated ECs was unaltered. These data suggest that t-PA treatment on ECs compromised antiplatelet-adhesion capability on their apical surface without altering the reactivity of their extracellular matrix towards platelets.

The Effects of Glycoprotein IIb/IIIa Antagonist RGDS on Platelet Aggregation and Release Reaction In Vitro.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3908-3908
Author(s):  
Shuangfeng Xie ◽  
Songmei Yin ◽  
Danian Nie ◽  
Yiqing Li ◽  
Xiuju Wang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Adhesion ◽  
Adenosine Diphosphate ◽  
Platelet Glycoprotein ◽  
High Concentration ◽  
Release Reaction ◽  
Dense Granules ◽  
Negative Effect ◽  
Platelet Release

Abstract Platelet activation, including platelet adhesion, platelet aggregation and platelet release reaction, played an important role in thrombogenesis. We all knew that Platelet glycoprotein IIb/IIIa antagonist was the most effective drug for anti-aggregation, while we don’t know clearly its effect on platelet release reaction and the relations between its effects on platelet aggregation and release reaction. Platelet release reactions included α-granules and dense granules releasing. When α-granules were released, its membrane glycoprotein CD62p was expressed in the platelet membrane. We used the CD62p expression as the index of platelet release reaction. In the current study, the 4-peptides RGDS (Arg-Gly-Asp-Ser) was used as glycoprotein IIb/IIIa antagonist. We detected the effects of RGDS on platelet aggregation and CD62p expression induced by adenosine diphosphate (ADP) (finial concentration, 5μmol/L) in vitro. 50, 100, 200, 400 and 800μmol/L RGDS were used separately in the test. RGDS of each concentration could significantly inhibited maximal platelet aggregation (PAG(M)) induced by ADP, the 50% inhibiting concentration was approximately 200μmol/L. 800μmol/L RGDS could inhibited PAG(M) by 80.48±8.18%. Only ≥200μmol/L RGDS could significantly inhibited platelet CD62p expression. 800μmol/L RGDS could inhibit platelet CD62p expression by 27.31±9.74%. The inhibiting effect of RGDS on PAG(M) and platelet CD62p expression had significantly correlation (r =0.976, P<0.05). These results indicated that RGDS in low concentration (<200μmol) had little negative effect on platelet release reaction induced by ATP, while in relatively high concentration (≥200μmol) RGDS could inhibit platelet release reaction. When RGDS concentrations were same its effect on platelet release reaction was much less than that on platelet aggregation, which indicated that platelet glycoprotein IIb/IIIa compound could only partly participated in the platelet release reaction but fully participated in platelet aggregation induced by ADP.

scholarly journals Inhibition by ricin of protein synthesis in vitro. Inhibition of the binding of elongation factor 2 and of adenosine diphosphate-ribosylated elongation factor 2 to ribosomes

1975 ◽  
Vol 146 (1) ◽  
pp. 127-131 ◽  
Author(s):  
L Montanaro ◽  
S Sperti ◽  
A Mattioli ◽  
G Testoni ◽  
F Stirpe
Keyword(s):  
Protein Synthesis ◽  
Binding Sites ◽  
Polypeptide Chain ◽  
Elongation Factor ◽  
Adenosine Diphosphate ◽  
Chain Elongation ◽  
Elongation Factor 2 ◽  
In Vitro Inhibition ◽  
Liver Ribosomes

The binding of EF2 (elongation factor 2) and of ADP-ribosyl-EF 2 to rat liver ribosomes is inhibited by ricin. This result suggests that the native enzyme and its ADP-ribose derivative have the same or closely related binding sites on the ribosome. The inhibition by ricin of the binding of EF 2 to ribosomes is consistent with the previous observation that ricin affects EF 2-catalysed translocation during polypeptide chain elongation.

CD157 is an important mediator of neutrophil adhesion and migration

Blood ◽  
2004 ◽  
Vol 104 (13) ◽  
pp. 4269-4278 ◽  
Author(s):  
Ada Funaro ◽  
Erika Ortolan ◽  
Bruna Ferranti ◽  
Lucia Gargiulo ◽  
Rosario Notaro ◽  
...  
Keyword(s):  
Cell Shape ◽  
Adenosine Diphosphate ◽  
Enzymatic Activities ◽  
Matrix Proteins ◽  
Β2 Integrin ◽  
Important Mediator ◽  
Adp Ribosyl Cyclase ◽  
And Migration ◽  
Cyclic Adenosine Diphosphate

Abstract CD157, a glycosylphosphatidylinositol (GPI)–anchored protein encoded by a member of the CD38 NADase/ADP-ribosyl cyclase gene family, is expressed on the surface of most human circulating neutrophils. This work demonstrates that CD157 is a receptor that induces reorganization of the cytoskeleton and significant changes in cell shape, and that signals mediated by CD157 act through modulation of cytosolic Ca2+ concentration. These signals are independent of the products of CD157's enzymatic activities (ie, cyclic adenosine diphosphate [ADP]–ribose and ADP-ribose). Indeed, the enzymatic activities of CD157 in circulating neutrophils as well as in dimethyl sulfoxide (DMSO)–differentiated (CD157+/CD38-) HL-60 cells, are hardly detectable. This work also shows that the receptorial activity relies on cross-talk between CD157 and β2 integrin. CD157 localizes in GM1-enriched lipid rafts and, upon activation, it migrates to the uropod, a structure specialized in motility and adhesive functions. Indeed, CD157 is involved in adhesion to extracellular matrix proteins and in chemotaxis induced in vitro by formyl-methionyl-leucyl-phenylalanine (fMLP). These findings were consistent with the results obtained in neutrophils from patients with paroxysmal nocturnal hemoglobinuria (PNH), in which CD157 is deficient. These neutrophils showed constant defects in adhesion and migration. Our data attribute specific and crucial roles to CD157 in the regulation of innate immunity during inflammation.

scholarly journals Changes in phosphatidylinositol-4,5-bisphosphate 10 seconds after stimulation of washed rabbit platelets with ADP

Blood ◽  
1982 ◽  
Vol 60 (6) ◽  
pp. 1247-1250
Author(s):  
JD Vickers ◽  
RL Kinlough-Rathbone ◽  
JF Mustard
Keyword(s):  
Shape Change ◽  
Adenosine Diphosphate ◽  
Cellular Responses ◽  
Release Reaction ◽  
Rabbit Platelets ◽  
Induced Aggregation ◽  
Platelet Shape ◽  
Stimulation Of

Adenosine diphosphate (ADP) induced aggregation of rabbit platelets, without the release reaction, causes a significant decrease (7%) in the amount of phosphatidylinositol-4,5-bisphosphate (PIP2) at 10 sec and at 60 sec (11%). In platelets prelabeled with 32P-phosphate, this decrease in PIP2 is associated with a decrease in PIP2 radioactivity, which is significant at 50 sec. The decrease in PIP2 is sufficient to mobilize about 0.18 nmole Ca2+/10(9) platelets. In view of the key role played by Ca2+ in ADP-induced platelet shape change and aggregation, this evidence is compatible with the hypothesis that changes in PIP2 can be a source of calcium for cellular responses to agonists.

The Role of Prostaglandins in the ADP-Induced Aggregation of Rabbit Platelets Shown by the Use of 15-Hydroxyprostaglandin Dehydrogenase

1978 ◽  
Vol 39 (03) ◽  
pp. 725-732 ◽  
Author(s):  
Robert B Wallis
Keyword(s):  
Platelet Rich Plasma ◽  
Shape Change ◽  
Rabbit Platelet ◽  
Direct Role ◽  
Initial Shape ◽  
Rabbit Platelets ◽  
Induced Aggregation ◽  
Aggregation Of Platelets

SummaryThe initial shape change and subsequent aggregation of platelets in citrated rabbit platelet-rich plasma caused by ADP in vitro was inhibited by 15-hydroxyprostaglandin dehydrogenase. This inhibition was NAD-dependent and was also seen when shape change and aggregation were initiated by sodium arachidonate or by collagen. The aggregation of gel-filtered rabbit platelets by thrombin was not, however, affected by removal of 15-hydroxyprostaglandins.Indomethacin was found to inhibit ADP-induced aggregation but at a concentration (250 μM) much higher than that required to inhibit collagen-induced aggregation. Moreover the platelet release reaction had not taken place 3 min after ADP stimulation. The direct role 15-hydroxyprostaglandin production in ADP-induced aggregation of rabbit platelets is proposed. The involvement of 15-hydroxyprostaglandins in platelet aggregation caused by other inducers is also discussed.

Inversion in Volvox tertius: the effects of con A

1981 ◽  
Vol 48 (1) ◽  
pp. 355-366
Author(s):  
G.W. Ireland ◽  
S.E. Hawkins
Keyword(s):  
Cell Division ◽  
Cell Shape ◽  
Shape Change ◽  
Fluorescein Isothiocyanate ◽  
Inhibitory Effect ◽  
Con A ◽  
Cell Shape Change ◽  
Enhanced Production ◽  
Inside Out

During the development of Volvox tertius spheroids, a single-celled gonidium enlarges and undergoes multiple incomplete cleavages to give an embryo which is ‘inside-out’ with respect to the adult organism. A morphogenetic movement, termed ‘inversion’, turns this hollow ball of cells ‘inside-out’ through a hole, the phialopore. In V. tertius this phialopore possesses 4 inwardly directed lips. Normal inversion was studied in vitro in slide chambers and involved cell-shape changes accompanied by the production of pseudopodia and the bending backwards of the phialopore lips. 100 micrograms/ml Con A specifically and reversibly blocked inversion. Despite the inhibitory effect on cell division, the blocking of inversion was not due to the blocking of the last cell division some 50–100 min prior to inversion. Neither did the first cell-shape change from pear- to spindle-shape appear blocked. A feature of inhibition by Con A was the enhanced production of pseudopodia by embryos blocked at inversion, and the abnormal production of pseudopodia by embryos blocked at earlier stages. Non-inverting embryos showed internal flagella. We suggest that the Con A block to inversion, which may be reversed by alpha-methyl mannoside, arises from the prevention of backwards-bending of the phialopore lips. Fluorescein-isothiocyanate-Con A bound to embryo and cell coat, ane more strongly to the embryo at pre-inversion. SDS-polyacrylamide gel analysis of proteins isolated from embryos showed 4 glycoprotein bands, but Con A binding to these bands could not be demonstrated.

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