Mg⁺⁺ - and Ca⁺⁺-Induced Platelet Aggregation and ADP^[*]

Summary

Reports on platelet aggregation after addition of calcium or magnesium to EDTA- PRP or platelet suspensions were confirmed. An aggregating principle was found in the EDTA-plasma and the supernatant of the platelet suspensions. Aggregation by magnesium in a platelet suspension was inhibited by adenosine and phosphoenol- pyruvic acid and pyruvate kinase, which suggested that the active principle was identical with ADP. Degradation of ADP in EDTA plasma was blocked.

It thus appears that aggregation induced by calcium or magnesium in EDTA-PRP and platelet suspension was due to accumulation of spontaneously liberated ADP, which was not degraded.

^* Supported by a grant from DGRST 68 01317.

^** Attaché de Recherche, I.N.S.E.R.M. Present address: Coagulation Laboratory, Allmänna Sjukhuset, 214 01 Malmö, Sweden.

• References

• 1 Brossmer R. About the human receptors for ADP and other aggregating substances. Abstracts of the simultaneous sessions, Xiith Congr. Internat. Soc. Hemat.. N.Y: 1968: 200.
• 2 Caen J, Michel H. L’activité agrégante du sérum (plasma défibriné par la thrombine). Rev. franç. Étud. clin. Biol 09: 1001 1964;
• 3 Caen J, Larrieu M. J, Samama M. L’hémostase. L’expansion scientifique. Paris; 1968
• 4 Cronberg S, Caen J. Platelet aggregation in washed suspensions. Scand J. Haemat.. (Submitted for publication.)
• 5 Cronberg S, Caen J. P. Release reaction in platelet suspensions induced by kaolin and other particles. Scand. J. Haemat.. (Submitted for publication.)
• 6 Gaarder A, Jonsen J, Laland S, Hellem A, Owren P. A. Adenosine diphosphate in red cells as a factor in the adhesiveness of human blood platelets. Nature (Lond) 192: 531 1961;
• 7 Gross R, Niemeyer G, Reuter H. Untersuchungen über die Aggregation menschlicher Blutplättchen. I. Mitteilung: Standardisierte Methoden zur quantitativen Bestimmung der Aggregation. Klin. Wschr 45: 931 1967;
• 8 Gross R, Niemeyer G, Reuter H. Localization of inhibition of platelet aggregation by incubation of platelet-rich EDTA-plasma at 37° C. Thrombos. Diathes. haemorrh. (Stuttg) 19: 1 1969;
• 9 Haslam R. J. Role of adenosine diphosphate in the aggregation of human blood platelets by thrombin and by fatty acids. Nature (Lond) 202: 765 1964;
• 10 Hellem A. J. The adhesiveness of human blood platelets in vitro. Scand. J. clin. Lab. Invest Suppl. 51 1960;
• 11 Holmsen H, Stormorken H. Kinetic studies on the breakdown of adenosine diphosphate in human plasma. Scand. J. clin. Lab. Invest 17, Suppl. 84: 138 1965;
• 12 Mason R. G, LeRoy E. C, Brinkhous K. M. Cation specificity of thrombocyte agglutinating factor (TAg). Fed. Proc 18: 492 1959;
• 13 des Prez R. M, Bryant R. E, Katz J. A, Brittingham T. E. Platelet aggregation by magnesium ion. Thrombos. Diathes. haemorrh. (Stuttg) 17: 516 1967;
• 14 Spaet T. H, Lejnieks I. Studies on the mechanism whereby platelets are clumped by adenosine diphosphate. Thrombos. Diathes. haemorrh. (Stuttg) 15: 36 1966;
• 15 Zucker M. B, Borelli J. Viscous metamorphosis produced by chilling and by clotting. Failure to find specific defect of viscous metamorphosis in PTA syndrome. Thrombos. Diathes. haemorrh. (Stuttg) 04: 424 1960;