Enhancement of collagen-induced aggregation of platelets in whole blood.
In order to elucidate the features of platelet aggregation in whole blood, studies were carried out on human blood. The platelet aggregation reaction was monitored by counting the residual free platelet number with an electronic particle counter (Coulter). Platelets in citrated whole blood were aggregated by a very small amount of collagen which did not aggregate platelets in citrated plasma. Such enhancement was not observed if ADP or epinephrine was used. By addition of isolated erythrocytes to platelet rich plasma, enhancement of the platelet response to collagen was obtained. The erythrocyte membrane stabilizer, Dilazep, abolished the enhancement effect of erythrocytes. Those results indicated that erythrocytes enhanced the platelet response to collagen. Although participation of ADP from the erythrocytes in the enhancement was suggested, the results of ADP determinations on suspensions of erythrocytes indicated that other factors of the erythrocytes might be involved in the enhancement.
D000244:Adenosine Diphosphate / Q000494:pharmacology; D001790:Blood Physiological Phenomena; D002452:Cell Count / Q000187:drug effects / Q000379:methods; D003094:Collagen / Q000494:pharmacology*; D004109:Dilazep / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D004912:Erythrocytes / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D013696:Temperature; D013997:Time Factors
D000244:Adenosine Diphosphate; D003094:Collagen; D004109:Dilazep; D004837:Epinephrine