Collagen-Induced Platelet Aggregation: -Evidence Against the Essential Role of Platelet Adenosine Diphosphate

Autor:	Barbara Nunn
Rok vydání:	1979
Předmět:	Apyrase Hematology Adenosine Adenosine diphosphate chemistry.chemical_compound chemistry Induced platelet aggregation High doses medicine Biophysics Platelet Serotonin Adenosine triphosphate medicine.drug
Zdroj:	Thrombosis and Haemostasis. 42:1193-1206
ISSN:	2567-689X 0340-6245
DOI:	10.1055/s-0038-1657015
Popis:	SummaryThe hypothesis that platelet ADP is responsible for collagen-induced aggregation has been re-examined. It was found that the concentration of ADP obtaining in human PRP at the onset of aggregation was not sufficient to account for that aggregation. Furthermore, the time-course of collagen-induced release in human PRP was the same as that in sheep PRP where ADP does not cause release. These findings are not consistent with claims that ADP alone perpetuates a collagen-initiated release-aggregation-release sequence. The effects of high doses of collagen, which released 4-5 μM ADP, were not inhibited by 500 pM adenosine, a concentration that greatly reduced the effect of 300 μM ADP. Collagen caused aggregation in ADP-refractory PRP and in platelet suspensions unresponsive to 1 mM ADP. Thus human platelets can aggregate in response to collagen under circumstances in which they cannot respond to ADP. Apyrase inhibited aggregation and ATP release in platelet suspensions but not in human PRP. Evidence is presented that the means currently used to examine the role of ADP in aggregation require investigation.
Databáze:	OpenAIRE
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