Properties of PAF-acether-induced platelet aggregation and secretion. Studies in gel-filtered human platelets |
| |
Authors: | E. Kloprogge G.H. de Haas G. Gorter J.W.N. Akkerman |
| |
Affiliation: | Department of Haematology, University Hospital Utrecht, and Department of Biochemistry, State University Utrecht, The Netherlands |
| |
Abstract: | Human platelets rapidly lose their responsiveness to PAF-acether after blood collection. We collected blood from fasting donors and prepared gel-filtered platelets that remained responsive to PAF-acether for about 6 hours. Log-dose response studies showed bi-phasic aggregation between 20 and 100 nM PAF-acether with secretion of dense-, - and lysosomal granule contents during the second wave of aggregation. Between 0.2 and 10 nM PAF-acether aggregation was weak and no secretion occurred whereas 300 nM PAF-acether or more induced maximal aggregation and secretion. Secretion, however, was never more than 70, 55, and 30% of maximal secretable amount of 5HT, βTG and βN, respectively. Aggregation and secretion were enhanced by fibrinogen (optimal concentration 0.3–0.7 g.l−1), required Ca2+ or Mg2+ but were inhibited when Mg2+ or Ca2+ were present at a concentration of 2 mM or more. These date show that human platelets are almost equally sensitive to PAF-acether as rabbit platelets, and respond with incomplete secretion of dense-, - and lysosomal granule contents. |
| |
Keywords: | Author Keywords: platelet-activating factor aggregation secretion PAF-acether platelets |
本文献已被 ScienceDirect 等数据库收录! |
|