secretion

Last reviewed 01/2018

Once activated, an elevation in intracellular calcium stimulates platelets to degranulate. An array of active substances are released or newly-formed:

  • ADP: stimulates aggregation
  • thromboxane A2: vasoconstrictor, platelet aggregator
  • von Willebrand factor: promotes adhesion
  • 5HT: vasoconstrictor, aggregation
  • Platelet derived growth factor: proliferation of fibroblasts, endothelial cells and smooth muscle cells; vasoconstriction
  • platelet activating factor: stimultes platelets and phagocytes
  • fibronectin: promotes adhesion
  • fibrinogen: interlinks platelets
  • thrombospondin: involved in aggregation
  • leukocyte chemotactic factors: inflammatory role