Efficient platelet δ-granule release induced by [Ca 2+]i elevation is modulated by GPIIbIIIa

Giuliana Gobbi, Ivonne Sponzilli, Prisco Mirandola, Pier Luigi Tazzari, Luigi Caimi, Antonio Cacchioli, Alessandro Matteucci, Gabriella Giuliani Piccari, Lucio Cocco, Marco Vitale

Research output: Contribution to journalArticlepeer-review


Intracellular Ca2+ elevation generates a cascade of events that leads to platelet activation and degranulation. The GPIIbIIIa-ligand molecular complex plays a central role in several aspects of platelet activation. Taking advantage of the flow cytometric simultaneous analysis of surface GPIIbIIIa expression and intracellular serotonin content, we demonstrate here that the functional inhibition of GPIIbIIIa generates an impairment of δ-granule release even upon maximal intracellular Ca2+ elevation. In healthy subjects, the GPIIbIIIa inhibitor tirofiban impairs platelet δ-granule release. Analogously, Glanzmann thrombasthenia patients show an impairment of δ-granule release that is proportional to their residual expression of platelet GPIIbIIIa. These data show that platelet surface expression of functional GPIIbIIIa is required for a fully efficient secretion of δ-granules and serotonin release. The implications of our findings are discussed in the light of the complex interplay between vescicle release and ligand-receptor triggering during platelet activation.

Original languageEnglish
Pages (from-to)309-313
Number of pages5
JournalInternational Journal of Molecular Medicine
Issue number2
Publication statusPublished - Aug 2006


  • δ-granules
  • Flow cytometry
  • Glanzmann thrombasthenia
  • Serotonin

ASJC Scopus subject areas

  • Genetics


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