Related Experiment Video
Updated: Aug 7, 2026

A Uniform Shear Assay for Human Platelet and Cell Surface Receptors via Cone-plate Viscometry
Published on: June 5, 2019
Efficient platelet delta-granule release induced by [Ca2+]i elevation is modulated by GPIIbIIIa
Giuliana Gobbi1, Ivonne Sponzilli, Prisco Mirandola
1Department of Anatomy, Pharmacology & Forensic Medicine, Human Anatomy Section, University of Parma, Parma, Italy.
Abstract:
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 delta-granule release even upon maximal intracellular Ca2+ elevation. In healthy subjects, the GPIIbIIIa inhibitor tirofiban impairs platelet delta-granule release. Analogously, Glanzmann thrombasthenia patients show an impairment of delta-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 delta-granules and serotonin release. The implications of our findings are discussed in the light of the complex interplay between vesicle release and ligand-receptor triggering during platelet activation.
More Related Videos
05:49Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets
Published on: November 29, 2024
04:37Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation
Published on: May 23, 2025
Related Concept Videos
IP3/DAG Signaling Pathway
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
G-Protein Gated Ion Channels
Sensory organs,...
GPCRs Regulate Adenylyl Cylase Activity
Two...
Activation and Inactivation of G Proteins