Glutamate mediates platelet activation through the AMPA receptor

J Exp Med. 2008 Mar 17;205(3):575-84. doi: 10.1084/jem.20071474. Epub 2008 Feb 18.

Abstract

Glutamate is an excitatory neurotransmitter that binds to the kainate receptor, the N-methyl-D-aspartate (NMDA) receptor, and the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (AMPAR). Each receptor was first characterized and cloned in the central nervous system (CNS). Glutamate is also present in the periphery, and glutamate receptors have been identified in nonneuronal tissues, including bone, heart, kidney, pancreas, and platelets. Platelets play a central role in normal thrombosis and hemostasis, as well as contributing greatly to diseases such as stroke and myocardial infarction. Despite the presence of glutamate in platelet granules, the role of glutamate during hemostasis is unknown. We now show that activated platelets release glutamate, that platelets express AMPAR subunits, and that glutamate increases agonist-induced platelet activation. Furthermore, we demonstrate that glutamate binding to the AMPAR increases intracellular sodium concentration and depolarizes platelets, which are important steps in platelet activation. In contrast, platelets treated with the AMPAR antagonist CNQX or platelets derived from GluR1 knockout mice are resistant to AMPA effects. Importantly, mice lacking GluR1 have a prolonged time to thrombosis in vivo. Our data identify glutamate as a regulator of platelet activation, and suggest that the AMPA receptor is a novel antithrombotic target.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Animals
  • Blood Platelets / drug effects
  • Blood Platelets / metabolism
  • Glutamic Acid / blood*
  • Glutamic Acid / pharmacology
  • Humans
  • In Vitro Techniques
  • Ion Transport
  • Kainic Acid / pharmacology
  • Male
  • Membrane Potentials
  • Mice
  • Mice, Knockout
  • Platelet Activation / drug effects
  • Platelet Activation / physiology*
  • Receptors, AMPA / agonists
  • Receptors, AMPA / antagonists & inhibitors
  • Receptors, AMPA / blood*
  • Receptors, AMPA / deficiency
  • Receptors, AMPA / genetics
  • Receptors, G-Protein-Coupled / agonists
  • Receptors, G-Protein-Coupled / blood
  • Receptors, N-Methyl-D-Aspartate / blood
  • Signal Transduction
  • Sodium / blood
  • Thrombosis / blood
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / blood
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology

Substances

  • Receptors, AMPA
  • Receptors, G-Protein-Coupled
  • Receptors, N-Methyl-D-Aspartate
  • Glutamic Acid
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • Sodium
  • Kainic Acid
  • glutamate receptor ionotropic, AMPA 1