AMPA protects cultured neurons against glutamate excitotoxicity through a phosphatidylinositol 3-kinase-dependent activation in extracellular signal-regulated kinase to upregulate BDNF gene expression

J Neurochem. 2004 Aug;90(4):807-18. doi: 10.1111/j.1471-4159.2004.02526.x.


The signal transduction and molecular mechanisms underlying alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA)-mediated neuroprotection are unknown. In the present study, we determined a major AMPA receptor-mediated neuroprotective pathway. Exposure of cerebellar granule cells to AMPA (500 microM) + aniracetam (1 microM), a known blocker of AMPA receptor desensitization, evoked an accumulation of brain-derived neurotropic factor (BDNF) in the culture medium and enhanced TrkB-tyrosine phosphorylation following the release of BDNF. AMPA also activated the src-family tyrosine kinase, Lyn, and the downstream target of the phosphatidylinositol 3-kinase (PI3-K) pathway, Akt. Extracellular signal regulated kinase (ERK), a component of the mitogen-activated protein kinase (MAPK) pathway, was also activated. K252a, a selective inhibitor of neurotrophin signaling, blocked the AMPA-mediated neuroprotection. The involvement of BDNF release in protecting neurons by AMPA was confirmed using a BDNF-blocking antibody. AMPA-mediated neuroprotection is blocked by PP1, an inhibitor of src family kinases, LY294002, a PI3-K inhibitor, or U0126, a MAPK kinase (MEK) inhibitor. Neuroprotective concentrations of AMPA increased BDNF mRNA levels that was blocked by the AMPA receptor antagonist, 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX). The increase in BDNF gene expression appeared to be the downstream target of the PI3-K-dependent activation of the MAPK cascade since MEK or the PI3-K inhibitor blocked the AMPA receptor-mediated increase in BDNF mRNA. Thus, AMPA receptors protect neurons through a mechanism involving BDNF release, TrkB receptor activation, and a signaling pathway involving a PI3-K dependent activation of MAPK that increases BDNF expression.

MeSH terms

  • Animals
  • Antibodies / pharmacology
  • Brain-Derived Neurotrophic Factor / antagonists & inhibitors
  • Brain-Derived Neurotrophic Factor / genetics*
  • Cells, Cultured
  • Enzyme Inhibitors / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Gene Expression Regulation / drug effects
  • Glutamic Acid / toxicity*
  • Mitogen-Activated Protein Kinases / drug effects
  • Mitogen-Activated Protein Kinases / metabolism*
  • Neurons / cytology
  • Neurons / drug effects*
  • Neurons / metabolism
  • Neuroprotective Agents / pharmacology
  • Neurotoxins / toxicity
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Protein Synthesis Inhibitors / pharmacology
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, trkB / drug effects
  • Receptor, trkB / metabolism
  • Receptors, AMPA / antagonists & inhibitors
  • Receptors, AMPA / metabolism
  • Signal Transduction / drug effects
  • Up-Regulation / drug effects
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology*
  • src-Family Kinases / drug effects
  • src-Family Kinases / metabolism


  • Antibodies
  • Brain-Derived Neurotrophic Factor
  • Enzyme Inhibitors
  • Excitatory Amino Acid Antagonists
  • Neuroprotective Agents
  • Neurotoxins
  • Protein Synthesis Inhibitors
  • RNA, Messenger
  • Receptors, AMPA
  • Glutamic Acid
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • Phosphatidylinositol 3-Kinases
  • Receptor, trkB
  • lyn protein-tyrosine kinase
  • src-Family Kinases
  • Mitogen-Activated Protein Kinases