A developmental switch of AMPA receptor subunits in neocortical pyramidal neurons.
AMPA receptors mediate most of the fast excitatory neurotransmission in the brain, and those lacking the glutamate receptor 2 (GluR2) subunit are Ca(2+)-permeable and expressed in cortical structures primarily by inhibitory interneurons. Here we report that synaptic AMPA receptors of excitatory layer 5 pyramidal neurons in the rat neocortex are deficient in GluR2 in early development, approximately before postnatal day 16, as evidenced by their inwardly rectifying current-voltage relationship, blockade of AMPA receptor-mediated EPSCs by external and internal polyamines, permeability to Ca(2+), and GluR2 immunoreactivity. Overall, these results indicate that neocortical pyramidal neurons undergo a developmental switch in the Ca(2+) permeability of their AMPA receptors through an alteration of their subunit composition. This has important implications for plasticity and neurotoxicity.
Kumar
Sanjay S
SS
Department of Neurology and Neurological Sciences, Stanford University Medical Center, Stanford, California 94305-5122, USA.
Bacci
Alberto
A
Kharazia
Viktor
V
Huguenard
John R
JR
D000375:Aging / Q000378:metabolism; D000818:Animals; D015317:Biogenic Polyamines / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D019579:Neocortex / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000502:physiology; D018408:Patch-Clamp Techniques; D021122:Protein Subunits; D017966:Pyramidal Cells / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D018091:Receptors, AMPA / Q000172:deficiency / Q000378:metabolism*; D013569:Synapses / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology
D015317:Biogenic Polyamines; D021122:Protein Subunits; D018091:Receptors, AMPA; C104722:glutamate receptor ionotropic, AMPA 2; D002118:Calcium