Long-term potentiation in the hippocampal CA1 region does not require insertion and activation of GluR2-lacking AMPA receptors.
Activity-dependent insertion of AMPA-type glutamate receptors is thought to underlie long-term potentiation (LTP) at Schaffer collateral fiber synapses on pyramidal cells in the hippocampal CA1 region. Although it is widely accepted that the AMPA receptors at these synapses contain glutamate receptor type 2 (GluR2) subunits, recent findings suggest that LTP in hippocampal slices obtained from 2- to 3-wk-old rodents is dependent on the transient postsynaptic insertion and activation of Ca(2+)-permeable, GluR2-lacking AMPA receptors. Here we examined whether LTP in slices prepared from adult animals exhibits similar properties. In contrast to previously reported findings, pausing synaptic stimulation for as long as 30 min post LTP induction had no effect on LTP maintenance in slices from 2- to 3-mo-old mice. LTP was also not disrupted by postinduction application of a selective blocker of GluR2-lacking AMPA receptors or the broad-spectrum glutamate receptor antagonist kynurenate. Although these results suggest that the role of GluR2-lacking AMPA receptors in LTP might be regulated during postnatal development, LTP in slices obtained from 15- to 21-day-old mice also did not require postinduction synaptic stimulation or activation of GluR2-lacking AMPA receptors. Thus the insertion and activation of GluR2-lacking AMPA receptors do not appear to be fundamental processes involved in LTP at excitatory synapses in the hippocampal CA1 region.
Gray
Erin E
EE
Interdepartmental PhD Program for Neuroscience, David Geffen School of Medicine at UCLA, 53-231 Center for the Health Sciences, Los Angeles, CA 90095-1751, USA.
Fink
Ann E
AE
Sariñana
Joshua
J
Vissel
Bryce
B
O'Dell
Thomas J
TJ
D000818:Animals; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D018756:GABA Antagonists / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000494:pharmacology; D017774:Long-Term Potentiation / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D010852:Picrotoxin / Q000494:pharmacology; D017966:Pyramidal Cells / Q000187:drug effects; D018091:Receptors, AMPA / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D007736:Kynurenic Acid; D010852:Picrotoxin; D018091:Receptors, AMPA; C104722:glutamate receptor ionotropic, AMPA 2