The Journal of Neuroscience, August 16, 2006, 26(33):8428-8440; doi:10.1523/JNEUROSCI.5410-05.2006
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Behavioral/Systems/Cognitive
Forebrain-Specific Glutamate Receptor B Deletion Impairs Spatial Memory But Not Hippocampal Field Long-Term Potentiation
Derya R. Shimshek,1
Vidar Jensen,3
Tansu Celikel,2
Yu Geng,1
Bettina Schupp,1
Thorsten Bus,1
Volker Mack,1
Verena Marx,1
Øivind Hvalby,3
Peter H. Seeburg,1 and
Rolf Sprengel1
Departments of 1Molecular Neurobiology and 2Cell Physiology, Max Planck Institute for Medical Research, D-69120 Heidelberg, Germany, and 3Molecular Neurobiology Research Group, Institute of Basic Medical Sciences, University of Oslo, N-0317 Oslo, Norway
Correspondence should be addressed to Rolf Sprengel, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany. Email: sprengel{at}mpimf-heidelberg.mpg.de
We demonstrate the fundamental importance of glutamate receptor B (GluR-B) containing AMPA receptors in hippocampal function by analyzing mice with conditional GluR-B deficiency in postnatal forebrain principal neurons (GluR-B
Fb). These mice are as adults sufficiently robust to permit comparative cellular, physiological, and behavioral studies. GluR-B loss induced moderate long-term changes in the hippocampus of GluR-B
Fb mice. Parvalbumin-expressing interneurons in the dentate gyrus and the pyramidal cells in CA3 were decreased in number, and neurogenesis in the subgranular zone was diminished. Excitatory synaptic CA3-to-CA1 transmission was reduced, although synaptic excitability, as quantified by the lowered threshold for population spike initiation, was increased compared with control mice. These changes did not alter CA3-to-CA1 long-term potentiation (LTP), which in magnitude was similar to LTP in control mice. The altered hippocampal circuitry, however, affected spatial learning in GluR-B
Fb mice. The primary source for the observed changes is most likely the AMPA receptor-mediated Ca2+ signaling that appears after GluR-B depletion, because we observed similar alterations in GluR-BQFb mice in which the expression of Ca2+-permeable AMPA receptors in principal neurons was induced by postnatal activation of a Q/R-site editing-deficient GluR-B allele.
Key words: conditional knock-out; GluR-B; AMPA receptors; LTP; learning and memory; Co2+ uptake; T-maze
Received Dec. 19, 2005;
revised June 26, 2006;
accepted June 26, 2006.
Correspondence should be addressed to Rolf Sprengel, Max Planck Institute for Medical Research, Jahnstrasse 29, D-69120 Heidelberg, Germany. Email: sprengel{at}mpimf-heidelberg.mpg.de
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S. Panicker, K. Brown, and R. A. Nicoll
Synaptic AMPA receptor subunit trafficking is independent of the C terminus in the GluR2-lacking mouse
PNAS,
January 22, 2008;
105(3):
1032 - 1037.
[Abstract]
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