Impairment of hippocampal mossy fiber LTD in mice lacking mGluR2.
Subtype 2 of the metabotropic glutamate receptor (mGluR2) is expressed in the presynaptic elements of hippocampal mossy fiber-CA3 synapses. Knockout mice deficient in mGluR2 showed no histological changes and no alterations in basal synaptic transmission, paired-pulse facilitation, or tetanus-induced long-term potentiation (LTP) at the mossy fiber-CA3 synapses. Long-term depression (LTD) induced by low-frequency stimulation, however, was almost fully abolished. The mutant mice performed normally in water maze learning tasks. Thus, the presynaptic mGluR2 is essential for inducing LTD at the mossy fiber-CA3 synapses, but this hippocampal LTD does not seem to be required for spatial learning.
Yokoi
M
M
Department of Biological Sciences, Kyoto University Faculty of Medicine, Kyoto 606, Japan.
Kobayashi
K
K
Manabe
T
T
Takahashi
T
T
Sakaguchi
I
I
Katsuura
G
G
Shigemoto
R
R
Ohishi
H
H
Nomura
S
S
Nakamura
K
K
Nakao
K
K
Katsuki
M
M
Nakanishi
S
S
D000818:Animals; D001369:Axons / Q000502:physiology*; D003521:Cyclopropanes / Q000494:pharmacology; D004558:Electric Stimulation; D018390:Gene Targeting; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000502:physiology*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation; D018782:Maze Learning; D051379:Mice; D018345:Mice, Knockout; D009473:Neuronal Plasticity; D017966:Pyramidal Cells / Q000502:physiology*; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects
D003521:Cyclopropanes; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C082313:2-(2,3-dicarboxycyclopropyl)glycine; D005998:Glycine