Allosteric enhancement of metabotropic glutamate receptor 5 function promotes spatial memory.
Group I metabotropic glutamate receptors (mGluRs) have been implicated in learning and memory formation. Recent findings indicate an important function of the group I mGluR subtype 5. Here, we used the Y-maze spatial alternation task and examined whether enhancement of intrinsic mGluR5 activity immediately after learning, i.e. during a critical period for memory consolidation, would have any consequences on long-term memory retention in rats. Intracerebroventricular application of the allosteric mGluR5 potentiator DFB (3,3'-difluorobenzaldazine) resulted in a marked improvement in spatial alternation retention when it was tested 24 h after training. The promnesic effect increased with the difficulty of the task and was apparently due to a substantial enhancement of consolidation. The applied dose of DFB did not cause behavioral changes in the open field, and was devoid of structural side-effects as evaluated by immunohistochemical examination. Our results suggest an important function of post-training mGluR5 activation in some types of hippocampus-dependent spatial learning.
Balschun
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Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany.
Zuschratter
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Wetzel
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D000494:Allosteric Regulation / Q000187:drug effects; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects / Q000502:physiology; D006834:Hydrazines / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010320:Parvalbumins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000502:physiology*; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology*; D018709:Statistics, Nonparametric; D013997:Time Factors
C481447:3,3'-difluorobenzaldazine; C578937:Grm5 protein, rat; D006834:Hydrazines; D009419:Nerve Tissue Proteins; D010320:Parvalbumins; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate