Intrahippocampal infusions of a metabotropic glutamate receptor antagonist block the memory of context-specific but not tone-specific conditioned fear.
The role of metabotropic glutamate receptors (mGluRs) in the acquisition of learning and memory using fear conditioning as a behavioral model was examined. The mGluR antagonist (R, S)-alpha-methyl-4-carboxyphenylglycine (MCPG) was infused into the hippocampus 30 min before fear conditioning, and freezing was measured during both acquisition and retention tests. The results show that pretraining antagonism of MCPG-sensitive mGluRs in the hippocampus impaired context-specific memory for an aversive event during testing. The memory for tone-specific fear, however, remained intact despite pretraining infusion of MCPG. Treating rats with MCPG did not affect context- or tone-specific fear during acquisition. Results suggest that mGluR activation may play an important role in hippocampally mediated memory consolidation.
Frohardt
R J
RJ
Department of Psychology, University of Vermont, Burlington 05405, USA. rfrohard@zoo.uvm.edu
Guarraci
F A
FA
Young
S L
SL
D000818:Animals; D001245:Association Learning / Q000187:drug effects*; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000187:drug effects*; D005239:Fear / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D011939:Mental Recall / Q000187:drug effects*; D010897:Pitch Discrimination / Q000187:drug effects*; D051381:Rats; D020318:Rats, Long-Evans; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000502:physiology*
D018094:Receptors, Metabotropic Glutamate