A SPECIFIC ROLE FOR GROUP II METABOTROPIC GLUTAMATE RECEPTORS IN HIPPOCAMPAL LONG-TERM DEPRESSION AND SPATIAL MEMORY


Altinbilek B., Manahan-Vaughan D.

NEUROSCIENCE, vol.158, no.1, pp.149-158, 2009 (Peer-Reviewed Journal) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 158 Issue: 1
  • Publication Date: 2009
  • Doi Number: 10.1016/j.neuroscience.2008.07.045
  • Journal Name: NEUROSCIENCE
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.149-158
  • Keywords: long-term potentiation, hippocampus, in vivo, EGLU, radial maze, mGIuR, FREELY MOVING RATS, CEREBELLAR GRANULE CELLS, SLOW-ONSET POTENTIATION, METHYL-D-ASPARTATE, GAMMA-MUTANT MICE, REGION IN-VIVO, DENTATE GYRUS, SYNAPTIC PLASTICITY, CA1 REGION, NOVELTY ACQUISITION

Abstract

Activity-dependent and sustained alterations in synaptic efficacy are widely regarded as the cellular correlates underlying learning and memory. Metabotropic glutamate receptors (mGluRs) are intrinsically involved in both hippocampal synaptic plasticity and spatial learning. Group 11 mGIuRs are required for persistent hippocampal long-term depression (LTD), but are not required for long-term potentiation (LTP) in the hippocampal CAI region in vivo. The role of these receptors in spatial learning, and in synaptic plasticity in the dentate gyrus in vivo has not yet been the subject of close scrutiny. We investigated the effects of group II mGIuR antagonism on LTP and LTD in the adult rat, at medial perforant path-dentate gyrus synapses, and on spatial learning in the eight-arm radial maze. Daily application of the group 2 mGIuR antagonist (2S)-alpha-ethylglutamic acid (EGLU) resulted in impairment of long-term (reference) memory with effects becoming apparent 6 days after training and drug-treatment began. Short-term (working) memory was unaffected throughout the 10-day study. Acute injection of EGLU did not affect either LTD or LTP in the dentate gyrus in vivo. Following six daily applications of EGLU a clear impairment of LTD but not LTP was apparent however.